Little Rock Air Quality in September

Across 2019–2025, Little Rock's September air quality had a median AQI of 58 (Moderate) over 210 monitored days in the Little Rock-North Little Rock-Conway, AR area. 1.9% of September days (4 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 86.7% of days. The cleanest September on record here was 2020 (median AQI 53, 0 days above 100) and the worst was 2025 (median 60, 2 days above 100, peak AQI 112).

58
Median AQI
Moderate
1.9%
Days above AQI 100
4 of 210 days
77
90th percentile AQI
worst 1 day in 10
122
Peak AQI
Unhealthy for Sensitive Groups
PM2.5
Main pollutant
86.7% of days
18.1%
Good days
38 of 210
  • Good: 18.1%
  • Moderate: 80.0%
  • Unhealthy for Sensitive Groups: 1.9%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Little Rock in September?

Moderate on a typical day: median AQI 58 across 2019–2025, with 1.9% of September days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 18.1% of September days were Good (AQI 0–50), 80.0% Moderate (51–100).
  • 4 days of 210 reached AQI 101+; the September peak was 122.
  • Best September: 2020; worst September: 2025.

Frequently asked questions

What is the air quality like in Little Rock in September?

Across 2019–2025, the median daily AQI in Little Rock in September was 58 (Moderate). 18.1% of days were Good, 80.0% Moderate, and 1.9% 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 Little Rock?

A typical September day in Little Rock 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 53 of September days (1.9%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

Which pollutant causes Little Rock's September air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 86.7% of September days in Little Rock. The highest September AQI recorded in 2019–2025 was 122 (Unhealthy for Sensitive Groups), in 2025.

Little Rock September air quality, year by year

Little Rock September air quality by year (Little Rock-North Little Rock-Conway, AR, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193062081PM2.5
2020cleanest3053073PM2.5
202130571112PM2.5
20223055069PM2.5
202330661122PM2.5
20243055084PM2.5
2025worst30602112PM2.5

What September air means in Little Rock

A typical September day in Little Rock 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 53 of September days (1.9%) 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 Little Rock'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 Little Rock runs above the national September norm; 1.9% of its September days topped AQI 100 versus 2.7% nationally (about the same).

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

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

Right now in Little Rock

The latest EPA AirNow observation puts Little Rock's AQI at 96 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current Little Rock air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Little Rock-North Little Rock-Conway, AR), 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.