Air Monitoring and Reporting

The Maine Department of Environmental Protection operates and maintains a variety of ambient air monitoring equipment around the state. Some of these instruments operate on a continuous basis and provide hourly averages of pollutants or meteorological data that is used in the evaluation of the air pollutant data. Data may also be collected over a twenty-four hour period such as particulates or it may be collected as a composite over an entire week. Examples of the latter are the atmospheric and mercury deposition monitoring programs. The number of monitoring sites and the pollutants that are monitored may vary from year to year depending on the expected concentrations of the pollutants, the origin of the pollutants and new programs based on changes in existing regulations or the establishment of new regulations. For more information, contact Andy Johnson (207) 480-0906.

Air Monitoring Data including:

Chronic Ambient Air Guidelines (2019): Ambient Air Guidelines (AAGs) represent chemical concentrations in ambient air, below which there is minimal risk of a deleterious health effect resulting from long-term inhalation exposure. The AAGs are derived to be protective for effects due to chronic exposure (“chronic” refers to long-term exposure); therefore, these guidelines are most appropriately compared with long-term average ambient air measurements (e.g., annual averages).

Emissions Inventory

  • MAIRIS is a free web based reporting system developed by the Maine Department of Environmental Protection to assist Maine facilities with their annual air emissions reporting requirements. Log in to MAIRIS.
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Monitoring Sites Map Legend

Annual Air Monitoring Plan 2022 - The Maine Department of Environmental Protection (ME DEP) operates a network of ambient air monitoring sites at locations across the state. ME DEP is required to submit an Annual Ambient Air Quality Monitoring Network Plan to the US Environmental Protection Agency (EPA). This document was subject to a 30-day public comment period with a draft posted on this web site before being submitted to EPA for review and approval. The final plan was submitted to EPA on August 10, 2021 and final approval was received on August 30, 2021.

The annual network plan describes to EPA which pollutants and other parameters DEP measures at its various ambient air monitoring sites and why they are measured at those specific locations. It also describes changes in the network - including new and closed locations, and new and discontinued measurements at existing locations - since the last network plan, as well as proposed changes in the network over the next 12 months.

Five Year Assessment of Maine's Ambient Air Monitoring Network (pdf) - The Five Year Monitoring Network Assessment is required by EPA and allows all who are invested in Maine’s air quality to consider DEP’s air monitoring program objectives in the context of “the bigger picture,” and from a vantage point five years into the future.Originally presented to EPA on October 7, 2020, this revision from May 19, 2021 reflects modifications incorporated after receiving comments and suggestions Region 1 staff.