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A hazy summer morning in MaineHazardous Air Pollutants

Hazardous air pollutants, also known as Air Toxics or by the acronym, HAPS, are approximately 200 air pollutants identified by EPA which, when their emissions are not controlled through available technology, are most likely to have the greatest impact on ambient air quality and human health.  The Emissions Inventory Program collects data every three years on emissions of hazardous air pollutants from nearly 200 facilities in Maine.

Information about reporting emissions of hazardous air pollutants can be found on the Reporting Requirements page.

A complete list of hazardous air pollutant chemicals and compounds can be found in DEP Rule's Chapter 137, "Emission Statements," Appendix A and on the HAPS List page.

Air Toxics Fees are based on the hazardous air pollutant inventory collected under the authority in Chapter 137, "Emission Statements."  Information about the Air Toxics Fees is found on the Air Toxics Fees page.

How do hazardous air pollutants affect human health and the environment?  Where do they come from?  What is being done to control them?  Visit the DEP's Air Toxics Program pages to learn more.

Hazardous Air Pollutants: Default Emission Factors

The Department of Environmental Protection’s Chapter 137, Section 3(C) requires the owner or operator of a facility that emits hazardous air pollutants (HAPs) to file an emissions statement every three years for those HAP emissions. In November 2008 several changes were made to the reporting requirements in Chapter 137:

  • Emissions must only be reported for facilities that are required to or have obtained a license.
  • Emissions must only be reported for equipment and processes included in the license.
  • Emissions of thirteen HAPs from all fuel-burning or combustion equipment included in the license must be reported, whether or not emissions exceed the Appendix A reporting thresholds.

Chapter 137, Section 5 provides a seven-step hierarchy for emission estimation methods.

  1. For sources with specification CEMs/PEMs monitoring systems that are required by statute, regulation, or license condition, emission data generated by these systems shall serve as the basis for emissions reported in the Chapter 137 inventory;
  2. For sources not subject to #1 above and for which reference method emission testing that has been deemed by the Department to be representative of current and normal operating conditions, emission data from such testing shall serve as the basis for estimating emissions reported in the Chapter 137 inventory;
  3. For sources not subject to either #1 or #2, emissions reported pursuant to this Chapter shall be estimated and reported on the basis of a facility-specific emission factor approved by the Department;
  4. For sources not subject to either #1, #2 or #3, emissions reported pursuant to this Chapter shall be estimated and reported on the basis of EPA-published emission factors, where available;
  5. For sources not subject to either #1, #2, #3 or #4, emissions reported pursuant to this Chapter shall be estimated and reported based on emissions factors from other industry and trade groups based on sound science, where available;
  6. For sources not subject to either #1, #2, #3, #4 or #5, emissions reported pursuant to this Chapter shall be estimated and reported based on default emission factors published by the Department, where available; or
  7. For sources not subject to any of the above sections, emissions reported pursuant to this Chapter shall be estimated and reported based on best engineering judgement.

When determining how to estimate your emissions, you should consider the method in #1 before #2, #2 before #3, and so on. Item #6 indicates that the Department will provide “default” emission factors to be applied only when, for a particular process or equipment, there is no data from CEMS/PEMS, data from stack testing, facility-specific emission factor approved by DEP, EPA-published emission factor, or emission factor from an industry or trade group based on sound science.

When developing the default emission factors referenced in #6, above, for the thirteen HAPs listed in Chapter 137, Section 3(C)(3), DEP reviewed already available factors from EPA, trade groups and source testing in Maine. The DEP identified equipment and processes described by numerous source classification codes (SCCs) for which no published emission factors were available.  We understand that many facilities have equipment and processes described by these SCCs for which HAP emission reporting is required under Chapter 137, Section 3(C)(3). To aid facility owners and operators in meeting the Chapter 137 requirements, the Department identified emission factors for other related SCCs that we would be willing to accept when used to estimate emissions for equipment and processes for which no other, better emission factor is available. We recognize that they may be low quality factors when applied in this manner, and we strongly encourage owners and operators to conduct source testing or otherwise determine more accurate emission factors for their facilities.

This year, the Department is once again providing Satellite i-Steps data files to facility owners and operators to use to build their 2008 annual inventory. These files will have pre-populated pollutant records using the default emission factors for the thirteen required HAPs for select fuel-burning and combustion-related process units. This is intended to save owners and operators the effort of creating new pollutant records, not to imply that DEP believes those factors are the most appropriate estimation method. Facility owners and operators may choose to use the default emission factors and to accept the HAP pollutant estimates, or provide their own estimate (using an alternative emission factor or other estimation method), when completing their Satellite i-Steps submittal. We will not require that the default factors be used - we are simply providing them as a way to pre-populate the pollutant records and as tool to help facilities meet the new requirements of Chapter 137.

 

Useful links

  • Maine Air Toxics Initiative - Maine DEP (http://www.maine.gov/dep/air/toxics/mati.htm) The Maine Air Toxics Initiative is a facilitated stakeholder process aimed at verifying whether or not the national air toxics assessment results seem reasonable, and if so, identification of which air toxics are the most responsible for creating health risks, the source of those pollutants, and creation of cost effective solutions to reduce the risk.
  • ChemFinder.Com (http://chemfinder.cambridgesoft.com/result.asp) includes a free search engine for basic queries, and subscription based searches of their scientific databases for more sophisticated searches. ChemFinder has been providing free chemical searching to hundreds of thousands of scientists since 1995. 

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