Median AQI
44
Good
Delaware · County air quality · 2025
Kent County, Delaware
Median AQI 44 (Good). 70.2% of monitored days rated Good, direct from EPA Air Quality System stations.
- 44
- Median AQI
- 70.2%
- Good-air days
- 0
- Unhealthy days
- 31%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Kent County's air is good on balance, more polluted than the median US county, a median AQI of 44 with 70.2% of 181 monitored days in the Good band, driven mainly by Ozone.
- 44
- median AQI · Good
- 70.2%
- days rated Good
- Ozone
- main pollutant
- 31%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 122.
Data updated July 2026
- Good · 127 d · 70.2%
- Moderate · 51 d · 28.2%
- USG · 3 d · 1.7%
How did Kent County's air break down in 2025?
Across 181 monitored days, 127 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 122 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 181 days monitored. Median AQI: 44 (Good).
Insights: Kent County, Delaware. EPA monitors recorded a median Air Quality Index of 44 across 181 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 127 (70%) fell in the Good band (AQI 0–50), 51 (28%) registered Moderate readings, and 3 (2%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 64, while the worst single-day peak hit 122 (USG). Residents averaged about 21.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (118 days), PM2.5 (63 days). Across the 2020–2025 trend window, good days shifted by -169 and the median AQI moved +5 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 122, usg but never Unhealthy. Nearby counties show comparable readings: New Castle (60.4% good, AQI 46); Sussex (79.6% good, AQI 43).
Air Quality Summary
Good Days
70.2%
127 of 181 monitored days
-4.8pp vs 75% target
Max AQI Recorded
122
USG
Health Grade
Moderate
90th-pct AQI 64
Kent County, Good days share 70.2%
National avg
Share of monitored days at AQI 0-50 (Good band).
Kent County, Unhealthy-or-worse share 0.0%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 181 monitored days across EPA AQI categories.
Good
127
70%
Moderate
51
28%
USG
3
2%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Kent County.
- Ozone · 118 days · 65.2%
- PM2.5 · 63 days · 34.8%
Health Impact Assessment
Moderate
Kent County's air quality is rated Moderate based on 70.2% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 70.2% of monitored days in 2025, with a median AQI of 44. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 118 of 181 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Kent County. Best year: 2020 (296 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 296 | 66 | 0 | 0 | 39 | 80 |
| 2021 | 260 | 98 | 2 | 0 | 42 | 108 |
| 2022 | 277 | 87 | 0 | 0 | 42 | 84 |
| 2023 | 216 | 124 | 5 | 2 | 46 | 207 |
| 2024 | 250 | 86 | 0 | 0 | 41 | 100 |
| 2025 | 127 | 51 | 3 | 0 | 44 | 122 |
How does Kent County compare?
How Kent County compares
Good-day share worse than US avg
Kent County 70.2%
New Castle County, Delaware 60.4%
US average 76.5%
Median AQI worse than US avg
Kent County 44
New Castle County, Delaware 46
US average 38
Unhealthy days / yr about average
Kent County 0
New Castle County, Delaware 1
US average 0
Other Counties in Delaware
Air quality comparison for nearby counties in Delaware.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Kent County.
Baltimore County, Maryland
AQI 44 · 70.4% good
Baltimore (City) County, Maryland
AQI 44 · 68.7% good
Bartholomew County, Indiana
AQI 44 · 69.2% good
Berks County, Pennsylvania
AQI 44 · 65.6% good
Bolivar County, Mississippi
AQI 44 · 70.3% good
Brewster County, Texas
AQI 44 · 69.0% good
What Kent County's air means for you
The air here stays in the breathable range year-round, with Ozone the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 44 means for exposure. Health guidance
- See how Kent County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Kent County with its Delaware neighbours before drawing a conclusion about the region. All of Delaware
Based on 181 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Kent County, Delaware? ▼
Kent County has a median Air Quality Index (AQI) of 44, rated "Good." 70.2% of monitored days (127 out of 181) had good air quality in 2025.
What is the main pollutant in Kent County? ▼
The primary pollutant in Kent County is Ozone (O3), which was the main AQI driver on 118 days (65% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Kent County have? ▼
In 2025, Kent County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 122.
Is the air quality in Kent County getting better or worse? ▼
Air quality in Kent County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 296 good days. Worst year: 2025 with 127 good days.
What does AQI 44 mean for health? ▼
Kent County's median AQI of 44 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Kent County compare to other counties in Delaware? ▼
Kent County has 70.2% good air days. Nearby counties in Delaware: New Castle (60.4% good), Sussex (79.6% good).
What is the 90th percentile AQI in Kent County? ▼
The 90th percentile AQI for Kent County is 64, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 122 (USG).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
Every figure on PlainAir 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.