New Orleans Air Quality in September

Across 2019–2025, New Orleans's September air quality had a median AQI of 52 (Moderate) over 210 monitored days in the New Orleans-Metairie, LA area. 0.5% of September days (1 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 59.5% of days. The cleanest September on record here was 2020 (median AQI 41, 0 days above 100) and the worst was 2025 (median 54, 1 day above 100, peak AQI 101).

52
Median AQI
Moderate
0.5%
Days above AQI 100
1 of 210 days
74
90th percentile AQI
worst 1 day in 10
101
Peak AQI
Unhealthy for Sensitive Groups
PM2.5
Main pollutant
59.5% of days
42.9%
Good days
90 of 210
  • Good: 42.9%
  • Moderate: 56.7%
  • Unhealthy for Sensitive Groups: 0.5%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in New Orleans in September?

Moderate on a typical day: median AQI 52 across 2019–2025, with 0.5% of September days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 42.9% of September days were Good (AQI 0–50), 56.7% Moderate (51–100).
  • 1 day of 210 reached AQI 101+; the September peak was 101.
  • Best September: 2020; worst September: 2025.

Frequently asked questions

What is the air quality like in New Orleans in September?

Across 2019–2025, the median daily AQI in New Orleans in September was 52 (Moderate). 42.9% of days were Good, 56.7% Moderate, and 0.5% 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 New Orleans?

A typical September day in New Orleans is Moderate (median AQI 52): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of September days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

Which pollutant causes New Orleans's September air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 59.5% of September days in New Orleans. The highest September AQI recorded in 2019–2025 was 101 (Unhealthy for Sensitive Groups), in 2025.

New Orleans September air quality, year by year

New Orleans September air quality by year (New Orleans-Metairie, LA, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193056097PM2.5
2020cleanest3041079PM2.5
20213049080PM2.5
20223054077PM2.5
20233055090O3
20243050084O3
2025worst30541101O3

What September air means in New Orleans

A typical September day in New Orleans is Moderate (median AQI 52): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of September days 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 52 is in line with New Orleans's whole-year median of 49, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median September AQI across every EPA metro area (100,699 metro-days, 2019–2025) is 43, so New Orleans runs above the national September norm; 0.5% of its September days topped AQI 100 versus 2.7% nationally (below average).

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

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

Right now in New Orleans

The latest EPA AirNow observation puts New Orleans's AQI at 43 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current New Orleans air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (New Orleans-Metairie, LA), 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.