Metro area air quality · 2025

Chambersburg-Waynesboro, PA

Median AQI 37 (Good). 91.5% of monitored days rated Good across this metro's EPA monitoring network.

37
Median AQI
91.5%
Good-air days
0
Unhealthy days
89%
Cleaner than US metros

Chambersburg-Waynesboro, PA posted a 2025 median AQI of 37 (Good) with 91.5% Good days

According to the U.S. EPA Air Quality System, the Chambersburg-Waynesboro, PA CBSA recorded a median AQI of 37 across 295 monitored days in 2025, with 91.5% rated Good and 0 unhealthy or worse. This is an annual metro comparison, not a live advisory.

Data source EPA Air Quality System (AQS)

Cleaner than US metros
The Chambersburg-Waynesboro, PA CBSA's 91.5% Good-day share places it cleaner than 89% of US metros in 2025.
Closest median-AQI peer
Alexandria, LA (73.7% Good, median AQI 37) is the closest nationwide median-AQI peer to Chambersburg-Waynesboro, PA.
2020–2025 Good-day shift
Chambersburg-Waynesboro, PA's Good-day share moved -8.5 points from 2020 to 2025 (median AQI +5).
Median AQI
Median AQI: 37

Aggregated from EPA Air Quality System (2025), 295 monitored days. EPA AQS →

The verdict

Chambersburg-Waynesboro, PA sits in the upper Good-day tercile among EPA CBSA metros on this site (91.5% of 295 monitored days). On the EPA scale the metro runs good, cleaner than most US metros, with a median AQI of 37 and 91.5% of 295 monitored days in the Good band.

37
median AQI · Good
91.5%
days rated Good
89%
cleaner than US metros
87
worst single reading

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

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • Chambersburg-Waynesboro, PA metro's Good-day share fell from 93.3% to 91.5% between the 2024 and 2025 EPA annual releases, a change of -1.7 percentage points.

Compared against 327 monitored days in 2024 and 295 in 2025. These are arithmetic differences between two stored EPA annual summaries, not a cause claim or a live advisory.

National release changes Two-year CSV

Chambersburg-Waynesboro, PA sits in the upper Good-day tercile among EPA CBSA metros on this site (91.5% of 295 monitored days). Signature read: 91.5% Good-day share (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 37 over 295 measured days in 2025 (Good / Excellent). The monitored-day split lands at 270 Good (92%), 25 Moderate (8%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 49; the highest single-day reading hit 87 (Moderate).

Across 2020–2025, Good-day share shifted -8.5 points and median AQI moved +5 (worsening). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Alexandria, LA (73.7% good, AQI 37); Athens, TN (78.2% good, AQI 37); Bennington, VT (83.6% good, AQI 37).

Best and worst city air quality →

Air Quality Summary

Median AQI

37

Good

Good Days

91.5%

270 of 295 days

Max AQI

87

Moderate

Health Grade

Excellent

90th pct: 49

AQI Day Breakdown (2025)

Distribution of 295 monitored days across EPA AQI categories.

Good

270

92%

Moderate

25

8%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Excellent

The Chambersburg-Waynesboro, PA metro area's air quality is rated Excellent based on 91.5% 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 Chambersburg-Waynesboro, PA metro compare?

How Chambersburg-Waynesboro, PA compares

Good-day share better than typical
Chambersburg-Waynesboro, PA 91.5%
Alexandria, LA 73.7%
Typical US metro 70.6%
Median AQI better than typical
Chambersburg-Waynesboro, PA 37
Alexandria, LA 37
Typical US metro 41
Unhealthy days / yr better than typical
Chambersburg-Waynesboro, PA 0
Alexandria, LA 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Chambersburg-Waynesboro, PA metro. Highest Good-day share: 2020 (100.0%, 363 of 363 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 363 0 0 32
2021 274 14 0 35
2022 225 12 0 39
2023 267 32 0 39
2024 305 22 0 35
2025 270 25 0 37

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Chambersburg-Waynesboro, PA (37).

Alexandria, LA

Median AQI 37 · 73.7% Good-day share

37

Athens, TN

Median AQI 37 · 78.2% Good-day share

37

Bennington, VT

Median AQI 37 · 83.6% Good-day share

37

Blacksburg-Christiansburg-Radford, VA

Median AQI 37 · 94.4% Good-day share

37

Cadillac, MI

Median AQI 37 · 86.0% Good-day share

37

Columbia, MO

Median AQI 37 · 93.2% Good-day share

37

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Chambersburg-Waynesboro, PA's 0 (independent of median AQI).

Aberdeen, SD

0 unhealthy-or-worse days · median AQI 27

27

Aberdeen, WA

0 unhealthy-or-worse days · median AQI 22

22

Adrian, MI

0 unhealthy-or-worse days · median AQI 41

41

Akron, OH

0 unhealthy-or-worse days · median AQI 45

45

Albany, GA

0 unhealthy-or-worse days · median AQI 46

46

Albany, OR

0 unhealthy-or-worse days · median AQI 27

27

Frequently Asked Questions

How many unhealthy air days does Chambersburg-Waynesboro, PA have? ▼
In 2025, the Chambersburg-Waynesboro, PA metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 87.
What is the air quality in the Chambersburg-Waynesboro, PA metro area? ▼
The Chambersburg-Waynesboro, PA metro area has a median Air Quality Index (AQI) of 37, rated "Good." 91.5% of monitored days (270 out of 295) had good air quality in 2025.
Is air quality in Chambersburg-Waynesboro, PA getting better or worse? ▼
Air quality in the Chambersburg-Waynesboro, PA metro is worsening across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2020 at 100.0% (363 of 363 days). Lowest qualifying Good-day share: 2023 at 89.3% (267 of 299 days).
What does AQI 37 mean for health? ▼
An AQI of 37 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
How does Chambersburg-Waynesboro, PA compare to other metro areas? ▼
The Chambersburg-Waynesboro, PA metro has 91.5% good air days. Similar metros: Alexandria, LA (73.7% good), Athens, TN (78.2% good), Bennington, VT (83.6% good).
What is the 90th percentile AQI for Chambersburg-Waynesboro, PA? ▼
The 90th percentile AQI for the Chambersburg-Waynesboro, PA metro area is 49, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 87 (Moderate).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Chambersburg-Waynesboro, PA, 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, Chambersburg-Waynesboro, PA · 2020–2025