Simi Valley, California Air Quality
Simi Valley air quality today — the AQI, the main pollutant, and whether it’s safe to exercise outside right now
Simi Valley, CA · Air quality right now
The air quality index in Simi Valley, CA is 54 (Moderate) right now — acceptable for most people.
Is it safe to be outside in Simi Valley today?
AQI 54 Yes — air quality is Moderate
Fine for most; unusually sensitive people can take it easy.Main pollutant: PM2.5Observed 12:00 AM PDT
Pollutants right now
- PM2.510 µg/m³Main pollutantfine particles — smoke, exhaust, soot
- PM1012 µg/m³coarse particles — dust, pollen, ash
- Ozone37 µg/m³smog — builds on hot, sunny days
- NO₂15 µg/m³nitrogen dioxide — traffic, combustion
ExerciseOK to run for most; sensitive athletes can ease the intensity.
How to read Simi Valley’s air quality
Guides: The AQI Scale, Explained · Air Quality Alerts, Decoded · How to Read a Wildfire Smoke Map · Why Wildfire Smoke Travels 1,000 Miles.
Air quality over time in Simi Valley
Across the EPA’s county records from 2020 to 2025, Simi Valley’s cleanest year was 2023 (median AQI 46) and its most polluted was 2021 (median AQI 53); the typical (median) day has trended cleaner since 2020.
| Year | Median AQI | Unhealthy+ | Main pollutant | USG | Moderate | Good |
|---|---|---|---|---|---|---|
| 2020 | 50 | 5 | Ozone | 21 | 155 | 185 |
| 2021 | 53 | 0 | Ozone | 10 | 198 | 157 |
| 2022 | 52 | 0 | Ozone | 11 | 183 | 171 |
| 2023 | 46 | 0 | Ozone | 12 | 133 | 220 |
| 2024 | 50 | 1 | Ozone | 14 | 160 | 191 |
| 2025 | 50 | 0 | Ozone | 8 | 167 | 190 |
“USG” is Unhealthy for Sensitive Groups (AQI 101–150); “Unhealthy+” combines the Unhealthy, Very Unhealthy, and Hazardous days. In 2024 the EPA tightened the annual fine-particle (PM2.5) standard to 9 µg/m³ from the previous 12 µg/m³, so counties near the old limit read worse against the new one. Source: EPA AQS annual summaries, 2020–2025.
Frequently asked
- What was the worst year for air quality in Simi Valley?
- In the EPA's 2020–2025 county records, 2020 had the most days above AQI 100: 26 days (21 Unhealthy for Sensitive Groups, 5 Unhealthy or worse). The highest median AQI came in 2021 (53; 2020's was 50).
- How many unhealthy air days does Simi Valley have?
- Across 2020–2025, 4% of the days reported for Simi Valley's county had an AQI above 100 (82 of 2192), about 14 days a year. 2025 had 8 days.
- What's the main air pollutant in Simi Valley?
- Ozone: it drove Simi Valley's county AQI on the most days in every year of the EPA's 2020–2025 records.