Pollutant Categorization for Specific Groups of Compounds

There are 208 individual air toxic chemicals and 18 groups of chemicals (see the  Air Toxics List) included in the 2011 air toxics emission inventory. Future emission inventories will cover the same list of chemicals. This list includes the 187 Hazardous Air Pollutants (HAPs) identified by the EPA, pollutants in the Great Lakes regional air toxics emission inventory project, and pollutants monitored in Minnesota’s outdoor air. The presentation of emissions data for specific groups of compounds is described below. Efforts are made to avoid the same emission being counted twice. On this website, emissions are reported for various chemical groups while the detailed chemical-specific emissions are available and can be obtained by contacting the MPCA.

Recommendations for reporting data for specific groups of compounds
Recommendations for reporting data for specific groups of compounds are summarized below in a hierarchy of the most preferred method to the least preferred method. For pollutant groups, only one reporting strategy per group per process should be used. Simultaneous use of more than one reporting strategy (e.g., reporting both individual chromium compounds and total chromium for the same source) will result in double counting.

Metal and Cyanide Groups

1. Report emissions of all individual metal and cyanide compounds; e.g., report emissions of arsenic trioxide, rather than emissions of arsenic compound as a whole. Reporting arsenic compound as a whole will not be accepted. All individual compounds should be reported as the mass of the total compounds, not just the metal within the compound.
2. Report just emissions of metal or cyanide within the compound; e.g., if you have emissions of 1 lb of arsenic trioxide, you can report 0.7574 lb of arsenic emissions within the arsenic trioxide.
   • Chromium - Since there is widely varying toxicity, you need to separate chromium compounds into trivalent (CHROMIUM III, CAS No.16065-83-1) and hexavalent chromium (CHROMIUM VI, CAS No. 18540-29-9) if possible. You may report emissions for chromium if you cannot separate emissions. If the emissions are reported for chromium, the emissions will be allocated to CHROMIUM III and CHROMIUM VI based on generic information when the data are used.
   • Do not include metals or cyanide already reported using the more preferred method in number 1.

Dioxins/Furans

Report mass emissions of the following 17 individual congeners of chlorinated dibenzodioxins (CDDs) and chlorinated dibenzofurans (CDFs).

Glycol Ethers

1. Report emissions for individual glycol ethers. All individual glycol ethers are shown on the air toxics pollutant list.
2. If you cannot report individual glycol ether emissions, report total emissions of glycol ethers as a group under pollutant code “GLYCOL ETHERS.” You should not report emissions of one pollutant under both the individual pollutant name and “GLYCOL ETHERS”. Please do not include the following compounds in glycol ethers. These compounds are often mistaken as being glycol ethers.

Butyl cellosolve (CAS No. 111-76-2) is shown on the air toxics list as an individual pollutant to support MPCA risk assessment needs.

Xylenes and Cresols

1. Report emissions for individual xylene and cresol isomers. If you report emissions for individual isomers do not report any emissions for total xylenes or total cresols to avoid double counting.
2. If you cannot report individual emissions of xylenes or cresols, report total emissions of xylenes or cresols as a group under “XYLENES ISO” (CAS No. 1330-20-7) or “CRESOLS MX IS” (CAS No. 1319-77-3).

Polycyclic Organic Matter (POM)

Report emissions of as many individual POM compounds as possible. All individual glycol ethers are shown on the AT pollutant list.