New Report on Air Pollution in Maryland: For Ozone Smog, Thirteen of 15 Graded Counties Post Worse Results; All Graded Counties Post Worst Results for Both Daily & Year-Round Particle Pollution

Today, the American Lung Association released the 2025 “State of the Air” report, which reveals that Maryland counties nearly always posted worse results for both ozone smog and fine particle pollution than it had in last year’s report. Smoke from wildfires in Canada in 2023 contributed to poorer air quality. Nationally, the report found that 156 million people (46%) are living in areas that had unhealthy levels of air pollution.

The Lung Association’s 26th annual “State of the Air” report grades exposure to 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. The report looks at the latest quality-assured air quality data from 2021-2023.

In the 42-jurisdiction Washington-Baltimore-Arlington, DC-MD-VA-WV-PA metro area, which covers 16 of Maryland’s 24 jurisdictions, all air pollution measures worsen. The metro area’s worst grade for daily particle pollution worsens from “C” to “F.” The mark for year-round particle pollution is now failing. The area ranks 36th worst in country for ozone smog, 2nd worst in the Mid-Atlantic (defined for this report as DC, DE, MD, NJ, PA, VA, WV), after the New York-Newark metro area.

The 16-county Philadelphia-Reading-Camden, PA-NJ-DE-MD metro area, which includes Cecil County, was named 3rd most polluted in Mid-Atlantic for both ozone smog and daily particle pollution; and 26th worst in the nation for year-round particle levels, 2nd worst in the Mid-Atlantic (after the Pittsburgh metro area).

"The air pollutants highlighted in this report are widespread and pose a risk to everyone’s health. Both ozone and particle pollution can lead to premature death and cause serious health issues such as asthma attacks, heart attacks, strokes, preterm births, and even problems with cognitive function later in life. Particle pollution can also increase the risk of lung cancer,” said Aleks Casper, Advocacy Director, VA, MD, DC, DE, American Lung Association. 

“Sadly, too many people in Maryland are living with dangerous levels of ozone and particle pollution. This pollution is making kids have asthma attacks, causing people who work outdoors to get sick and unable to work, and even contributing to low birth weight in babies. We’re urging Maryland policymakers to continue their commitment to improve our air quality. We’re also calling on everyone to support the vital work of the U.S. Environmental Protection Agency (EPA).” 

Air Pollution in Maryland’s metro areas:

The 42-jurisdiction Washington-Baltimore-Arlington, DC-MD-VA-WV-PA metro area, including 16 of Maryland’s 24 jurisdictions, worsened for all three measures of air pollution covered in the report. Baltimore County was again worst in the metro area for ozone smog, with its even worse level in this year’s report resulting in the area’s national ranking dropping from 44th worst to 36th worst.

The metro area’s worst grade for short-term particle pollution worsened from a “C” to an “F” in the District of Columbia, ranking the metro area at 53rd most polluted, worse than the area’s 64th worst rank in last year’s report. For the year-round average level of particle pollution, the District also worsened from last year’s passing level and now received a failing grade for its average level of pollution above the federal standard. The metro area worsened to 66th worst in the nation for the year-round level, distinctly worse than the area's ranking in last year's report of 90th worst.

The 16-county Philadelphia-Reading-Camden, PA-NJ-DE-MD metro area, including Cecil County, MD, also worsened for all three measures of air pollution. Philadelphia County earned straight “F” grades and was worst in the metro area for all three measures. Despite worsening for ozone, the metro area’s rank improved to 43rd worst from 35th most polluted in the nation.

The metro area’s worst grade for short-term particle pollution worsened from a “C” to an “F” in Philadelphia County, ranking the metro area at 30th most polluted, much worse than the area’s 73rd worst rank in last year’s report. For the year-round average level of particle pollution, Philadelphia County significantly worsened from last year’s level and again received a failing grade for its average level of pollution above the federal standard. The Philadelphia metro area worsened to 26th worst in the nation for the year-round level, far worse than the area's ranking in last year's report of 65th worst.

Maryland also includes the Salisbury-Ocean Pines, MD metro area, but air quality is not measured in any of its three counties.

Summary for Maryland Counties:

• Three counties earned “F” grades for ozone smog in this year’s report: Baltimore (worst in the state), Harford, and Prince George’s. All but two of the 15 jurisdictions receiving grades for ozone smog posted worse levels: Anne Arundel remained unchanged and retained its “C” grade. Garrett County retained its “A” grade, for zero days with high levels of ozone pollution, in this year’s report.
• Despite the widespread worsening of air quality for particle pollution in the state, no jurisdiction earned an “F” grade for the daily measure. Baltimore and Cecil (worst in the state) Counties posted “D” grades. The other nine graded jurisdictions all earned “C’s,” all worsening from “A” grades posted in last year’s report—and all of those with the exception of Baltimore City, after several years of straight “A’s.”
• All ten counties graded for the year-round measure of particle pollution posted worse levels in this year’s report, but all nevertheless received passing grades. Baltimore County had the worst level in Maryland.

The “State of the Air” report found that 156 million people in the U.S. (46%) live in an area that received a failing grade for at least one measure of air pollution and 42.5 million people live in areas with failing grades for all three measures. The report also found that a person of color in the U.S. is more than twice as likely as a white individual to live in a community with a failing grade on all three pollution measures. Notably, Hispanic individuals are nearly three times as likely as white individuals to live in a community with three failing grades.

In this year’s “State of the Air” report, the Lung Association is calling on everyone to support the U.S. Environmental Protection Agency. EPA is essential to protecting people’s health from ozone and particle pollution. Without EPA staff and programs, families won’t know what’s in the air they are breathing, and efforts to clean up air pollution will be undone. Join the American Lung Association in advocating to protect EPA’s expert staff and lifesaving programs. See the full report results and take action at Lung.org/sota.