2026 Annual Air Quality Monitoring Network Plan - Public Comment Draft

Notice:

In accordance with federal regulations (CFR 58.10), the Alaska Department of Environmental Conservation (DEC) maintains a statewide air quality monitoring network to protect public health and ensure compliance with EPA standards. Each year, DEC publishes its Annual Network Plan to outline the current monitoring footprint, describe station locations, and propose network modifications for the calendar year. This annual process also serves to inform the public and the EPA Regional Administrator of any planned changes to the state’s monitoring network, such as adding or removing monitoring sites or instruments, to ensure the network continues to meet both state and federal monitoring requirements.

To support the public review process, the Annual Network Plan is made available for public comment approximately five to six weeks prior to July 1 submission deadline to EPA. This ensures sufficient time to complete the mandatory 30-day public commend period and allows for an additional period to address and incorporate any comments received before the plan is finalized for submission.

Table of Tables

Table 1 State Monitoring Sites

Table 2 CBSA’s of Alaska

Table 3 Summary of Monitoring Compliance

Table 4 Minimum SLAMS

Table 5 Alaska DEC Regulatory Monitoring Sites, 2026

Table 6 CO Monitoring Sites

Table 7 PM Sites

Table 8 NCore Gaseous Monitoring and Met Monitoring

Table 9 Compliance Summary

Table 10 PM_2.5 Methods, Designation, and Sampling Frequency

Table 11 PM₁₀ Methods, Designation, and Sampling Frequency

Table 12 Gaseous Methods, Designation, and Sampling Frequency

Table 13 PM_2.5 Speciation Methods

Table 14 Required Monitors Under NAA and LMP Plans

Table 15 PM_2.5 Design Values (µg/m³)

Table 16 DV Ozone (O₃) (ppm)

Table 17 DV Sulfur Dioxide (SO₂) (ppb)

Table 18 DV Carbon Monoxide (CO) (ppm)

Table 19 PM₁₀ Design Values (µg/m³)

Table 20 Instrument Inventory – Garden, Anchorage (AQS 02‑020‑0018)

Table 21 Instrument Inventory – Laurel, Anchorage (AQS 02-020-0045)

Table 22 Instrument Inventory – Parkgate, Eagle River (AQS 02-020-1004)

Table 23 Instrument Inventory – Plant Materials Center (PMC), Palmer (AQS 02-170-0010)

Table 24 Instrument Inventory – A Street, Fairbanks (AQS 020900040)

Table 25 Instrument Inventory – NCore Fairbanks: Particulate Matter (AQS 02-090-0034)

Table 26 Instrument Inventory – NCore Fairbanks: Gaseous Pollutants (AQS 02-090-0034)

Table 27 Instrument Inventory – NCore Fairbanks: Speciation & Meteorology (AQS 02-090-0034)

Table 28 Instrument Inventory – Hurst Road, North Pole (AQS 020900035)

Table 29 Instrument Inventory – Floyd Dryden, Juneau (AQS 021100004)

Table 30 Plant Materials Center (PMC) – Palmer (AQS 02-170-0010)

Table 31 Garden – Anchorage (AQS 02-020-0018)

Table 32 Laurel – Anchorage (AQS 02-020-0045)

Table 33 Parkgate – Eagle River (AQS 02-020-1004)

Table 34 A Street – Fairbanks (AQS 02-090-0040)

Table 35 Hurst Road – North Pole (AQS 02-090-0035)

Table 36 NCore – Fairbanks (AQS 02-090-0034)

Table 37 Floyd Dryden – Juneau (AQS 02-110-0004)

Table 38 Monitor Start Dates and Method Start Dates (2026)

Table 39 PM_2.5 Network Evaluation Form

Table 40 PM_2.5 Network Evaluation Form

Table 41 PM_2.5 Minimum Monitoring Requirements

Table 42 PM₁₀ Network Evaluation Form

Table 43 Number of PM₁₀ Stations within AMQA Regulatory Network

Table 44 PM₁₀ Minimum Monitoring Requirements

Table 45 CO Site Evaluation Form

Table 46 CO SLAMS Sites Required per Population

Table 47 O₃ Network Evaluation Form

Table 48 O₃ SLAMS Sites Required per Population

Table 49 SLAMS O₃ Monitoring Minimum Requirements

Table 50 Ozone Monitoring Season by State

Table 51 SO₂ Network Evaluation Form

Table 52 SO₂ SLAMS Sites Required per Population

Table 53 Minimum SO₂ Monitoring Requirements

Table 54 NO₂ Network Evaluation Form

Table 55 NO₂ SLAMS Sites Required per Population

Table 56 Summary of Appendix E Forms: PM

Table 57 Summary of Appendix E Forms: CO

Table 58 Summary of Appendix E Forms: O₃, SO₂, NO , Diff, and NO_y

Table 59 Blank Part 58 Appendix E Form for PM

Table 60 Blank Part 58 Appendix E Form for CO

Table 61 Blank Part 58 Appendix E Form for O₃

Table 62 Blank Part 58 Appendix E Form for SO₂

Table 63 Blank Part 58 Appendix E Form for NO , NO_x, NO₂, and NO_y

Definitions and Acronyms

ADT average daily traffic

AADT annual average daily traffic

AK Alaska

AMQA Air Monitoring and Quality Assurance Program

ANP annual network plan

AQI air quality index

AQS Air Quality Systems

ARM Approved Regional Method

ARP The American Rescue Plan

CAA Clean Air Act

CASTNET Clean Air Status and Trends Network

CBJ City & Borough of Juneau

CBSA Core Base Statistical Area

Census U.S. Census Bureau

CFR Code of Federal Regulations

CO carbon monoxide

CSN Chemical Speciation Network

DEC Alaska Department of Environmental Conservation

DV design value

EEWR exceptional event waiver request

EPA U.S. Environmental Protection Agency

FEM Federal Equivalent Method

FNSB Fairbanks North Star Borough

FRM Federal Reference Method

HVAC heating and ventilation air conditioning system

IMPROVE Interagency Monitoring of Protected Visual Environments

IRA Inflation Reduction Act

LC local (actual) conditions of temperature and pressure

LMP limited maintenance plan

m³ cubic meter

Mat-Su Matanuska Susitna

MFC mass flow controller

MOA Municipality of Anchorage

MSA metropolitan statistical area

µg micrograms

µSA micropolitan statistical areas

NAA nonattainment area

NAAQS National Ambient Air Quality Standards

NATTS National Air Toxics Trends Station

NCore National Core Multi-Pollutant Monitoring Stations

NIST National Institute of Standards and Technology

NO nitric oxide

NO₂ nitrogen dioxide

NO_x nitrogen oxides

NO_y reactive nitrogen compounds

NPAP National Performance Audit Program

NWS National Weather Service

O₃ ozone

OMB U.S. Office of Management and Budget

PAHs polycyclic aromatic hydrocarbons

Pb lead

Pb-TSP lead total suspended particulate

PM particulate matter

PMC Plant Materials Center

PM₁ particulate matter with an aerodynamic diameter less than 1 micrometer

PM_2.5 particulate matter with an aerodynamic diameter less than 2.5 micrometers

PM₁₀ particulate matter with an aerodynamic diameter less than 10 micrometers

PM_10-2.5 particulate matter with an aerodynamic diameter between 2.5 and 10 micrometers

POC parameter occurrence code

ppb parts per billion

ppm parts per million

PQAO Primary Quality Assurance Organization

QA quality assurance

QC quality control

QAPP Quality Assurance Project Plans

R10 EPA Region 10

RadNet Radiation Monitoring Network

RH relative humidity

S scalar

SCC sharp cut cyclone

SIP State Implementation Plan

SLAMS State and Local Air Monitoring Stations

SO₂ sulfur dioxide

SOP standard operating procedures

SPM special purpose monitor

STD standard conditions of temperature and pressure

STN Speciation Trend Network

V vector

VOC volatile organic compounds

VPD vehicles per day

VSCC very sharp cut cyclone

WD wind direction

WGS World Geodetic System

WS wind speed

Executive Summary

The 2026 Annual Network Plan (ANP) for the Alaska Department of Environmental Conservation (DEC) outlines the state’s air quality monitoring strategy, ensuring compliance with 40 CFR Part 58 and protecting public health and the environment. DEC, consistent with its mission to enhance the health, safety, and welfare of the people of the State, is committed to ensuring that all Alaskans, regardless of location, have access to clean air and information about air quality.

Overview

DEC’s air quality monitoring efforts largely focus on population centers and areas with historical air quality concerns, measuring criteria pollutants as mandated by the U.S. Environmental Protection Agency (EPA). Due to ongoing budget constraints, most of the network is maintained at the minimum regulatory level, with no expansion planned in the near future. Even so, DEC continues to innovate and address Alaska’s unique challenges—such as its vast geography and remote communities—through targeted initiatives that help improve access to air quality data in underserved areas.

Key Updates for 2026-2027

The primary changes planned for 2026 include replacing an aging second generation Met One BAM 1020 PM₁₀ monitor at the NCore station with a third generation model, purchasing and deploying WiFi–enabled particulate sensors to expand the wildfire smoke monitoring network in rural Alaska, and operating and enhancing the National Air Toxics Trends Network station (NATTS) in the Fairbanks nonattainment area to improve overall network reliability, coverage, and efficiency.

Proposed Changes

In 2024, DEC proposed discontinuing carbon monoxide (CO) monitoring at the Anchorage Garden site for calendar year 2025 due to consistently low concentrations over the past 20 years, and the conclusion of the second 10-year maintenance period. EPA approved this change in their 2024 ANP response letter, contingent upon completion of a State Implementation Plan (SIP) modification removing the monitoring requirement. Although those SIP modifications could not be completed in 2025, they are now underway and are expected to be finalized in the fourth quarter of 2026. Once finalized, CO monitoring at the Garden site will be discontinued.

Innovation and Community Engagement

DEC’s Community-Based Sensor Network leverages low-cost sensors to provides real-time air quality data in many remote Alaska communities and is a valuable resource for rural communities, researchers, and wildland fire managers. The data collected by the network empowers residents to protect their health and participate in local air quality improvements. With the network, DEC has fostered community outreach, accessible data sharing tools, and hands on training that build local capacity and trust. DEC’s network is keeping pace with national trends in community scale monitoring with low-cost sensors while pioneering aspects of air quality sensing not inherent to other states, such as limited community access via roads, challenging environmental conditions, and limited cellular and internet connectivity

Public Health

DEC is committed to protecting public health by ensuring that accurate, timely air quality data informs both policy decisions and community actions. This commitment extends to underserved and rural communities across Alaska, where DEC works to improve air quality statewide. Building on this foundation, DEC has also developed new approaches to help residents better understand potential health impacts, most notably through the collection of air toxics data in the PM_2.5 non-attainment area. This work provides deeper insight into the chemical constituents of local air and strengthens the state’s ability to guide effective public health communication.

Stakeholder Engagement

DEC is committed to transparency and clear communication and welcomes public input throughout the ANP development process. DEC collaborates with residents, federal and local partners, and the research communities on a wide range of initiatives. These partnerships allow DEC to meet regulatory requirements, respond to community needs, and support informed decision-making statewide

Introduction

This document constitutes the 2026 Annual Monitoring Network Plan submitted by DEC to fulfill the requirements of 40 CFR 58.10. As required, this plan was made available for public inspection and comment for at least 30 days prior to submission to EPA. After public review, all comments received were reviewed and addressed as appropriate.

This plan describes Alaska’s current air quality monitoring network, demonstrates compliance with applicable federal requirements, and outlines anticipated network changes, including proposed relocations or discontinuations of monitoring stations within 18 months following plan submission. All required stations must be operational by January 1, 2026, and the completed plan must be submitted to the EPA Regional Administrator by July 1, 2026.

The plan provides both an overview as well as detailed information for each existing and any proposed monitoring, including Air Quality System (AQS) site identification numbers, geographic locations, sampling and analytical methods, and operating schedules, as outlined in the sections that follow. DEC also notes that EPA is in the process of transitioning from the current AQS platform to a modernized data system known as the Unified Platform, which is anticipated to begin initial operation near the end of calendar year 2026. During this transition period, AQS will continue to operate alongside the Unified Platform until the new system is fully functional allowing EPA to phase‑out of AQS. DEC will continue coordinating with EPA throughout this process to ensure uninterrupted data reporting and system compatibility.

Alaska’s vast geography and remote communities present unique challenges for air quality monitoring. This plan addresses these challenges through innovative strategies—such as expanding low-cost sensor networks in rural areas—that strengthen the state’s ability to reach underserved regions. In doing so, DEC reaffirms its commitment to maintaining‑ a robust monitoring network that meets or exceeds EPA standards and supports the protection of public health and the environment through regulatory compliance, transparency, and active engagement with stakeholders.

Air Quality Monitoring Requirements

Regulatory Framework

DEC is required by 40 CFR 58.10 to establish and maintain an air quality surveillance system, including State and Local Air Monitoring Stations (SLAMS), National Core Multi-Monitoring (NCore) stations, PM_2.5 Chemical Speciation Network (CSN) stations, and Special Purpose Monitoring (SPM) stations. This plan ensures compliance with federal regulations, including 40 CFR 58, Appendices A, C, D, and E, which cover data quality assurance, monitoring methods, network design criteria, and specific location criteria. DEC’s monitoring network is designed to meet these requirements while addressing Alaska’s unique environmental and geographic challenges.

Monitoring Priorities and Strategies

DEC prioritizes monitoring the six criteria pollutants regulated under the National Ambient Air Quality Standards (NAAQS): particulate matter (PM_2.5 and PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), ozone (O₃), and lead (Pb). Monitoring efforts are focused on population centers such as Anchorage, Fairbanks, and Juneau, as well as rural and remote areas where unique sources like wildland fires, road dust, and biomass burning significantly influence air quality. DEC collaborates with local governments and tribal villages to ensure comprehensive coverage, particularly for PM₁₀ in rural communities and PM_2.5 during wildfire seasons. This strategy aligns with federal requirements while addressing Alaska’s distinct air quality challenges.

Current Monitoring Network

As of May 2026, Alaska’s ambient air monitoring network includes the following sites in Table 1, strategically located to meet minimum monitoring requirements for Alaskan Core-Based Statistical Areas (CBSAs).

Table 1: State Monitoring Sites

Region	Site	AQS ID	Location	Pollutants Monitored	Station Type
Anchorage	Garden	02-020-0018	3000 East 16^th Ave, Anchorage, AK	PM₁₀, PM_2.5, CO	SLAMS
Anchorage	Laurel	02-020-0045	4335 Laurel St, Anchorage, AK	PM₁₀	SPM
Anchorage	Parkgate	02-020-1004	11723 Old Glenn Hwy, Eagle River, AK	PM₁₀	SLAMS
Anchorage	Plant Materials Center (PMC)	02-170-0010	5310 Bodenburg Spur Rd, Palmer, AK	PM₁₀, PM_2.5	SLAMS
Fairbanks	A Street	02-090-0040	397 Hamilton Ave, Fairbanks, AK	PM_2.5	SLAMS
Fairbanks	NCore	02-090-0034	907 Terminal St, Fairbanks, AK	PM₁₀, PM_2.5, PM_10-2.5, CO, SO₂, O₃, NO , NO_y, Speciation	NCore CSN
Fairbanks	Hurst Road	02-090-0035	3288 Hurst Rd, North Pole, AK	PM_2.5, SO₂, Speciation, PAHs, Carbonyls, VOCs, Metals	SLAMS NATTS CSN
Juneau	Floyd Dryden	02-110-0004	3800 Mendenhall Loop Rd, Juneau, AK	PM₁₀, PM_2.5	SLAMS

Detailed information for each site, including sampling methods, operating schedules, and compliance with siting criteria, is provided in the State of Alaska Ambient Air Monitoring Network section and the appendices of this plan. The network exceeds minimum requirements in several areas, particularly for PM_2.5 and PM₁₀, ensuring robust data collection for public health protection.

Compliance with Federal Standards

DEC ensures compliance with federal standards through:

Network Evaluation Forms: Completed for each criteria pollutant under 40 CFR 58, Appendix D, confirming that the network meets design and minimum monitoring requirements.
Siting Evaluation Forms: Completed under 40 CFR 58, Appendix E, ensuring proper siting of all monitors.
Data Quality Assurance: Adherence to 40 CFR 58, Appendix A for SLAMS and SPM monitors.
Monitoring Methods: Compliance with 40 CFR 58, Appendix C for approved monitoring methods.
Waivers: Any waivers requested or granted by the EPA Regional Administrator are detailed in Appendix H.

