Las Vegas Air Quality in September
Across 2019–2025, Las Vegas's September air quality had a median AQI of 66 (Moderate) over 210 monitored days in the Las Vegas-Henderson-Paradise, NV area. 6.2% of September days (13 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 80.0% of days. The cleanest September on record here was 2023 (median AQI 52, 0 days above 100) and the worst was 2022 (median 64, 5 days above 100, peak AQI 480).
- Good: 20.0%
- Moderate: 73.8%
- Unhealthy for Sensitive Groups: 4.3%
- Unhealthy or worse: 1.9%
Reduce Indoor Ozone in Las Vegas
Today's main pollutant in Las Vegas is ground-level ozone (AQI 31). 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 Las Vegas in September?
Moderate on a typical day: median AQI 66 across 2019–2025, with 6.2% of September days above AQI 100. Ground-level ozone is the main driver.
- ✓20.0% of September days were Good (AQI 0–50), 73.8% Moderate (51–100).
- ✓13 days of 210 reached AQI 101+; the September peak was 480.
- ✓Best September: 2023; worst September: 2022.
Frequently asked questions
What is the air quality like in Las Vegas in September?▾
Across 2019–2025, the median daily AQI in Las Vegas in September was 66 (Moderate). 20.0% of days were Good, 73.8% Moderate, and 6.2% 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 Las Vegas?▾
A typical September day in Las Vegas is Moderate (median AQI 66): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 16 of September days (6.2%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Las Vegas's September air quality problems?▾
Ground-level ozone set the daily AQI on 80.0% of September days in Las Vegas. The highest September AQI recorded in 2019–2025 was 480 (Hazardous), in 2022.
Las Vegas September air quality, year by year
Las Vegas September air quality by year (Las Vegas-Henderson-Paradise, NV, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 64 | 0 | 90 | O3 |
| 2020 | 30 | 79 | 4 | 174 | O3 |
| 2021 | 30 | 69 | 1 | 108 | O3 |
| 2022worst | 30 | 64 | 5 | 480 | O3 |
| 2023cleanest | 30 | 52 | 0 | 84 | O3 |
| 2024 | 30 | 74 | 3 | 170 | O3 |
| 2025 | 30 | 53 | 0 | 84 | O3 |
What September air means in Las Vegas
A typical September day in Las Vegas is Moderate (median AQI 66): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 16 of September days (6.2%) 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 66 is above Las Vegas's whole-year median of 62, 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 Las Vegas runs above the national September norm; 6.2% of its September days topped AQI 100 versus 2.7% nationally (above average).
September is part of Las Vegas's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Las Vegas
The latest EPA AirNow observation puts Las Vegas's AQI at 31 (O3). The figures above are multi-year month statistics, not today's reading.
View current Las Vegas air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Las Vegas-Henderson-Paradise, NV), 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.