Bakersfield Air Quality in September
Across 2019–2025, Bakersfield's September air quality had a median AQI of 100 (Moderate) over 210 monitored days in the Bakersfield, CA area. 49.5% of September days (104 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 71.4% of days. The cleanest September on record here was 2025 (median AQI 76, 7 days above 100) and the worst was 2020 (median 154, 28 days above 100, peak AQI 267).
- Good: 6.2%
- Moderate: 44.3%
- Unhealthy for Sensitive Groups: 33.3%
- Unhealthy or worse: 16.2%
Reduce Indoor Ozone in Bakersfield
Today's main pollutant in Bakersfield is ground-level ozone (AQI 74). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in Bakersfield in September?
Moderate on a typical day: median AQI 100 across 2019–2025, with 49.5% of September days above AQI 100. Ground-level ozone is the main driver.
- ✓6.2% of September days were Good (AQI 0–50), 44.3% Moderate (51–100).
- ✓104 days of 210 reached AQI 101+; the September peak was 267.
- ✓Best September: 2025; worst September: 2020.
Frequently asked questions
What is the air quality like in Bakersfield in September?▾
Across 2019–2025, the median daily AQI in Bakersfield in September was 100 (Moderate). 6.2% of days were Good, 44.3% Moderate, and 49.5% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is September a good time for outdoor exercise in Bakersfield?▾
A typical September day in Bakersfield is Moderate (median AQI 100): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 2 of September days (49.5%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Bakersfield's September air quality problems?▾
Ground-level ozone set the daily AQI on 71.4% of September days in Bakersfield. The highest September AQI recorded in 2019–2025 was 267 (Very Unhealthy), in 2020.
Bakersfield September air quality, year by year
Bakersfield September air quality by year (Bakersfield, CA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 84 | 11 | 151 | O3 |
| 2020worst | 30 | 154 | 28 | 267 | O3 |
| 2021 | 30 | 116 | 22 | 253 | O3 |
| 2022 | 30 | 104 | 15 | 177 | O3 |
| 2023 | 30 | 86 | 8 | 156 | O3 |
| 2024 | 30 | 100 | 13 | 154 | O3 |
| 2025cleanest | 30 | 76 | 7 | 140 | O3 |
What September air means in Bakersfield
A typical September day in Bakersfield is Moderate (median AQI 100): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 2 of September days (49.5%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
September's median AQI of 100 is above Bakersfield's whole-year median of 72, making it one of the area's dirtier periods. Nationally, the median September AQI across every EPA metro area (100,699 metro-days, 2019–2025) is 43, so Bakersfield runs above the national September norm; 49.5% of its September days topped AQI 100 versus 2.7% nationally (above average).
September is part of Bakersfield's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Bakersfield
The latest EPA AirNow observation puts Bakersfield's AQI at 74 (O3). The figures above are multi-year month statistics, not today's reading.
View current Bakersfield air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Bakersfield, 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.