Planned Enhancements

To enhance monitoring capabilities, DEC is expanding its Community-Based Air Monitoring Network, currently consisting of 71 QuantAQ Modulair^TM sensor pods. These sensors provide real-time data in rural and outlying communities, improving coverage and enabling quicker responses to air quality events. As of May 2026, DEC’s current and anticipated sensor network includes:

Regulatory Sites: Eight pods are operational at NCore (Fairbanks), Garden (Anchorage), and Floyd Dryden (Juneau).
Rural Communities: 45 pods are deployed across Alaska, including Kotzebue, Ketchikan, and others.
Future Expansion: Research into Wi-Fi-enabled sensors is underway to expand coverage into the Interior of Alaska.

Additionally, DEC plans to replace an aging continuous PM₁₀ regulatory instrument at the Fairbanks NCore monitoring station and will discontinue CO monitoring at the Anchorage Garden site upon EPA approval of a SIP modification. These refinements will optimize resources while maintaining compliance.

State of Alaska Ambient Air Monitoring Network

The State of Alaska Ambient Air Monitoring Network, managed by DEC, plays a vital role in safeguarding public health and the environment by monitoring air quality across Alaska’s diverse landscapes. The network was developed following requirements listed in 40 CFR Part 58 and related EPA technical guidance. Building on this regulatory framework, DEC operates an air monitoring network that fulfills all federal requirements and supports consistent, high quality measurement of pollutants of interest across Alaska. This framework provides the basis for minimum monitoring requirements and objectives within CBSAs and the siting criteria outlined in the sections below.

Minimum Monitoring Requirements

Federal Regulatory Framework

Federal regulations under 40 CFR 58.10 requires states to establish and maintain air monitoring networks based on population sizes within CBSAs, as defined by the U.S. Office of Management and Budget (OMB) and the Census Bureau. Alaska’s network monitors four CBSAs: Anchorage Metropolitan Statistical Area (MSA), Fairbanks MSA, Juneau Micropolitan Statistical Area (μSA), and Ketchikan μSA. The populations of these CBSAs are captured in Table 2 . These population-based monitoring network requirements ensure adequate coverage of pollutants affecting public health and compliance with the NAAQS.

Core Based Statistical Areas

Table 2: CBSA’s of Alaska

Core Based Statistical Areas	Population
Anchorage MSA	405,821
Municipality of Anchorage	287,155
Matanuska-Susitna Borough	118,666
Fairbanks MSA Fairbanks North Star Borough	93,972
Juneau µSA City and Borough of Juneau	31,609
Ketchikan µSA Ketchikan Gateway Borough	13,549

Pollutant Monitoring Requirements

DEC ensures compliance with the minimum monitoring requirements for criteria pollutants across all CBSAs, as outlined in Table 3 and Table 4 . No monitoring is required for Ketchikan µSA due to population and pollutant levels below required thresholds. The Anchorage, Fairbanks, and Juneau CBSA’s meet or exceed requirements for PM, CO, and ozone, or have been granted specific waivers noted in more detail in the Monitoring Waivers section.

Table 3: Summary of Monitoring Compliance

CBSA	Pollutant	Required Sites	Actual Sites	Compliance Status
Anchorage MSA	PM_2.5	0	2	Exceeds Requirements
Anchorage MSA	PM₁₀	3-4	3	Meets Requirements
Anchorage MSA	CO	1	1	Meets Requirements
Fairbanks MSA	PM_2.5	1	3	Exceeds Requirements
Fairbanks MSA	PM₁₀	0	1	Exceeds Requirements
Fairbanks MSA	CO	1	1	Meets Requirements
Fairbanks MSA	SO₂	0	1	Exceeds Requirements
Fairbanks MSA	NO₂	0	0	Meets Requirements
Fairbanks MSA	O₃	0	1	Exceeds Requirements
Juneau μSA	PM_2.5	0	1	Exceeds Requirements
Juneau μSA	PM₁₀	0	1	Exceeds Requirements
Ketchikan μSA	PM_2.5	0	0	Meets Requirements

Table 4: Minimum SLAMS

Criteria Pollutant	Comments	Anchorage MSA	Fairbanks MSA
PM_2.5	Most recent 3-year design value ≥ 85% of NAAQS	0	1
PM_2.5	Most recent 3-year design value < 85% of NAAQS	0	0
PM₁₀	Two monitoring sites based on PM₁₀ Limited Maintenance Plans (Juneau and Eagle River).	3-4	0
Pb	Waiver for source-oriented monitoring - see Appendix H	0	0
CO	Two monitoring sites based on CO Limited Maintenance Plans (Fairbanks and Anchorage); Fairbanks also meets NCore requirement	0	0
O₃	Most recent 3-year design value ≥ 85% of NAAQS. Waiver for Anchorage MSA population-based monitoring requirement – See Appendix H	0	0
SO₂	NCore site requirement	0	0
NO₂	Requirement based on population numbers. Alaska does not meet the threshold requirement	0	0

Lead

Alaska does not meet the population thresholds specified in 40 CFR 58, Appendix D for population-based lead (Pb) monitoring, so no routine Pb monitoring is required. However, Red Dog Mine, one of the world’s largest zinc producers and a significant lead bearing ore operation in northwest Alaska, remains a potential source of lead emissions that must be periodically evaluated. DEC first received an EPA waiver for the monitoring requirement in 2016 after dispersion modeling demonstrated that ambient Pb concentrations would remain well below 50 percent of the three-month rolling Pb NAAQS. EPA renewed the waiver in 2021, and federal regulations require that it be reassessed every five years as part of Alaska’s Network Assessment.

For the most recent renewal cycle, DEC worked with EPA Region 10 and Teck Alaska Inc. to complete updated modeling using revised emissions and meteorological data. The 2025 analysis confirmed that the mine continues to meet the criterion for waiver eligibility, with modeled concentrations remaining below 50 percent of the applicable standard. DEC formally requested and received approval for renewal of the waiver in EPA’s 2025 Annual Network Plan approval letter. The next evaluation of this waiver will occur as part of the 2030 five-year Network Assessment. This waiver is discussed in more detail later in this report.

Current Monitoring Sites

Overview

DEC operates a statewide ambient air monitoring network designed to meet the requirements of 40 CFR Part 58 and to characterize air quality conditions within Alaska’s three CBSAs: the Anchorage MSA, the Fairbanks MSA, and the Juneau μSA. The network focuses on population centers, nonattainment areas, and communities with documented wintertime PM_2.5 and PM₁₀ impacts driven by cold climate, topographic inversions, residential wood combustion, and stagnation episodes.

The 2026 monitoring network maintains the geographic coverage of the 2025 network while incorporating routine instrument updates and replacements. All regulatory monitors continue to meet the siting criteria in 40 CFR Part 58, Appendix E, except where an EPA‑approved waiver applies. Sites and instrumentation are summarized in Table 5, while more detailed method designations and sampling schedules are located in Appendix B – Instrument Inventory. Monitor specific AQS metadata (parameter codes, method codes, unit codes, and parameter occurrence codes (POC)) are provided in Appendix C – AQS Monitor Metadata.

Table 5: Alaska DEC Regulatory Monitoring Sites, 2026

Region / CBSA	Site Name	AQS ID	Location	Pollutants Monitored	Station Type	Notes
Anchorage MSA	Garden	02‑020‑0018	3000 E 16th Ave, Anchorage	PM₁₀, PM_2.5, CO	SLAMS	CO discontinuation expected upon SIP approval (LMP)
Anchorage MSA	Laurel	02‑020‑0045	4335 Laurel St, Anchorage	PM₁₀	SPM	PM₁₀ SPM supporting completeness requirements
Anchorage MSA	Parkgate (Eagle River)	02‑020‑1004	11723 Old Glenn Hwy, Eagle River	PM₁₀	SLAMS	Required PM₁₀ site for Eagle River LMP
Mat–Su (Anchorage MSA)	Plant Materials Center (PMC)	02‑170‑0010	5310 Bodenburg Spur Rd, Palmer	PM₁₀, PM_2.5	SLAMS	Replaced Butte site (EPA approved relocation)
Fairbanks MSA	A Street	02‑090‑0040	397 Hamilton Ave, Fairbanks	PM_2.5	SLAMS	FEM designated continuous PM_2.5 (2024); EPA siting waiver in effect
Fairbanks MSA	NCore	02‑090‑0034	907 Terminal St, Fairbanks	PM₁₀, PM_2.5, CO, SO₂, O₃, NO , NO_y, PM_10-2.5, Speciation	NCore	Includes trace gas, PM, met, and CSN measurements
Fairbanks MSA	Hurst Road	02‑090‑0035	3288 Hurst Rd, North Pole	PM_2.5, SO₂, Speciation, NATTS: PAH, PM₁₀ Metals, Carbonyls, VOCs	SLAMS	SO₂ upgraded to T100U trace level in 2024. NATTS sampling started January 2026
Juneau μSA	Floyd Dryden	02‑110‑0004	3800 Mendenhall Loop Rd, Juneau	PM₁₀, PM_2.5	SLAMS	PM_2.5 FRM is primary SLAMS sampler (1‑in‑3 schedule)

Monitoring Objectives

Overview

DEC’s monitoring network is designed to meet the siting and design objectives in 40 CFR Part 58 Appendix D. Across the state, monitors are positioned to characterize peak pollutant levels during winter stagnation events (periods of time where air flow or convection is minimal or non-existent), measure typical residential exposure, assess impacts from local emission sources, and provide background and regional transport information. Detailed instrument designations and sampling schedules are provided in Appendices B and C.

Anchorage Metropolitan Statistical Area (MSA)

In the Anchorage MSA, DEC’s monitors characterize neighborhood‑scale air quality in residential areas, assess impacts from road dust and local sources, and meet Limited Maintenance Plan (LMP) requirements for carbon monoxide and PM₁₀. The network supports daily AQI reporting, population‑exposure assessment, and regulatory determinations for the Anchorage and Eagle River communities.

Matanuska-Susitna Borough (Anchorage MSA)

The Plant Materials Center (PMC) site collects representative air quality data within the Palmer–Butte area, capturing elevated particulate levels driven by valley meteorology, local dust sources, and residential combustion. The site also houses multi‑height meteorological sensors and serves as Alaska’s designated PM_2.5 regional transport/background site, fulfilling applicable Appendix D network requirements.

Fairbanks North Star Borough (FNSB)

Monitoring in the Fairbanks and North Pole areas is focused on capturing worst‑case wintertime PM_2.5 concentrations, including those caused by severe inversions and home heating emissions. The network includes the A Street monitor for Fairbanks-area maximum-impact conditions, the Hurst Road monitor representing North Pole’s highest concentrations, and the Fairbanks NCore station providing multi‑pollutant measurements, speciation data, and long-term trend information. Combined, these sites support NAAQS compliance determinations, SIP implementation, and public AQI reporting.

Juneau μSA

The Floyd Dryden monitor provides neighborhood‑scale PM_2.5 and PM₁₀ measurements for the Mendenhall Valley, capturing conditions influenced by wintertime cold pools and community emissions from home heating and slash pile burning. The site also fulfills the PM₁₀ monitoring requirement for the Juneau LMP.

Siting Criteria

DEC ensures that its eight ambient air monitoring sites comply with the siting criteria outlined in 40 CFR Part 58, Appendix E. These criteria guarantee accurate, representative, and consistent air quality data collection, critical for public health and regulatory compliance. When these criteria are not met, a waiver from EPA is required. Current siting criteria waivers are listed in Appendix H of this report.

In 2014, EPA Region 10 provided site evaluation forms to assess compliance with the probe and monitoring path siting criteria specified in 40 CFR Part 58, Appendix E. These forms were distributed to the individual site operators for completion. Summaries of the completed site evaluation forms are organized into three tables PM, CO, and all other gaseous pollutants and are presented in Appendix E of this report.

Monitoring site photos and location maps can be found at: https://dec.alaska.gov/air/air-monitoring/instruments-sites/site-info/.

40 CFR Part 58, Appendix A sets the national quality assurance framework for air monitoring data used to determine compliance with the National Ambient Air Quality Standards. It outlines required QA plans, performance objectives, audits, and measurement checks that monitoring organizations must follow to verify and validate data is accurate, consistent, and comparable across the country. The operation of each monitoring site complies with the requirements outlined in 40 CFR Part 58, Appendix A. Furthermore, all SPM sites are operated following the same protocols as SLAMS, thereby ensuring full compliance with these requirements.

Carbon Monoxide Sites

CO monitoring sites adhere to the siting criteria outlined in 40 CFR Part 58, Appendix C, ensuring accurate measurement of CO concentrations. Key requirements include:

Probe Inlets: Positioned at least 1 meter from structures to avoid interference.
Probe Heights: 2.5-3.5 meters for micro-scale or 3-15 meters for other scales.
Airflow: Unobstructed for at least 270 degrees (or 180 degrees for building-side probes).
Obstructions: At least twice the height of dominant CO sources to minimize local influences.

CO monitoring occurs at Garden (AQS ID: 02-020-0018) and NCore (AQS ID: 02-090-0034). Table 6 lists the CO monitoring sites in Anchorage and Fairbanks.

In the 2024 ANP, EPA R10 provisionally approved the discontinuation of the CO monitor at the Anchorage Garden site (AQS ID: 02-020-0018), contingent upon approval of a SIP modification wherein the monitor is not required. This approval was based on the monitor showing attainment during the previous five years and having a probability of less than 10% chance of exceeding 80% of the CO NAAQS over the next three years.

Table 6: CO Monitoring Sites

Site Name	AQS ID	Monitoring Scale	Probe Distance from Wall (meters)>	Height (meters)	Unrestricted Air Flow	Spacing from Roadway (meters)	Trees
Garden	02-020-0018	Neighborhood	1	3	180 degrees unobstructed	7.6	Yes
NCore	02-090-0034	Neighborhood	Not applicable	3	360 degrees unobstructed	70	10 m

One tree at the Anchorage Garden site is within 10 meters of the sample inlet. Based on previous site inspections by the Quality Assurance (QA) Officer and EPA Auditors, it was determined the single tree does not significantly contribute to scavenging carbon monoxide from the sample pathway and a waiver was not required.

Particulate Matter Sites

Particulate matter (PM₁₀ and PM_2.5) monitoring sites comply with 40 CFR 58, Appendix D, ensuring representative data for population exposure and NAAQS compliance. Key requirements include:

Probe Heights: 2-7 meters for micro-scale or 2-15 meters for other scales.
Separation from Walls: Minimum 2 meters to avoid airflow restrictions.
Airflow: Unobstructed for at least 270 degrees (or 180 degrees for street canyon sites).
Roadway spacing: 2-10 meters for street canyon sites, 5-15 meters for traffic corridors, or based on traffic volume for other scales.
Traffic and Trees: Traffic volume typically <10,000 vehicles per day (VPD); no trees within 10 meters to prevent particle interference.

PM monitoring occurs at Garden, Laurel, Parkgate, Plant Materials Center, A Street. Hurst Road, NCore, and Floyd Dryden. A Street operates under a siting waiver due to its proximity to a roadway (Appendix H). Table 7 lists all PM monitoring sites in Alaska and summarizes their compliance with the siting criteria specific to Appendix E of 40 CFR Part 58 (see also Appendix E).

Table 7: PM Sites

Site Name	AQS ID	Monitoring Scale PM₁₀	Monitoring Scale PM_2.5	Height (meters)	Spacing from Obstructions (meters)	Spacing from Roadway (meters)	Traffic (VPD)	Trees within 10 meters?
Garden	02-020-0018	Neighborhood	Neighborhood	11.2	No Obstructions	14	Sunrise Dr: 770 Airport Heights Dr: 1,280	No
Laurel	02-020-0045	Microscale	NA	6.4	No Obstructions	11	Tudor Rd: 29,500	No
Parkgate	02-020-1004	Neighborhood	Neighborhood	10.4	No Obstructions	44	Old Glenn Hwy: 13,300	No
Plant Materials Center	02-170-0010	Neighborhood	Neighborhood	4.4	No Obstructions	180	Bodenburg Spur Rd: 60	No
A Street	02-090-0040	NA	Neighborhood	4.3	No Obstructions	5.8	Hamilton Ave: 1,300 Farewell Ave: 3,770	No
NCore	02-090-0034	Neighborhood	Neighborhood	4.5	No Obstructions	70	Phillips Field Rd: 5,250 Driveway St: 850	No
Hurst Road	02-090-0034	NA	Neighborhood	4.7	No Obstructions	21	Hurst Rd: 3,110	No
Floyd Dryden	02-110-0004	Neighborhood	Neighborhood	10	No Obstructions	100	Mendenhall Loop Rd: 8,120	No

NCore Site

The NCore site in Fairbanks (AQS ID: 02-090-0034), part of the National Core multi-pollutant monitoring network, measures PM_2.5, PM₁₀, CO, SO₂, O₃, NO , NO_y, Chemical Speciation, and meteorological parameters at a neighborhood scale. It adheres to the siting criteria for each parameter, as specified in 40 CFR 58, Appendices C, D, and E, ensuring comprehensive data for research and compliance. Table 8 lists all gaseous monitors at the NCore site and summarizes their compliance with the siting criteria specific to Appendix E of 40 CFR Part 58 (see also Appendix E).

