Median AQI
40
Good
Maryland · County air quality · 2025
Prince George's County, Maryland
Median AQI 40 (Good). 83.8% of monitored days rated Good, direct from EPA Air Quality System stations.
- 40
- Median AQI
- 83.8%
- Good-air days
- 0
- Unhealthy days
- 66%
- Cleaner than US counties
Prince George's County's 2025 annual median AQI is 40 (Good), with 83.8% Good days
According to the U.S. EPA Air Quality System, Prince George's County, Maryland posted a 2025 median AQI of 40 (Good) across 365 monitored days, with 83.8% rated Good and 0 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Prince George's County's 83.8% Good-day share places it cleaner than 66% of US counties in 2025.
- Closest median-AQI peer
- Anderson County (91.3% Good, median AQI 40) is the closest nationwide median-AQI peer to Prince George's County.
- 2020–2025 trend
- Prince George's County's floor-qualifying Good-day share is stable from 2020 to 2025 (85.8% → 83.8%).
- Median AQI
- Median AQI: 40
The verdict
According to EPA Air Quality System monitoring data, Prince George's County's air is good on balance, cleaner than the median US county, a median AQI of 40 with 83.8% of 365 monitored days in the Good band, driven mainly by Ozone.
- 40
- median AQI · Good
- 83.8%
- days rated Good
- Ozone
- main pollutant
- 66%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 126.
Annual release change
What changed in the 2025 EPA annual release
- Prince George's County's Good-day share rose from 76.5% to 83.8% between the 2024 and 2025 EPA annual releases, a change of +7.3 percentage points.
Data updated August 2026
- Good · 306 d · 83.8%
- Moderate · 56 d · 15.3%
- USG · 3 d · 0.8%
How did Prince George's County's air break down in 2025?
Across 365 monitored days, 306 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 126 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 365 days monitored. Median AQI: 40 (Good).
Insights: Prince George's County, Maryland. EPA monitors recorded a median Air Quality Index of 40 across 365 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 306 (84%) fell in the Good band (AQI 0–50), 56 (15%) registered Moderate readings, and 3 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 57, while the worst single-day peak hit 126 (USG). Residents averaged about 25.2 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (276 days), PM2.5 (84 days), NO2 (5 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -2.0 points and the median AQI moved +1 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 126, usg but never Unhealthy. Nearby counties show comparable readings: Anne Arundel (87.6% good, AQI 40); Baltimore (64.7% good, AQI 45); Baltimore (City) (68.1% good, AQI 43); Calvert (94.6% good, AQI 38); Carroll (90.3% good, AQI 38); Cecil (79.8% good, AQI 41).
Air Quality Summary
Good Days
83.8%
306 of 365 monitored days
8.8pp vs 75% target
Max AQI Recorded
126
USG
Health Grade
Good
90th-pct AQI 57
Prince George's County, Good days share 83.8%
National avg
Share of monitored days at AQI 0-50 (Good band).
Prince George's 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 365 monitored days across EPA AQI categories.
Good
306
84%
Moderate
56
15%
USG
3
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Prince George's County.
- Ozone · 276 days · 75.6%
- PM2.5 · 84 days · 23.0%
- NO₂ · 5 days · 1.4%
Health Impact Assessment
Good
Prince George's County's air quality is rated Good based on 83.8% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 83.8% of monitored days in 2025, with a median AQI of 40. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 276 of 365 monitored days.
5-Year Air Quality Trend
Air quality is stable in Prince George's County. Highest Good-day share: 2020 (85.8%, 314 of 366 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 314 | 51 | 1 | 0 | 39 | 105 |
| 2021 | 287 | 73 | 5 | 0 | 41 | 129 |
| 2022 | 313 | 51 | 1 | 0 | 39 | 101 |
| 2023 | 253 | 101 | 8 | 3 | 44 | 192 |
| 2024 | 280 | 83 | 3 | 0 | 39 | 129 |
| 2025 | 306 | 56 | 3 | 0 | 40 | 126 |
How does Prince George's County compare?
How Prince George's County compares
Good-day share better than typical
Prince George's County 83.8%
Anderson County, South Carolina 91.3%
Typical US county 76.0%
Median AQI worse than typical
Prince George's County 40
Anderson County, South Carolina 40
Typical US county 39
Unhealthy days / yr better than typical
Prince George's County 0
Anderson County, South Carolina 0
Typical US county 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Prince George's County (40), not geographic neighbors.
Anderson County, South Carolina
Median AQI 40 · 91.3% Good-day share
Andrew County, Missouri
Median AQI 40 · 86.9% Good-day share
Anne Arundel County, Maryland
Median AQI 40 · 87.6% Good-day share
Bergen County, New Jersey
Median AQI 40 · 71.1% Good-day share
Blair County, Pennsylvania
Median AQI 40 · 76.9% Good-day share
Brazos County, Texas
Median AQI 40 · 68.5% Good-day share
Same primary pollutant: Ozone
Ozone led the AQI on the most monitored days here. These peers share that driver and the closest Good-day share (a second relationship type beyond median-AQI neighbors).
Bristol County, Massachusetts
83.8% Good-day share · median AQI 38
Essex County, New York
83.8% Good-day share · median AQI 41
Tolland County, Connecticut
83.7% Good-day share · median AQI 40
Kent County, Maryland
84.0% Good-day share · median AQI 38
Berkeley County, West Virginia
83.6% Good-day share · median AQI 39
Bennington County, Vermont
83.6% Good-day share · median AQI 37
Maryland counties on the map
Geographic containment only, other monitored counties in Maryland, independent of AQI or pollutant match.
What Prince George's 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 40 means for exposure. Health guidance
- See how Prince George's County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Prince George's County with its Maryland neighbours before drawing a conclusion about the region. All of Maryland
Based on 365 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
Keep exploring the annual AQI record
Air-quality reading list
Frequently Asked Questions
What is the air quality in Prince George's County, Maryland? ▼
Prince George's County has a median Air Quality Index (AQI) of 40, rated "Good." 83.8% of monitored days (306 out of 365) had good air quality in 2025.
What is the main pollutant in Prince George's County? ▼
The primary pollutant in Prince George's County is Ozone (O3), which was the main AQI driver on 276 days (76% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Prince George's County have? ▼
In 2025, Prince George's County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 126.
Is the air quality in Prince George's County getting better or worse? ▼
Air quality in Prince George's County is stable 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 85.8% (314 of 366 days). Lowest qualifying Good-day share: 2023 at 69.3% (253 of 365 days).
What does AQI 40 mean for health? ▼
Prince George's County's median AQI of 40 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Prince George's County compare to other counties in Maryland? ▼
Prince George's County has 83.8% good air days. Nearby counties in Maryland: Anne Arundel (87.6% good), Baltimore (64.7% good), Baltimore (City) (68.1% good), Calvert (94.6% good), Carroll (90.3% good), Cecil (79.8% good).
What is the 90th percentile AQI in Prince George's County? ▼
The 90th percentile AQI for Prince George's County is 57, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 126 (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. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Prince George's County, Maryland · 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.