As shown in the graphic above from DNREC’s Annual Air Quality Report for 2023 (the most recent full calendar year of certified ambient air, and the standard for air quality reporting), Delaware continues to make steady progress toward cleaner air. /DNREC graphic

The Delaware Department of Natural Resources and Environmental Control has released its Annual Air Quality Report for 2023, presenting the latest data from the DNREC Division of Air Quality’s statewide air quality monitoring network. The report is based on the most recent full calendar year of certified ambient air data – the standard for air quality reporting – and indicates the state continues to make progress toward cleaner air for Delawareans.

DNREC’s air quality report serves as a vital tool for tracking environmental trends, supporting public health and as a touchstone for helping to shape the state’s policy decisions. The report shows that in 2023, all pollutants except ozone and fine particulate matter (PM2.5) remained below the National Ambient Air Quality Standards (NAAQS) for Delaware. Air toxics in Wilmington – the state’s most urban and industrialized area – either remained low or continued to decline, signaling encouraging long-term trends in public health protection.

Though the full report was favorable for Delaware, vast volumes of smoke from widespread Canadian wildfires during spring and early summer of 2023 contributed to multiple days of elevated ozone and PM2.5 – underscoring how vulnerable Delaware’s air quality is to pollution transported from outside the state. But while Delaware, like much of the East Coast, was impacted by the wildfires, the state’s investment in continuous monitoring along with a robust network of sensors allowed DNREC to communicate health advisories quickly to the public.

In 2023, Delaware experienced 353 days with air quality rated “good” or “moderate” on the Air Quality Index — meaning more than 96% of the year offered clean or acceptable air for most residents.

Monitoring data is available on the DNREC website, de.gov/airdata, and through the EPA’s AirNow.gov for ozone and particulates. Every day the Air Quality Index (AQI) tells users how clean or polluted the outdoor air is, also listing associated health effects from the pollutants that may be of concern. The AQI translates air quality data into numbers and colors that help people understand when to take appropriate action to protect their health.

“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.”

While Delaware has made important gains, the 2023 air quality report also reinforces the need for continued focus and investment in air quality research, regulation and public engagement. In particular, ozone and PM2.5 remain pollutants of concern, especially during warmer months and in communities near traffic corridors or industrial sources.

“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.”

The air quality report also addresses – and clarifies – Delaware’s ozone classification. While New Castle County is designated as “Serious Non-Attainment” for ozone, this classification is due to its inclusion in the Philadelphia Non-Attainment Area – not because of local exceedances. In fact, air monitoring by the Division of Air Quality shows that all three Delaware counties meet federal standards for all criteria pollutants, including ozone – meaning that Delawareans are breathing clean air.

The full 2023 Annual Air Quality Report is available online at de.gov/airmonitoring.

About DNREC
The Delaware Department of Natural Resources and Environmental Control protects and manages the state’s natural resources, protects public health, provides outdoor recreational opportunities and educates Delawareans about the environment. The DNREC Division of Air Quality monitors and regulates all emissions to the air. For more information, visit the website and connect with @DelawareDNREC on Facebook, Instagram, X (formerly known as Twitter) or LinkedIn.

Media contacts: Michael Globetti, michael.globetti@delaware.gov; Nikki Lavoie, nikki.lavoie@delaware.gov 

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