Metro area air quality · 2025
Johnstown, PA
Median AQI 41 (Good). 74.5% of monitored days rated Good across this metro's EPA monitoring network.
- 41
- Median AQI
- 74.5%
- Good-air days
- 0
- Unhealthy days
- 56%
- Cleaner than US metros
Johnstown, PA posted a 2025 median AQI of 41 (Good) with 74.5% Good days
According to the U.S. EPA Air Quality System, the Johnstown, PA CBSA recorded a median AQI of 41 across 365 monitored days in 2025, with 74.5% 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 Johnstown, PA CBSA's 74.5% Good-day share places it cleaner than 56% of US metros in 2025.
- Closest median-AQI peer
- Adrian, MI (69.3% Good, median AQI 41) is the closest nationwide median-AQI peer to Johnstown, PA.
- 2020–2025 Good-day shift
- Johnstown, PA's Good-day share moved +12.4 points from 2020 to 2025 (median AQI -3).
- Median AQI
- Median AQI: 41
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
Johnstown, PA's Good-day share (74.5%) sits in the middle CBSA tercile on this extract. On the EPA scale the metro runs good, cleaner than the median US metro, with a median AQI of 41 and 74.5% of 365 monitored days in the Good band.
- 41
- median AQI · Good
- 74.5%
- days rated Good
- 56%
- cleaner than US metros
- 115
- 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
- Johnstown, PA metro's peak single-day AQI rose from 87 to 115 between the 2024 and 2025 EPA annual releases, a change of +28 points.
- Johnstown, PA metro's Good-day share rose from 73.7% to 74.7% between the 2024 and 2025 EPA annual releases, a change of +1.0 percentage points.
Johnstown, PA's Good-day share (74.5%) sits in the middle CBSA tercile on this extract. Signature read: 74.5% Good-day share (mid tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 41 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 272 Good (75%), 92 Moderate (25%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 58; the highest single-day reading hit 115 (USG).
Across 2020–2025, Good-day share shifted +12.4 points and median AQI moved -3 (improving). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Adrian, MI (69.3% good, AQI 41); Albany-Schenectady-Troy, NY (67.7% good, AQI 41); Ann Arbor, MI (69.3% good, AQI 41).
Air Quality Summary
Median AQI
41
Good
Good Days
74.5%
272 of 365 days
Max AQI
115
USG
Health Grade
Moderate
90th pct: 58
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
272
75%
Moderate
92
25%
USG
1
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Johnstown, PA metro area's air quality is rated Moderate based on 74.5% 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 Johnstown, PA metro compare?
How Johnstown, PA compares
5-Year Air Quality Trend
Air quality is improving in the Johnstown, PA metro. Highest Good-day share: 2025 (74.7%, 272 of 364 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 228 | 138 | 0 | 44 | 90 |
| 2021 | 169 | 183 | 0 | 51 | 130 |
| 2022 | 171 | 191 | 0 | 52 | 119 |
| 2023 | 213 | 147 | 2 | 46 | 201 |
| 2024 | 269 | 96 | 0 | 42 | 87 |
| 2025 | 272 | 92 | 0 | 41 | 115 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Johnstown, PA (41).
Adrian, MI
Median AQI 41 · 69.3% Good-day share
Albany-Schenectady-Troy, NY
Median AQI 41 · 67.7% Good-day share
Ann Arbor, MI
Median AQI 41 · 69.3% Good-day share
Bowling Green, KY
Median AQI 41 · 75.6% Good-day share
Brunswick, GA
Median AQI 41 · 74.3% Good-day share
Decatur, AL
Median AQI 41 · 78.4% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Johnstown, PA's 0 (independent of median AQI).
Aberdeen, SD
0 unhealthy-or-worse days · median AQI 27
Aberdeen, WA
0 unhealthy-or-worse days · median AQI 22
Akron, OH
0 unhealthy-or-worse days · median AQI 45
Albany, GA
0 unhealthy-or-worse days · median AQI 46
Albany, OR
0 unhealthy-or-worse days · median AQI 27
Alexandria, LA
0 unhealthy-or-worse days · median AQI 37
Frequently Asked Questions
How many unhealthy air days does Johnstown, PA have? ▼
What is the air quality in the Johnstown, PA metro area? ▼
Is air quality in Johnstown, PA getting better or worse? ▼
What does AQI 41 mean for health? ▼
How does Johnstown, PA compare to other metro areas? ▼
What is the 90th percentile AQI for Johnstown, PA? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Johnstown, 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, Johnstown, PA · 2020–2025