American Lung Association Reports on Air Quality in Delaware: All Counties Continue at Best Ever for Ozone Smog, New Castle Earns First Passing Gradend Sussex its First “A” for the Measure

New Castle County Dropped From Nation’s Cleanest Counties for 24-Hour Particle Pollution, But Kent and Sussex Counties Continue to Earn “A” Grade
The 2023 “State of the Air” report, released today by the American Lung Association, finds that Delaware’s air quality showed mixed results for some of the most harmful and widespread types of air pollution: fine particle pollution and ozone smog. Nationally, the report found that nearly 120 million people, or more than one in three, in the U.S. live in counties that had unhealthy levels of ozone or particle pollution.

The 16-county Philadelphia-Reading-Camden, PA-NJ-DE-MD metro area, which includes Delaware’s New Castle and Kent Counties, improved to its best-ever results for ozone smog. Additionally, while Kent County remained unchanged at its ‘B’ grade, New Castle County posted its first passing grade, a “D” which indicates there are still too many days with poor air quality. Meanwhile, in the five-county Salisbury-Cambridge, MD-DE metro area, Sussex County earned its first “A” grade by recording zero days with unhealthy levels of ozone.

In contrast, New Castle County, having earned an “A” in last year’s report by posting zero days with unhealthy levels of fine particle pollution, is no longer listed among the cleanest and earned a “B” grade, which demonstrates . But Kent and Sussex Counties continued to earn ‘A’ grades for their 12th straight year.

The Lung Association’s 24th annual “State of the Air” report grades Americans’ exposure to unhealthy levels of ground-level ozone air pollution, annual particle pollution and short-term spikes in particle pollution over a three-year period. This year’s report covers 2019-2021.

“As we can see from this year’s report data, there is much work to be done in the Philadelphia metro area to improve our air quality,” said Deb Brown, Chief Mission Officer for the Lung Association. “Even one poor air quality day is one too many for our residents at highest risk, such as children, older adults, individuals who are pregnant and those living with chronic disease. 

“Delaware must seize the opportunity to make a significant improvement to the health and wellbeing of all Delawareans by moving forward with the implementation of the Advanced Clean Cars II. This health-protective standard would accelerate the transition to zero emission vehicles and improve air quality in the state,” said Brown.

Nationally, the report found that ozone pollution has generally improved across the nation, thanks in large part to the success of the Clean Air Act. However, more work remains to fully clean up harmful pollution, and short-term particle pollution continues to get worse. In addition, some communities bear a greater burden of air pollution. Out of the nearly 120 million people who live in areas with unhealthy air quality, a disproportionate number – more than 64 million (54%) – are people of color. In fact, people of color were 64% more likely than white people to live in a county with a failing grade for at least one measure, and 3.7 times as likely to live in a county with a failing grade for all three measures.

For daily spikes in ozone air pollution: Based on Philadelphia County’s annual weighted average of 6.5 days (an “F” grade) with unhealthy levels of ozone smog, “State of the Air” ranked the Philadelphia metro area as the 28th most polluted city in the nation. Despite the improvement, its ranking was slightly worse than its placement at 29th worst in last year’s report. The Salisbury-Cambridge metro area, also despite improvement (Dorchester County, MD earning a “C” grade for 1.3 high-ozone days, fewer than in last year’s report), likewise ranked worse in this year’s report—65th worst compared with last year’s 75th placement.  Both metro areas improved to their best-ever results for ozone smog

For the 24-hour measure of fine particle pollution, the grade for the worst county in the Philadelphia metro area remained a “D,” again in Delaware County, PA, with the number of unhealthy days (2.3) remaining unchanged in this year’s report. Because of widespread worsening elsewhere in the country, the metro area’s rank for daily spikes of fine particle pollution improved from tied for 44th worst to tied for 55th worst. Also, the Salisbury-Cambridge metro area remained listed among the nation’s cleanest for the 12th consecutive year.

For the year-round measure of fine particle pollution, all Delaware counties were recorded as having incomplete data in the 2023 “State of the Air” report. Nevertheless, the report found that the year-round particle pollution level of the worst county (Camden, NJ) in the Philadelphia metro area was that area’s best ever and was significantly lower than in last year’s report. The area was tied for 46th most polluted in the country, much better than its ranking of tied for 18th last year. Further, the Salisbury-Cambridge metro area, primarily because less-polluted Dorchester County, MD, became the only remaining reporting county, improved from tied for 164th worst to tied for 190th worst (now ranking tied for 9th best in the country, and the area’s best ever).

The American Lung Association is calling on President Biden to urgently move forward on several measures to clean up air pollution nationwide, including new pollution limits on ozone and particle pollution and new measures to clean up power plants and vehicles. See the full report results and sign the petition at
For more information, contact:

Valerie Gleason
[email protected]

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