Metro area air quality · 2024

Greenfield Town, MA

Median AQI 36 (Good). 81.1% of monitored days rated Good across this metro's EPA monitoring network.

36
Median AQI
81.1%
Good-air days
0
Unhealthy days
68%
Cleaner than US metros

Aggregated from EPA Air Quality System (2024), 365 monitored days. EPA AQS → · NOAA →

Insights: Greenfield Town, MA metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 36 over 365 measured days in 2024, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 296 Good days (81%), 69 Moderate (19%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 56 while the highest single-day reading hit 94 (Moderate). Metro residents averaged roughly 24.3 clean-air days per 30-day window across the reporting year.

Across the 2020–2024 trend window, good days shifted by +50 and the median AQI moved -7 points, which classifies the multi-year trajectory as improving. 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 Barnstable Town, MA (94.3% good, AQI 36); Bemidji, MN (84.2% good, AQI 36); Bennington, VT (91.0% good, AQI 36).

Air Quality Summary

Median AQI

36

Good

Good Days

81.1%

296 of 365 days

Max AQI

94

Moderate

Health Grade

Good

90th pct: 56

AQI Day Breakdown (2024)

Distribution of 365 monitored days across EPA AQI categories.

Good

296

81%

Moderate

69

19%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Greenfield Town, MA metro area's air quality is rated Good based on 81.1% good air days. No unhealthy air days were recorded in 2024.

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

How does the Greenfield Town, MA metro compare?

How Greenfield Town, MA compares

Good-day share better than US avg
Greenfield Town, MA 81.1%
Barnstable Town, MA 94.3%
US average 70.2%
Median AQI better than US avg
Greenfield Town, MA 36
Barnstable Town, MA 36
US average 41
Unhealthy days / yr better than US avg
Greenfield Town, MA 0
Barnstable Town, MA 0
US average 1

5-Year Air Quality Trend

Air quality is improving in the Greenfield Town, MA metro. Best year: 2024 (296 good days).

Year Good Moderate Unhealthy Median AQI
2020 246 119 0 43
2021 228 137 0 44
2022 271 93 0 40
2023 246 113 1 43
2024 296 69 0 36

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Greenfield Town, MA.

Barnstable Town, MA

AQI 36 · 94.3% good

36

Bemidji, MN

AQI 36 · 84.2% good

36

Bennington, VT

AQI 36 · 91.0% good

36

Brookings, SD

AQI 36 · 79.8% good

36

Cadillac, MI

AQI 36 · 89.1% good

36

Crestview-Fort Walton Beach-Destin, FL

AQI 36 · 93.2% good

36

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Air Quality Guides

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Health Effects of Air Pollution

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Frequently Asked Questions

What is the air quality in the Greenfield Town, MA metro area? ▼
The Greenfield Town, MA metro area has a median Air Quality Index (AQI) of 36, rated "Good." 81.1% of monitored days (296 out of 365) had good air quality in 2024.
How many unhealthy air days does Greenfield Town, MA have? ▼
In 2024, the Greenfield Town, MA metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 94.
Is air quality in Greenfield Town, MA getting better or worse? ▼
Air quality in the Greenfield Town, MA metro is improving based on 5-year trends (2020-2024). Best year: 2024 with 296 good days. Worst year: 2021 with 228 good days.
What does AQI 36 mean for health? ▼
An AQI of 36 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 Greenfield Town, MA? ▼
The 90th percentile AQI for the Greenfield Town, MA metro area is 56, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 94 (Moderate).
How does Greenfield Town, MA compare to other metro areas? ▼
The Greenfield Town, MA metro has 81.1% good air days. Similar metros: Barnstable Town, MA (94.3% good), Bemidji, MN (84.2% good), Bennington, VT (91.0% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2024. The AQS collects ambient air monitoring data from state, local, and tribal monitoring agencies across the United States.

Metrics: Air Quality Index (AQI) is calculated using EPA-standard breakpoints for six criteria pollutants: PM2.5, PM10, Ozone, NO2, CO, and SO2. Median AQI, max AQI, and 90th percentile AQI are computed from daily measurements. Good days percentage reflects days with AQI 0–50.

Coverage: 501 metro areas (Core Based Statistical Areas). Only metros with active monitoring stations are included. Unmonitored areas are not represented.

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

Source: U.S. EPA, AirNow / AQS Air Quality Index readings and pollutant concentrations · 2025