Metro area air quality · 2025

Indiana, PA

Median AQI 39 (Good). 74.8% of monitored days rated Good across this metro's EPA monitoring network.

39
Median AQI
74.8%
Good-air days
0
Unhealthy days
56%
Cleaner than US metros

Indiana, PA posted a 2025 median AQI of 39 (Good) with 74.8% Good days

According to the U.S. EPA Air Quality System, the Indiana, PA CBSA recorded a median AQI of 39 across 365 monitored days in 2025, with 74.8% 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 Indiana, PA CBSA's 74.8% Good-day share places it cleaner than 56% of US metros in 2025.
Closest median-AQI peer
Bay City, MI (70.4% Good, median AQI 39) is the closest nationwide median-AQI peer to Indiana, PA.
2020–2025 Good-day shift
Indiana, PA's Good-day share moved -16.2 points from 2020 to 2025 (median AQI +2).
Median AQI
Median AQI: 39

Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →

The verdict

Indiana, PA's Good-day share (74.8%) 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 39 and 74.8% of 365 monitored days in the Good band.

39
median AQI · Good
74.8%
days rated Good
56%
cleaner than US metros
122
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
  • Indiana, PA metro's Good-day share fell from 81.5% to 75.2% between the 2024 and 2025 EPA annual releases, a change of -6.3 percentage points.
  • Indiana, PA metro's peak single-day AQI rose from 74 to 122 between the 2024 and 2025 EPA annual releases, a change of +48 points.

Compared against 357 monitored days in 2024 and 363 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

Indiana, PA's Good-day share (74.8%) sits in the middle CBSA tercile on this extract. Signature read: 74.8% 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 39 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 273 Good (75%), 90 Moderate (25%), and 2 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 59; the highest single-day reading hit 122 (USG).

Across 2020–2025, Good-day share shifted -16.2 points and median AQI moved +2 (worsening). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Bay City, MI (70.4% good, AQI 39); Brainerd, MN (74.3% good, AQI 39); Cambridge, MD (86.0% good, AQI 39).

Understanding AQI →

Air Quality Summary

Median AQI

39

Good

Good Days

74.8%

273 of 365 days

Max AQI

122

USG

Health Grade

Moderate

90th pct: 59

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

273

75%

Moderate

90

25%

USG

2

1%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Indiana, PA metro area's air quality is rated Moderate based on 74.8% 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 Indiana, PA metro compare?

How Indiana, PA compares

Good-day share better than typical
Indiana, PA 74.8%
Bay City, MI 70.4%
Typical US metro 70.6%
Median AQI better than typical
Indiana, PA 39
Bay City, MI 39
Typical US metro 41
Unhealthy days / yr better than typical
Indiana, PA 0
Bay City, MI 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Indiana, PA metro. Highest Good-day share: 2020 (91.4%, 320 of 350 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 320 30 0 37
2021 218 128 0 44
2022 264 100 0 42
2023 264 92 2 41
2024 291 66 0 37
2025 273 90 0 39

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Indiana, PA (39).

Bay City, MI

Median AQI 39 · 70.4% Good-day share

39

Brainerd, MN

Median AQI 39 · 74.3% Good-day share

39

Cambridge, MD

Median AQI 39 · 86.0% Good-day share

39

Charleston, WV

Median AQI 39 · 77.0% Good-day share

39

Dalton, GA

Median AQI 39 · 90.3% Good-day share

39

Harrisonburg, VA

Median AQI 39 · 80.0% Good-day share

39

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Indiana, 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 Indiana, PA have? ▼
In 2025, the Indiana, PA metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 122.
What is the air quality in the Indiana, PA metro area? ▼
The Indiana, PA metro area has a median Air Quality Index (AQI) of 39, rated "Good." 74.8% of monitored days (273 out of 365) had good air quality in 2025.
Is air quality in Indiana, PA getting better or worse? ▼
Air quality in the Indiana, 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 91.4% (320 of 350 days). Lowest qualifying Good-day share: 2021 at 63.0% (218 of 346 days).
What does AQI 39 mean for health? ▼
An AQI of 39 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 Indiana, PA compare to other metro areas? ▼
The Indiana, PA metro has 74.8% good air days. Similar metros: Bay City, MI (70.4% good), Brainerd, MN (74.3% good), Cambridge, MD (86.0% good).
What is the 90th percentile AQI for Indiana, PA? ▼
The 90th percentile AQI for the Indiana, PA metro area is 59, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 122 (USG).

Data Sources

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