Lancaster, California Air Quality
Lancaster air quality today — the AQI, the main pollutant, and whether it’s safe to exercise outside right now
Lancaster, CA · Air quality right now
The air quality index in Lancaster, CA is 50 (Good) right now — safe for outdoor activity.
Is it safe to be outside in Lancaster today?
AQI 50 Yes — air quality is Good
Air is clean — great for outdoor activity.Main pollutant: PM2.5Observed 6:00 AM PDT
Pollutants right now
- PM2.517 µg/m³Main pollutantfine particles — smoke, exhaust, soot
- PM1024 µg/m³coarse particles — dust, pollen, ash
- Ozone40 µg/m³smog — builds on hot, sunny days
- NO₂14 µg/m³nitrogen dioxide — traffic, combustion
ExerciseOK to run — no air-quality limits on outdoor exercise.
How to read Lancaster’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 Lancaster
Across the EPA’s county records from 2020 to 2025, Lancaster’s cleanest year was 2023 (median AQI 67) and its most polluted was 2020 (median AQI 85); the typical (median) day has trended cleaner since 2020.
| Year | Median AQI | Unhealthy+ | Main pollutant | USG | Moderate | Good |
|---|---|---|---|---|---|---|
| 2020 | 85 | 60 | Ozone | 77 | 194 | 35 |
| 2021 | 79 | 27 | PM2.5 | 70 | 259 | 9 |
| 2022 | 74 | 29 | Ozone | 65 | 254 | 17 |
| 2023 | 67 | 35 | PM2.5 | 52 | 237 | 41 |
| 2024 | 80 | 55 | Ozone | 78 | 195 | 38 |
| 2025 | 74 | 32 | Ozone | 66 | 228 | 39 |
“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 Lancaster?
- In the EPA's 2020–2025 county records, 2020 had the most days above AQI 100: 137 days (77 Unhealthy for Sensitive Groups, 60 Unhealthy or worse). It also had the highest median AQI, 85.
- How many unhealthy air days does Lancaster have?
- Across 2020–2025, 29% of the days reported for Lancaster's county had an AQI above 100 (646 of 2192), about 108 days a year. 2025 had 98 days.
- What's the main air pollutant in Lancaster?
- Ozone drove Lancaster's county AQI on the most days in 4 of 6 years (2020–2025); PM2.5 in 2021, 2023.