Manchester Air Quality in Fall
Across 2019–2025, Manchester's fall (September–November) air quality had a median AQI of 32 (Good) over 637 monitored days in the Manchester-Nashua, NH area. 0.2% of fall days (1 of 637) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 89.5% of days. The cleanest fall on record here was 2021 (median AQI 30, 0 days above 100) and the worst was 2023 (median 32, 1 day above 100, peak AQI 119).
- Good: 95.0%
- Moderate: 4.9%
- Unhealthy for Sensitive Groups: 0.2%
- Unhealthy or worse: 0.0%
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How is the air in Manchester in fall?
Good on a typical day: median AQI 32 across 2019–2025, with 0.2% of fall days above AQI 100. Ground-level ozone is the main driver.
- ✓95.0% of fall days were Good (AQI 0–50), 4.9% Moderate (51–100).
- ✓1 day of 637 reached AQI 101+; the fall peak was 119.
- ✓Cleanest month: October; worst month: September.
Frequently asked questions
What is the air quality like in Manchester in fall?▾
Across 2019–2025, the median daily AQI in Manchester in fall was 32 (Good). 95.0% of days were Good, 4.9% Moderate, and 0.2% 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 Manchester?▾
A typical fall day in Manchester sits in the Good range (median AQI 32), 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 Manchester's fall air quality problems?▾
Ground-level ozone set the daily AQI on 89.5% of fall days in Manchester. The highest fall AQI recorded in 2019–2025 was 119 (Unhealthy for Sensitive Groups), in 2023.
Manchester fall air quality, year by year
Manchester fall air quality by year (Manchester-Nashua, NH, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 91 | 31 | 0 | 74 | O3 |
| 2020 | 91 | 31 | 0 | 64 | O3 |
| 2021cleanest | 91 | 30 | 0 | 53 | O3 |
| 2022 | 91 | 33 | 0 | 61 | O3 |
| 2023worst | 91 | 32 | 1 | 119 | O3 |
| 2024 | 91 | 32 | 0 | 84 | O3 |
| 2025 | 91 | 33 | 0 | 100 | O3 |
What fall air means in Manchester
A typical fall day in Manchester sits in the Good range (median AQI 32), 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 32 is below Manchester's whole-year median of 37, making it one of the area's cleaner periods. Nationally, the median Fall AQI across every EPA metro area (296,275 metro-days, 2019–2025) is 40, so Manchester runs below the national Fall norm; 0.2% of its Fall days topped AQI 100 versus 1.5% nationally (below average).
Within the season, October is the cleanest month (median AQI 31, 0.0% of days above 100) and September the worst (median 33, 0.5% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Manchester
The latest EPA AirNow observation puts Manchester's AQI at 24 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current Manchester air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Manchester-Nashua, NH), 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.