Air Quality in Washington-Baltimore-Arlington Metro Area Worst in Four Years for Ozone Smog, Finds 2019 'State of the Air' Report, But Had Best Ever Results for Two Measures of Particle Pollution

American Lung Association's 20th annual air quality report finds more than 4 in 10 Americans live with unhealthy air quality, Capital area's air quality continues to rank among nation's 25 worst

The American Lung Association’s 2019 “State of the Air” report found that air quality in the Washington-Baltimore-Arlington, DC-VA-MD-WV-PA metro area was the worst in four years for ozone smog.  Nevertheless, the area improved to its best ever performance for its twelfth consecutive year for year-round particle pollution, but the metro area continued to rank among the 50 worst in the country for this pollutant.

The 20th annual air quality “report card” tracks Americans’ exposure to unhealthful levels of ozone and particle pollution, both of which can be deadly. The report also found that for the fourteenth year in a row, the Washington metro area equaled or improved upon its number of unhealthy days for particle pollution.

“Residents of Washington and the entire metro area should be aware that we’re breathing unhealthy air, driven by local emissions, upwind sources, and extreme heat as a result of climate change, placing our health and lives at risk,” said Kevin Stewart, the American Lung Association’s Director of Environmental Health for Advocacy and Public Policy. “In addition to challenges here in the nation’s capital and the other 40 counties and cities in this huge metro area, the 20th-anniversary ‘State of the Air’ report highlights that more than 4 in 10 Americans are living with unhealthy air, and we’re heading in the wrong direction when it comes to protecting public health.”

This year’s report covers the most recent quality-assured data available collected by states, cities, counties, tribes and federal agencies in 2015-2017. Notably, those three years were the hottest recorded in global history. 

Each year the “State of the Air” provides a report card on the two most widespread outdoor air pollutants, ozone pollution, also known as smog, and particle pollution, often called soot. The report analyzes particle pollution in two ways: through average annual particle pollution levels and short-term spikes in particle pollution. Both ozone and particle pollution are dangerous to public health and can increase the risk of premature death and other serious health effects such as lung cancer, asthma attacks, cardiovascular damage, and developmental and reproductive harm.

Ozone Pollution in Washington-Baltimore-Arlington, DC-VA-MD-WV-PA

Compared to the 2018 report, the metro area again significantly increased the number of unhealthy days of high ozone in this year’s report, earning the area an F grade and worsening its ranking to 16th from 17th worst in the country.  Baltimore County, MD, jumped to an average 16.8 days of high ozone from 13.7 last year, and more than twice as many as it had (6.8 days) in the 2017 report.

“Ozone especially harms children, older adults and those with asthma and other lung diseases,” said Stewart. “When older adults or children with asthma breathe ozone-polluted air, too often they end up in the doctor’s office, the hospital or the emergency room. Ozone can even shorten life itself.” 

This report documents how warmer temperatures brought by climate change make ozone more likely to form and harder to clean up. This year’s report showed that ozone levels increased in most cities nationwide, in large part due to the record-breaking global heat experienced in the three years tracked in the report. 

Particle Pollution in Washington-Baltimore-Arlington, DC-VA-MD-WV-PA

The 2019 report also found year-round particle pollution levels were again lower than in the previous year’s report. Nationwide, the best progress in this year’s report came in reducing year-round levels of particle pollution. Though the metro area continued to meet the national air quality standard for the year-round measure, it still ranked 43rd worst in the nation, but did improve from 35th worst last year.  Berkeley County, WV, was worst in the metro area.

“Particle pollution is made of soot or tiny particles that come from coal-fired power plants, industrial sources, diesel emissions, wildfires and wood-burning devices. These particles are so small that they can lodge deep in the lungs and trigger asthma attacks, heart attacks and strokes, and can even be lethal,” said Stewart. “Year-round particle pollution levels have dropped thanks to the cleanup of coal-fired power plants and the retirement of old, dirty diesel engines.”

“State of the Air” 2019 also tracked short-term spikes in particle pollution, as these can be extremely dangerous and even lethal. This year’s report also found that the metro area matched last year’s performance posting the fewest number of days with unhealthy levels of particle pollution.  Both the District of Columbia and the City of Baltimore recorded the most days high in this pollutant in the metro, but earned a “B” grade, matching the District’s mark last year.

While improvements have continued locally, many of these spikes in the western United States were directly linked to weather patterns leading to drought or to wildfire events, which are increasing in frequency and intensity in many areas of the country due to climate change. 

While the report examined data from 2015-2017, this 20th annual report online provides information on air pollution trends back to the first report. Learn more about Washington-Baltimore-Arlington area rankings, as well as air quality across area states and the nation, in the 2019 “State of the Air” report at For media interested in speaking with an expert about lung health, healthy air, and threats to air quality, contact Annette Eyer at [email protected] or 717.971.1124. 

For more information, contact:

Allison MacMunn
[email protected]

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