Lung Association Report Reveals that All Delaware Counties Post Worse Levels for Ozone and Daily Particle Pollution; Kent and Sussex End 13-Year Streak of Straight A’s for Daily Particle Pollution

Today, the American Lung Association released the 2025 “State of the Air” report, which reveals that all Delaware counties posted worse levels for both ozone smog and fine particle pollution compared to last year. While New Castle retained its "C" grade for ozone, Kent dropped from a "B" to a "C" and Sussex lost its "A," earning a "B." For fine particle pollution, all counties earned straight "D's," with Kent and Sussex ending a 13-year streak of straight "A's." The decline in air quality is partly attributed to smoke from Canadian wildfires in 2023, which contributed to the worsened pollution levels. 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.

The 16-county Philadelphia-Reading-Camden, PA-NJ-DE-MD metro area, which includes Delaware’s New Castle and Kent Counties, was named 3rd most polluted in Mid-Atlantic (defined for this report as DC, DE, MD, NJ, PA, VA, WV) 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.

"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 Deb Brown, Chief Mission Officer, American Lung Association. 

“Sadly, too many people in the First State 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 Delaware policymakers to continue their work 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 Delaware:

The 16-county Philadelphia-Reading-Camden, PA-NJ-DE-MD metro area, including New Castle and Kent Counties, worsened for all three measures of 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.

The Salisbury-Ocean Pines, MD metro area has taken the place of the former Salisbury-Cambridge, DE-MD metro area that had included Sussex County, which is now no longer listed within a metro area.

Summary for Delaware Counties:

• Though all measures for ozone smog and daily particle pollution worsened, no county in the state posted a failing grade.
• For ozone smog, New Castle County worsened but retained its “C” grade. Kent County worsened from “B” to “C.” Sussex County ended two years with “A” grades by posting a “B.”
• For the daily measure of fine particle pollution, all counties earned “D’s.” New Castle County worsened from last year’s “B,” but Kent and Sussex Counties snapped their 13-year streak of straight “A’ grades for this measure.
• Though data sufficient to report grades for the year-round measures of particle pollution had been incomplete statewide for the past two reporting years, New Castle County rejoined the list by posting a value very slightly better than its last previous figure in the 2022 report, earning a passing mark.

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.

Get involved and help the mission of the American Lung Association. The LUNG FORCE Walk in Philadelphia is coming up on May 10, 2025 held for the first time at the Philadelphia Zoo. Learn more at  LUNGFORCE.org/philadelphia.