Riverside Air Quality in April
Across 2019–2025, Riverside's April air quality had a median AQI of 93 (Moderate) over 210 monitored days in the Riverside-San Bernardino-Ontario, CA area. 40.0% of April days (84 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 76.2% of days. The cleanest April on record here was 2020 (median AQI 66, 9 days above 100) and the worst was 2023 (median 103, 17 days above 100, peak AQI 660).
- Good: 6.2%
- Moderate: 53.8%
- Unhealthy for Sensitive Groups: 32.4%
- Unhealthy or worse: 7.6%
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 April?
Moderate on a typical day: median AQI 93 across 2019–2025, with 40.0% of April days above AQI 100. Ground-level ozone is the main driver.
- ✓6.2% of April days were Good (AQI 0–50), 53.8% Moderate (51–100).
- ✓84 days of 210 reached AQI 101+; the April peak was 660.
- ✓Best April: 2020; worst April: 2023.
Frequently asked questions
What is the air quality like in Riverside in April?▾
Across 2019–2025, the median daily AQI in Riverside in April was 93 (Moderate). 6.2% of days were Good, 53.8% Moderate, and 40.0% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is April a good time for outdoor exercise in Riverside?▾
A typical April day in Riverside is Moderate (median AQI 93): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 3 of April days (40.0%) 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 April air quality problems?▾
Ground-level ozone set the daily AQI on 76.2% of April days in Riverside. The highest April AQI recorded in 2019–2025 was 660 (Hazardous), in 2023.
Riverside April air quality, year by year
Riverside April 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 | 30 | 90 | 11 | 150 | O3 |
| 2020cleanest | 30 | 66 | 9 | 197 | O3 |
| 2021 | 30 | 97 | 12 | 147 | O3 |
| 2022 | 30 | 99 | 14 | 660 | O3 |
| 2023worst | 30 | 103 | 17 | 660 | O3 |
| 2024 | 30 | 88 | 11 | 193 | O3 |
| 2025 | 30 | 86 | 10 | 154 | O3 |
What April air means in Riverside
A typical April day in Riverside is Moderate (median AQI 93): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 3 of April days (40.0%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
April's median AQI of 93 is above Riverside's whole-year median of 89, making it one of the area's dirtier periods. Nationally, the median April AQI across every EPA metro area (100,677 metro-days, 2019–2025) is 44, so Riverside runs above the national April norm; 40.0% of its April days topped AQI 100 versus 0.7% nationally (above average).
April is part of Riverside's spring season (March, April, May); the spring 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.