Durham Air Quality in Summer
Across 2019–2025, Durham's summer (June–August) air quality had a median AQI of 46 (Good) over 643 monitored days in the Durham-Chapel Hill, NC area. 0.5% of summer days (3 of 643) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 54.6% of days. The cleanest summer on record here was 2025 (median AQI 41, 0 days above 100) and the worst was 2023 (median 49, 3 days above 100, peak AQI 121).
- Good: 62.5%
- Moderate: 37.0%
- Unhealthy for Sensitive Groups: 0.5%
- Unhealthy or worse: 0.0%
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How is the air in Durham in summer?
Good on a typical day: median AQI 46 across 2019–2025, with 0.5% of summer days above AQI 100. Ground-level ozone is the main driver.
- ✓62.5% of summer days were Good (AQI 0–50), 37.0% Moderate (51–100).
- ✓3 days of 643 reached AQI 101+; the summer peak was 121.
- ✓Cleanest month: August; worst month: June.
Frequently asked questions
What is the air quality like in Durham in summer?▾
Across 2019–2025, the median daily AQI in Durham in summer was 46 (Good). 62.5% of days were Good, 37.0% Moderate, and 0.5% reached Unhealthy for Sensitive Groups or worse, based on 643 monitored days in EPA's Air Quality System.
Is summer a good time for outdoor exercise in Durham?▾
A typical summer day in Durham sits in the Good range (median AQI 46), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of summer days reached AQI 101+ in 2019–2025.
Which pollutant causes Durham's summer air quality problems?▾
Ground-level ozone set the daily AQI on 54.6% of summer days in Durham. The highest summer AQI recorded in 2019–2025 was 121 (Unhealthy for Sensitive Groups), in 2023.
Durham summer air quality, year by year
Durham summer air quality by year (Durham-Chapel Hill, NC, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 92 | 47 | 0 | 87 | O3 |
| 2020 | 91 | 43 | 0 | 97 | PM2.5 |
| 2021 | 92 | 49 | 0 | 89 | PM2.5 |
| 2022 | 92 | 44 | 0 | 93 | O3 |
| 2023worst | 92 | 49 | 3 | 121 | O3 |
| 2024 | 92 | 53 | 0 | 97 | PM2.5 |
| 2025cleanest | 92 | 41 | 0 | 77 | O3 |
What summer air means in Durham
A typical summer day in Durham sits in the Good range (median AQI 46), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of summer days reached AQI 101+ in 2019–2025.
Summer's median AQI of 46 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 Summer AQI across every EPA metro area (308,645 metro-days, 2019–2025) is 46, so Durham runs in line with the national Summer norm; 0.5% of its Summer days topped AQI 100 versus 3.6% nationally (below average).
Within the season, August is the cleanest month (median AQI 44, 0.0% of days above 100) and June the worst (median 50, 1.0% 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.