Table 8: NCore Gaseous Monitoring and Met Monitoring

Parameter Name	Monitoring Scale	Height (meters)	Spacing from Obstructions (meters)	Spacing from Roadway (meters)	Traffic (VPD)	Trees <10 m?
NO_y, NO & DIF	Neighborhood	3	No Obstructions	70	5,250	None
O₃	Neighborhood	3	No Obstructions	70	5,250	None
SO₂ (1 hr & 5 min)	Neighborhood	3	No Obstructions	70	5,250	None
T_amb, WS, & WD	Neighborhood	3	No Obstructions	70	5,250	None
T_amb, WS, & WD	Neighborhood	10	No Obstructions	70	5,250	None
Relative Humidity	Neighborhood	3	No Obstructions	70	5,250	None

Compliance Summary

All sites comply with 40 CFR Part 58, Appendix E, as verified by 2026 site evaluation forms (Appendix E). One waiver is noted for A Street due to the site’s proximity to a roadway being less than 10 meters. Table 9 summarizes site compliance.

Table 9: Compliance Summary

Site Name	AQS ID	Compliance Status	Siting Criteria Met	Waivers/ Exemptions
Garden	02-020-0018	Fully Compliant	Yes	None
Laurel	02-020-0045	Fully Compliant	Yes	None
Parkgate	02-020-1004	Fully Compliant	Yes	None
Plant Materials Center	02-170-0010	Fully Compliant	Yes	None
A Street	02-090-0040	Compliant; Siting waiver granted	Yes	Siting waiver for roadway proximity (Appendix H)
NCore	02-090-0034	Fully Compliant	Yes	None
Hurst Road	02-090-0035	Fully Compliant	Yes	None
Floyd Dryden	02-110-0004	Fully Compliant	Yes	None

Monitoring Methods, Designation and Sampling Frequency

Overview

DEC operates a statewide network of FRM, FEM, and SPM instruments in accordance with the requirements of 40 CFR Part 58, including Appendices A (Quality Assurance), C (Ambient Monitoring Methods), D (Network Design Criteria), and E (Probe and Path Siting Criteria). All monitors designated for comparison to the NAAQS use EPA‑approved FRM/FEM methods and meet applicable siting, performance, and quality assurance criteria. EPA‑approved siting waivers remain in effect where required.

SPM monitors are deployed strategically to address spatial coverage needs, characterize winter PM_2.5 stagnation events, support Air Quality Index (AQI) reporting, provide supplemental information on local emission impacts, and evaluate new monitoring technologies. SPM data are not used for NAAQS determinations unless an SPM meets all applicable FRM/FEM and Appendix E siting requirements and is designated accordingly.

Instrument-specific AQS parameter codes, method codes, start dates, and POCs are provided in Appendix C of the Network Plan and are consistent with current AQS records.

PM_2.5 Monitoring Methods

DEC operates a combination of FRM filter samplers and FEM continuous analyzers to provide a robust PM_2.5 dataset for CBSAs, nonattainment areas NAA, and community exposure assessment. DEC operates a mix of FRM samplers and FEM continuous analyzers across the network to meet federal PM_2.5 monitoring requirements. The selection of FRM or FEM instrumentation varies by site based on regulatory needs, data completeness objectives, and regional monitoring priorities. Table 10 summarizes the PM_2.5 method type, designation, sampling frequency, and regulatory role for each monitor in the network.

Table 10: PM_2.5 Methods, Designation, and Sampling Frequency

Site	Instrument	Method Type	Designation	Frequency	Regulatory Role
Garden (Anchorage)	Met One BAM 1020 (VSCC)	Continuous	FEM	Continuous	SLAMS FEM; AQI + year-round exposure
Garden (Anchorage)	Thermo Partisol 2000i (VSCC)	Filter-based	FRM	1‑in‑6	Collocated FRM for NAAQS comparability
Plant Materials Center (Mat-Su)	Met One BAM 1020 (VSCC)	Continuous	FEM	Continuous	SLAMS FEM, Regional Transport
A Street (Fairbanks)	Met One BAM 1020 (VSCC)	Continuous	FEM	Continuous	Primary FEM for PM_2.5 NAA
A Street (Fairbanks)	Thermo Partisol 2025i (VSCC)	Filter-based	FRM	1‑in‑1	Primary FRM; NAAQS comparable
Hurst Road (North Pole)	Thermo Partisol 2025i (VSCC)	Filter-based	FRM	1‑in‑1	Maximum Impact Site
Hurst Road (North Pole)	Thermo Partisol 2025i (VSCC)	Filter-based	FRM	1‑in‑3	N/A
Hurst Road (North Pole)	Met One BAM 1020 (SCC)	Continuous	SPM (non-FEM)	Continuous	Supplemental PM_2.5; not regulatory
Hurst Road (North Pole)	URG 3000N	Chemical Speciation	CSN	1‑in‑3	N/A
Hurst Road (North Pole)	SuperSASS	Chemical Speciation	CSN	1‑in‑3	N/A
NCore (Fairbanks)	URG 3000N	Chemical Speciation	CSN	1‑in‑3	N/A
NCore (Fairbanks)	SuperSASS	Chemical Speciation	CSN	1‑in‑3	N/A
NCore (Fairbanks)	Thermo Partisol 2025i (VSCC)	Filter-based	FRM	1‑in‑3	N/A
NCore (Fairbanks)	Met One BAM 1020	Continuous	FEM	Continuous	N/A
Floyd Dryden (Juneau)	Thermo Partisol 2025i (VSCC)	Filter‑based	FRM	1-in-3	N/A
Floyd Dryden (Juneau)	Teledyne T640x	Continuous	SPM (non-regulatory FEM)	Continuous	Supplemental PM_2.5 for AQI only (not used for NAAQS)

PM₁₀ Monitoring Methods

PM₁₀ monitoring supports regulatory requirements in Anchorage, Fairbanks, and Juneau, including LMP areas and site‑specific planning needs. DEC operates both FRM and FEM technologies to ensure continuous and filter‑based datasets for compliance and exposure assessment. The sites, methods, and their regulatory roles are summarized below in Table 11 .

Table 11: PM₁₀ Methods, Designation, and Sampling Frequency

Site	Instrument	Method	Designation	Frequency	Regulatory Role
Garden (Anchorage)	Met One BAM 1020	Continuous	FEM	Continuous	Primary PM₁₀ FEM
Garden (Anchorage)	Thermo Partisol 2000i	Filter	FRM	1‑in‑6	Collocated PM₁₀ FRM
Laurel (Anchorage)	Met One BAM 1020	Continuous	SPM	Continuous	Microscale site used for road dust data support.
Parkgate (Eagle River)	Met One BAM 1020	Continuous	FEM	Continuous	PM₁₀ LMP requirement
Plant Materials Center (Mat-Su)	Met One BAM 1020	Continuous	FEM	Continuous	SLAMS PM₁₀ FEM
NCore (Fairbanks)	Met One BAM 1020	Continuous	FEM	Continuous	NCore PM₁₀ FEM
Floyd Dryden (Juneau)	Teledyne T640X	Continuous	FEM	Continuous	Juneau PM₁₀ LMP requirement

Gaseous Criteria Pollutant Methods

DEC operates continuous trace‑level analyzers consistent with 40 CFR Part 58 Appendix D §3 at the Fairbanks NCore site. CO monitoring remains active at the Garden site (Anchorage) until the associated SIP revision is submitted and approved, which is expected in 2026 quarter four. These instruments and methods are summarized in Table 12 .

Table 12: Gaseous Methods, Designation, and Sampling Frequency

Pollutant	Site	Instrument	Designation	Frequency	Notes
CO	Garden (Anchorage)	Thermo 48i‑TLE	FRM	Continuous	Required for LMP until SIP approval
CO	NCore (Fairbanks)	Teledyne API T300U	FRM	Continuous	Required NCore parameter
SO₂	Hurst Road (North Pole)	Teledyne T100U (trace‑level)	FEM	Continuous	NAA SPM
SO₂	NCore (Fairbanks)	Thermo 43i (trace‑level)	FEM	Continuous	Required NCore parameter
O₃	NCore (Fairbanks)	Thermo 49iQ (UV photometric)	FEM	Continuous	Required NCore parameter
NO /NOy	NCore (Fairbanks)	Teledyne T200U (chemiluminescence)	-	Continuous	Required reactive nitrogen suite (NO + NO_y + NO_y–NO )

Chemical Speciation Network (CSN)

DEC operates CSN samplers (Table 13) consistent with 40 CFR Part 58 Appendix D §4.8 to support PM_2.5 chemical composition analyses, source characterization, and NAA planning.

Table 13: PM_2.5 Speciation Methods

Site	Instrument	Frequency	Notes
NCore (Fairbanks)	URG 3000N / SuperSASS	1‑in‑3	Required CSN site (meets 40 CFR 58 App. D §4.8)
Hurst Road (North Pole)	URG 3000N / SuperSASS	1‑in‑3	Supplemental speciation for PM_2.5 NAA (sulfate/carbon characterization; non‑regulatory)

Sampling Frequency Requirements (40 CFR 58.12 Compliance)

DEC meets or exceeds all federal sampling‑frequency requirements for PM_2.5, PM₁₀, gaseous pollutants, and chemical speciation. PM_2.5 FRM sampling is conducted every day at A Street, Hurst Road, and the Fairbanks NCore site, exceeding the 1‑in‑3 federal minimum. Continuous FEM analyzers operate at all SLAMS and NCore locations to support daily reporting and data completeness. PM₁₀ monitoring schedules meet the requirements for the Anchorage and Fairbanks MSAs and the Juneau μSA. Gaseous pollutants (CO, NO_y, SO₂, and O₃) are monitored continuously at the Fairbanks NCore site as required for the multipollutant NCore program. For chemical speciation, the required NCore CSN sampler operates on a 1‑in‑3 schedule, and DEC also runs a supplemental speciation sampler at Hurst Road at the same frequency, exceeding the 1‑in‑6 minimum for supplemental CSN sites.

Primary SLAMS vs. SPM Identification

Primary SLAMS monitors include PM_2.5 and PM₁₀ samplers at Garden, Parkgate, PMC, A Street, Hurst Road, and Floyd Dryden, as well as regulatory CO monitoring at Garden and SO₂ at Hurst Road. Other instruments in the network are designated as SPMs, including PM_2.5 and PM₁₀ samplers at Laurel; supplemental continuous PM_2.5 and meteorological measurements at Hurst Road; and meteorological systems at A Street, PMC, and the Fairbanks NCore site. Although SPMs are typically not used for NAAQS determinations unless they meet all FRM/FEM and siting criteria in Appendix E, DEC’s Laurel PM₁₀ SPM is treated as regulatory‑grade due to EPA’s acceptance of its data despite its roadway‑setback limitations.

All sampling frequencies, designations, and method codes used in DEC’s network comply with 40 CFR Part 58 and Appendices A, C, D, and E, and match the metadata contained in EPA’s AQS records.

Collocation and Quality Assurance Requirements

DEC implements a comprehensive QA and Quality Control (QC) program that fulfills all applicable requirements of 40 CFR Part 58, including Appendices A (Quality Assurance Requirements), C (Ambient Monitoring Methods), D (Network Design Criteria), and E (Probe and Path Siting Criteria). The QA program ensures that all SLAMS, NCore sites, and SPMs generate data of known, consistent, and documented quality.

Regulatory monitoring data undergo thorough verification for precision, bias, completeness, comparability, and operational performance. DEC maintains a coordinated system of calibrations, independent audits, flow checks, siting verifications, and multi‑tiered data validation procedures consistent with EPA’s Quality System framework. Instrument and parameter‑level metadata, including method codes and operating characteristics, are provided in Appendix B (Instrument Inventory) and Appendix C (AQS Monitor Metadata).

Collocated Monitoring

DEC maintains collocated PM_2.5 and PM₁₀ samplers at key locations to evaluate measurement precision and ensure comparability in accordance with 40 CFR Part 58 Appendix A. At the Hurst Road SLAMS site in North Pole, a primary Thermo Partisol 2025i FRM sampler operates alongside a collocated Partisol on a one-in-three day schedule, supporting PM_2.5 precision requirements for the Serious Nonattainment Area and improving interpretation of chemical speciation data. In Anchorage, the Garden site operates both PM_2.5 and PM₁₀ collocated instruments, using a Met One BAM 1020 FEM as the primary sampler and a Thermo Partisol 2000i FRM for collocation. This configuration provides required PM_2.5 and supplemental PM₁₀ precision checks, ensures comparability between FEM and FRM measurements, and supports SLAMS quality assurance and population exposure assessments. Instrument configurations and additional collocation metadata are provided in Appendices B and C.

Chemical Speciation Network (CSN) QA and Collocation

DEC operates CSN samplers at the Fairbanks NCore site and at the Hurst Road SLAMS site to support multipollutant monitoring objectives, PM_2.5 source characterization, and long‑term chemical trend analysis. CSN activities follow Appendix A requirements, the CSN Technical Assistance Document, and associated field and laboratory QA protocols. These include certified filter handling and chain‑of‑custody procedures, documented flow audits and calibration checks, and routine laboratory performance evaluations. The Fairbanks NCore site serves as the required CSN location, while Hurst Road provides supplemental speciation data for non-attainment planning. Additional instrument configurations and CSN method details are provided in Appendices B and C of this report.

NCore Trace-Level QA Requirements

The Fairbanks NCore station follows the enhanced trace‑level quality‑assurance requirements in 40 CFR Part 58 Appendix A §3.3. These procedures include routine zero/span and precision checks, annual multi‑point calibrations, and periodic independent performance audits for trace‑level CO, SO₂, O₃, and reactive nitrogen analyzers. Meteorological sensors are also verified and calibrated on a regular schedule. Together, these requirements ensure the high‑quality, stable measurements needed for long‑term trend analysis and multipollutant characterization.

Flow Rate and Audit Requirements

DEC performs all required flow checks, calibrations, and performance audits for particulate samplers and gaseous analyzers in accordance with 40 CFR Part 58 Appendix A. Routine quality‑control flow verifications and semi‑annual independent audits are conducted for FRM and continuous particulate monitors to ensure each instrument operates within the required tolerances. Gaseous analyzers undergo regular zero/span checks, annual multi‑point calibrations, and annual performance evaluations, including National Performance Audit Program (NPAP) audits where applicable. All flow and calibration standards are NIST‑traceable, and documentation is maintained consistent with DEC’s quality system and Appendix A requirements. These procedures ensure that particulate and gaseous measurements used for regulatory purposes remain accurate, consistent, and fully comparable to national monitoring standards.

Data Validation and Completeness

DEC uses a three-tiered data‑validation process to ensure that all measurements submitted to EPA’s Air Quality System (AQS) meet federal quality‑assurance requirements. Validation includes automated screening for completeness and instrument performance, review of operator and calibration records, comparison with collocated and nearby monitors, and a final supervisory review before data are certified. DEC maintains at least 75% data completeness for all pollutants used in NAAQS determinations, consistent with Appendix A requirements.

Documentation, Records, and PQAO Participation

DEC serves as Alaska’s Primary Quality Assurance Organization (PQAO) and ensures that consistent QA/QC procedures are applied across all regulatory monitoring sites. As the PQAO, DEC maintains an up‑to‑date Quality Management Plan (QMP), pollutant‑specific Quality Assurance Project Plans (QAPPs), and current standard operating procedures (SOPs). DEC prepares required QA summary reports and submits the annual data certification to EPA each year. Calibration logs, audit results, maintenance records, and validation documentation are retained in accordance with federal record‑keeping requirements.

