Metro area air quality · 2025

Dover, DE

Median AQI 41 (Good). 75.6% of monitored days rated Good across this metro's EPA monitoring network.

41
Median AQI
75.6%
Good-air days
0
Unhealthy days
57%
Cleaner than US metros

Dover, DE posted a 2025 median AQI of 41 (Good) with 75.6% Good days

According to the U.S. EPA Air Quality System, the Dover, DE CBSA recorded a median AQI of 41 across 365 monitored days in 2025, with 75.6% rated Good and 0 unhealthy or worse. This is an annual metro comparison, not a live advisory.

Data source EPA Air Quality System (AQS)

Cleaner than US metros
The Dover, DE CBSA's 75.6% Good-day share places it cleaner than 57% of US metros in 2025.
Closest median-AQI peer
Adrian, MI (69.3% Good, median AQI 41) is the closest nationwide median-AQI peer to Dover, DE.
2020–2025 Good-day shift
Dover, DE's Good-day share moved -5.3 points from 2020 to 2025 (median AQI +2).
Median AQI
Median AQI: 41

Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →

The verdict

The Dover, DE metro runs good on the EPA scale, cleaner than the median US metro, a median AQI of 41 with 75.6% of 365 monitored days in the Good band.

41
median AQI · Good
75.6%
days rated Good
57%
cleaner than US metros
122
worst single reading

No day crossed into the Unhealthy tier across the metro's monitors in 2025.

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • Dover, DE metro's peak single-day AQI rose from 100 to 122 between the 2024 and 2025 EPA annual releases, a change of +22 points.
  • Dover, DE metro's Good-day share rose from 74.4% to 76.5% between the 2024 and 2025 EPA annual releases, a change of +2.0 percentage points.

Compared against 336 monitored days in 2024 and 361 in 2025. These are arithmetic differences between two stored EPA annual summaries, not a cause claim or a live advisory.

National release changes Two-year CSV

Insights: Dover, DE metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 41 over 365 measured days in 2025, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 276 Good days (76%), 85 Moderate (23%), and 4 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 62 while the highest single-day reading hit 122 (USG). Metro residents averaged roughly 22.7 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -5.3 points and the median AQI moved +2 points, which classifies the multi-year trajectory as worsening. The metro recorded no Unhealthy-tier days in this annual dataset. Metros with comparable AQI profiles include Adrian, MI (69.3% good, AQI 41); Albany-Schenectady-Troy, NY (67.7% good, AQI 41); Ann Arbor, MI (69.3% good, AQI 41).

Air Quality Summary

Median AQI

41

Good

Good Days

75.6%

276 of 365 days

Max AQI

122

USG

Health Grade

Good

90th pct: 62

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

276

76%

Moderate

85

23%

USG

4

1%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Dover, DE metro area's air quality is rated Good based on 75.6% good air days. No unhealthy air days were recorded in 2025.

Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.

How does the Dover, DE metro compare?

How Dover, DE compares

Good-day share better than typical
Dover, DE 75.6%
Adrian, MI 69.3%
Typical US metro 70.6%
Median AQI about typical
Dover, DE 41
Adrian, MI 41
Typical US metro 41
Unhealthy days / yr better than typical
Dover, DE 0
Adrian, MI 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Dover, DE metro. Highest Good-day share: 2020 (81.8%, 296 of 362 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 296 66 0 39
2021 260 98 0 42
2022 277 87 0 42
2023 216 124 2 46
2024 250 86 0 41
2025 276 85 0 41

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Dover, DE (41).

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Dover, DE's 0 (independent of median AQI).

More Air Quality Data

Explore EPA air quality rankings and guides across U.S. metros and counties.

Air Quality Guides

Frequently Asked Questions

What is the air quality in the Dover, DE metro area?
The Dover, DE metro area has a median Air Quality Index (AQI) of 41, rated "Good." 75.6% of monitored days (276 out of 365) had good air quality in 2025.
How many unhealthy air days does Dover, DE have?
In 2025, the Dover, DE metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 122.
Is air quality in Dover, DE getting better or worse?
Air quality in the Dover, DE metro is worsening across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2020 at 81.8% (296 of 362 days). Lowest qualifying Good-day share: 2023 at 63.2% (216 of 342 days).
What does AQI 41 mean for health?
An AQI of 41 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
What is the 90th percentile AQI for Dover, DE?
The 90th percentile AQI for the Dover, DE metro area is 62, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 122 (USG).
How does Dover, DE compare to other metro areas?
The Dover, DE metro has 75.6% good air days. Similar metros: Adrian, MI (69.3% good), Albany-Schenectady-Troy, NY (67.7% good), Ann Arbor, MI (69.3% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2025. See our methodology for how AQI, median, and coverage figures are computed.

Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary files (metro-level) · 2020–2025

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Every figure on PlainAirData is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.