State air quality · 2025
Puerto Rico Air Quality Ranking
Across 8 monitored counties, the typical county in Puerto Rico posts a median AQI of 22 (Good) and 84.0% of monitored days were rated Good, from EPA AQS.
- 22
- Avg median AQI
- 84.0%
- Good-air days
- 8
- Counties monitored
- 83%
- Cleaner than US states
Puerto Rico's typical county median AQI is 22 (Good) across 8 monitored counties
According to the U.S. EPA Air Quality System, Puerto Rico monitors 8 counties with a day-weighted Good-day share of 84.0%. Cleanest: Mayagnez County (97.8% Good). Most polluted: Catano County (60.6%). These are annual summaries, not live AirNow readings.
Data source EPA Air Quality System (AQS)
- Cleaner than US states
- Puerto Rico's day-weighted Good-day share of 84.0% places it cleaner than 83% of US states.
- In-state spread
- Within Puerto Rico, Guayama County leads at 98.0% Good days while Catano County sits at 60.6% across 8 monitored counties.
- 2024→2025 release
- Puerto Rico's Good-day share moved -1.0 points vs the 2024 EPA annual release.
- Typical median AQI
- Typical median AQI: 22
Verify with AirNow → · EPA AQS →
EPA state monitoring brief
AQS state key PUERTO-RICO
Puerto Rico · 2025 EPA AQS · 8 counties · med AQI 22 · 84.0% Good · Mayagnez→Catano spread
- GOOD 22 Median AQI · Good
- SHARE 84.0% Good-day share
- COUNT 8 Counties monitored
- UNH 2 Unhealthy+ days
- RANK 83% Cleaner than states
- PM25 62.0% Main pollutant share
Good-day share peers
Puerto Rico's 84.0% Good-day share is cleaner than 83% of monitored US states; Mayagnez and Catano County bracket the in-state range. Open Guayama County →
According to EPA AQS annual summaries on PlainAirData, Puerto Rico ranks #9 of 52 by day-weighted good-day share (84.0%) and #2 by mean county median AQI (21.5). Hawaii is #1 of 52 by day-weighted good-day share (93.8% of monitored days) at mean county median-AQI #4 (27.3) ≠ Alaska #1 lowest mean county median AQI (20.3) at good-day share #8 (84.4%).
Data updated August 2026
What changed, what drives it, and how thick is the sample
Three derived views WPR-style word count does not substitute for: release-over-release movement from county annual rows, the EPA main-pollutant day mix, and how many counties sit below the 100-day ranking floor.
Release change
84.0%
Good-day share in 2025, down 1.0 percentage points vs 2024. County-mean median AQI 22, within half a point of the 2024 county-mean median.
Pollutant mix
PM2.5
Main driver on 62.0% of pollutant-assigned days.
- PM2.5 62.0%
- CO 17.8%
- Ozone 15.0%
- PM10 5.2%
Monitoring coverage
189
Average monitored days per county in the latest release. 1 of 8 counties sit below the 100-day floor used for cleanest/most-polluted claims.
Counties Monitored
8
Good Days %
84.0%
Avg Median AQI
22
Total Unhealthy Days
2
Best Air Quality
Mayagnez County
Worst Air Quality
Catano County
Where Puerto Rico sits nationally
COUNT-derived placement among 52 US states with at least 365 monitored days in the latest county release. Puerto Rico's day-weighted Good-day share is 84.0% - cleaner than 83% of that comparison set.
Puerto Rico Good-day share vs. every US state
Day-weighted share of monitored days in the Good band (AQI 0–50) - EPA AQS annual release
84.0% Cleaner than 83% higher than 83% of 52 US states
Each bar is a band; taller bars hold more US states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source U.S. Environmental Protection Agency, Air Quality System (AQS) · 2025
Which counties in Puerto Rico have the cleanest and most polluted air?
Cleanest counties in Puerto Rico
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025. See our methodology for how AQI and median figures are computed.
Coverage: 8 counties in Puerto Rico with active monitoring stations. Unmonitored counties are not represented.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files, aggregated to the state level · 2020–2025
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.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.