Delaware reports steady progress in air quality despite wildfire setbacks

Delaware continues to make gains in improving air quality, according to the 2023 Annual Air Quality Report released by the state’s Department of Natural Resources and Environmental Control (DNREC).

The report, based on data from the DNREC Division of Air Quality’s statewide monitoring network, shows most pollutants remained below federal limits — though ozone and fine particulate matter (PM2.5) remain persistent concerns.

The report highlights that in 2023, Delaware experienced 353 days — over 96% of the year — with air quality rated as “good” or “moderate” on the federal Air Quality Index (AQI).

However, widespread Canadian wildfires during the spring and early summer triggered several days of elevated ozone and PM2.5 levels, temporarily impacting air quality across the state.

READ: Doodles in Dewey back for 20th anniversary weekend of furry fun and fundraising

“Even with environmental challenges beyond our control and coming our way as happened with wildfire smoke, Delaware’s air quality data continue to show steady progress,” said DNREC Division of Air Quality Director Angela Marconi. “This reflects not only decades of work to reduce emissions locally, but also our state’s ongoing collaboration in regional efforts to be key in delivering cleaner air and having a significant impact toward healthier communities.”

Despite the wildfire-related setbacks, state officials say the long-term outlook remains positive.

Air toxics in Wilmington, the state’s most industrialized area, remained low or declined further.

Most pollutants continued to meet or fall below the National Ambient Air Quality Standards (NAAQS), with the exception of ozone and PM2.5 — both known to be exacerbated by high temperatures and pollution from vehicles and industry.

“The story of Delaware’s air is one of significant and steady progress over the years,” said DNREC Secretary Greg Patterson. “We still have challenges however, ones that affect the health of both our people and the planet. That’s why we need policies, programs and tools in place to reduce emissions and pollutants and continue to make Delaware’s air even cleaner.”

One point of clarification in the report addresses Delaware’s ozone classification.

While New Castle County is listed as “Serious Non-Attainment” for ozone, DNREC says the designation stems from its inclusion in the broader Philadelphia Non-Attainment Area — not from local pollution.

All three Delaware counties currently meet federal air quality standards for all major pollutants.

The state’s monitoring system, paired with public communication tools like AirNow.gov and DNREC’s own air data portal (de.gov/airdata), allows for real-time tracking of air quality and health alerts when pollution levels rise.

The full 2023 report is available here.