Fairbanks PM_2.5 Serious Nonattainment Area

The Fairbanks North Star Borough remains designated as a Serious PM_2.5 Nonattainment Area. DEC operates the required PM_2.5 and multipollutant monitors at A Street, Hurst Road, and the Fairbanks NCore station to support NAAQS determinations, SIP implementation, and winter stagnation analysis. The network combines daily FRM sampling, continuous FEM measurements, trace‑gas monitoring at NCore, and supporting meteorology to characterize both maximum‑impact conditions and typical residential exposure. If EPA approves dividing the current nonattainment area into Fairbanks and North Pole zones, A Street will serve as the maximum‑impact monitor for the Fairbanks zone, while Hurst Road will continue as the maximum‑impact monitor for the North Pole zone.

Collectively, these monitors provide the full dataset needed for regulatory assessments, trend evaluation, and public AQI reporting. Detailed monitor configurations and designations are provided in Appendices B and C of this report.

Anchorage Carbon Monoxide Limited Maintenance Plan (CO LMP)

Anchorage remains designated under the 2^nd 10-year CO Limited Maintenance Plan (LMP), stemming from elevated CO originating from vehicle exhaust. The LMP requires operation of a regulatory CO monitor to identify if contingency measures should be triggered to prevent an exceedance of the standard. DEC is undertaking efforts to remove the monitoring requirements in the SIP which would allow removal of the continuous CO monitor. This would be completed upon EPA approval of the revision based on DEC’s demonstration that the area is eligible to discontinue the monitor. DEC operates the required CO FEM analyzer at the Garden site, supporting CO trend assessment, population exposure evaluation, and AQI reporting. CO monitoring will continue until a future SIP revision is submitted and approved.

Eagle River PM₁₀ Limited Maintenance Plan (PM₁₀ LMP)

The Eagle River neighborhood remains subject to a PM₁₀ LMP that requires a representative PM₁₀ SLAMS monitor. DEC meets this requirement through the Parkgate station, which operates a continuous PM₁₀ FEM analyzer providing the data needed for road‑dust characterization, AQI reporting, and NAAQS comparability. The site fully satisfies all PM₁₀ LMP monitoring obligations.

Mendenhall Valley (Juneau) PM₁₀ Limited Maintenance Plan

The Juneau Mendenhall Valley PM₁₀ LMP requires operation of a representative PM₁₀ SLAMS monitor. DEC meets this requirement at the Floyd Dryden station, which includes continuous PM₁₀ FEM monitoring and complementary PM_2.5 measurements that support AQI reporting, community assessment, and trend analysis. The site remains fully compliant with all SIP based and federal LMP requirements.

Demonstration of Compliance

DEC meets or exceeds all monitoring obligations for PM_2.5, PM₁₀, and CO under applicable SIPs, LMPs, and federal regulations. Compliance is demonstrated through operation of required FRM and FEM monitors at or above federal sampling frequencies, continuous analyzers that enhance AQI reporting and data completeness, adherence to SLAMS and NCore siting and method requirements, and maintenance of monitors consistent with SIP and LMP commitments. DEC also deploys supplemental SPM monitors where additional spatial characterization is needed and routinely evaluates monitoring needs using trends, design values, population distribution, and winter meteorology. DEC will continue annual network evaluations and implement modifications necessary to maintain NAAQS comparability and protect public health.

Table 14: Required Monitors Under NAA and LMP Plans

Area / Plan	Site Name	AQS ID	Pollutant	POC	Reason Required
Fairbanks PM_2.5 Serious NAA	Hurst Road (North Pole)	02‑090‑0035	PM_2.5	1	PM_2.5 Serious NAA SIP requirement – North Pole Maximum impact site
Fairbanks PM_2.5 Serious NAA	A Street	02‑090‑0040	PM_2.5	1	SLAMS monitor – Fairbanks Maximum impact site
Anchorage CO LMP	Garden	02‑020‑0018	CO	1	Required CO LMP monitor (FEM)
Eagle River PM₁₀ LMP	Parkgate	02‑020‑1004	PM₁₀	3	Required PM₁₀ LMP monitor
Juneau PM₁₀ LMP	Floyd Dryden	02‑110‑0004	PM₁₀	3	Required PM₁₀ LMP monitor

Monitoring Waivers

DEC maintains several monitoring waivers within the network to address site specific operational constraints and ensure that high quality data can still be collected under Alaska’s unique conditions. All waiver requests are reviewed and approved by EPA to confirm that these adjustments do not diminish monitoring integrity or compromise public health protection. The waiver process also reinforces transparency and accountability between DEC, Alaskan communities, and EPA.

Anchorage MSA Ozone Monitoring

On October 15^th, 2018, EPA granted a waiver of the ozone monitoring requirement for the Anchorage MSA. The MSA’s population triggered a monitoring obligation, but historical ozone measurements throughout the area consistently showed concentrations well below 80% of the NAAQS. This waiver was valid through 2023.

Following a request from DEC in the 2023 ANP, EPA approved a five-year extension of the waiver on October 30^th, 2023, pursuant to 40 CFR Part 58, Appendix D, Section 4.1(b). EPA concurred with the DEC’s assessment that ozone levels in the Anchorage MSA remain well below 80% of the NAAQS, with a continued low likelihood of exceedances. The current waiver is effective through October 2028.

The waiver extension is included in the 2023 Alaska ANP Approval Letter and can be found on the DEC’s ANP website (https://dec.alaska.gov/air/air-monitoring/guidance/monitoring-plans/).

Lead Source Oriented Monitoring Waiver

To address source-oriented lead monitoring requirements at the Red Dog Mine, DEC consulted with EPA and pursued a modeling demonstration to show compliance with the lead NAAQS at the ambient boundary. On August 11, 2016, the EPA approved Alaska’s initial waiver request for lead monitoring at the Red Dog Mine based on dispersion modeling results, which demonstrated that the maximum 3-month rolling average lead concentration at the mine boundary did not exceed 50% of the lead NAAQS. Pursuant to 40 CFR Part 58, Appendix D, Section 4.5(a)(ii), this waiver must be renewed every five years as part of the Alaska 5-year Air Monitoring Network Assessment.

DEC submitted an updated waiver request to the EPA on June 12, 2020, which included a new modeling analysis performed by Teck Alaska Inc., the mine operator, and reviewed by the DEC. The EPA approved the renewed waiver on December 7, 2021. Subsequently that waiver required renewal in 2025 and DEC began working with Teck Alaska on a renewal of that waiver in the fall of 2024.

Teck Alaska’s preliminary report indicated an increase in overall emissions. Because previous modeling showed that the Red Dog Mine emissions were near the waiver threshold, the EPA requested updated emission rates and new modeling runs. The updated modeling results were used to support that review process.

Those updated modeling runs, and subsequent analysis demonstrate that the maximum 3-month average concentration remains below 50% of the lead NAAQS (0.070 µg/m³ or 47%). Upon completion of Teck and DEC’s analysis, EPA Region 10 was supplied with the results of the analysis for preliminary review on June 24^th, 2025. EPA’s preliminary review did not identify approvability issues and subsequently EPA requested the addition of the waiver request as part of the 2025 ANP submission and was subsequently approved on October 23^rd, 2025. The waiver will be subject to its next renewal with the 2030 5 Year Air Monitoring Network Assessment.

The previous EPA approval letters, submissions, and supporting documentation for the lead monitoring waivers are included in Appendix H of this report and are also available on the DEC website (https://dec.alaska.gov/air/air-monitoring/guidance/waivers/).

A Street Siting Wavier

The A Street SLAMS station is located in a residential neighborhood on the east side of Fairbanks, adjacent to the former Nordale Elementary School. The site was selected because of its proximity to homes that rely on solid fuel heating and its identification as a PM_2.5 hotspot, making it an appropriate maximum impact monitor for the Fairbanks Air Quality Zone. Placement on school district property provides long term stability and supports monitoring near a historically sensitive population, although the number of children in the area has decreased since the school grounds were repurposed.

The station’s location also reflects a balance between minimizing disruption to school activities and ensuring representativeness of neighborhood air quality. As a result, the monitor was sited closer to the A Street roadway than the recommended 15-meter setback in 40 CFR Part 58, Appendix E—specifically, approximately 3-meters from the sidewalk and beginning of the paved shoulder. This deviation is justified because the roadway experiences very low traffic volumes and is frequently snow or ice covered for much of the year, reducing the influence of direct roadway emissions. Since the primary monitoring objective at this location is to characterize PM_2.5 impacts from residential solid fuel combustion, any contribution from roadway emissions is expected to be minimal and does not compromise the integrity of the data.

On October 30^th, 2023, the EPA approved a waiver for the proximity-to-roadway siting criteria at the A Street site, pursuant to 40 CFR Part 58, Appendix E, Figure E-1. EPA concurred that the site is sufficiently representative of neighborhood-scale air quality for the intended monitoring objectives. Documentation of waiver approval is included in the 2023 Alaska ANP Approval Letter in Appendix I on the DEC website (https://dec.alaska.gov/air/air-monitoring/guidance/waivers/).

Network Modifications Completed in 2026

DEC implemented a significant update to the state’s ambient air monitoring network in 2026, strengthening the ability to assess potential health impacts when regulatory standards are exceeded and improving the information available for community outreach. A key enhancement was the installation and activation of a NATTS station at the North Pole Hurst Road SLAMS site, marking the network’s first comprehensive, long-term air toxics monitoring installation in the Fairbanks North Star Borough. This addition enhances the state’s capacity to characterize hazardous air pollutants, evaluate associated health risks, and contribute to national trends analyses. Additional network adjustments made throughout 2026 further align Alaska’s monitoring system with federal requirements while addressing emerging community and regulatory needs.

Air Toxics Program

Air pollution is comprised of many additional pollutants besides the six regulatory criteria pollutants. DEC previously operated an air toxics monitoring program, which was discontinued in the early 2000’s due to budget constraints.

FNSB has been in non-attainment for PM_2.5 since 2009. The main component of PM_2.5 in this area is organic carbon, which is predominantly from woodsmoke from residential home heating. Woodsmoke contains numerous toxic constituents, but DEC currently lacks comprehensive data on the air toxics levels in the community.

In 2023, DEC submitted a grant application and received Inflation Reduction Act (IRA) funds to support the establishment of a NATTS in Alaska. The funding was awarded by EPA in the spring of 2025. DEC began Air Toxics sampling in January 2026 at the Hurst Road air monitoring station in the North Pole zone of the FNSB PM_2.5 non-attainment area. Sampling began in January 2026 with polycyclic aromatic hydrocarbons (PAHs) and PM₁₀ metals sampling. Carbonyl sampling began March 2026, and VOC Sampling began April 2026. In total, DEC is collecting data on 62 air toxics and expects the NATTS site will provide valuable knowledge within the community.

Planned Network Modifications in 2026

Anchorage Garden Site CO Monitoring

Over the past two decades, CO concentrations in Anchorage have declined significantly, with no exceedances of the NAAQS reported. For the past three years, 8-hour maximum CO values have remained below 30% of the NAAQS and have not exceeded 41% in the last 10 years.

Given these sustained low concentrations, the DEC is seeking a SIP modification to conclude the second 10-year Limited Maintenance Plan period. EPA previously approved plans to remove the monitor once the SIP modification is complete. DEC plans to continue CO monitoring as long as the instrument remains operational until the modification is approved. If the monitor fails and is not repairable, DEC has a sensor pod at the station with a collocation history to the regulatory monitor and if conditions changed, may inform DEC of any need for contingency measures, until the SIP modification is approved.

Regulatory Monitoring Sites

At this time, the DEC does not anticipate any other changes to the regulatory ambient air monitoring network for 2026.

Community-Based Air Sensor Monitoring Project

While the existing long-term regulatory monitoring network meets federal requirements for the number of stations and pollutants monitored, it is primarily limited to Alaska’s population centers and does not adequately characterize conditions in outlying and rural communities.

Recent advances in sensor technology have enabled the development and commercial availability of smaller, portable, and more affordable air quality sensors. This new generation of low-cost sensor technology provides DEC with the opportunity to expand air quality monitoring into areas that were previously cost-prohibitive to reach.

Beginning in 2023, DEC launched the Community-Based Air Monitoring Project, deploying AQMesh and QuantAQ MODULAIR^TM low-cost sensor pods across the state. Initial funding was through the ARP grant, though that funding source expired January 31, 2026. The sensor network is designed to provide real-time air quality data and trend information, empowering community members to better understand baseline air quality in their areas. While the data collected are non-regulatory, it is available to the public upon request and are displayed in near-real-time on DEC’s air quality index (AQI) website: https://experience.arcgis.com/experience/8655256b056a48f6a19788d43cdab30f.

DEC has phased out AQMesh sensors and solely employs QuantAQ MODULAIR^TM and MODULAIR^TM-PM sensors. The MODULAIR^TM pods measure particulate matter (PM₁, PM_2.5, and PM₁₀), CO, NO , NO₂, and O₃. The MODULAIR^TM-PM pods measure particulate matter (PM₁, PM_2.5, and PM₁₀) only. As of April 2026, DEC operates a fleet of 71 QuantAQ pods statewide.

These pods are deployed in a wide range of communities, including: Anchorage, Bethel, Big Lake, Cordova, Delta Junction, Denali National Park, Eagle, Fairbanks (2), Galena, Gerstle River, Girdwood, Glennallen, Haines, Homer, Hoonah, Huslia, Juneau, Kenai, Ketchikan, Kodiak, Kotzebue, Napaskiak, Nenana, Ninilchik, Nome, North Pole, Salcha, Seward, Sitka, Skagway, Soldotna, Sutton-Alpine, Talkeetna, Tok, Tyonek, Valdez, Wasilla, Willow, Wrangell, and Yakutat. Additionally, eight quality assurance pods are collocated at DEC regulatory monitoring sites: Fairbanks NCore (3), Anchorage Garden (3), and Juneau Floyd Dryden (2). DEC has partnered with the Bureau of Land Management to deploy the Anchorage and Glennallen sensors, and the National Park Service to deploy the Denali National Park and Talkeetna sensors.

During the initial rollout, DEC identified that cellular network coverage in some Alaskan communities was incompatible with the communication systems of the primary sensor manufacturers. To address this, DEC purchased Wi-Fi-enabled QuantAQ MODULAIR^TM-PM pods to further expand the network into the Interior of Alaska where cellular service is limited or unavailable; community outreach and site selection is in progress.

APPENDIX A NAAQS SUMMARY TABLES

Table 15: PM_2.5 Design Values (µg/m³)

PM_2.5 Monitoring Sites	AQS ID	2025 98^th Percentile	2024 98^th Percentile	2023 98^th Percentile	2025 Weighted Annual Mean	2024 Weighted Annual Mean	2023 Weighted Annual Mean	2025 24-hour Design Value	2025Annual Design Value
Garden/ Anchorage	02-020-0018	23.8	16.8	14.2	5.1	5.0	4.2	18	4.8
Butte/ Matanuska-Susitna Valley	02-170-0008	n/a	n/a	17.5	n/a	n/a	4.1	n/a¹	n/a
Plant Materials Center/ Matanuska-Susitna Valley	02-170-0010	16.1	16.2	n/a	2.7	3.8	n/a	n/a²	n/a
NCore Site/ Fairbanks	02-090-0034	26.9 (36.6)	23.1 (35.8)	20.0 (30.7)	6.6 (8.5)	6.8 (8.5)	6.4 (8.4)	23.3 (34.4)	6.6 (8.5)
Hurst Road/ North Pole	02-090-0035	41.1 (56.6)	54.0 (57.3)	51.9 (62.5)	8.4 (10.2)	10.3 (12.5)	9.5 (11.7)	49.0 (59)	9.4 (11.5)
A Street/ Fairbanks	02-090-0040	22.8 (34.2)	25.0 (35.9)	27.8 (34.4)	6.6 (8.4)	7.0 (8.5)	7.0 (8.5)	25.2 (35)	6.9 (8.5)
Floyd Dryden/ Juneau	02-110-0004	24.9	16.9	15.9	5.2	4.5	4.7	19	4.8

Table 16: DV Ozone (O₃) (ppm)

Monitoring Sites	AQS ID	2025 Valid Days	2025 Percent Complete	2025 4^th Max	2024 Valid Days	2024 Percent Complete	2024 4^th Max	2023 Valid Days	2023 Percent Complete	2023 4^th Max	3-Year Percent Complete	3-Year Design Value
NCore/ Fairbanks	02-090-0034	302	83	0.051	361	99	0.052	350	96	0.050	93	0.051

Table 17: DV Sulfur Dioxide (SO₂) (ppb)

Monitoring Sites	AQS ID	2025 99^th Percentile	2025 Completed Quarters	2024 99^th Percentile	2024 Completed Quarters	2023 99^th Percentile	2023 Completed Quarters	3-Year Design Value
NCore/ Fairbanks	02-090-0034	13.8	4	11.1	4	14.7	4	13
Hurst Road/ Fairbanks	02-090-0035	5.6	4	4.9	4	5.6	4	5

Table 18: DV Carbon Monoxide (CO) (ppm)

Monitoring Sites	AQS ID	2025 Exceedances	2025 1^st Max 8-hour	2025 2^nd Max 8-hour	2024 Exceedances	2024 1^st Max 8-hour	2024 2^nd Max 8-hour	2023 Exceedances	2023 1^st Max 8-hour	2023 2^nd Max 8-hour
NCore/ Fairbanks	02-090-0034	0	1.8	1.8	0	3.2	2.1	0	2.3	1.9
Garden/ Anchorage	02-090-0018	0	2.8	2.6	0	3.1	2.7	0	2.6	2.4

Table 19: PM₁₀ Design Values (µg/m³)³

PM₁₀ Monitoring Sites	AQS ID	2025 Exceedances	2025 1^st Max 24-hr	2025 2^nd Max 24-hr	2024 Exceedances	2024 1^st Max 24-hr	2024 2^nd Max 24-hr	2023 Exceedances	2023 1^st Max 24-hr	2023 2^nd Max 24-hr
Garden/ Anchorage	02-020-0018	0	74	67	0	63	57	0	59	53
Laurel/ Anchorage	02-020-0045	1	173	141	0	134	106	0	95	88
Parkgate/ Anchorage	02-020-1004	0	102	87	0	54	52	0	59	59
NCore/ Fairbanks	02-090-0034	0	97	88	1	113	90	1	170	138
Butte/ Matanuska-Susitna Valley	02-170-0008	n/a	n/a	n/a	n/a	n/a	n/a	0	132	130
Plant Materials Center/ Matanuska-Susitna Valley	02-170-0010	0	235	64	0	118	78	n/a	n/a	n/a
Floyd Dryden/ Juneau	02-110-0004	0	49	36	0	32	29	0	44	36

APPENDIX B INSTRUMENT INVENTORY

Overview

This appendix provides a comprehensive inventory of regulatory air monitoring instruments operated by DEC for the 2025–2026 monitoring period. Information is organized by monitoring site and includes instrument make and model, applicable federal method designation, sampling frequency, and station classification.

