Birmingham Air Quality in September

Across 2019–2025, Birmingham's September air quality had a median AQI of 60 (Moderate) over 210 monitored days in the Birmingham-Hoover, AL area. 3.8% of September days (8 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 73.3% of days. The cleanest September on record here was 2020 (median AQI 52, 0 days above 100) and the worst was 2019 (median 70, 7 days above 100, peak AQI 119).

60
Median AQI
Moderate
3.8%
Days above AQI 100
8 of 210 days
87
90th percentile AQI
worst 1 day in 10
119
Peak AQI
Unhealthy for Sensitive Groups
PM2.5
Main pollutant
73.3% of days
24.3%
Good days
51 of 210
  • Good: 24.3%
  • Moderate: 71.9%
  • Unhealthy for Sensitive Groups: 3.8%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Birmingham in September?

Moderate on a typical day: median AQI 60 across 2019–2025, with 3.8% of September days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 24.3% of September days were Good (AQI 0–50), 71.9% Moderate (51–100).
  • 8 days of 210 reached AQI 101+; the September peak was 119.
  • Best September: 2020; worst September: 2019.

Frequently asked questions

What is the air quality like in Birmingham in September?

Across 2019–2025, the median daily AQI in Birmingham in September was 60 (Moderate). 24.3% of days were Good, 71.9% Moderate, and 3.8% 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 Birmingham?

A typical September day in Birmingham is Moderate (median AQI 60): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 26 of September days (3.8%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

Which pollutant causes Birmingham's September air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 73.3% of September days in Birmingham. The highest September AQI recorded in 2019–2025 was 119 (Unhealthy for Sensitive Groups), in 2019.

Birmingham September air quality, year by year

Birmingham September air quality by year (Birmingham-Hoover, AL, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
2019worst30707119O3
2020cleanest3052094PM2.5
20213057071PM2.5
20223056093PM2.5
202330711101PM2.5
20243057087PM2.5
202530560100O3

What September air means in Birmingham

A typical September day in Birmingham is Moderate (median AQI 60): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 26 of September days (3.8%) 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 60 is above Birmingham's whole-year median of 56, 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 Birmingham runs above the national September norm; 3.8% of its September days topped AQI 100 versus 2.7% nationally (above average).

September is part of Birmingham's fall season (September, October, November); the fall page pools all three months.

Activity-specific thresholds: running, cycling, kids' sports.

Right now in Birmingham

The latest EPA AirNow observation puts Birmingham's AQI at 53 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current Birmingham air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Birmingham-Hoover, AL), 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.