New ‘State of the Air’ Report Finds Bangor Only Metro Area in Nation on All 3 Cleanest Cities Lists; Portland-Lewiston-South Portland Metro Area Matches Best-Ever Ozone Result

Today, the American Lung Association released its 27th annual “State of the Air” report, which reveals that the Bangor, ME metro area (Penobscot County) is the only metro area in the nation to appear on all three of the Cleanest Cities lists, while the Portland-Lewiston-South Portland metro area improved to match its best-ever result for ozone smog.

The report findings show continued strong air quality in Bangor, with A grades for ozone and the daily measure of particle pollution, along with ranking 10th best in the nation for the year-round average of particle pollution, There was some progress in southern Maine, where Portland-Lewiston-South Portland showed improvement in ozone pollution, but continued to receive a C grade, and also kept the same result as in last year’s report for the daily measure of fine particle pollution, retaining its C grade. Year-round averages of particle pollution in the metro area also saw improvement.

Other parts of the state showed declines, improvements or continued strong performance for certain pollution measures, highlighting air quality contrasts across Maine communities. In particular:

• Cumberland and York Counties tied for the worst value for ozone smog in Maine, for which they posted C grades.  
• Cumberland and Aroostook Counties tied for the worst in the state for the daily (short-term) measure of particle pollution, earning C grades.
• Cumberland County was worst in the state for the year-round measure of fine particles, but improved since last year’s report.
• Eight Maine counties were listed among the cleanest in the country for ozone smog—Androscoggin, Aroostook, Kennebec, Oxford, Penobscot, Sagadahoc, Washington and York.
• Six Maine counties graded for the daily measure of particle pollution also earned an A for this measure—Androscoggin, Hancock, Kennebec, Oxford, Penobscot and Washington.
• Hancock County tied for 9th cleanest county in the country for the year-round measure of fine particle pollution. Androscoggin County tied for 24th best.

The Lung Association’s “State of the Air” report grades counties’ air quality in terms of unhealthy levels of ground-level ozone air pollution (also known as smog), and year-round and short-term spikes in particle pollution (also known as soot), over a three-year period (2022-2024). The report also ranks counties and metropolitan areas for cleanest and most polluted lists for each pollutant.

Nationally, the report finds that 33.5 million children in the U.S., or 46% of people under 18 years old, live in an area that received a failing grade for at least one measure of air pollution. In total, 44% of people of all ages in the U.S. (152 million people in total) live in a county that received a failing grade for at least one measure of air pollution. 32.9 million people live in counties with failing grades for all three measures.

Ozone and particle pollution are widespread and can impact anyone’s health, but infants, children and teens are more susceptible to health impacts. Their lungs are still developing, they breathe more air for their body size than adults and they are frequently exposed to outdoor air. Air pollution exposure in childhood can cause long-term harm, including reduced lung growth, new asthma cases, increased risk of respiratory diseases and impaired cognitive functioning later in life. More broadly, both pollutants can cause premature death and other serious health effects such as asthma attacks, heart attacks and strokes, and preterm births. Particle pollution can also cause lung cancer. 

“Clean air is essential to the health and wellbeing of families across Maine. Children deserve to breathe air that won’t make them sick,” said Lance Boucher, assistant vice president of state public policy for the American Lung Association. “Thankfully, local air quality has improved, but clean air takes work. Unfortunately, the U.S. Environmental Protection Agency’s (EPA) rollbacks of critical healthy air rules are impacting our residents. We urge Maine policymakers to take action to improve our air quality and we are calling on everyone to tell EPA that our kids’ health counts.”

Key Findings Portland-Lewiston-South Portland, ME metro area:
Ground-level Ozone Pollution: 
Ozone “smog” affects the largest number of people in the U.S. Smog forms when gases from tailpipes, smokestacks, factories and other pollution sources react with sunlight. It is a powerful respiratory irritant with effects that have been likened to a sunburn of the lungs.  

• The Portland-Lewiston-South Portland, ME metro area ranked 135th worst in the nation for ozone pollution.
  • The ranking was based on the area’s worst county’s average number of unhealthy days—1 day per year, a C grade, in Cumberland and York Counties, Maine.
  • This was better than the area's ranking in last year's report of 108th worst, with 1.7 days per year, a C grade.  

Particle Pollution: 
Fine particle pollution can be extremely dangerous and even deadly. These particles come from wildfires, wood-burning stoves, coal-fired power plants, diesel engines and other sources. The report has two grades for particle pollution: one for “short-term” particle pollution, or daily spikes, and one for the annual average “year-round” level that represents the concentration of particles in each location.

• Short-term Particle Pollution: 
  • The ranking was based on the area’s worst county’s average number of unhealthy days—1 day per year, a C grade, in Cumberland County, Maine.
  • This was worse than the area's ranking in last year's report of 139th worst, with 1 day per year, a C grade.  
• For the year-round average level of particle pollution, the area’s worst county, Cumberland County, Maine, received a passing grade for pollution levels below the federal standard. 
  • The Portland-Lewiston-South Portland, ME metro area ranked 171st worst in the nation.
  • This was worse than the area's ranking in last year's report of 176th worst in the nation even though the average slightly improved. 

Key Findings Bangor, ME metro area:
Ground-level Ozone Pollution:

• The Bangor metro area ranked among the nation’s cleanest cities for ozone pollution for its 9th year in a row.
  • The ranking was based on the area’s worst county average number of unhealthy days—0 days per year in Penobscot County, ME, for which it earned an A grade. 

Particle Pollution: 

• Short-term Particle Pollution: 
  • The Bangor, ME metro area ranked among the nation's cleanest cities for short-term particle pollution for the 17th year in a row. The ranking was based on the area’s worst county’s average number of unhealthy days—0 days per year, an A grade, in Penobscot County, ME. 
  • For the year-round average level of particle pollution, the area’s worst county, Penobscot County, ME, received a passing grade for pollution levels below the federal standard. 
• The Bangor, ME metro area ranked 202nd worst in the nation (10th best among the nation's cleanest cities). 
  • This was worse than the area's ranking in last year's report of 204th worst in the nation (5th best among the nation's cleanest cities). 

In addition to the findings for Maine, other notable results include: 

• The Boston-Worcester-Providence, MA-RI-NH metro area worsened to a failing grade for the daily measure of fine particle pollution, ranking 53rd worst in the nation, down from 114th worst in last year’s report, but it posted its best-ever result for the year-round measure, improving from 110th worst to 164th worst. Nevertheless, a worse and again failing grade was posted for ozone smog, with Washington County, Rhode Island yet again worst in the metro area.

The Lung Association is calling on everyone to urge EPA to value the health of America’s kids. Historically, EPA has played an essential role in protecting people’s health from air pollution. The current EPA has retreated from its public health foundation by rolling back clean air protections. This EPA has also taken the recent step of eliminating health-related information from its economic analyses, meaning that the costs of pollution to kids, families and communities will not be counted as policies are undone. EPA must not devalue kids’ health.

See the full report results and take action at Lung.org/sota.

Get involved and help the mission of American Lung Association. The Trek Across Maine in Pineland Farms is coming up on June 19-June 21, 2026. Learn more at TrekAcrossMaine.org.