Wilmington Air Quality in 2021
In 2021, Wilmington's air quality (Philadelphia-Camden-Wilmington, PA-NJ-DE-MD area) had a median daily AQI of 56 (Moderate) across 365 monitored days. 15 days (4.1%) reached Unhealthy for Sensitive Groups or worse, 98 were Good, and the year's peak AQI was 153 (Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 275 of those days. The cleanest month of 2021 was March (median AQI 52, 0 days above 100) and the worst was July (median 67, 6 days above 100, peak 153).
- Good: 26.8%
- Moderate: 69.0%
- Unhealthy for Sensitive Groups: 3.6%
- Unhealthy or worse: 0.5%
Extra Protection for Wilmington Homes
Air quality in Wilmington is moderate (AQI 52), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
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How was Wilmington's air quality in 2021?
Moderate on a typical day: median AQI 56, with 15 days above AQI 100 out of 365 monitored — the 5th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2021: 153 (Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 275 days.
- ✓Cleanest month: March; worst: July.
Frequently asked questions
What was the average AQI in Wilmington in 2021?▾
EPA's Air Quality System puts Wilmington's (Philadelphia-Camden-Wilmington, PA-NJ-DE-MD) median daily AQI for 2021 at 56, which is Moderate. 15 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 153.
Which month had the worst air quality in Wilmington in 2021?▾
The cleanest month of 2021 was March (median AQI 52, 0 days above 100) and the worst was July (median 67, 6 days above 100, peak 153).
Was 2021 a good or bad year for Wilmington's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 5th cleanest by days above AQI 100. 2021's median of 56 is in line with the area's typical annual median of 56.
Wilmington month by month in 2021
Wilmington air quality month by month, 2021 (Philadelphia-Camden-Wilmington, PA-NJ-DE-MD, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 56 | 0 | 99 | PM2.5 |
| February | 28 | 56 | 0 | 76 | PM2.5 |
| Marchcleanest | 31 | 52 | 0 | 88 | PM2.5 |
| April | 30 | 54 | 0 | 90 | PM2.5 |
| May | 31 | 53 | 1 | 108 | O3 |
| June | 30 | 54 | 4 | 115 | PM2.5 |
| Julyworst | 31 | 67 | 6 | 153 | PM2.5 |
| August | 31 | 60 | 4 | 151 | PM2.5 |
| September | 30 | 53 | 0 | 79 | PM2.5 |
| October | 31 | 53 | 0 | 82 | PM2.5 |
| November | 30 | 60 | 0 | 88 | PM2.5 |
| December | 31 | 63 | 0 | 84 | PM2.5 |
How 2021 compares
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 5th cleanest by days above AQI 100.
2021's median of 56 is in line with the area's typical annual median of 56.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Wilmington
The latest EPA AirNow observation puts Wilmington's AQI at 52 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Wilmington air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Philadelphia-Camden-Wilmington, PA-NJ-DE-MD), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.