The Working Waterfront

Maine’s mixed grades on air pollution

Lung Association releases ‘State of the Air’ report

Posted 2021-07-15
Last Modified 2021-07-15

This year’s “State of the Air” report from the American Lung Association finds that Maine reported mixed results for air pollution throughout its counties and metro areas. Both Bangor and Portland metro areas were named among the cleanest cities for short-term particle pollution, while Portland reported a worsened level of year-round particle pollution, and Bangor fell off the “cleanest 25 cities for year-round particle pollution” due to lack to data.

Portland also showed improved levels of ozone and Bangor ranked for the fourth consecutive year as one of the cleanest cities for ozone. Particle pollution and ozone pollution are two of the most harmful and widespread types of air pollution.

See the full report at

Overall, the report reinforced the fact that emissions from factories, power plants, diesel- and gasoline-powered motor vehicles (cars and trucks) and equipment play a role in forming ozone and generating dangerous fine particle pollution. Together, with the rising temperatures due to climate change, air quality in the U.S. is in danger of being degraded, and residents across the country are at an increased risk of air pollution harming health.

In addition, studies show that air pollution exposure is linked to greater risk of respiratory infections, including some evidence that suggests that exposure to air pollution may make people more vulnerable to COVID-19 infection.

The Lung Association has and will continue to support Maine’s consideration of the Transportation and Climate Initiative Program.

County Grades on ozone:

  • Every county maintained its grade for ozone from last year’s report: Penobscot (A), Androscoggin (A), Cumberland (B), York (C), Kennebec (A), Aroostook (A), Hancock (D), Knox (C), Oxford (A), Washington (C)
  • York, Hancock, and Knox counties recorded slightly less levels of ozone than in last year’s report, but not enough to impact the grade.
  • York County was the most polluted in the Portland metro area, but improved to the fewest unhealthy days ever, 1.5 days. The worst period had been from 2001-2003 when the metro area had 22.7 days of high ozone on average.

Notable county grades on particle pollution:

  • Throughout the state, all counties maintained A grades for short-term particle pollution, with the exception of Aroostook which maintained its C grade from last year.
  • All counties continued to meet the national standard for year-round particle pollution
  • Cumberland County was the only county to measure worsened year-round particle pollution
  • For the fourth consecutive time both Androscoggin and Cumberland counties posted zero unhealthy days for short-term particle pollution
  • All other counties did not collect this data

The year’s report found that nationwide, more than 4 in 10 people (135 million) lived with polluted air, placing their health and lives at risk. In Maine, more than 300,000 residents live with lung diseases like asthma, COPD and lung cancer, as well as heart disease.  They are already at risk, making them more vulnerable to the effects of air pollution.