Metro area air quality · 2024
Riverside-San Bernardino-Ontario, CA
Median AQI 97 (Moderate). 7.1% of monitored days rated Good across this metro's EPA monitoring network.
- 97
- Median AQI
- 7.1%
- Good-air days
- 98
- Unhealthy days
- 0%
- Cleaner than US metros
Aggregated from EPA Air Quality System (2024), 366 monitored days. EPA AQS → · NOAA →
Insights: Riverside-San Bernardino-Ontario, CA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 97 over 366 measured days in 2024, which corresponds to a Moderate band and a Very Poor metro-wide health grade. The monitored-day split lands at 26 Good days (7%), 176 Moderate (48%), and 66 Unhealthy-for-Sensitive-Groups (18%). The 90th-percentile AQI finished at 185 while the highest single-day reading hit 593 (Hazardous). Metro residents averaged roughly 2.1 clean-air days per 30-day window across the reporting year.
Across the 2020–2024 trend window, good days shifted by +3 and the median AQI moved -1 points, which classifies the multi-year trajectory as stable. The metro recorded 98 unhealthy-or-worse days combined, on those days the EPA recommends that sensitive groups limit prolonged outdoor exertion, and many schools and athletic programs adjust outdoor activity accordingly. Metros with comparable AQI profiles include Phoenix-Mesa-Scottsdale, AZ (6.8% good, AQI 86); Los Angeles-Long Beach-Anaheim, CA (10.1% good, AQI 80); Bakersfield, CA (20.8% good, AQI 72).
Air Quality Summary
Median AQI
97
Moderate
Good Days
7.1%
26 of 366 days
Max AQI
593
Hazardous
Health Grade
Very Poor
90th pct: 185
AQI Day Breakdown (2024)
Distribution of 366 monitored days across EPA AQI categories.
Good
26
7%
Moderate
176
48%
USG
66
18%
Unhealthy
71
19%
Very Unhealthy
26
7%
Hazardous
1
0%
Health Impact Assessment
The Riverside-San Bernardino-Ontario, CA metro area's air quality is rated Very Poor based on 7.1% good air days. There were 98 unhealthy days in 2024 when outdoor activity should be limited.
Air quality posed significant health risk in 2024. Sensitive groups, including people with asthma, COPD, cardiovascular conditions, children, pregnant women, and adults over 65, should monitor AirNow.gov alerts and limit outdoor activity on Unhealthy (AQI 151+) and Very Unhealthy (201+) days. Peak readings reached AQI 593, beyond EPA's standard 0-500 scale, indicating an extreme event.
Sensitive group advisory
People with asthma, COPD, heart disease, children, pregnant women, and adults 65+ should follow EPA AQI alerts daily and limit outdoor exertion when AQI exceeds 100. Real-time conditions: airnow.gov.
Note: EPA's standard AQI scale caps at 500. The 593 peak reading represents an extreme event extrapolated beyond the index's design range. See EPA wildfire smoke guidance.
How does the Riverside-San Bernardino-Ontario, CA metro compare?
How Riverside-San Bernardino-Ontario, CA compares
5-Year Air Quality Trend
Air quality is stable in the Riverside-San Bernardino-Ontario, CA metro. Best year: 2023 (35 good days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 23 | 167 | 72 | 98 | 584 |
| 2021 | 9 | 190 | 69 | 97 | 486 |
| 2022 | 9 | 206 | 61 | 87 | 1683 |
| 2023 | 35 | 187 | 51 | 84 | 660 |
| 2024 | 26 | 176 | 71 | 97 | 593 |
Metros with Similar Air Quality
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Frequently Asked Questions
What is the air quality in the Riverside-San Bernardino-Ontario, CA metro area? ▼
How many unhealthy air days does Riverside-San Bernardino-Ontario, CA have? ▼
Is air quality in Riverside-San Bernardino-Ontario, CA getting better or worse? ▼
What does AQI 97 mean for health? ▼
What is the 90th percentile AQI for Riverside-San Bernardino-Ontario, CA? ▼
How does Riverside-San Bernardino-Ontario, CA compare to other metro areas? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2024. The AQS collects ambient air monitoring data from state, local, and tribal monitoring agencies across the United States.
Metrics: Air Quality Index (AQI) is calculated using EPA-standard breakpoints for six criteria pollutants: PM2.5, PM10, Ozone, NO2, CO, and SO2. Median AQI, max AQI, and 90th percentile AQI are computed from daily measurements. Good days percentage reflects days with AQI 0–50.
Coverage: 501 metro areas (Core Based Statistical Areas). Only metros with active monitoring stations are included. Unmonitored areas are not represented.
Read our methodology , how this data is sourced, computed, and verified.
Source: U.S. EPA, AirNow / AQS Air Quality Index readings and pollutant concentrations · 2025