Table 20: Instrument Inventory – Garden, Anchorage (AQS 02‑020‑0018)

Parameter	Instrument Model	Method	Frequency	Station Type	Notes
PM_2.5	Thermo Partisol 2000i	FRM	1‑in‑6	SLAMS	Secondary PM_2.5 sampler
PM₁₀	Thermo Partisol 2000i	FRM	1-in-6	SLAMS	-
PM_2.5	Met One BAM 1020	FEM	Continuous	SLAMS	Primary continuous PM_2.5 FEM
PM₁₀	Met One BAM 1020	FEM	Continuous	SLAMS	-
CO	Thermo 48i-TLE	FRM	Continuous	SLAMS	Scheduled for discontinuation pending SIP revision (Anchorage CO LMP)

Table 21: Instrument Inventory – Laurel, Anchorage (AQS 02-020-0045)

Parameter	Instrument Model	Method	Frequency	Station Type	Notes
PM₁₀	Met One BAM 1020	FEM	Continuous	SPM	SPM; supplemental, regulatory use

Table 22: Instrument Inventory – Parkgate, Eagle River (AQS 02-020-1004)

Parameter	Instrument Model	Method	Frequency	Station Type	Notes
PM₁₀	Met One BAM 1020	FEM	Continuous	SLAMS	Regulatory PM₁₀ FEM

Table 23: Instrument Inventory – Plant Materials Center (PMC), Palmer (AQS 02-170-0010)

Parameter	Instrument Model	Method	Frequency	Station Type	Notes
PM_2.5	Met One BAM 1020	FEM	Continuous	SLAMS	Successor to former Butte site
PM₁₀	Met One BAM 1020	FEM	Continuous	SLAMS	-
AmbT	Met One T‑200	-	Continuous	-	3 m & 10 m
RH	Met One 083E	-	Continuous	-	4 m
WS	RM Young 86004	-	Continuous	-	4 m & 10 m
WD	RM Young 86004	-	Continuous	-	4 m & 10 m

Table 24: Instrument Inventory – A Street, Fairbanks (AQS 02-090-0040)

Parameter	Instrument Model	Method	Frequency	Station Type	Notes
PM_2.5	Thermo Partisol 2025i	FRM	1-in-1	SLAMS	Primary FRM sampler
PM_2.5	Met One BAM 1020	FEM	Continuous	SLAMS	FEM designation effective 2024
AmbT	Met One T‑200	-	Continuous	-	4 m & 10 m
WS	RM Young 86004	-	Continuous	-	4 m & 10 m
WD	RM Young 86004	-	Continuous	-	4 m & 10 m

Table 25: Instrument Inventory – NCore Fairbanks: Particulate Matter (AQS 02-090-0034)

Parameter	Instrument Model	Method	Frequency	Station Type	Notes
PM_2.5	Thermo Partisol 2025i	FRM	1‑in‑1	NCore	Primary FRM sampler
PM_2.5	Met One BAM 1020	FEM	Continuous	NCore	Continuous FEM sampler
PM₁₀	Met One BAM 1020	FEM	Continuous	NCore	FRM PM₁₀ sampler
PM coarse	Derived	-	-	NCore	Calculated from PM₁₀ and PM_2.5

Table 26: Instrument Inventory – NCore Fairbanks: Gaseous Pollutants (AQS 02-090-0034)

Parameter	InstrumentModel	Method	Frequency	Station Type	Notes
CO	Teledyne T300U	FRM/FEM	Continuous	NCore	Trace level NCore requirement
SO₂	Thermo 43iQ TL	FEM	Continuous	NCore	Trace level NCore requirement
NO	Teledyne T200U	FEM	Continuous	NCore	Trace level NCore requirement
NO_y	Teledyne T200U	FEM	Continuous	NCore	Trace level NCore requirement
O₃	Thermo 49iQ	FEM	Continuous	NCore	Standard ozone analyzer

Table 27: Instrument Inventory – NCore Fairbanks: Speciation & Meteorology (AQS 02-090-0034)

Parameter	Instrument Model	Method	Frequency	Station Type	Notes
PM_2.5 Speciation	URG 3000N	CSN	1‑in‑3	NCore	Updated via ARP funding
PM_2.5 Speciation	Met One Super SASS	CSN	1-in-3	NCore	-
AmbT	Met One T‑200	-	Continuous	-	3 m & 10 m
RH	Met One 083E	-	Continuous	-	3 m
WS	RM Young 86004	-	Continuous	-	3 m & 10 m
WD	RM Young 86004	-	Continuous	-	3 m & 10 m

Table 28: Instrument Inventory – Hurst Road, North Pole (AQS 02-090-0035)

Parameter	Instrument Model	Method	Frequency	Station Type	Notes
PM_2.5	Thermo Partisol 2025i	FRM	1‑in‑3	SLAMS	Primary PM_2.5 analyzer
PM_2.5	Thermo Partisol 2025i	FRM	1‑in‑3	SLAMS	Secondary PM_2.5 analyzer
PM_2.5	Met One BAM 1020	FEM	Continuous	SLAMS	-
SO₂	Teledyne T100U	FEM	Continuous	SLAMS	Trace-level analyzer
PM_2.5 Speciation	URG 3000N	CSN	1‑in‑3	SLAMS	CSN site supporting PM_2.5 source apportionment
PM_2.5 Speciation	Met One Super SASS	CSN	1-in-3	SLAMS	CSN site supporting PM_2.5 source apportionment
VOCs (TO 15A)	ATEC 8001	TO-15A	1-in-6	NATTS	-
Carbonyls (TO 11A)	ARA Carbonyl Sampler	TO-11A	1-in-6	NATTS	-
Metals (PM₁₀, IO 3.5)	Thermo Partisol 2000i	IO-3.5	1-in-6	NATTS	-
PAHs (TO 13A / ASTM D6209)	Tisch TE 1000D BLX High Volume Sampler	TO-13A / ASTM D6209	1-in-6	NATTS	-
AmbT	Met One T‑200	-	Continuous	-	3 m & 10 m
RH	Met One 083E	-	Continuous	-	3 m
WS	RM Young 86004	-	Continuous	-	3 m & 10 m
WD	RM Young 86004	-	Continuous	-	3 m & 10 m

Table 29: Instrument Inventory – Floyd Dryden, Juneau (AQS 02-110-0004)

Parameter	Instrument Model	Method	Frequency	Station Type	Notes
PM_2.5	Thermo Partisol 2025i	FRM	1‑in‑3	SLAMS	Designated primary FRM sampler
PM_2.5	Teledyne T640X	SPM	Continuous	SLAMS	Used for AQI and public information
PM₁₀	Teledyne T640X	FEM	Continuous	SLAMS	Primary PM₁₀ FEM sampler
WS	RM Young 05305	-	Continuous	-	3 m
WD	RM Young 05305	-	Continuous	-	3 m

APPENDIX C AQS MONITOR METADATA

Overview

This appendix provides the complete set of AQS metadata required under 40 CFR 58.10(b) for all SLAMS, NCore, and SPM stations operated by DEC.

For each monitor and pollutant parameter, this appendix lists:

AQS parameter code
Unit code
Method code
Parameter Occurrence Code (POC)
Instrument type (cross referenced to Appendix B – Instrument Inventory)
Reporting designation (FRM, FEM, trace level, met, derived)

This appendix complements:

Current Monitoring Sites section (site level narrative)
Table 5 – Alaska DEC Regulatory Monitoring Sites
APPENDIX B INSTRUMENT INVENTORY
Siting Criteria section

Together, these provide complete documentation for EPA’s review under 40 CFR Part 58.

Table 30: Plant Materials Center (PMC) – Palmer (AQS 02-170-0010)

Parameter	Parameter Code	Unit Code	POC	Method Code	Type	Instrument
PM₁₀ Standard Conditions	81102	001	3	122	FEM	Met One BAM 1020
PM₁₀ Local Conditions	85101	105	3	122	FEM	Met One BAM 1020
PM_2.5 Local Conditions	88101	105	3	170	FEM	Met One BAM 1020
Ambient Temp 3 m	62101	017	2	040	Meteorology	Met One T‑200
Ambient Temp 10 m	62101	017	1	040	Meteorology	Met One T‑200
Relative Humidity 4 m	62201	019	1	061	Meteorology	Met One 083E
Wind Direction 4 m	61104	014	2	065	Meteorology	RMYoung Ultrasonic
Wind Direction 10 m	61104	014	1	065	Meteorology	RMYoung Ultrasonic
Wind Speed 4 m	61103	011	2	065	Meteorology	RMYoung Ultrasonic
Wind Speed 10 m	61103	011	1	065	Meteorology	RMYoung Ultrasonic

Table 31: Garden – Anchorage (AQS 02-020-0018)

Parameter	Param Code	Unit Code	POC	Method Code	Type	Instrument
Carbon Monoxide	42101	007	1	554	Trace level	Thermo 48i‑TLE
PM₁₀ Local Conditions (FEM)	85101	105	3	122	FEM	BAM 1020
PM₁₀ Standard Conditions (FEM)	81102	001	3	122	FEM	BAM 1020
PM_2.5 Local Conditions (FEM)	88101	105	3	170	FEM	BAM 1020
PM_2.5 Local Conditions (FRM)	88101	105	2	143	FRM	Thermo Partisol 2000i
PM₁₀ Local Conditions (FRM)	85101	105	2	126	FRM	Thermo Partisol 2000i
PM₁₀ Standard Conditions (FRM)	81102	001	2	126	FRM	Thermo Partisol 2000i

Table 32: Laurel – Anchorage (AQS 02-020-0045)

Parameter	Param Code	Unit Code	POC	Method Code	Type	Instrument
PM₁₀ Standard Conditions	81102	001	3	122	FEM	Met One BAM 1020
PM₁₀ Local Conditions	85101	105	3	122	FEM	Met One BAM 1020

Table 33: Parkgate – Eagle River (AQS 02-020-1004)

Parameter	Param Code	Unit Code	POC	Method Code	Type	Instrument
PM₁₀ Local Conditions	85101	105	3	122	FEM	Met One BAM 1020
PM₁₀ Standard Conditions	81102	001	3	122	FEM	Met One BAM 1020

Table 34: A Street – Fairbanks (AQS 02-090-0040)

Parameter	Param Code	Unit Code	POC	Method Code	Type	Instrument
PM_2.5 Local Conditions (FEM)	88101	105	3	170	FEM	Met One BAM 1020
PM_2.5 Local Conditions (FRM)	88101	105	1	145	FRM	Thermo Partisol 2025i
Temperature (3–4 m)	62101	017	2	040	Met	Met One T‑200
Temperature (10 m)	62101	017	1	040	Met	Met One T‑200
Wind Speed (3–10 m)	61103	011	1–2	068	Met	RMYoung 86004
Wind Direction (3–10 m)	61104	014	1–2	068	Met	RMYoung 86004

Table 35: Hurst Road – North Pole (AQS 02-090-0035)

Parameter	Param Code	Unit Code	POC	Method Code	Type	Instrument
PM_2.5 Local Conditions (FEM)	88501	105	3	731	FEM	Met One BAM 1020
PM_2.5 Local Conditions (FRM primary)	88101	105	1	145	FRM	Thermo Partisol 2025i
PM_2.5 Local Conditions (FRM collocated)	88101	105	2	145	FRM	Thermo Partisol 2025i
SO₂ (1‑min)	42401	008	1	560	Trace level FEM	Thermo 43iQ TL
SO₂ (5‑min)	42401	008	2	560	Trace level FEM	Thermo 43iQ TL
Temperature (3–23 m)	62101	017	1–3	040	Met	Met One T‑200
Relative Humidity	62201	019	1	061	Met	Met One 083E
Wind Speed (3–23 m)	61103	011	1–3	068	Met	RMYoung 86004
Wind Direction (3–23 m)	61104	014	1–3	068	Met	RMYoung 86004

Table 36: NCore – Fairbanks (AQS 02-090-0034)

Parameter	Param Code	Unit Code	POC	Method Code	Type	Instrument
PM₁₀ Local Conditions	85101	105	3	122	FEM	Met One BAM 1020
PM₁₀ Standard Conditions	81102	001	3	122	FEM	Met One BAM 1020
PM_2.5 Local Conditions	88101	105	3	170	FEM	Met One BAM 1020
PM_10-2.5 (coarse)	86101	105	1	185	FEM (calculated)	Met One BAM 1020
CO	42101	007	1	593	Trace level	Teledyne T300U
NO	42601	008	2	699	Trace level	Teledyne T200U
NO_y	42600	008	1	699	Trace level	Teledyne T200U
NO_y ‑NO	42612	008	1	699	Trace level	Teledyne T200U
SO₂	42401	008	1	560	Trace level	Thermo 43iQ TL
O₃	44201	008	1	047	FEM	Thermo 49iQ
Temperature (3 m)	62101	017	2	040	Met	Met One T‑200
Temperature (10 m)	62101	017	1	040	Met	Met One T‑200
Relative Humidity	62201	019	1	061	Met	Met One 083E
Wind Speed (3 & 10 m)	61103	011	1–2	068	Met	RMYoung
Wind Direction (3 & 10 m)	61104	014	1–2	068	Met	RMYoung
PM_2.5 Local Conditions (FRM)	88101	105	1	145	FRM	Thermo Partisol 2025i

Table 37: Floyd Dryden – Juneau (AQS 02-110-0004)

Parameter	Param Code	Unit Code	POC	Method Code	Type	Instrument
PM₁₀ Local Conditions	85101	105	3	239	FEM	Teledyne T640x
PM₁₀ Standard Conditions	81102	001	3	239	FEM	Teledyne T640x
PM_2.5 Local Conditions (secondary)	88502	105	3	238	FEM	Teledyne T640x
PM_2.5 Local Conditions (FRM)	88101	105	1	145	FRM	Thermo Partisol 2025i
Temperature	62101	017	3	040	Met	Teledyne T640x
Wind Speed	61103	011	1	065	Met	RMYoung 05305
Wind Direction	61104	014	1	065	Met	RMYoung 05305

Table 38: Monitor Start Dates and Method Start Dates (2026)

