Air Quality Rankings for Puerto Rico 2026
Puerto Rico has 11 cities with EPA air quality data. Juncos, Puerto Rico has the cleanest air with a 5-year average AQI of 9. Catano, Puerto Rico has the highest AQI at 42.
| # | City | 5yr Avg AQI | Current AQI | Worst Pollutant | Trend | Grade |
|---|---|---|---|---|---|---|
| 1 | Juncos, Puerto Rico | 9 | 9 | Ozone | Improving | A |
| 2 | Caguas, Puerto Rico | 10 | 6 | NO2 | Improving | A |
| 3 | San Juan, Puerto Rico | 10 | 7 | CO | Improving | A |
| 4 | Bayamon, Puerto Rico | 18 | 22 | CO | Improving | A |
| 5 | Adjuntas, Puerto Rico | 19 | 14 | PM2.5 | Improving | A |
| 6 | Guayama, Puerto Rico | 24 | 15 | PM2.5 | Improving | B |
| 7 | Fajardo, Puerto Rico | 28 | 30 | PM2.5 | Worsening | B |
| 8 | Ponce, Puerto Rico | 29 | 30 | PM10 | Stable | B |
| 9 | Guaynabo, Puerto Rico | 29 | 32 | NO2 | Worsening | C |
| 10 | Mayagnez, Puerto Rico | 31 | 25 | PM2.5 | Worsening | C |
| 11 | Catano, Puerto Rico | 42 | 52 | PM2.5 | Worsening | D |
Air quality data for Puerto Rico is sourced from the EPA Air Quality System (AQS), which monitors outdoor air quality at thousands of stations nationwide.
Frequently Asked Questions
Juncos, Puerto Rico has the best air quality in Puerto Rico with a 5-year average AQI of 9 and a grade of A.
Puerto Rico has 11 cities with EPA air quality monitoring data in our database, covering multiple years of AQI measurements.
The Air Quality Index (AQI) measures five major pollutants: ground-level ozone, particulate matter (PM2.5 and PM10), carbon monoxide, sulfur dioxide, and nitrogen dioxide. Lower AQI values indicate cleaner air — 0-50 is "Good," while 150+ is "Unhealthy."
Cities ranked by 5-year average AQI (lower is better). Grades factor in average AQI, trend direction, unhealthy days, and dominant pollutant.