Riverside Air Quality in October
Across 2019–2025, Riverside's October air quality had a median AQI of 87 (Moderate) over 217 monitored days in the Riverside-San Bernardino-Ontario, CA area. 36.0% of October days (78 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 57.6% of days. The cleanest October on record here was 2025 (median AQI 77, 1 day above 100) and the worst was 2020 (median 122, 22 days above 100, peak AQI 340).
- Good: 2.8%
- Moderate: 61.3%
- Unhealthy for Sensitive Groups: 20.3%
- Unhealthy or worse: 15.7%
Extra Protection for Riverside Homes
Air quality in Riverside is moderate (AQI 58), with fine particles (PM2.5) 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.
Recommended: Coway AP-1512HH Mighty — True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
As an Amazon Associate, we earn from qualifying purchases.
How is the air in Riverside in October?
Moderate on a typical day: median AQI 87 across 2019–2025, with 36.0% of October days above AQI 100. Ground-level ozone is the main driver.
- ✓2.8% of October days were Good (AQI 0–50), 61.3% Moderate (51–100).
- ✓78 days of 217 reached AQI 101+; the October peak was 486.
- ✓Best October: 2025; worst October: 2020.
Frequently asked questions
What is the air quality like in Riverside in October?▾
Across 2019–2025, the median daily AQI in Riverside in October was 87 (Moderate). 2.8% of days were Good, 61.3% Moderate, and 36.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is October a good time for outdoor exercise in Riverside?▾
A typical October day in Riverside is Moderate (median AQI 87): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 3 of October days (36.0%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Riverside's October air quality problems?▾
Ground-level ozone set the daily AQI on 57.6% of October days in Riverside. The highest October AQI recorded in 2019–2025 was 486 (Hazardous), in 2020.
Riverside October air quality, year by year
Riverside October air quality by year (Riverside-San Bernardino-Ontario, CA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 90 | 11 | 190 | O3 |
| 2020worst | 31 | 122 | 22 | 340 | O3 |
| 2021 | 31 | 71 | 4 | 486 | O3 |
| 2022 | 31 | 71 | 10 | 406 | O3 |
| 2023 | 31 | 72 | 12 | 170 | O3 |
| 2024 | 31 | 119 | 18 | 204 | O3 |
| 2025cleanest | 31 | 77 | 1 | 119 | O3 |
What October air means in Riverside
A typical October day in Riverside is Moderate (median AQI 87): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 3 of October days (36.0%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
October's median AQI of 87 is in line with Riverside's whole-year median of 89, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median October AQI across every EPA metro area (102,872 metro-days, 2019–2025) is 38, so Riverside runs above the national October norm; 36.0% of its October days topped AQI 100 versus 1.3% nationally (above average).
October is part of Riverside's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Riverside
The latest EPA AirNow observation puts Riverside's AQI at 58 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Riverside air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Riverside-San Bernardino-Ontario, 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.