Phoenix Air Quality in 2021
In 2021, Phoenix's air quality (Phoenix-Mesa-Scottsdale, AZ area) had a median daily AQI of 125 (Unhealthy for Sensitive Groups) across 365 monitored days. 238 days (65.2%) reached Unhealthy for Sensitive Groups or worse, 9 were Good, and the year's peak AQI was 297 (Very Unhealthy). Ground-level ozone set the daily AQI on 269 of those days. The cleanest month of 2021 was February (median AQI 65, 0 days above 100) and the worst was April (median 214, 30 days above 100, peak 236).
- Good: 2.5%
- Moderate: 32.3%
- Unhealthy for Sensitive Groups: 27.9%
- Unhealthy or worse: 37.3%
Extra Protection for Phoenix Homes
Air quality in Phoenix is moderate (AQI 75), with particle pollution the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
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How was Phoenix's air quality in 2021?
Unhealthy for Sensitive Groups on a typical day: median AQI 125, with 238 days above AQI 100 out of 365 monitored — the 7th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2021: 297 (Very Unhealthy).
- ✓Ground-level ozone was the main pollutant on 269 days.
- ✓Cleanest month: February; worst: April.
Frequently asked questions
What was the average AQI in Phoenix in 2021?▾
EPA's Air Quality System puts Phoenix's (Phoenix-Mesa-Scottsdale, AZ) median daily AQI for 2021 at 125, which is Unhealthy for Sensitive Groups. 238 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 297.
Which month had the worst air quality in Phoenix in 2021?▾
The cleanest month of 2021 was February (median AQI 65, 0 days above 100) and the worst was April (median 214, 30 days above 100, peak 236).
Was 2021 a good or bad year for Phoenix's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 7th cleanest by days above AQI 100 — the worst year on record here. 2021's median of 125 is above the area's typical annual median of 79.
Phoenix month by month in 2021
Phoenix air quality month by month, 2021 (Phoenix-Mesa-Scottsdale, AZ, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 143 | 31 | 297 | O3 |
| Februarycleanest | 28 | 65 | 0 | 87 | PM2.5 |
| March | 31 | 192 | 31 | 221 | O3 |
| Aprilworst | 30 | 214 | 30 | 236 | O3 |
| May | 31 | 93 | 11 | 129 | O3 |
| June | 30 | 95 | 13 | 203 | O3 |
| July | 31 | 108 | 20 | 198 | O3 |
| August | 31 | 100 | 15 | 182 | O3 |
| September | 30 | 213 | 30 | 239 | O3 |
| October | 31 | 197 | 31 | 217 | O3 |
| November | 30 | 86 | 6 | 125 | PM10 |
| December | 31 | 101 | 20 | 140 | O3 |
How 2021 compares
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 7th cleanest by days above AQI 100 — the worst year on record here.
2021's median of 125 is above the area's typical annual median of 79.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Phoenix
The latest EPA AirNow observation puts Phoenix's AQI at 75 (PM10). The figures above are multi-year annual statistics, not today's reading.
View current Phoenix air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Phoenix-Mesa-Scottsdale, AZ), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.