Los Angeles Air Quality in 2021
In 2021, Los Angeles's air quality (Los Angeles-Long Beach-Anaheim, CA area) had a median daily AQI of 80 (Moderate) across 365 monitored days. 98 days (26.8%) reached Unhealthy for Sensitive Groups or worse, 9 were Good, and the year's peak AQI was 281 (Very Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 198 of those days. The cleanest month of 2021 was March (median AQI 57, 0 days above 100) and the worst was August (median 129, 21 days above 100, peak 179).
- Good: 2.5%
- Moderate: 70.7%
- Unhealthy for Sensitive Groups: 19.5%
- Unhealthy or worse: 7.4%
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How was Los Angeles's air quality in 2021?
Moderate on a typical day: median AQI 80, with 98 days above AQI 100 out of 365 monitored — the 4th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2021: 281 (Very Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 198 days.
- ✓Cleanest month: March; worst: August.
Frequently asked questions
What was the average AQI in Los Angeles in 2021?▾
EPA's Air Quality System puts Los Angeles's (Los Angeles-Long Beach-Anaheim, CA) median daily AQI for 2021 at 80, which is Moderate. 98 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 281.
Which month had the worst air quality in Los Angeles in 2021?▾
The cleanest month of 2021 was March (median AQI 57, 0 days above 100) and the worst was August (median 129, 21 days above 100, peak 179).
Was 2021 a good or bad year for Los Angeles's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 4th cleanest by days above AQI 100. 2021's median of 80 is above the area's typical annual median of 74.
Los Angeles month by month in 2021
Los Angeles air quality month by month, 2021 (Los Angeles-Long Beach-Anaheim, CA, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 71 | 1 | 184 | PM2.5 |
| February | 28 | 63 | 0 | 96 | PM2.5 |
| Marchcleanest | 31 | 57 | 0 | 80 | PM2.5 |
| April | 30 | 71 | 4 | 133 | O3 |
| May | 31 | 80 | 3 | 129 | O3 |
| June | 30 | 124 | 19 | 195 | O3 |
| July | 31 | 112 | 17 | 187 | O3 |
| Augustworst | 31 | 129 | 21 | 179 | O3 |
| September | 30 | 103 | 16 | 161 | O3 |
| October | 31 | 66 | 3 | 281 | PM2.5 |
| November | 30 | 84 | 7 | 158 | PM2.5 |
| December | 31 | 72 | 7 | 155 | PM2.5 |
How 2021 compares
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 4th cleanest by days above AQI 100.
2021's median of 80 is above the area's typical annual median of 74.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Los Angeles
The latest EPA AirNow observation puts Los Angeles's AQI at 41 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Los Angeles air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Los Angeles-Long Beach-Anaheim, CA), 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.