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Air Home > Programs > Air Toxics > Maine Air Toxics Initiative
Air toxics come from many sources, including stationary and mobile sources.

Maine Air Toxics Initiative


Various federal programs have significantly reduced the exposure of Maine people to air toxics. However, two National Air Toxics Assessments (NATA), conducted by the U.S. Environmental Protection Agency (EPA) using 1996 and 1999 emissions data, suggested that Maine citizens face unacceptable exposure to air toxics.

In response to this potential risk, the Maine Department of Environmental Protection undertook the Maine Air Toxics Initiative (MATI). MATI is a facilitated stakeholder process aimed at verifying whether or not the NATA 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. This holistic assessment of air toxics risks will enable Maine to target available resources for maximum risk reduction. The ultimate goal of this project is to reduce exposure of all Maine citizens to acceptable levels of air toxics.

In 2003, Maine DEP convened the Air Toxics Advisory Committee (ATAC).  The ATAC is composed of community organizations, government organizations (local, state and federal), industrial organizations and environmental organizations having an interest in air toxics. Jonathan Reitman, an independent, outside facilitator is facilitating the project. EPA awarded Maine DEP with a Healthy Communities Grant to help fund the Maine Air Toxics Initiative.

The ATAC met on several occasions from 2003 to 2005 to reach the first step in the Scope of Work for the Maine Air Toxics Initiative (MATI), which was to develop the following Air Toxics Priority List for Maine.

Final Maine Air Toxics Priority List

Rank
Pollutant Category

1

Acrolein

2

Polycyclic Organic Matter

3

Manganese

4

Formaldehyde

5

Nickel

6

1,3-Butadiene

7

Diesel Particulate Matter (PM)

8

2,4-Toluene Diisocyanate

9

Sulfuric Acid

10

Benzene

11

Lead

12

Cadmium

13

Dioxins

14

Chromium

15

Arsenic

16

Cyanide and Cyanide Compounds

17

Mercury

18

Brominated Flame Retardants

19

Particulate Matter from Nano-Technology

20

Acetaldehyde

21

Tetrachloroethylene (Perchloroethylene)

22

Chloroform

23

Carbon Tetrachloride

24

Ethylene Dichloride

25

Ethylene Dibromide

26

Methyl Bromide

27

Chlorine

28

Hydrochloric Acid

29

Chlorine Dioxide

 

The priority list is based on the ATAC's evaluation of existing data from ambient air monitoring programs, emissions inventories, chemical toxicity databases, and national air modeling.  A schematic of the process used to develop the list and summary description of the process can be found in the ATAC's Consensus Report.  A detailed explanation is contained in documents located on the Background Documents page.

On November 18, 2005, the ATAC concluded that significant quantities of a wide range of air toxics compounds are emitted by point, area and mobile sources in Maine.  The ATAC also found that there remains a considerable degree of uncertainty in many source categories resulting from imprecise emission factors and/or limited data on the activity level of some source categories.  Nevertheless, the ATAC found it appropriate to move to the next phase defined in the MATI Scope of Work, while continuously improving the emission estimates by updating data as new information becomes available.

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Phase II of the Maine Air Toxics Initiative

For Phase II of the MATI, the ATAC appointed subcommittees to develop appropriate early actions and identify a long-term, targeted strategy with clear implementation goals and timeframes to reduce air toxics to acceptable levels.  These strategies could include:

  • economic incentives;
  • targeted, pollution prevention programs;
  • voluntary programs;
  • enhancement of existing regulatory programs;
  • new legislation at the state level;
  • partnering with regional agencies to resolve interstate issues; or
  • no action at all.

The goal was a consensus recommendation from each subcommittee, or failing that, options for the ATAC to consider.  The three subcommittees formed by the ATAC were:

  • Science Assessment Subcommittee (SAS):  This subcommittee was charged with evaluating and verifing the scientific data used in MATI to develop the Air Toxics Priority List; locate regions of the state where air toxics are of particular concern; and evaluate the assumptions that underly air toxics reduction options. The SAS recommended ...
  • Stationary Sources Subcommittee (S3): This subcommittee explored short- and long-term reduction strategies for pollutants on the Air Toxics Priority List, focusing on ways to reduce the most risk for the least cost. Recommendations from this subcommittee included...
  • Mobile Sources Subcommittee (MoSS): Similar to the S3 subcommittee, MoSS explored cost-effective air toxic reduction strategies, but for mobile sources. The MoSS recommended...

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Final ATAC Recommendations

On June 26, 2007, the ATAC met and reached agreement on recommended strategies to reduce air toxic emissions in Maine.  The report contains an Air Toxic Priority List, and notes that most air toxic emissions in Maine are combustion by-products. After evaluating pending regulations due to existing air programs, the ATAC recommends the following air toxic emission reduction strategies:

  • For stationary sources (both large and small)
    • energy conservation
    • a multi-pollutant analysis of reductions in emissions from residential wood combustion
  • For mobile sources
    • Statewide expansion of Cumberland County’s On Board Diagnostics & Repair program (OBD)
    • Five (5) programs to reduce Vehicle Miles Traveled (VMT) & increasing vehicle occupancy
    • An anti-idling program
  • Additional data analysis, focusing on potential hot-spot areas of air toxics.

The next step is for the Department to take the ATAC recommendations and develop our air toxics strategy. This strategy will map out concrete goals, steps, resource allocations and timelines to achieve air toxic reductions. The plan will include provisions for continued gathering, analysis and communication of air toxics data.

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The work of the Maine Air Toxics Initiative is chronicled on this website. Readers are encouraged to visit the MATI Background Documents to view current working documents, MATI progress reports, meeting minutes, subcommittee reports and the other documents that formed the basis of the Air Toxics Priority List.


Useful Links

  • Risk Assessment for Toxic Air Pollutants: A Citizen's Guide - U.S. EPA (http://www.epa.gov/oar/oaqps/air_risc/3_90_024.html) Designed for the general public, this guide explains the risk assessment process in four, easy to understand steps. A great "read first" document to understand the concepts of toxicity, dose and risk.

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