Site	Parameter	POC	Monitor Start Date⁴	Method Start Date	Notes
Plant Materials Center	PM₁₀, PM_2.5	3	10/26/2023	01/01/2024	Butte → PMC relocation approved by EPA
Garden	PM_2.5 FRM	2	Existing	01/01/2023	Partisol FRM established prior to 2025
Garden	PM_2.5 FEM	3	Existing	01/01/2024	FEM BAM PM_2.5 operational in 2024
Laurel	PM₁₀	3	Existing	Existing	SPM supporting completeness
Parkgate	PM₁₀	3	Existing	Existing	Required PM₁₀ SLAMS site
A Street	PM_2.5 FEM	3	Existing	01/01/2024	FEM status established 2024
A Street	PM_2.5 FRM	1	Existing	Existing	FRM Partisol pre‑dating FEM
Hurst Road	PM_2.5 FRM (primary)	1	Existing	Existing	Primary Serious NAA FRM
Hurst Road	PM_2.5 FEM	3	Existing	01/01/2023	BAM operational prior to 2025
Hurst Road	SO₂	1	Existing	Mid-2024	T100U upgrade
NCore	Multi‑pollutant	1–3	Existing	Varies by pollutant	NCore site operational for many years
Floyd Dryden	PM_2.5 FRM	1	02/18/2024	02/18/2024	2025i FRM installation date
Floyd Dryden	PM_2.5 FEM (T640x)	3	Existing	01/01/2024	Switched from primary to secondary
Floyd Dryden	PM₁₀ (T640x)	3	Existing	Existing	Continues as primary PM₁₀ FEM

APPENDIX D NETWORK EVALUATION FORMS

Table 39: PM_2.5 Network Evaluation Form

Applicable Section	Requirement	Criteria Met?	Comments / Supporting Notes
4.7.1(a)	States, and where applicable local agencies must operate the minimum number of required PM_2.5 SLAMS sites listed in Table D‑5 of this appendix. Use the form below and Table D‑5 to verify if each of your MSAs have the appropriate number of SLAMS FRM/FEM/ARM samplers.	Yes	Anchorage: 2; Fairbanks: 3; Juneau: 1. All meet or exceed requirements.
4.7.1(b)	Each required SLAMS FRM/FEM/ARM monitoring station or site must be sited to represent area‑wide air quality in the given MSA (typically neighborhood or urban spatial scale, though micro‑ or middle‑scale okay if it represents many such locations throughout the MSA).	Yes	All PM_2.5 SLAMS/NCore sites are neighborhood‑scale.
4.7.1(b)(1)	At least one SLAMS FRM/FEM/ARM monitoring station is to be sited at neighborhood or larger scale in an area of expected maximum concentration for each MSA where monitoring is required by 4.7.1(a).	Yes	A Street is the current max‑impact site. Hurst Road becomes max‑impact upon SIP approval of the Fairbanks/North Pole split.
4.7.1(b)(2)	For CBSAs with a population of 1,000,000 or more persons, at least one FRM/FEM/ARM PM_2.5 monitor is to be collocated at a near‑road NO₂ station.	N/A	No CBSA in Alaska meets this threshold.
4.7.1(b)(3)	For MSAs with additional required SLAMS sites, a FRM/FEM/ARM monitoring station is to be sited in an area of poor air quality.	Yes	Fairbanks PM_2.5 SLAMS sites (A Street, Hurst Road) represent highest‑impact areas.
4.7.2	Each State must operate continuous PM_2.5 analyzers equal to at least one‑half (round up) the minimum required sites listed in Table D‑5 of this appendix. At least one required continuous analyzer in each MSA must be collocated with one of the required FRM/FEM/ARM monitors, unless at least one of the required FRM/FEM/ARM monitors is itself a continuous FEM or ARM monitor, in which case no collocation requirement applies.	Yes	Continuous FEM analyzers at Garden, PMC, A Street, Hurst Road, and NCore. Requirement exceeded.
4.7.3	Each State shall install and operate at least one PM_2.5 site to monitor for regional background and at least one PM_2.5 site to monitor regional transport (note locations in comment field). Non‑reference PM_2.5 monitors such as IMPROVE can be used to meet this requirement.	Yes	PMC serves background/transport role; IMPROVE supports transport.
4.7.4	Each State shall continue to conduct chemical speciation monitoring and analyses at sites designated to be part of the PM_2.5 Speciation Trends Network (STN).	Yes	Required STN speciation at Fairbanks NCore; supplemental speciation at Hurst Road.

Table 40: PM_2.5 Network Evaluation Form

MSA Population⁵^,⁶	Most recent 3-year design value ≥ 85% of any PM_2.5 NAAQS⁷	Most recent 3-year design value < 85% of any PM_2.5 NAAQS⁸^,⁹
>1 million	3	2
500K to 1 million	2	1
50K to <500K	1	0

Table 41: PM_2.5 Minimum Monitoring Requirements

MSA Description¹⁰	MSA population¹¹^,¹²	Design Value for years 2021-2023 24-hr/Annual Avg. µg/m³	Minimum required number of PM_2.5 SLAMS FRM/FEM/ARM sites (from Table D-5)	Present number of PM_2.5 SLAMS FRM/FEM/ARM sites in MSA	Present number of continuous PM_2.5 FEM/ARM analyzers in MSA	Present number of continuous PM_2.5 STN analyzers in MSA
Anchorage MSA	405,821	-	-	-	-	-
Municipality of Anchorage	287,155	0	1	1	0	-
Garden	-	18 / 4.8	SLAMS (FRM + FEM)	1	1	0
Matanuska-Susitna Valley Borough	118,666	-	1	0	1	0
PMC (Palmer)	-	n/a	SLAMS (FEM)	0	1	0
Fairbanks North Star Borough MSA	93,972	-	1	5	3	2 speciation
A Street	-	25.2 / 6.9	SLAMS (FRM/FEM)	1	1	0
NCore	-	23.3 / 6.6	NCore (FRM/FEM)	1	1¹³	1 speciation
Hurst Road	-	49.0 / 9.4	SLAMS	2	1¹⁴	1 speciation
City and Borough of Juneau µSA	31,609	-	0	1	1	0
Floyd Dryden	-	19 / 4.8	SLAMS	1	1	0

Table 42: PM₁₀ Network Evaluation Form

Applicable Section	Requirement	Criteria Met?	Comments
4.6(a)	Table D‑4 indicates the approximate number of permanent stations required in MSAs to characterize national and regional PM₁₀ air quality trends and geographical patterns. Use the form below and Table D‑4 to verify if your PM₁₀ network has the appropriate number of samplers.	Yes	Anchorage MSA operates 3 PM₁₀ sites (Garden, Laurel/Parkgate, PMC. Fairbanks MSA operates 1 PM₁₀ site (NCore), and Juneau µSA operates 1 PM₁₀ site (Floyd Dryden)

Comments:

All site locations are based on historical agreements among the EPA, DEC and (where applicable) local agencies.
One exceedance on May 7, 2019, at the Butte site caused the entire Anchorage MSA to be categorized as high concentration. DEC qualified the exceedance day data as RJ (high winds). This one day could be the basis for a 2019 EEWR should EPA request DEC or EPA start another PM₁₀ designation process. Thus, DEC assumes that medium concentration is applicable when these exceptional events are excluded from the compliance calculations (Section 6, Table A-5 with assumed EEWRs).

Table 43: Number of PM₁₀ Stations within AMQA Regulatory Network

MSA Description¹⁵	MSA population¹⁶^,¹⁷	Minimum required number of PM₁₀ stations (from Table D-4)	Present number of PM₁₀ stations in MSA
Anchorage MSA (Municipality of Anchorage + Matanuska-Susitna Valley Borough)	405,821	3-4 (high conc) / 1-2 (med conc; high winds EE exceedances removed)	3 SLAMS (1 Collocate)
Fairbanks North Star Borough MSA	93,972	0 (low conc)	1 (NCore, collocated)
City and Borough of Juneau µSA	31,609	0 (low conc)	1 (SLAMS)

Table 44: PM₁₀ Minimum Monitoring Requirements

MSA Population¹⁸^,¹⁹	High Concentration²⁰	Medium Concentration²¹	Low Concentration²²^,²³
>1 million	6-10	4-8	2-4
500K to 1 million	4-8	2-4	1-2
250K to 500K	3-4	1-2	0-1
100K to 250K	1-2	0-1	0

Table 45: CO Site Evaluation Form

Applicable Section	Requirement	Criteria Met?	Comments
4.2.1(a)	One CO monitor is required to operate collocated with one required near-road NO₂ monitor in CBSAs having a population of 1,000,000 or more persons. If a CBSA has more than one required near-road NO₂ monitor, only one CO monitor is required to be collocated with a near-road NO₂ monitor within that CBSA.	N/A	No Alaska CBSA meets the 1,000,000‑population threshold.
4.2.2(a)	Has the EPA Regional Administrator required additional CO monitoring stations above the minimum number of monitors required in 4.2.1? If so, note location in comment field	Yes	Anchorage Garden CO monitor remains required under the CO LMP until SIP modification is finalized; Fairbanks NCore also operates CO as part of NCore requirements.

Table 46: CO SLAMS Sites Required per Population

MSA population²⁴^,²⁵	CBSA Population²⁶^,²⁷	Minimum Required # of SLAMS CO Sites	Present # of SLAMS CO Sites in MSA
Municipality of Anchorage & Matanuska-Susitna Valley Borough (MSA) (combined)	405,821	0	1²⁸
Fairbanks North Star Borough	93,972	0	1²⁹

Table 47: O₃ Network Evaluation Form

Applicable Section	Requirement	Criteria Met?	Comments
4.1(b)	At least one O₃ site for each MSA, or CSA if multiple MSAs are involved, must be designed to record the maximum concentration (note location in comment field).	Yes	Fairbanks NCore site (AQS 02‑090‑0034) was established in August 2011. It serves as the maximum‑concentration O₃ monitor and operates year‑round.
4.1(c)	The appropriate spatial scales for O₃ sites are neighborhood, urban, and regional (note deviations in comment field).	Yes	Fairbanks NCore O₃ site meets neighborhood/urban scale criteria; no deviations.
4.1(f)	Confirm that the monitoring agency consulted with EPA R10 when siting the maximum O₃ concentration site.	Yes	NCore site siting was coordinated with EPA Region 10 as part of NCore network approval.
4.1(i)	O₃ is being monitored at SLAMS monitoring sites during the “ozone season” as specified in Table D-3 of Appendix D to Part 58.	Yes	Fairbanks NCore monitors O₃ year‑round; Anchorage MSA is covered under an EPA O₃ monitoring waiver extended to 2028. Palmer O₃ was discontinued at the end of ozone season 2018.

Table 48: O₃ SLAMS Sites Required per Population

MSA Description³⁰^,³¹	MSA Population³²^,³³	Minimum required number of SLAMS O₃ sites (from Table D-2)	Present number of SLAMS O₃ sites in CBSA	Comments
Municipality of Anchorage & Matanuska-Susitna Valley Borough (MSA) (combined)	405,821	1	0	See EPA ozone waiver link³⁴
Fairbanks North Star Borough	93,972	0	1³⁵	NCore site

Table 49: SLAMS O₃ Monitoring Minimum Requirements

MSA population³⁶^,³⁷	Most recent 3-year design value concentrations ≥85% of any O₃ NAAQS³⁸	Most recent 3-year design value concentrations <85% of any O₃ NAAQS³⁹^,⁴⁰
> 10 million	4	2
4-10 million	3	1
350,000 - < 4 million	2	1
50,000 - < 350,000⁴¹	1	0

Table 50: Ozone Monitoring Season by State

State	Start Month	End Month
Alaska	April	October
Idaho	May	September
Oregon	May	September
Washington	May	September

Table 51: SO₂ Network Evaluation Form

Applicable Section	Requirement	Criteria Met?	Comment
4.4.1	State and, where appropriate, local agencies must operate a minimum number of required SO₂ monitoring sites (based on PWEI calculation specified in 4.4.2 – use Table 1 and 2 below to determine minimum requirement for each CBSA).	Yes	PWEI values for all Alaska CBSAs fall below monitoring thresholds; no SO₂ monitors are required.
4.4.2(a)(1)	Is the monitor sited within the boundaries of the parent CBSA and is it one of the following site types: population exposure, highest concentration, source impacts, general background, or regional transport?	N/A	No CBSA has a minimum SO₂ monitoring requirement.
4.4.3(a)	Has the EPA Regional Administrator required additional SO₂ monitoring stations above the minimum number of monitors required in 4.4.2? If so, note location in comment field.	No	-
4.4.5(a)	Is your agency counting an existing SO₂ monitor at an NCore site in a CBSA with a minimum monitoring requirement?	N/A	-

Notes:

The State of Alaska has no CBSAs which require SO₂ monitoring. One of the operating SO₂ monitors is located at the multi-pollutant NCore site in the Fairbanks North Star Borough operated for compliance with NCore site requirements. The other SO₂ analyzer was added to the Hurst Road site in 2021. This data will be helpful for interpreting the sulfate information gained from the speciation monitor at this site.

Table 52: SO₂ SLAMS Sites Required per Population

CBSA Description⁴²	CBSA population⁴³^,⁴⁴	Total amount of SO₂ in tons per year emitted within the CBSA (from 2017 NEI⁴⁵	PWEI (population x total emissions ÷ 1,000,000)	Present number of SO₂ monitors in CBSA
Anchorage Municipality	287,155	262.0	74.9	0
Matanuska-Susitna Borough	118,666	326.4	37.6	0
Fairbanks North Star Borough	93,972	6,904.6	654.8	2⁴⁶
Juneau City and Borough	31,609	71.7	2.3	0
Ketchikan Gateway Borough	13,549	37.5	0.5	0

Table 53: Minimum SO₂ Monitoring Requirements

PWEI (Population weighted Emission Index) Value	Required number of SO₂ monitors
>= 1,000,000	3
>= 100,000 but < 1,000,000	2
>= 5,000 but < 100,000	1

Table 54: NO₂ Network Evaluation Form

Applicable Section	Requirement	Criteria Met?	Comment
4.3.2(a)	Near-road NO₂ Monitors: One microscale near-road NO₂ monitoring station in each CBSA with a population of 1,000,000 or more persons.	N/A	No Alaska CBSA exceeds 1,000,000 population.
4.3.2(a)	Near-road NO₂ Monitors: An additional near-road NO₂ monitoring station is required for any CBSA with a population of 2,500,000 persons, or in any CBSA with a population of 500,000 or more persons that has one or more roadway segments with 250,000 or greater annual ADT count.	N/A	No Alaska CBSA meets population or ADT thresholds.
4.3.2(b)	Near-road NO₂ Monitors: Measurements at required near-road NO₂ monitor sites utilizing chemiluminescence FRMs must include at a minimum: NO , NO₂, and NO_x.	N/A	-
4.3.3(a)	Area-wide NO₂ Monitoring: One monitoring station in each CBSA with a population of 1,000,000 or more persons to monitor a location of expected highest NO₂ concentrations representing the neighborhood or larger spatial scales.	N/A	Alaska has no CBSA ≥ 1,000,000 population.

Notes:

The State of Alaska has no CBSA with a population of 1,000,000. Within the Fairbanks North Star Borough, NO , NOy, and Difference is currently being analyzed, which satisfies the NCore requirement for NO₂.

