Baltimore Metro Area Receives “F” Grades for Ozone Smog, “B’s” for Short-term Measure of Fine Particle Pollution, Finds 2021 ‘State of the Air’ Report

American Lung Association’s annual air quality report finds over 40% of Americans breathing unhealthy air

This year’s “State of the Air” report from the American Lung Association finds that the Baltimore-Columbia-Towson, MD metro area (Central Maryland, comprising six counties and the City of Baltimore) showed improvement over last year’s report’s worst values for ozone smog and the year-round measure of fine particle pollution. The figure for the short-term (daily) measure of particle pollution remained unchanged. The Central Maryland area is part of the larger Washington-Baltimore-Arlington, DC-MD-VA-WV-PA metro area, for which the Lung Association assigns ranks. See the full report, based on the three years of data from 2017 through 2019, at . 

The worst grades in the metro area for the daily measure of particle pollution (a “B” in three jurisdictions) and ozone smog (an “F” in four jurisdictions) remain of concern even though the latter showed improvement over last year’s results. “Clearly, both show room for improvement and more must be done to protect the health of people at risk,” said American Lung Association Director of Environmental Health Kevin Stewart. “There are dozens of days when the air pollution levels are high enough to harm health and trigger asthma attacks, heart attacks and stroke, placing children, older adults, and people living with chronic lung and heart disease at particular risk. Ozone and particle pollution are the nation’s most harmful and widespread air pollutants, and both can be deadly. In addition, more exposure to particle pollution is linked to worse health outcomes from COVID-19, including more deaths.” 

“The American Lung Association’s 2021 ‘State of the Air’ report shows that despite some nationwide progress on cleaning up air pollution, more than 40% of Americans live with unhealthy ozone or particle pollution,” said Stewart. “People of color are significantly more likely to breathe polluted air than white people. As the nation works to address climate change and continue reducing air pollution, we must prioritize the health of disproportionately burdened communities.”  

Ozone Pollution in the Baltimore metro area - Compared to the 2020 report, Central Maryland experienced significantly fewer unhealthy days of high ozone. Harford County was the county in the metro area with the worst performance for ozone in this year’s report, reporting a weighted average of 9.3 days (an “F” grade) with unhealthy levels of this pollutant, displacing last year’s worst county, Baltimore County, which had posted an average of 14.2 days (also an “F”) high in ozone. The area’s best result was 6.7 days (still an “F”) in the 2017 report. These results drove the larger Washington-Baltimore-Arlington metro area’s ranking as it improved to 22nd most polluted from 20th worst in the country last year, again placing the metro area among the nation’s 25 worst cities for this pollutant.   

“Ozone pollution can harm even healthy people, but is particularly dangerous for children, older adults and people with lung diseases such as COPD or asthma,” said Stewart. “Breathing ozone-polluted air can trigger asthma attacks in both adults and children with asthma, which can land them in the doctor’s office or the emergency room. Ozone can even shorten people’s lives.”   

Particle Pollution in the Baltimore metro area: The “State of the Air” 2021 found that year-round particle pollution levels in Central Maryland improved as Baltimore City displaced Howard County for the worst value in the area. In contrast, the larger Washington-Baltimore-Arlington metro area, after improving for 13 straight years, hit a worse annual average in the District’s year-round value, but still met the air quality standard for this pollutant. Therefore, that area’s ranking worsened to 39th most polluted in the country from 49th worst in last year’s report.  

The report also tracked short-term spikes in particle pollution, which can be extremely dangerous and even lethal. For the 16th year in a row the Washington-Baltimore-Arlington metro area equaled or improved upon the previous year’s number of unhealthy days on average for particle pollution. In 2017-2019, it matched the past three years’ unchanged lowest level ever, with Baltimore City, MD and Berkeley County, WV, each recording the same worst result in this year’s report, a weighted average of 0.7 days (a “B” grade). Due to improvements in other areas of the country, the larger metro area’s ranking worsened to 57th most polluted in the nation from 64th worst in last year’s report.  

“Particle pollution can lodge deep in the lungs and can even enter the bloodstream. It can trigger asthma attacks, heart attacks and strokes and cause lung cancer,” said Stewart. Particle pollution comes from industry, coal-fired power plants, construction, agriculture, vehicles, wildfires and wood-burning devices.”   

The year’s report found that nationwide, more than four in 10 people (135 million) lived with polluted air, placing their health and lives at risk. In the Baltimore metro area, air pollution placed the health of 2.8 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 than white people, 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 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 Val.Gleason at [email protected] or 717-971-1123.  



For more information, contact:

Valerie Gleason
[email protected]

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