Metro area air quality · 2025

Manchester-Nashua, NH

Median AQI 38 (Good). 82.5% of monitored days rated Good across this metro's EPA monitoring network.

38
Median AQI
82.5%
Good-air days
0
Unhealthy days
70%
Cleaner than US metros

Aggregated from EPA Air Quality System (2025), 274 monitored days. EPA AQS →

The verdict

The Manchester-Nashua, NH metro runs good on the EPA scale, cleaner than the median US metro, a median AQI of 38 with 82.5% of 274 monitored days in the Good band.

38
median AQI · Good
82.5%
days rated Good
70%
cleaner than US metros
123
worst single reading

No day crossed into the Unhealthy tier across the metro's monitors in 2025.

Insights: Manchester-Nashua, NH metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 38 over 274 measured days in 2025, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 226 Good days (82%), 44 Moderate (16%), and 4 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 56 while the highest single-day reading hit 123 (USG). Metro residents averaged roughly 24.7 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, good days shifted by -125 and the median AQI moved +1 points, which classifies the multi-year trajectory as worsening. The metro avoided any Unhealthy-tier days entirely, an outcome that typically reflects favorable wind patterns, lower industrial density, or effective regional emission controls. Metros with comparable AQI profiles include Appleton, WI (78.5% good, AQI 38); Atlantic City-Hammonton, NJ (79.6% good, AQI 38); Barnstable Town, MA (92.5% good, AQI 38).

Air Quality Summary

Median AQI

38

Good

Good Days

82.5%

226 of 274 days

Max AQI

123

USG

Health Grade

Good

90th pct: 56

AQI Day Breakdown (2025)

Distribution of 274 monitored days across EPA AQI categories.

Good

226

82%

Moderate

44

16%

USG

4

1%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Manchester-Nashua, NH metro area's air quality is rated Good based on 82.5% good air days. No unhealthy air days were recorded in 2025.

Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.

How does the Manchester-Nashua, NH metro compare?

How Manchester-Nashua, NH compares

Good-day share better than US avg
Manchester-Nashua, NH 82.5%
Appleton, WI 78.5%
US average 71.3%
Median AQI better than US avg
Manchester-Nashua, NH 38
Appleton, WI 38
US average 41
Unhealthy days / yr better than US avg
Manchester-Nashua, NH 0
Appleton, WI 1
US average 1

5-Year Air Quality Trend

Air quality is worsening in the Manchester-Nashua, NH metro. Best year: 2020 (351 good days).

Year Good Moderate Unhealthy Median AQI
2020 351 15 0 37
2021 328 35 0 37
2022 329 36 0 39
2023 305 55 0 39
2024 328 38 0 37
2025 226 44 0 38

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Manchester-Nashua, NH.

Appleton, WI

AQI 38 · 78.5% good

38

Atlantic City-Hammonton, NJ

AQI 38 · 79.6% good

38

Barnstable Town, MA

AQI 38 · 92.5% good

38

Bay City, MI

AQI 38 · 71.8% good

38

Cadillac, MI

AQI 38 · 89.5% good

38

Claremont-Lebanon, NH-VT

AQI 38 · 81.3% good

38

More Air Quality Data

Explore EPA air quality rankings and guides across U.S. metros and counties.

Cleanest Metro Areas

U.S. metros ranked by their share of Good air-quality days.

Worst Air Quality

Counties and metros with the most unhealthy air days.

All Metro Areas

Annual AQI by CBSA for every monitored U.S. metro area.

Best and Worst City Air

What drives urban air quality and how metro areas compare.

Air Quality Guides

Frequently Asked Questions

What is the air quality in the Manchester-Nashua, NH metro area? ▼
The Manchester-Nashua, NH metro area has a median Air Quality Index (AQI) of 38, rated "Good." 82.5% of monitored days (226 out of 274) had good air quality in 2025.
How many unhealthy air days does Manchester-Nashua, NH have? ▼
In 2025, the Manchester-Nashua, NH metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 123.
Is air quality in Manchester-Nashua, NH getting better or worse? ▼
Air quality in the Manchester-Nashua, NH metro is worsening based on 5-year trends (2020-2025). Best year: 2020 with 351 good days. Worst year: 2025 with 226 good days.
What does AQI 38 mean for health? ▼
An AQI of 38 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
What is the 90th percentile AQI for Manchester-Nashua, NH? ▼
The 90th percentile AQI for the Manchester-Nashua, NH metro area is 56, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 123 (USG).
How does Manchester-Nashua, NH compare to other metro areas? ▼
The Manchester-Nashua, NH metro has 82.5% good air days. Similar metros: Appleton, WI (78.5% good), Atlantic City-Hammonton, NJ (79.6% good), Barnstable Town, MA (92.5% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2025. See our methodology for how AQI, median, and coverage figures are computed.

Read our methodology , how this data is sourced, computed, and verified.

Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary files (metro-level) · 2020–2025

Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.