Wilmington Air Quality in Spring
Across 2019–2025, Wilmington's spring (March–May) air quality had a median AQI of 53 (Moderate) over 644 monitored days in the Philadelphia-Camden-Wilmington, PA-NJ-DE-MD area. 0.6% of spring days (4 of 644) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 63.5% of days. The cleanest spring on record here was 2025 (median AQI 51, 0 days above 100) and the worst was 2024 (median 54, 2 days above 100, peak AQI 129).
- Good: 38.2%
- Moderate: 61.2%
- Unhealthy for Sensitive Groups: 0.6%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Wilmington
Today's main pollutant in Wilmington is ground-level ozone (AQI 31). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in Wilmington in spring?
Moderate on a typical day: median AQI 53 across 2019–2025, with 0.6% of spring days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓38.2% of spring days were Good (AQI 0–50), 61.2% Moderate (51–100).
- ✓4 days of 644 reached AQI 101+; the spring peak was 129.
- ✓Cleanest month: March; worst month: May.
Frequently asked questions
What is the air quality like in Wilmington in spring?▾
Across 2019–2025, the median daily AQI in Wilmington in spring was 53 (Moderate). 38.2% of days were Good, 61.2% Moderate, and 0.6% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is spring a good time for outdoor exercise in Wilmington?▾
A typical spring day in Wilmington is Moderate (median AQI 53): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of spring days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Wilmington's spring air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 63.5% of spring days in Wilmington. The highest spring AQI recorded in 2019–2025 was 129 (Unhealthy for Sensitive Groups), in 2024.
Wilmington spring air quality, year by year
Wilmington spring air quality by year (Philadelphia-Camden-Wilmington, PA-NJ-DE-MD, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 92 | 52 | 0 | 87 | PM2.5 |
| 2020 | 92 | 52 | 0 | 80 | PM2.5 |
| 2021 | 92 | 53 | 1 | 108 | PM2.5 |
| 2022 | 92 | 55 | 0 | 93 | PM2.5 |
| 2023 | 92 | 56 | 1 | 108 | PM2.5 |
| 2024worst | 92 | 54 | 2 | 129 | PM2.5 |
| 2025cleanest | 92 | 51 | 0 | 97 | O3 |
What spring air means in Wilmington
A typical spring day in Wilmington is Moderate (median AQI 53): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of spring days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Spring's median AQI of 53 is in line with Wilmington's whole-year median of 56, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Spring AQI across every EPA metro area (307,196 metro-days, 2019–2025) is 43, so Wilmington runs above the national Spring norm; 0.6% of its Spring days topped AQI 100 versus 0.8% nationally (about the same).
Within the season, March is the cleanest month (median AQI 53, 0.0% of days above 100) and May the worst (median 54, 1.4% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Wilmington
The latest EPA AirNow observation puts Wilmington's AQI at 31 (O3). The figures above are multi-year season 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.