Boston Metro Area Air Improves Across the Board, Lung Association Reports

With continued failing grades on ozone, Boston metro area ranks as one of the cleanest cities for short-term particle pollution, and shows drastic long-term progress

This year’s “State of the Air” report from the American Lung Association finds that the Boston metro area rankings have improved for both particle pollution and ozone pollution, two of the most harmful and widespread types of air pollution. The metro area ranked for the second year in a row as one of the cleanest cities for short-term particle pollution and was highlighted as the only metro area in the northeast region for improved year-round particle pollution in a year when 10 other regional cities worsened. Boston also showed slightly improved levels of ozone, despite continued failing grades.  See the full report at Lung.org/sota.

“The Boston metro area has become an important example for how public policy can contribute to better air quality.  The American Lung Association’s 2021 “State of the Air” report shows continued good news for Bostonians, and highlights continued progress to be made,” said American Lung Association Director for Advocacy in Massachusetts Trevor Summerfield. “Aside from the good news for local Boston residents, this year’s report also reinforced what we already know: that nationwide, people of color are significantly more likely to breathe polluted air and that climate change continues to be a serious public health concern.”

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 United States 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 recently applauded Massachusetts for joining the Transportation and Climate Initiative (TCI) Program. By joining the TCI Program, Massachusetts has taken a big, bold and necessary step forward for public health. The program is an important tool to reduce transportation pollution, improve air quality, reduce the carbon pollution that causes climate change, improve health and invest in cleaner, faster and more reliable public transportation.  It stands to make a significant impact throughout the state for the coming years, but especially for Boston area and other heavily trafficked metro areas. 

Ozone Pollution in the Boston metro area
Compared to the 2020 report, the Boston metro area experienced fewer unhealthy days of high ozone in this year’s report.  While Bristol County, the metro area’s most ozone-polluted county maintained its failing grade for ozone pollution, it shows a clear picture of long-term improvement. This year’s report showed a weighted average of 5.5 days with unhealthy ozone for the county – an improvement over its average of 6.8 days in last year’s report  - and a vast improvement over its worst-ever average of 34.2 days in the 1997-1999 report.   

Despite significant progress in recent decades, the report continues to show that nearly 4 million residents in the Boston Metro area are being exposed to air earning D or F grades for unhealthy ozone levels. 

Particle Pollution in the Boston metro area
“State of the Air” 2021 found that year-round particle pollution levels in the Boston metro area were lower than in last year’s report, a stark different from other northeast cities (10 of which showed increase year round particle pollution).  The report also tracked short-term spikes in particle pollution, which can be extremely dangerous and even lethal. The report found that the Boston metro area also had less days when short-term particle pollution reached unhealthy levels, earning it a second consecutive year among the cleanest cities in the country. All eleven graded counties in the metro area reported a weighted average of zero unhealth air days, earning A grades across the board.   

(Our report uses the Boston-Worcester-Providence, MA-RI-NH-CT Consolidated Statistical Area as defined by the U. S. Office of Management and Budget, which includes Barnstable, Bristol, Essex, Middlesex, Norfolk, Plymouth, Suffolk, and Worcester, Massachusetts; Windham, Connecticut; Belknap, Hillsborough, Merrimack, Rockingham and Strafford, New Hampshire, and Bristol, Kent, Newport, Providence and Washington, Rhode Island.)

Summerfield continued, “We know that during the COVID-19 pandemic, people across the country  - including the Boston community - are facing multiple threats to their lung health at once, including from unhealthy air pollution. Although we saw some good news this year, we must not be complacent. It’s critical to keep looking at the state of our air quality and the things that impact it – like climate change and emissions.  We simply must continue to protect and preserve everyone’s right to breathe clean, healthy air and protect themselves from harmful air pollution.”

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 New York city, both ozone and particle pollution placed the health of 22.5 million residents at risk, including those who are more vulnerable to the effects of air pollution, such as older adults, children and people with a lung disease. The report also shows that people of color were 61% more likely to live in a county with unhealthy air, and three times more likely to live in a county that failed all three air quality grades. The report also finds that climate change made air quality worse and harder to clean up.

The Lung Association’s annual air quality “report card” tracks and grades Americans’ exposure to unhealthful levels of particle pollution (also known as soot) and ozone (smog) over a three-year period – this year’s report covers 2017-2019. The report analyzes particle pollution in two ways: average annual levels and short-term spikes. Both ozone and particle pollution can cause premature death and other serious health effects such as asthma attacks and cardiovascular damage, and are linked to developmental and reproductive harm. Particle pollution can also cause lung cancer.

Learn more about “State of the Air” at Lung.org/sota and sign the petition for the Biden Administration to promote clean air, a safe climate and environmental justice. Media interested in speaking with an expert about lung health, clean air and threats to air quality can contact Jennifer Solomon at [email protected] or 516-680-8927. 

For more information, contact:

Jennifer Solomon
(516) 680-8927
[email protected]

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