Solid Fuel-Fired Heating Device Visible Emission and Opacity Limits

Visible Emission and Opacity Limits are set out in 18 AAC 50.075 and FNSB PM_2.5 SIP Section 7.12 (PDF)

Area	Opacity Limit During PM_2.5 Advisories / Episodes Called by DEC or a Local Air Program	Opacity Limit Year Round
FNSB PM_2.5 Nonattainment Area Map (PDF)	During PM2.5 Episodes: Solid fuel-fired heating devices may not operate without a waiver from the Department or local air quality program. During PM2.5 Advisories: Visible emissions may not exceed 20% opacity (for more than six minutes in any one hour, except during the first 15 minutes after the initial startup when the opacity must be less than 50%)	No Black Smoke
State Wide	During PM2.5 Advisories: Visible emissions may not exceed 20% opacity (except for six minutes each hour or 15 minutes after startup)	No Black Smoke

Area

Opacity Limit During PM_2.5 Advisories / Episodes Called by DEC or a Local Air Program

Opacity Limit Year Round

FNSB PM_2.5 Nonattainment Area Map (PDF)

During PM2.5 Episodes: Solid fuel-fired heating devices may not operate without a waiver from the Department or local air quality program.

During PM2.5 Advisories: Visible emissions may not exceed 20% opacity (for more than six minutes in any one hour, except during the first 15 minutes after the initial startup when the opacity must be less than 50%)

No Black Smoke

State Wide

During PM2.5 Advisories: Visible emissions may not exceed 20% opacity (except for six minutes each hour or 15 minutes after startup)

No Black Smoke

Visible Emission Evaluation Procedures

DEC uses EPA Method 9 with Alaska-specific modifications (SIP Vol. 3., sec. IV-3, Appendix IV-3 (PDF)) to measure opacity.
The Alaska-specific modifications allow readings through water vapor.
DEC is also exploring the use of the camera-based Method 9 alternative (EPA ALT-082 (PDF)) that is based on ASTM D7520-09.
You do not need to use these procedures to estimate the opacity of your smoke. Try using the images below as a guide.
Air Quality Complaint Form

Opacity Information

(Images above provided by Alaska Environmental Resources, LLC.)

What are Visible Emissions?

Emissions you can see
Smoke
Steam, particulate matter, and gases

What is Smoke Opacity?

Opacity is a measure of how much light visible emissions block.
High opacity means dirtier smoke is coming out of the chimney.
High opacity smoke is a signal that your heating appliance is not operating efficiently and is producing too much pollution.
There are easy steps you can take to burn more efficiently, reduce opacity, and produce less pollution.

What factors affect opacity?

Combustion efficiency
Operating temperature
Wood moisture content
Airflow
Size of the fire
Type of appliance
Age and condition of the appliance
Types of fuels burned

How can I reduce smoke opacity?

Burn dry wood
Only burn clean fuels
Mix wetter wood with cleaner burning compressed wood logs
Increase airflow by opening the damper
Build small, hot fires
Don't let your fire smolder
Maintain your appliance
Inspect your stove and make any necessary repairs
Consider upgrading to a newer appliance
Consider using less polluting heaters that use pellets, propane, oil, or electricity instead

Staff Contact:

Cory McDonald

Phone: 907-451-5172

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