Riverside Air Quality in August
Across 2019–2025, Riverside's August air quality had a median AQI of 156 (Unhealthy) over 217 monitored days in the Riverside-San Bernardino-Ontario, CA area. 89.9% of August days (195 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 95.4% of days. The cleanest August on record here was 2023 (median AQI 150, 23 days above 100) and the worst was 2019 (median 169, 31 days above 100, peak AQI 201).
- Good: 0.5%
- Moderate: 9.7%
- Unhealthy for Sensitive Groups: 29.5%
- Unhealthy or worse: 60.4%
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
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How is the air in Riverside in August?
Unhealthy on a typical day: median AQI 156 across 2019–2025, with 89.9% of August days above AQI 100. Ground-level ozone is the main driver.
- ✓0.5% of August days were Good (AQI 0–50), 9.7% Moderate (51–100).
- ✓195 days of 217 reached AQI 101+; the August peak was 236.
- ✓Best August: 2023; worst August: 2019.
Frequently asked questions
What is the air quality like in Riverside in August?▾
Across 2019–2025, the median daily AQI in Riverside in August was 156 (Unhealthy). 0.5% of days were Good, 9.7% Moderate, and 89.9% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is August a good time for outdoor exercise in Riverside?▾
A typical August day in Riverside is Unhealthy (median AQI 156): everyone should limit prolonged outdoor exertion, and sensitive groups should avoid it; about 90% of August days (89.9%) were at AQI 101+.
Which pollutant causes Riverside's August air quality problems?▾
Ground-level ozone set the daily AQI on 95.4% of August days in Riverside. The highest August AQI recorded in 2019–2025 was 236 (Very Unhealthy), in 2019.
Riverside August air quality, year by year
Riverside August 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 |
|---|---|---|---|---|---|
| 2019worst | 31 | 169 | 31 | 201 | O3 |
| 2020 | 31 | 161 | 31 | 236 | O3 |
| 2021 | 31 | 164 | 29 | 215 | O3 |
| 2022 | 31 | 151 | 29 | 218 | O3 |
| 2023cleanest | 31 | 150 | 23 | 205 | O3 |
| 2024 | 31 | 156 | 25 | 205 | O3 |
| 2025 | 31 | 156 | 27 | 202 | O3 |
What August air means in Riverside
A typical August day in Riverside is Unhealthy (median AQI 156): everyone should limit prolonged outdoor exertion, and sensitive groups should avoid it; about 90% of August days (89.9%) were at AQI 101+.
August's median AQI of 156 is above Riverside's whole-year median of 89, making it one of the area's dirtier periods. Nationally, the median August AQI across every EPA metro area (104,152 metro-days, 2019–2025) is 45, so Riverside runs above the national August norm; 89.9% of its August days topped AQI 100 versus 3.5% nationally (above average).
August is part of Riverside's summer season (June, July, August); the summer 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.