Median AQI
39
Good
New York · County air quality · 2025
Monroe County, New York
Median AQI 39 (Good). 74.3% of monitored days rated Good, direct from EPA Air Quality System stations.
- 39
- Median AQI
- 74.3%
- Good-air days
- 0
- Unhealthy days
- 43%
- Cleaner than US counties
Monroe County's 2025 annual median AQI is 39 (Good), with 74.3% Good days
According to the U.S. EPA Air Quality System, Monroe County, New York posted a 2025 median AQI of 39 (Good) across 365 monitored days, with 74.3% 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
- Monroe County's 74.3% Good-day share places it cleaner than 43% of US counties in 2025.
- Closest median-AQI peer
- Aiken County (90.6% Good, median AQI 39) is the closest nationwide median-AQI peer to Monroe County.
- 2020–2025 trend
- Monroe County's floor-qualifying Good-day share is stable from 2020 to 2025 (75.1% → 74.2%).
- Median AQI
- Median AQI: 39
The verdict
According to EPA Air Quality System monitoring data, Monroe County's air is good on balance, more polluted than the median US county, a median AQI of 39 with 74.3% of 365 monitored days in the Good band, driven mainly by Ozone.
- 39
- median AQI · Good
- 74.3%
- days rated Good
- Ozone
- main pollutant
- 43%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 135.
Annual release change
What changed in the 2025 EPA annual release
- Monroe County's peak single-day AQI rose from 90 to 135 between the 2024 and 2025 EPA annual releases, a change of +45 points.
Data updated August 2026
- Good · 271 d · 74.2%
- Moderate · 87 d · 23.8%
- USG · 7 d · 1.9%
How did Monroe County's air break down in 2025?
Across 365 monitored days, 271 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 135 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 365 days monitored. Median AQI: 39 (Good).
Insights: Monroe County, New York. EPA monitors recorded a median Air Quality Index of 39 across 365 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 271 (74%) fell in the Good band (AQI 0–50), 87 (24%) registered Moderate readings, and 7 (2%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 61, while the worst single-day peak hit 135 (USG). Residents averaged about 22.3 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (209 days), PM2.5 (156 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -0.9 points and the median AQI moved -2 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 135, usg but never Unhealthy. Nearby counties show comparable readings: Albany (68.5% good, AQI 39); Bronx (59.2% good, AQI 45); Chautauqua (89.0% good, AQI 36); Dutchess (94.0% good, AQI 34); Erie (63.8% good, AQI 44); Essex (83.8% good, AQI 41).
Air Quality Summary
Good Days
74.3%
271 of 365 monitored days
-0.8pp vs 75% target
Max AQI Recorded
135
USG
Health Grade
Moderate
90th-pct AQI 61
Monroe County, Good days share 74.3%
National avg
Share of monitored days at AQI 0-50 (Good band).
Monroe 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
271
74%
Moderate
87
24%
USG
7
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 Monroe County.
- Ozone · 209 days · 57.3%
- PM2.5 · 156 days · 42.7%
Health Impact Assessment
Moderate
Monroe County's air quality is rated Moderate based on 74.3% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 74.3% of monitored days in 2025, with a median AQI of 39. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 209 of 365 monitored days.
5-Year Air Quality Trend
Air quality is stable in Monroe County. Highest Good-day share: 2020 (75.1%, 275 of 366 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 275 | 91 | 0 | 0 | 41 | 81 |
| 2021 | 239 | 126 | 0 | 0 | 43 | 100 |
| 2022 | 270 | 93 | 2 | 0 | 42 | 126 |
| 2023 | 237 | 120 | 3 | 5 | 42 | 176 |
| 2024 | 271 | 95 | 0 | 0 | 38 | 90 |
| 2025 | 271 | 87 | 7 | 0 | 39 | 135 |
How does Monroe County compare?
How Monroe County compares
Good-day share worse than US avg
Monroe County 74.3%
Aiken County, South Carolina 90.6%
US average 76.0%
Median AQI about average
Monroe County 39
Aiken County, South Carolina 39
US average 39
Unhealthy days / yr better than US avg
Monroe County 0
Aiken County, South Carolina 0
US average 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as Monroe County (39), not geographic neighbors.
Aiken County, South Carolina
Median AQI 39 · 90.6% Good-day share
Albany County, New York
Median AQI 39 · 68.5% Good-day share
Anderson County, Tennessee
Median AQI 39 · 94.3% Good-day share
Bay County, Michigan
Median AQI 39 · 70.4% Good-day share
Berkeley County, West Virginia
Median AQI 39 · 83.6% Good-day share
Boyd County, Kentucky
Median AQI 39 · 80.0% 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).
Campbell County, Wyoming
74.3% Good-day share · median AQI 44
Centre County, Pennsylvania
74.3% Good-day share · median AQI 41
Cumberland County, Maine
74.3% Good-day share · median AQI 39
Tooele County, Utah
74.3% Good-day share · median AQI 44
Hunterdon County, New Jersey
74.2% Good-day share · median AQI 41
Adams County, Pennsylvania
74.4% Good-day share · median AQI 42
New York counties on the map
Geographic containment only, other monitored counties in New York, independent of AQI or pollutant match.
What Monroe 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 39 means for exposure. Health guidance
- See how Monroe County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Monroe County with its New York neighbours before drawing a conclusion about the region. All of New York
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 Monroe County, New York? ▼
Monroe County has a median Air Quality Index (AQI) of 39, rated "Good." 74.3% of monitored days (271 out of 365) had good air quality in 2025.
What is the main pollutant in Monroe County? ▼
The primary pollutant in Monroe County is Ozone (O3), which was the main AQI driver on 209 days (57% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Monroe County have? ▼
In 2025, Monroe County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 135.
Is the air quality in Monroe County getting better or worse? ▼
Air quality in Monroe 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 75.1% (275 of 366 days). Lowest qualifying Good-day share: 2023 at 64.9% (237 of 365 days).
What does AQI 39 mean for health? ▼
Monroe County's median AQI of 39 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does Monroe County compare to other counties in New York? ▼
Monroe County has 74.3% good air days. Nearby counties in New York: Albany (68.5% good), Bronx (59.2% good), Chautauqua (89.0% good), Dutchess (94.0% good), Erie (63.8% good), Essex (83.8% good).
What is the 90th percentile AQI in Monroe County? ▼
The 90th percentile AQI for Monroe County is 61, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 135 (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 Monroe County, New York · 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.