Atlanta Air Quality in September
Across 2019–2025, Atlanta's September air quality had a median AQI of 58 (Moderate) over 210 monitored days in the Atlanta-Sandy Springs-Roswell, GA area. 6.2% of September days (13 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 61.0% of days. The cleanest September on record here was 2020 (median AQI 51, 0 days above 100) and the worst was 2019 (median 74, 6 days above 100, peak AQI 172).
- Good: 25.7%
- Moderate: 68.1%
- Unhealthy for Sensitive Groups: 5.7%
- Unhealthy or worse: 0.5%
Extra Protection for Atlanta Homes
Air quality in Atlanta is moderate (AQI 56), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
Recommended: Coway AP-1512HH Mighty — True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
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How is the air in Atlanta in September?
Moderate on a typical day: median AQI 58 across 2019–2025, with 6.2% of September days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓25.7% of September days were Good (AQI 0–50), 68.1% Moderate (51–100).
- ✓13 days of 210 reached AQI 101+; the September peak was 172.
- ✓Best September: 2020; worst September: 2019.
Frequently asked questions
What is the air quality like in Atlanta in September?▾
Across 2019–2025, the median daily AQI in Atlanta in September was 58 (Moderate). 25.7% of days were Good, 68.1% 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 Atlanta?▾
A typical September day in Atlanta is Moderate (median AQI 58): 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 Atlanta's September air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 61.0% of September days in Atlanta. The highest September AQI recorded in 2019–2025 was 172 (Unhealthy), in 2019.
Atlanta September air quality, year by year
Atlanta September air quality by year (Atlanta-Sandy Springs-Roswell, GA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019worst | 30 | 74 | 6 | 172 | O3 |
| 2020cleanest | 30 | 51 | 0 | 84 | PM2.5 |
| 2021 | 30 | 61 | 0 | 100 | PM2.5 |
| 2022 | 30 | 53 | 2 | 150 | PM2.5 |
| 2023 | 30 | 59 | 1 | 105 | PM2.5 |
| 2024 | 30 | 56 | 0 | 100 | PM2.5 |
| 2025 | 30 | 58 | 4 | 112 | O3 |
What September air means in Atlanta
A typical September day in Atlanta is Moderate (median AQI 58): 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 58 is above Atlanta's whole-year median of 54, 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 Atlanta 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 Atlanta's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Atlanta
The latest EPA AirNow observation puts Atlanta's AQI at 56 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current Atlanta air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Atlanta-Sandy Springs-Roswell, GA), 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.