Table 55: NO₂ SLAMS Sites Required per Population

CBSA Description⁴⁷	CBSA population⁴⁸^,⁴⁹	Present number of Area-wide NO₂ sites
Municipality of Anchorage & Matanuska-Susitna Valley Borough (MSA) (combined)	405,821	0
Fairbanks North Star Borough (MSA)	93,972	0⁵⁰
City and Borough of Juneau (µSA)	31,609	0

APPENDIX E SUMMARY OF MONITORING PATH & SITING CRITERIA EVALUATION FORM

Table 56: Summary of Appendix E Forms: PM

Site Information	Garden	Laurel	Parkgate	Plant Material Center	A Street	Hurst Road	NCore	Floyd Dryden
Parameter(s)	PM_2.5, PM₁₀, PM_10-2.5	PM_2.5, PM₁₀, PM_10-2.5	PM_2.5, PM₁₀, PM_10-2.5	PM_2.5, PM₁₀, PM_10-2.5	PM_2.5, PM₁₀, PM_10-2.5	PM_2.5, PM₁₀, PM_10-2.5	PM_2.5, PM₁₀, PM_10-2.5	PM_2.5, PM₁₀, PM_10-2.5
Address	3000 E 16^th Ave, Anchorage, AK 99508	4335 Laurel St, Anchorage, AK 99508	11723 Old Glenn Hwy, Eagle River, AK 99577	5310 Bodenburg Spur Rd, Palmer, AK, 99645	397 Hamilton Ave, Fairbanks, AK 99701	3288 Hurst Rd, North Pole, AK 99705	809 Pioneer Rd/907 Terminal St Fairbanks, AK 99701	3800 Mendenhall Loop Rd, Juneau, AK 99801
AQS ID	02-020-0018	02-020-0045	02-020-1004	02-170-0010	02-090-0040	02-090-0035	02-090-0034	02-110-0004
2. HORIZONTAL AND VERTICAL PLACEMENT	11.2 meters. Meets criteria.	6.4 meters. Meets criteria.	10.4 meters. Meets criteria.	4.4 meters. Meets criteria.	4.3m above the ground. Meets criteria.	Approximately 4.7 meters for FRM’s. Approximately 4 meters for BAM. Meets criteria.	Approximately 4.5m above ground surface and 1m spacing for FRM & FEMs. No building obstructions. Meets criteria.	Site ~ 10m from ground level. Nearest penthouse wall >15m. Meets criteria.
3. SPACING FROM MINOR SOURCES (a)	Chimney 3.8 meters away. Meets criteria. Monitors are on a wooden platform atop a black tar roof, surrounded by paved a paved parking lot.	Maximum impact site, winter graveled streets. Meets criteria. Monitor is on a wooden platform atop a black tar roof, surrounded by paved parking lots and roads.	Paved parking lot >10 meter Paved road >25 meter. Meets criteria. Monitor is on a wooden platform atop a silicone roof and surrounded by paved parking lots and roads	17 meters from gravel access road only used by PMC employees. Meets criteria. Site is surrounded by vegetative ground cover during summer, and snow in the winter.	Near a school and a neighborhood. Meets criteria. Site is surrounded by grass on three sides and a paved roadway on the remaining side	Adjacent gravel parking lot with relatively low traffic load. Meets criteria. Ground cover is grass on three sides of the site. A gravel parking lot is on the south side. There is a motorized paved path to the south. Snow covers the ground the majority of the year.	Approximately 260m to Aurora Wood Processing. Approximately 400m to coal power plant. Meets criteria. Site is built on a washed gravel pad and surrounded by grass during the summer and snow during the winter.	On roof of building there is a kitchen vent ~ 15m from site and furnace flue ~ 20m away. Meets criteria. Monitors on wooden platform on a roof, surrounded by paved parking lot.
4. SPACING FROM OBSTRUCTIONS (a)	Inlet observed to have unrestricted flow and located away from obstacles. Meets criteria.	The inlet has unrestricted airflow and is located away from obstacles. Meets criteria.	The inlet is observed to have unrestricted airflow and is located away from obstacles. Meets criteria.	The inlet has unrestricted airflow and is located away from obstacles. Meets criteria.	Currently two inlets. Meets criteria.	No obstacles. Meets criteria.	Airflow is unrestricted and no obstacles present. Meets criteria.	No obstacles. Meets criteria.
4. SPACING FROM OBSTRUCTIONS (b)	The inlet observed to have unrestricted airflow within specified arc. Meets criteria.	Inlet has unrestricted airflow in specified arc. Monitor has rooftop placement and does not have walls, parapets, or structures within 2 meters. Meets criteria.	>7.8 meters away from side of the building. Meets criteria.	>20 meters away from nearest building. Meets criteria.	360 degrees of unrestricted airflow. Meets criteria.	Unrestricted. Meets criteria.	Inlets have 360-degree airflow availability. Meets criteria.	High-volume RadNet monitor located ~ 8m from site. Meets criteria.
5. SPACING FROM TREES (a)	>10 meters. Meets criteria.	>27 meters. Meets criteria.	Nearest tree >45 meters away. Meets criteria.	Nearest tree >40 meters away. Meets criteria.	>10m away from trees. Meets criteria.	Distance is 10 meters. Meets criteria.	Woody vegetation does not exceed height of sample inlets and nearest dripline is approximately 10m from site shelter. Meets criteria.	>20m to drip line. Meets criteria.
5. SPACING FROM TREES (c)*	Site is not a microscale site, so not applicable. Meets criteria.	No trees between source and probe inlet. Meets criteria.	Not a microscale sites. Meets criteria.	Not a microscale site. Meets criteria.	Meets criteria.	None. Meets criteria.	N/A, not a micro-scale site. Meets criteria.	NA
6. SPACING FROM ROADWAYS	Spacing from roadways is within requirements. Meets criteria.	11 meters to Tudor Rd. Meets criteria.	>25 meters. Meets criteria.	>10 meters.	<1000 ADT, and about 5.8 meters from road (10m is requested). Meets criteria.	Approximately 21 meters. AADT 3110 vehicle count (latest 2024).Meets criteria.	Approximately 85m to approximately 4,000 ADT roadway, approximately 240m to approximately 10,000 ADT roadway, latest data available from 2024. Minimum distance met, 10m Meets criteria.	Site located on roof of building on the opposite side of parking lot. Nearest small residential road ~ 100m (paved) and ~ 300m from larger commuter road (paved). Meets criteria.
Changes that might compromise siting?⁵¹	No	No	No	No	No	No	No	No

Table 57: Summary of Appendix E Forms: CO

Site Information	Garden	NCore
Parameter(s)	CO	CO
Address	3000 E 16^th Ave Anchorage, AK 99508	809 Pioneer Rd/907 Terminal St Fairbanks, Alaska
AQS ID	02-020-0018	02-090-0034
2. HORIZONTAL AND VERTICAL PLACEMENT	2.8 meters above ground 1.1 meters from wall	Approximately 3m above ground surface and 1m spacing for FRMs. No building obstructions.
3. SPACING FROM MINOR SOURCES	The monitor probe is not near local, minor sources.	Approximately 260m to Aurora Wood Processing. Approximately 400m to coal power plant.
4. SPACING FROM OBSTRUCTIONS (a)	The probe inlet observed to have unrestricted airflow and located away from obstacles.	Airflow is unrestricted and no obstacles present.
4. SPACING FROM OBSTRUCTIONS (b)	The probe inlet observed to have unrestricted airflow within specified arc.	Inlets have 360-degree airflow availability.
5. SPACING FROM TREES (a)	1 spruce tree 2.3 m from probe inlet	Woody vegetation does not exceed height of sample inlets and nearest dripline is approximately 10m from site shelter.
5. SPACING FROM TREES (c)	N/A, not a micro-scale site.	N/A, not a micro-scale site.
6. SPACING FROM ROADWAYS	N/A, not a micro-scale site.	N/A, not a micro-scale site.
9. PROBE MATERIAL & RESIDENCE TIME (a)	CO: 24 sec	Observed response in approximately 8.5 seconds on 4/16/26.
9. PROBE MATERIAL & RESIDENCE TIME (c)	FEP Teflon	Yes, meets criteria; glass and FEP used.
Changes that might compromise siting?⁵²	No	No

Table 58: Summary of Appendix E Forms: O₃, SO₂, NO , Diff, and NO_y

Site Information	NCore	NCore	NCore	Hurst Road
Parameters	O₃	SO₂	NO , Diff, &NO_y	SO₂
2. HORIZONTAL AND VERTICAL PLACEMENT	Approximately 3m above ground surface and 1m spacing for FRMs. No building obstructions.	Approximately 3m above ground surface and 1m spacing for FRMs. No building obstructions.	Approximately 3m above ground surface and 1m spacing for FRMs. Not a micro-scale site. No building obstructions.	Approximately 3 meters above ground level on windward side.
3. SPACING FROM MINOR SOURCES	Approximately 260m to Aurora Wood Processing. Approximately 400m to coal power plant.	Approximately 260m to Aurora Wood Processing. Approximately 400m to coal power plant.	Approximately 260m to Aurora Wood Processing. Approximately 400m to coal power plant.	No nearby minor sources
3. SPACING FROM MINOR SOURCES (b)	No combustion furnace/flues located within 50m of Site.	N/A	N/A	N/A
4. SPACING FROM OBSTRUCTIONS (a)	Airflow is unrestricted and no obstacles present.	Airflow is unrestricted and no obstacles present.	Airflow is unrestricted and no obstacles present.	Airflow is unrestricted and no obstacles present.
4. SPACING FROM OBSTRUCTIONS (b)	Inlets have 360-degree airflow availability.	Inlets have 360-degree airflow availability.	Inlets have 360-degree airflow availability.	Airflow unrestricted facing predominant wind direction.
4. SPACING FROM OBSTRUCTIONS (d)	N/A	N/A	Approximately 85m to approximately 4,000 ADT roadway, approximately 240m to approximately 10,000 ADT roadway	N/A
5. SPACING FROM TREES (a)	Woody vegetation does not exceed height of sample inlets and nearest dripline is approximately 10m from site shelter.	Woody vegetation does not exceed height of sample inlets and nearest dripline is approximately 10m from site shelter.	Woody vegetation does not exceed height of sample inlets and nearest dripline is approximately 10m from site shelter.	Tree dripline is greater than 10m away
5. SPACING FROM TREES (c)	N/A, not a micro-scale site.	N/A, not a micro-scale site.	N/A, not a micro-scale site.	N/A, not a micro-scale site.
6. SPACING FROM ROADWAYS	Minimum distance met, 10m	N/A	Minimum distance met, 10m	N/A
9. PROBE MATERIAL & RESIDENCE TIME (a)	Yes, meets criteria; glass and FEP used.	Yes, meets criteria; glass and FEP used.	Yes, meets criteria; FEP used.	Meets criteria; FEP used.
9. PROBE MATERIAL & RESIDENCE TIME (c)	Observed response in approximately 8.7 seconds on 4/16/26.	Observed response in approximately 7.2 seconds on 4/16/26.	Observed response in approximately 22.4 seconds on 4/16/26.	Not an NCore site; Sample Residence time is less than 20 seconds
Changes that might compromise siting?⁵³	No	No	No	No

Table 59: Blank Part 58 Appendix E Form for PM

Applicable Section	Requirement	Observed	Criteria Met? (yes, no, N/A)
2. HORIZONTAL AND VERTICAL PLACEMENT	2-15 meters above ground level for neighborhood or larger spatial scale, 2-7 meters for microscale spatial scale sites and middle spatial scale PM_10-2.5 sites. 1 meter vertically or horizontally away from any supporting structure, walls, etc., and away from dusty or dirty areas. If located near the side of a building or wall, then locate on the windward side relative to the prevailing wind direction during the season of highest concentration potential.	-	-
3. SPACING FROM MINOR SOURCES	(a) For neighborhood or larger spatial scales avoid placing the monitor near local, minor sources. The source plume should not be allowed to inappropriately impact the air quality data collected at a site. Particulate matter sites should not be located in an unpaved area unless there is vegetative ground cover year round.	-	-
4. SPACING FROM OBSTRUCTIONS	(a) To avoid scavenging, the inlet must have unrestricted airflow and be located away from obstacles. The separation distance must be at least twice the height that the obstacle protrudes above the probe inlet.	-	-
4. SPACING FROM OBSTRUCTIONS	(b) The inlet must have unrestricted airflow in an arc of at least 180 degrees. This arc must include the predominant wind direction for the season of greatest pollutant concentration potential. For particle sampling, a minimum of 2 meters of separation from walls, parapets, and structures is required for rooftop site placement.	-	-
5. SPACING FROM TREES	(a) To reduce possible interference the inlet must be at least 10 meters or further from the drip line of trees.	-	-
5. SPACING FROM TREES	(c) No trees should be between source and probe inlet for microscale sites.	-	-
6. SPACING FROM ROADWAYS	Spacing from roadways is dependent on the spatial scale and ADT count. See section 6.3(b) and Figure E-1 for specific requirements.	-	-

Table 60: Blank Part 58 Appendix E Form for CO

Applicable Section	Requirement	Observed	Criteria Met? (yes, no, N/A)
2. HORIZONTAL AND VERTICAL PLACEMENT	For neighborhood or larger spatial scale sites the probe must be located 2-15 meters above ground level and must be at least 1 meter vertically or horizontally away from any supporting structure, walls, etc., and away from dusty or dirty areas. If located near the side of a building or wall, then locate on the windward side relative to the prevailing wind direction during the season of highest concentration potential.	-	-
3. SPACING FROM MINOR SOURCES	(a) For neighborhood scale avoid placing the monitor probe inlet near local, minor sources. The source plume should not be allowed to inappropriately impact the air quality data collected at a site.	-	-
4b. SPACING FROM OBSTRUCTIONS	(a) To avoid scavenging, the probe inlet must have unrestricted airflow and be located away from obstacles. The separation distance must be at least twice the height that the obstacle protrudes above the probe inlet (exception is street canyon or source-oriented sites where buildings and other structures are unavoidable).	-	-
4b. SPACING FROM OBSTRUCTIONS	(b) The probe inlet must have unrestricted airflow in an arc of at least 180 degrees. This arc must include the predominant wind direction for the season of greatest pollutant concentration potential.	-	-
5. SPACING FROM TREES	(a) To reduce possible interference the probe inlet must be at least 10 meters or further from the drip line of trees.	-	-
(c) No trees should be between source and probe inlet for microscale sites.	-	-	-
6. SPACING FROM ROADWAYS	(b) Microscale CO monitor probes in downtown areas or urban street canyon locations shall be located a minimum distance of 2 meters and a maximum distance of 10 meters from the edge of the nearest traffic lane.	-	-
6. SPACING FROM ROADWAYS	(c) Microscale CO monitor inlet probes in downtown areas or urban street canyon locations shall be located at least 10 meters from an intersection and preferably at a midblock location.	-	-
9. PROBE MATERIAL & RESIDENCE TIME	(a) Sampling train material must be FEP Teflon or borosilicate glass (e.g., Pyrex) for reactive gases.	-	-
9. PROBE MATERIAL & RESIDENCE TIME	(c) Sampling probes for reactive gas monitors at site must have a sample residence time less than 20 seconds.	-	-

Table 61: Blank Part 58 Appendix E Form for O₃

Applicable Section	Requirement	Observed	Criteria Met? (yes, no, N/A)
2. HORIZONTAL AND VERTICAL PLACEMENT	2-15 meters above ground level. 1 meter vertically or horizontally away from any supporting structure, walls, etc., and away from dusty or dirty areas. If located near the side of a building or wall, then locate on the windward side relative to the prevailing wind direction during the season of highest concentration potential.	-	-
3. SPACING FROM MINOR SOURCES	(a) For neighborhood scale avoid placing the monitor probe inlet near local, minor sources. The source plume should not be allowed to inappropriately impact the air quality data collected at a site.	-	-
3. SPACING FROM MINOR SOURCES	(b) To minimize scavenging effects, the probe inlet must be away from furnace or incineration flues or other minor sources of SO₂ or NO .	-	-
4. SPACING FROM OBSTRUCTIONS	(a) To avoid scavenging, the probe inlet must have unrestricted airflow and be located away from obstacles. The separation distance must be at least twice the height that the obstacle protrudes above the probe inlet.	-	-
4. SPACING FROM OBSTRUCTIONS	(b) The probe inlet must have unrestricted airflow in an arc of at least 180 degrees. This arc must include the predominant wind direction for the season of greatest pollutant concentration potential.	-	-
5. SPACING FROM TREES	(a) To reduce possible interference the probe inlet must be at least 10 meters or further from the drip line of trees.	-	-
5. SPACING FROM TREES	(c) No trees should be between source and probe inlet for microscale sites.	-	-
6. SPACING FROM ROADWAYS	See spacing requirements table below	-	-
9. PROBE MATERIAL & RESIDENCE TIME	(a) Sampling train material must be FEP Teflon or borosilicate glass (e.g., Pyrex).	-	-
9. PROBE MATERIAL & RESIDENCE TIME	(c) Sampling probes for reactive gas monitors at NCore must have a sample residence time less than 20 seconds.	-	-

Table 62: Blank Part 58 Appendix E Form for SO₂

Applicable Section	Requirement	Observed	Criteria Met (yes, no, N/A)
2. HORIZONTAL AND VERTICAL PLACEMENT	2-15 meters above ground level. 1 meter vertically or horizontally away from any supporting structure, walls, etc., and away from dusty or dirty areas. If located near the side of a building or wall, then locate on the windward side relative to the prevailing wind direction during the season of highest concentration potential.	-	-
3. SPACING FROM MINOR SOURCES	(a) For neighborhood scale avoid placing the monitor probe inlet near local, minor sources. The source plume should not be allowed to inappropriately impact the air quality data collected at a site.	-	-
4. SPACING FROM OBSTRUCTIONS	(a) To avoid scavenging, the probe inlet must have unrestricted airflow and be located away from obstacles. The separation distance must be at least twice the height that the obstacle protrudes above the probe inlet.	-	-
4. SPACING FROM OBSTRUCTIONS	(b) The probe inlet must have unrestricted airflow in an arc of at least 180 degrees. This arc must include the predominant wind direction for the season of greatest pollutant concentration potential.	-	-
5. SPACING FROM TREES	(a) To reduce possible interference the probe inlet must be at least 10 meters or further from the drip line of trees.	-	-
5. SPACING FROM TREES	(c) No trees should be between source and probe inlet for microscale sites.	-	-
6. SPACING FROM ROADWAYS	There are no roadway spacing requirements for SO₂.	-	-
9. PROBE MATERIAL & RESIDENCE TIME	(a) Sampling train material must be FEP Teflon or borosilicate glass (e.g., Pyrex).	-	-
9. PROBE MATERIAL & RESIDENCE TIME	(c) Sampling probes for reactive gas monitors at NCore must have a sample residence time less than 20 seconds.	-	-

