Irvine Best & Worst AQI Days: Air Quality Guide
The worst air quality day on record for Irvine (Los Angeles-Long Beach-Anaheim, CA area) was October 11, 2021, when the daily AQI reached 281 (Very Unhealthy), set by coarse dust (PM10). Across 2,557 monitored days in 2019–2025, 10 of the 10 worst days were Unhealthy (AQI 151+) or worse; 6 of the 10 were driven by ground-level ozone and 3 by fine particulate matter (PM2.5), and 8 of them fell in 2020. The cleanest day was December 31, 2022 at AQI 31 (Good); the 10 best days span 5 different years.
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When were Irvine's worst and best air quality days?
Worst: October 11, 2021, AQI 281 (Very Unhealthy, PM10). Best: December 31, 2022, AQI 31 (Good). Based on 2,557 EPA-monitored days in the Los Angeles-Long Beach-Anaheim, CA area, 2019–2025.
- ✓10 of the 10 worst days were Unhealthy (AQI 151+) or worse; the 10th-worst was AQI 217 (Very Unhealthy).
- ✓Ground-level ozone drove 6 of the 10 worst days.
- ✓2020 accounts for 8 of the 10 worst days.
Frequently asked questions
What was the worst air quality day in Irvine?▾
October 11, 2021: the Los Angeles-Long Beach-Anaheim, CA area's daily AQI hit 281 (Very Unhealthy), driven by coarse dust (PM10). That is the highest of 2,557 monitored days in 2019–2025.
What was the best air quality day in Irvine?▾
December 31, 2022, with a daily AQI of 31 (Good). The daily AQI is the highest reading from any monitor in the area, so even the cleanest day reflects the area's worst monitor.
What was Irvine's worst air quality day in 2025?▾
June 18, 2025, AQI 201 (Very Unhealthy), set by ground-level ozone, in peak ozone season.
Which pollutant causes Irvine's worst air days?▾
Ground-level ozone set the AQI on 6 of the 10 worst days; fine particulate matter (PM2.5) on 3. The tables above list the defining pollutant for every day.
Irvine's 10 worst air quality days, 2019–2025
Highest daily AQI recorded for the Los Angeles-Long Beach-Anaheim, CA area (EPA AQS). The daily AQI is the highest reading from any monitor in the area that day.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2021 page) | 281 | Very Unhealthy | PM10 — coarse dust (PM10) |
| 2 | (2020 page) | 250 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 3 | (2020 page) | 235 | Very Unhealthy | O3 — ground-level ozone |
| 4 | (2024 page) | 230 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 5 | (2020 page) | 223 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 6 | (2020 page) | 222 | Very Unhealthy | O3 — ground-level ozone, in peak ozone season |
| 7 | (2020 page) | 220 | Very Unhealthy | O3 — ground-level ozone |
| 8 | (2020 page) | 220 | Very Unhealthy | O3 — ground-level ozone, in peak ozone season |
| 9 | (2020 page) | 218 | Very Unhealthy | O3 — ground-level ozone, in peak ozone season |
| 10 | (2020 page) | 217 | Very Unhealthy | O3 — ground-level ozone, in peak ozone season |
Worst day of each year in Irvine
The single highest-AQI day in each year on record. Click a year for its full month-by-month statistics.
| Year | Worst day | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 2019 | 201 | Very Unhealthy | O3 — ground-level ozone, in peak ozone season | |
| 2020 | 250 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2021 | 281 | Very Unhealthy | PM10 — coarse dust (PM10) | |
| 2022 | 209 | Very Unhealthy | O3 — ground-level ozone | |
| 2023 | 210 | Very Unhealthy | O3 — ground-level ozone, in peak ozone season | |
| 2024 | 230 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2025 | 201 | Very Unhealthy | O3 — ground-level ozone, in peak ozone season |
Irvine's 10 best air quality days, 2019–2025
Lowest daily AQI recorded for the Los Angeles-Long Beach-Anaheim, CA area. Ties are listed most recent first.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2022 page) | 31 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 2 | (2020 page) | 31 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 3 | (2020 page) | 35 | Good | O3 — ground-level ozone |
| 4 | (2023 page) | 37 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 5 | (2025 page) | 38 | Good | O3 — ground-level ozone |
| 6 | (2025 page) | 38 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 7 | (2024 page) | 38 | Good | O3 — ground-level ozone |
| 8 | (2023 page) | 38 | Good | O3 — ground-level ozone |
| 9 | (2023 page) | 38 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 10 | (2023 page) | 38 | Good | O3 — ground-level ozone |
Right now in Irvine
The latest EPA AirNow observation puts Irvine's AQI at 48 (PM2.5). The days above are historical records, not today's reading.
View current Irvine 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.