air toxics

Air toxic

Environmental Protection Agency's
Reference Concentrations (RfCs)

This ranking is based on EPA's Reference Concentration (RfC). A RfC is an estimate of a continuous inhalation exposure concentration to people (including sensitive subgroups) that is likely to be without risk of deleterious effects during a lifetime. An RfC is reported in milligrams of pollutant per cubic meter of air (mg/m3 ).

The following are the pollutants in the 1999 Alaska Air Toxics Emission Inventory considered to be some of the most toxic for non-cancer effects as they correspond to the ten lowest reference concentrations:

Rank
Chemical Name
RfC mg/m 3
Comments

1

Chromium VI chromic acid mists and dissolved Cr (VI) aerosols (PDF)
0.000008
n/a
2
Cadmium compounds (PDF)
0.00001
RfC from California Environmental Protection Agency
2
Hexamethylene-1,6-Diisocyanate (PDF)
0.00001
n/a
3
Acrolein (PDF)
0.00002
n/a
3
Beryllium Compounds (PDF)
0.00002
n/a
4
2-Chloroacetophenone (PDF)
0.00003
n/a
4
Arsenic Compounds (inorganic including arsine) (PDF)
0.00003
RfC from California Environmental Protection Agency
5
Arsine (PDF)
0.00005
n/a
5
Manganese Compounds (PDF)
0.00005
n/a
5
Nickel Compounds (PDF)
0.00005
RfC from California Environmental Protection Agency
6
Chlorine (PDF)
0.00006
RfC from California Environmental Protection Agency
7
2,4-Toluene Diisocyanate (PDF)
0.00007
RfC for mixture of Toluene 2,4- and 2,6-Diisocyanate
7
Phosphorus (PDF)
0.00007
RfC from California Environmental Protection Agency
8
Chromium VI Particulates (PDF)
0.0001
n/a
9
1,2-Dibromo-3-Chloropropane (PDF)
0.0002
n/a
9
Antimony Compounds (PDF)
0.0002
RfC for Antimony Trioxide
9
Ethylene Dibromide (Dibromoethane) (PDF)
0.0002
n/a
9
Hexachlorocyclopentadiene (PDF)
0.0002
n/a
9
Hydrazine (PDF)
0.0002
RfC from California Environmental Protection Agency
10
Lindane (all isomers) (PDF)
0.0003
RfC from California Environmental Protection Agency
10
Elemental Mercury (PDF)
0.0003
n/a
10
Phosgene (PDF)
0.0003
RfC from California Environmental Protection Agency
10
Phosphine (PDF)
0.0003
n/a

 

The following pollutants in the 1999 Alaska Air Toxics Emission Inventory also have RfCs:

Dichlorvos Methylene diphenyl diisocyante (MDI) Acrylamide
Allyl Chloride Chlordane Acrylic Acid
Aniline Epichlorohydrin (1-Chloro-2,3-epoxypropane) Methyl Isocyanate
Acrylonitrile
Maleic Anhydride Nitrobenzene
Cyanide Compounds Ethylene Thiourea Hexachlorobenzene
Naphthalene Vinyl Bromide Cresols/Cresylic Acid (isomers and mixture)
Propylene Dichloride (1,2-Dichloropropane)
Ethylene Oxide Methyl Bromide(Bromomethane)
Phenol
Styrene Oxide 2,4-Dinitrotoluene
Chloroprene Triethylamine 1,3-Butadiene
Acetaldehyde
Benzidine Bis(2-ethylhexyl)phthalate (DEHP)
Isophorone 1,2-Epoxybutane 1,3-Dichloropropene
2-Nitropropane
4,4'-Methylenedianiline Chlorobenzene
Diethanolamine 2-Methoxyethanol 2-Butoxyethanol
Hydrochloric Acid Elemental Selenium Vinylidene Chloride (1,1-Dichloroethylene)
Dimethyl Formamide
Hydrogen Fluoride (Hydrofluoric acid) Propylene Oxide
Carbon Tetrachloride Acetonitrile Benzene (including benzene from gasoline)
Hexachloroethane Methyl Isobutyl Ketone (Hexone) Hexachlorobutadiene
Methylchloride (Chloromethane)
Pentachlorophenol Vinyl Chloride
Phthalic Anhydride 1,2,4-Trichlorobenzene 2-Ethoxyethanol
Hexane Vinyl acetate Cumene
Chloroform
1,1,2-Trichloroethane Toluene
Ethylene dichloride (1,2-Dichloroethane)
Ethylene Glycol Carbon Disulfide
Ethylidene dichloride (1,1-Dichloroethane) Trichloroethylene 1,4-Dichlorobenzene(p)
Ethyl Benzene Methyl Methacrylate Methyl Ethyl Ketone (2-Butanone)
Styrene Methyl Chloroform (1,1,1-Trichloroethane) Methyl Tert Butyl Ether
Methylene 1,4-Dioxane (1,4-Diethyleneoxide) Ethyl Chloride (Chloroethane)
Methanol Methylene chloride (Dichloromethane)

 

To explore the possible health effects of these and other pollutants, please visit the following internet sites:

  • https://www.epa.gov/iris - The Environmental Protection Agency's list of non-cancer and cancer risk values for many pollutants.
  • https://www.atsdr.cdc.gov/index.html - The Agency for Toxic Substances and Disease Registry list of pollutants and corresponding Minimum Risk Levels.
  • http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?HSDB - The National Institutes of Health, National Library of Medicine's toxicology data file focusing on the toxicology of potentially hazardous chemicals.
  • https://www.epa.gov/haps/health-effects-notebook-hazardous-air-pollutants - The Environmental Protection Agency's list of hazardous air pollutants, including summaries of uses, sources and potential health effects.
  • https://www.atsdr.cdc.gov/toxfaqs/index.asp - The Agency for Toxic Substances and Disease Registry list of Frequently Asked Questions about contaminants found at Hazardous Waste Sites.