Table 63: Blank Part 58 Appendix E Form for NO , NO_x, NO₂, and NO_y

Applicable Section	Requirement	Observed	Criteria Met? (yes, no, N/A)
2. HORIZONTAL AND VERTICAL PLACEMENT	For neighborhood or larger spatial scale sites the probe must be located 2-15 meters above ground level and must be at least 1 meter vertically or horizontally away from any supporting structure, walls, etc., and away from dusty or dirty areas. Microscale near-road NO₂ monitoring sites are required to have sampler inlets between 2 and 7 meters above ground level. If located near the side of a building or wall, then locate the sampler probe on the windward side relative to the prevailing wind direction during the season of highest concentration potential.	-	-
3. SPACING FROM MINOR SOURCES	(a) For neighborhood scale and larger avoid placing the monitor probe inlet near local, minor sources. The source plume should not be allowed to inappropriately impact the air quality data collected at a site.	-	-
4. SPACING FROM OBSTRUCTIONS	(a) To avoid scavenging, the probe inlet must have unrestricted airflow and be located away from obstacles. The separation distance must be at least twice the height that the obstacle protrudes above the probe inlet.	-	-
4. SPACING FROM OBSTRUCTIONS	(b) The probe inlet must have unrestricted airflow in an arc of at least 180 degrees. This arc must include the predominant wind direction for the season of greatest pollutant concentration potential.	-	-
4. SPACING FROM OBSTRUCTIONS	(d) For near-road NO₂ monitoring stations, the monitor probe shall have an unobstructed air flow, where no obstacles exist at or above the height of the monitor probe, between the monitor probe and the outside nearest edge of the traffic lanes of the target road segment.	-	-
5. SPACING FROM TREES	(a) To reduce possible interference the probe inlet must be at least 10 meters or further from the drip line of trees.	-	-
5. SPACING FROM TREES	(c) No trees should be between source and probe inlet for microscale sites.	-	-
6. SPACING FROM ROADWAYS	See spacing requirements table below	-	-
9. PROBE MATERIAL & RESIDENCE TIME	(a) Sampling train material must be FEP Teflon or borosilicate glass (e.g., Pyrex).	-	-
9. PROBE MATERIAL & RESIDENCE TIME	(c) Sampling probes for reactive gas monitors at NCore and at NO₂ sites must have a sample residence time less than 20 seconds.	-	-

APPENDIX F ADDITIONAL MONITORING PROJECTS

SMOKE MONITORING FOR AIR QUALITY ADVISORIES

Wildland fire smoke is a recurring and significant air quality concern in Alaska, often impacting both nearby and distant communities during the summer months. Large wildfires can degrade air quality to unhealthy or hazardous levels, posing a risk to public health – especially for sensitive groups such as children, the elderly, and individuals with respiratory or heart conditions.

DEC collaborates closely with the Alaska Fire Service, the Alaska Wildland Fire Coordinating Group, and other partners to assess and communicate air quality impacts from wildland fires. Air quality advisories are issued statewide using two primary methods:

Continuous monitoring data from regulatory and low-cost sensor networks (where available)
Visibility assessments in areas lacking real-time monitoring coverage.

During the 2026 wildfire season, DEC will continue to partner with other agencies to expand the deployment of low-cost sensors in affected areas as needed. The DEC meteorologist or air quality staff, with support from the National Weather Service (NWS), use meteorological models and air monitoring data to forecast smoke movement and predict areas at risk for poor air quality. Real-time air quality data, advisories, and forecasts are made available to the public through DEC’s website and partner platforms.

In addition to wildfire response, prescribed burns are conducted in collaboration with the Alaska Division of Forestry & Fire Protection and the Alaska Department of Fish & Game to manage fuels and enhance wildlife habitat. Air quality is monitored before and during these operations to minimize impacts on residents and sensitive areas. Public notices are issued if smoke is expected to affect communities, and air quality monitors are strategically placed to track particulate levels and support timely community notifications.

VOLCANIC ASH MONITORING

Alaska’s active volcanoes can produce ash clouds that impact air quality and public health. In the event of a volcanic eruption, the DEC coordinates with the Alaska Volcano Observatory to monitor ash concentrations. A PM₁₀ Met One E-BAM equipped with an AIRSIS communication system is deployed to provide near real-time data, enabling the DEC meteorologist to issue timely air quality advisories for affected regions.

RADIATION MONITORING

DEC operates three RadNet radiation monitoring sites in Anchorage, Fairbanks, and Juneau as part of the national network. In August 2021, the Anchorage RadNet monitor was relocated from the Alaska State Public Health Laboratory (5455 Doctor MLK Jr. Avenue) to the Garden site (3000 E 16^th Avenue), and operational responsibility was transferred to the DEC Air Quality Division. DEC now manages RadNet equipment at all three sites, ensuring continuous monitoring for radiological events that could impact Alaskan communities.

APPENDIX G IMPROVE NETWORK

The Alaska Regional Haze State Implementation Plan (SIP) includes a comprehensive monitoring strategy to measure, estimate, and characterize air quality and visibility impairment at Alaska’s four federally designated Class I areas: Denali National Park and Preserve, Tuxedni Wilderness Area, Simeonof Wilderness Area, and the Bering Sea Wilderness Area. These areas, established under the 1977 Clean Air Act Amendments, are protected for their exceptional natural visibility and air quality.

To support the SIP and meet the requirements of the federal Regional Haze Rule, Alaska participates in the national IMPROVE (Interagency Monitoring of Protected Visual Environments) network. The IMPROVE program provides long-term, speciated particulate monitoring to assess visibility impairment and track progress toward natural visibility conditions. Alaska currently operates four IMPROVE monitoring stations, representing three of the four Class I areas. Monitors are deployed at Denali National Park and Preserve, Tuxedni Wilderness Area, and Simeonof Wilderness Area specifically to meet Regional Haze Rule requirements. Due to its extreme remoteness, there is no air monitoring at the Bering Sea Wilderness Area.

Data from these IMPROVE sites are critical for evaluating visibility trends, identifying pollutant sources, and demonstrating progress toward the SIP’s goals. Alaska’s SIP requires showing improvement in visibility on the 20% most impaired days, while ensuring no degradation on the 20% clearest days, as part of the long-term national goal to restore natural visibility conditions by 2064.

Monitoring site details and additional information about Alaska’s Regional Haze program are available on the DEC’s Regional Haze website (http://dec.alaska.gov/air/anpms/regional-haze). IMPROVE monitoring data and site information can also be accessed through the EPA’s IMPROVE program portal website (http://vista.cira.colostate.edu/improve).

APPENDIX H WAIVERS

A Street Siting Criteria Waiver (see 2024 Annual Network Plan EPA Approval Letter)

2023 ANP Response & Anchorage Ozone Monitoring Waiver Approval (see 2023 Annual Network Plan EPA Approval Letter and 2024 Annual Network Plan EPA Approval Letter)

Red Dog Mine Lead Waiver (see Red Dog Mine Lead Monitoring Waiver)

Footnotes

There is no valid design value for Butte in 2024 as the site closed in 2023 and was replaced by the Plant Materials Center monitoring site.↩︎
The Plant Materials Center began operations in 2024 and will not have a valid design value calculation until three years of complete data have been captured at the site.↩︎
Exceedance exceptional event values not included.↩︎
“Existing” indicates continuous operation prior to 2023 with no method change in the review period.↩︎
Population based on population estimates for July 1, 2025, obtained from the United States Census Bureau, U.S. Census Bureau Alaska Data↩︎
NCore site requirement is satisfied with NO_y monitoring↩︎
All sites are in compliance with groundcover criteria.↩︎
All sites are in compliance with groundcover criteria.↩︎
All sites are in compliance with groundcover criteria.↩︎
see https://bit.ly/409LMSc ↩︎
Minimum monitoring requirements for PM_2.5 SLAMS sites are determined by MSA population, consistent with 40 CFR Part 58, Appendix D, Table D‑5.↩︎
Population based on population estimates for July 1, 2025 obtained from the United States Census Bureau, U.S. Census Bureau Alaska Data ↩︎
Met One BAM w/ SCC; per discussion with EPA VSCC cyclone removed↩︎
Met One BAM w/ SCC; per discussion with EPA VSCC cyclone removed↩︎
see https://www.census.gov/geographies/reference-files/time-series/demo/metro-micro/delineation-files.html ↩︎
Minimum monitoring requirements apply to the Metropolitan statistical area (MSA). CBSA includes both MSAs and micropolitan statistical areas.↩︎
Population based on population estimates for July 1, 2025, obtained from the United States Census Bureau, U.S. Census Bureau Alaska Data ↩︎
Selection of urban areas and actual numbers of stations per area will be jointly determined by EPA and the State agency.↩︎
High concentration areas are those for which ambient PM₁₀ data show ambient concentrations exceeding the PM₁₀ NAAQS by 20 percent or more.↩︎
High concentration areas are those for which ambient PM₁₀ data show ambient concentrations exceeding the PM₁₀ NAAQS by 20 percent or more.↩︎
Medium concentration areas are those for which ambient PM₁₀ data show ambient concentrations exceeding 80 percent of the PM₁₀ NAAQS.↩︎
Low concentration areas are those for which ambient PM₁₀ data show ambient concentrations less than 80 percent of the PM₁₀ NAAQS.↩︎
These minimum monitoring requirements apply in the absence of a design value.↩︎
see https://www.census.gov/geographies/reference-files/time-series/demo/metro-micro/delineation-files.html↩︎
Minimum monitoring requirements apply to the Metropolitan statistical area (MSA). CBSA includes both MSAs and micropolitan statistical areas.↩︎
Minimum monitoring requirements apply to the Metropolitan statistical area (MSA). CBSA includes both MSAs and micropolitan statistical areas.↩︎
Population based on population estimates for July 1, 2025, obtained from the United States Census Bureau, U.S. Census Bureau Alaska Data↩︎
Monitoring sites in both MSAs satisfy their respective CO Limited Maintenance Plans requirements.↩︎
Monitoring sites in both MSAs satisfy their respective CO Limited Maintenance Plans requirements.↩︎
see https://www.census.gov/geographies/reference-files/time-series/demo/metro-micro/delineation-files.html↩︎
Minimum monitoring requirements apply to the Metropolitan statistical area (MSA). CBSA includes both MSAs and micropolitan statistical areas.↩︎
Minimum monitoring requirements apply to the Metropolitan statistical area (MSA). CBSA includes both MSAs and micropolitan statistical areas.↩︎
Population based on population estimates for July 1, 2025, obtained from the United States Census Bureau, U.S. Census Bureau Alaska Data↩︎
DEC received an EPA 5-Year Ozone NAAQS Monitoring Requirement Waiver for the Anchorage MSA, which was extended until 2028.↩︎
Fulfills State of Alaska NCore requirement↩︎
Minimum monitoring requirements apply to the Metropolitan statistical area (MSA). CBSA includes both MSAs and micropolitan statistical areas.↩︎
Population based on latest available Census estimates↩︎
The ozone (O3) National Ambient Air Quality Standards (NAAQS) levels and forms are defined in 40 CFR part 50.↩︎
The ozone (O3) National Ambient Air Quality Standards (NAAQS) levels and forms are defined in 40 CFR part 50.↩︎
These minimum monitoring requirements apply in the absence of a design value.↩︎
Metropolitan statistical areas (MSA) must contain an urbanized area of 50,000 or more population.↩︎
See https://www.census.gov/geographies/reference-files/time-series/demo/metro-micro/delineation-files.html ↩︎
Minimum monitoring requirements apply to the Metropolitan statistical area (MSA). CBSA includes both MSAs and micropolitan statistical areas.↩︎
Based on population estimates for July 1, 2025, obtained from the United States Census Bureau, U.S. Census Bureau QuickFacts: Juneau City and Borough (County), Alaska; Fairbanks North Star Borough, Alaska; Matanuska-Susitna Borough, Alaska; Anchorage Municipality (County), Alaska; Alaska ↩︎
see 2020 National Emissions Inventory (NEI) Data | US EPA ↩︎
One monitor present to satisfy NCore requirement.↩︎
see https://www.census.gov/geographies/reference-files/time-series/demo/metro-micro/delineation-files.html↩︎
Minimum monitoring requirements apply to the Metropolitan statistical area (MSA). CBSA includes both MSAs and micropolitan statistical areas.↩︎
Population based on population estimates for July 1, 2025, obtained from the United States Census Bureau, U.S. Census Bureau Alaska Data↩︎
NCore site requirement is satisfied with NO_y monitoring↩︎
All sites are in compliance with groundcover criteria.↩︎
All sites are in compliance with groundcover criteria.↩︎
All sites are in compliance with groundcover criteria.↩︎

2026 Annual Air Quality Monitoring Network Plan - Public Comment Draft

Table of Tables

Definitions and Acronyms

Executive Summary

Overview

Key Updates for 2026-2027

Proposed Changes

Innovation and Community Engagement

Public Health

Stakeholder Engagement

Introduction

Air Quality Monitoring Requirements

Regulatory Framework

Monitoring Priorities and Strategies

Current Monitoring Network

Compliance with Federal Standards

Planned Enhancements

State of Alaska Ambient Air Monitoring Network

Minimum Monitoring Requirements

Federal Regulatory Framework

Core Based Statistical Areas

Pollutant Monitoring Requirements

Lead

Current Monitoring Sites

Monitoring Objectives

Anchorage Metropolitan Statistical Area (MSA)

Matanuska-Susitna Borough (Anchorage MSA)

Fairbanks North Star Borough (FNSB)

Juneau μSA

Siting Criteria

Carbon Monoxide Sites

Particulate Matter Sites

NCore Site

Compliance Summary

Monitoring Methods, Designation and Sampling Frequency

PM2.5 Monitoring Methods

PM10 Monitoring Methods

Gaseous Criteria Pollutant Methods

Chemical Speciation Network (CSN)

Sampling Frequency Requirements (40 CFR 58.12 Compliance)

Primary SLAMS vs. SPM Identification

Collocation and Quality Assurance Requirements

Collocated Monitoring

Chemical Speciation Network (CSN) QA and Collocation

NCore Trace-Level QA Requirements

Flow Rate and Audit Requirements

Data Validation and Completeness

Documentation, Records, and PQAO Participation

Fairbanks PM2.5 Serious Nonattainment Area

Anchorage Carbon Monoxide Limited Maintenance Plan (CO LMP)

Eagle River PM10 Limited Maintenance Plan (PM10 LMP)

Mendenhall Valley (Juneau) PM10 Limited Maintenance Plan

Demonstration of Compliance

Monitoring Waivers

Anchorage MSA Ozone Monitoring

Lead Source Oriented Monitoring Waiver

A Street Siting Wavier

Network Modifications Completed in 2026

Air Toxics Program

Planned Network Modifications in 2026

Anchorage Garden Site CO Monitoring

Regulatory Monitoring Sites

Community-Based Air Sensor Monitoring Project

APPENDIX A NAAQS SUMMARY TABLES

APPENDIX B INSTRUMENT INVENTORY

APPENDIX C AQS MONITOR METADATA

APPENDIX D NETWORK EVALUATION FORMS

APPENDIX E SUMMARY OF MONITORING PATH & SITING CRITERIA EVALUATION FORM

APPENDIX F ADDITIONAL MONITORING PROJECTS

APPENDIX G IMPROVE NETWORK

APPENDIX H WAIVERS

Footnotes

PM_2.5 Monitoring Methods

PM₁₀ Monitoring Methods

Fairbanks PM_2.5 Serious Nonattainment Area

Eagle River PM₁₀ Limited Maintenance Plan (PM₁₀ LMP)

Mendenhall Valley (Juneau) PM₁₀ Limited Maintenance Plan