Durham Air Quality in Fall

Across 2019–2025, Durham's fall (September–November) air quality had a median AQI of 41 (Good) over 637 monitored days in the Durham-Chapel Hill, NC area. 0.0% of fall days (0 of 637) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 61.2% of days. The cleanest fall on record here was 2020 (median AQI 37, 0 days above 100) and the worst was 2024 (median 43, 0 days above 100, peak AQI 60).

41
Median AQI
Good
0.0%
Days above AQI 100
0 of 637 days
55
90th percentile AQI
worst 1 day in 10
77
Peak AQI
Moderate
PM2.5
Main pollutant
61.2% of days
73.6%
Good days
469 of 637
  • Good: 73.6%
  • Moderate: 26.4%
  • Unhealthy for Sensitive Groups: 0.0%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Durham in fall?

Good on a typical day: median AQI 41 across 2019–2025, with 0.0% of fall days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 73.6% of fall days were Good (AQI 0–50), 26.4% Moderate (51–100).
  • 0 days of 637 reached AQI 101+; the fall peak was 77.
  • Cleanest month: October; worst month: November.

Frequently asked questions

What is the air quality like in Durham in fall?

Across 2019–2025, the median daily AQI in Durham in fall was 41 (Good). 73.6% of days were Good, 26.4% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 637 monitored days in EPA's Air Quality System.

Is fall a good time for outdoor exercise in Durham?

A typical fall day in Durham sits in the Good range (median AQI 41), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of fall days reached AQI 101+ in 2019–2025.

Which pollutant causes Durham's fall air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 61.2% of fall days in Durham. The highest fall AQI recorded in 2019–2025 was 77 (Moderate), in 2024.

Durham fall air quality, year by year

Durham fall air quality by year (Durham-Chapel Hill, NC, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20199142074PM2.5
2020cleanest9137072PM2.5
20219142061PM2.5
20229139060PM2.5
20239141071PM2.5
2024worst9143060PM2.5
20259140077PM2.5

What fall air means in Durham

A typical fall day in Durham sits in the Good range (median AQI 41), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of fall days reached AQI 101+ in 2019–2025.

Fall's median AQI of 41 is in line with Durham's whole-year median of 44, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Fall AQI across every EPA metro area (296,275 metro-days, 2019–2025) is 40, so Durham runs in line with the national Fall norm; 0.0% of its Fall days topped AQI 100 versus 1.5% nationally (below average).

Within the season, October is the cleanest month (median AQI 38, 0.0% of days above 100) and November the worst (median 43, 0.0% above 100).

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

Right now in Durham

The latest EPA AirNow observation puts Durham's AQI at 41 (PM2.5). The figures above are multi-year season statistics, not today's reading.

View current Durham air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Durham-Chapel Hill, NC), 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.