Metro area air quality · 2025

Indianapolis-Carmel-Anderson, IN

Median AQI 54 (Moderate). 37.5% of monitored days rated Good across this metro's EPA monitoring network.

54
Median AQI
37.5%
Good-air days
2
Unhealthy days
6%
Cleaner than US metros

Indianapolis-Carmel-Anderson, IN posted a 2025 median AQI of 54 (Moderate) with 37.5% Good days

According to the U.S. EPA Air Quality System, the Indianapolis-Carmel-Anderson, IN CBSA recorded a median AQI of 54 across 365 monitored days in 2025, with 37.5% rated Good and 2 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 Indianapolis-Carmel-Anderson, IN CBSA's 37.5% Good-day share places it cleaner than 6% of US metros in 2025.
Closest median-AQI peer
Baton Rouge, LA (35.6% Good, median AQI 54) is the closest nationwide median-AQI peer to Indianapolis-Carmel-Anderson, IN.
2020–2025 Good-day shift
Indianapolis-Carmel-Anderson, IN's Good-day share moved +8.6 points from 2020 to 2025 (median AQI -2).
Median AQI
Median AQI: 54

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

The verdict

Indianapolis-Carmel-Anderson, IN lands in the lower Good-day tercile (37.5% Good), a thinner clean-air share than most CBSA peers here. On the EPA scale the metro runs moderate, among the more polluted US metros, with a median AQI of 54 and 37.5% of 365 monitored days in the Good band.

54
median AQI · Moderate
37.5%
days rated Good
6%
cleaner than US metros
170
worst single reading

2 days reached Unhealthy or worse across the metro's monitors in 2025.

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • Indianapolis-Carmel-Anderson, IN metro's peak single-day AQI rose from 138 to 170 between the 2024 and 2025 EPA annual releases, a change of +32 points.
  • Indianapolis-Carmel-Anderson, IN metro's Good-day share rose from 35.7% to 38.2% between the 2024 and 2025 EPA annual releases, a change of +2.4 percentage points.
  • Indianapolis-Carmel-Anderson, IN metro's Unhealthy-category days rose from 0 to 2 between the 2024 and 2025 EPA annual releases, a change of +2 days.

Compared against 361 monitored days in 2024 and 359 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

Indianapolis-Carmel-Anderson, IN lands in the lower Good-day tercile (37.5% Good), a thinner clean-air share than most CBSA peers here. Signature read: 37.5% Good-day share (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 54 over 365 measured days in 2025 (Moderate / Poor). The monitored-day split lands at 137 Good (38%), 220 Moderate (60%), and 6 Unhealthy-for-Sensitive-Groups (2%). The 90th-percentile AQI finished at 74; the highest single-day reading hit 170 (Unhealthy).

Across 2020–2025, Good-day share shifted +8.6 points and median AQI moved -2 (improving). The annual record contains 2 days at Unhealthy or worse. Metros with comparable AQI profiles include Baton Rouge, LA (35.6% good, AQI 54); Cleveland-Elyria, OH (42.5% good, AQI 54); Columbus, OH (39.7% good, AQI 54).

Health effects of air pollution →

Air Quality Summary

Median AQI

54

Moderate

Good Days

37.5%

137 of 365 days

Max AQI

170

Unhealthy

Health Grade

Poor

90th pct: 74

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

137

38%

Moderate

220

60%

USG

6

2%

Unhealthy

2

1%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Poor

The Indianapolis-Carmel-Anderson, IN metro area's air quality is rated Poor based on 37.5% good air days. There were 2 unhealthy days in 2025 when outdoor activity should be limited.

Air quality is acceptable most days, but 6 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 170. Sensitive groups should monitor real-time conditions at AirNow.gov.

How does the Indianapolis-Carmel-Anderson, IN metro compare?

How Indianapolis-Carmel-Anderson, IN compares

Good-day share worse than typical
Indianapolis-Carmel-Anderson, IN 37.5%
Baton Rouge, LA 35.6%
Typical US metro 70.6%
Median AQI worse than typical
Indianapolis-Carmel-Anderson, IN 54
Baton Rouge, LA 54
Typical US metro 41
Unhealthy days / yr worse than typical
Indianapolis-Carmel-Anderson, IN 2
Baton Rouge, LA 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is improving in the Indianapolis-Carmel-Anderson, IN metro. Highest Good-day share: 2025 (38.2%, 137 of 359 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 106 253 0 56
2021 80 278 0 58
2022 95 255 1 56
2023 80 261 2 60
2024 129 232 0 55
2025 137 220 2 54

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Indianapolis-Carmel-Anderson, IN (54).

Baton Rouge, LA

Median AQI 54 · 35.6% Good-day share

54

Cleveland-Elyria, OH

Median AQI 54 · 42.5% Good-day share

54

Columbus, OH

Median AQI 54 · 39.7% Good-day share

54

Detroit-Warren-Dearborn, MI

Median AQI 54 · 36.2% Good-day share

54

Tucson, AZ

Median AQI 54 · 33.7% Good-day share

54

Atlanta-Sandy Springs-Roswell, GA

Median AQI 53 · 41.1% Good-day share

53

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Indianapolis-Carmel-Anderson, IN's 2 (independent of median AQI).

Ardmore, OK

2 unhealthy-or-worse days · median AQI 45

45

Bridgeport-Stamford-Norwalk, CT

2 unhealthy-or-worse days · median AQI 44

44

Chattanooga, TN-GA

2 unhealthy-or-worse days · median AQI 49

49

Cincinnati, OH-KY-IN

2 unhealthy-or-worse days · median AQI 56

56

Columbus, GA-AL

2 unhealthy-or-worse days · median AQI 48

48

Davenport-Moline-Rock Island, IA-IL

2 unhealthy-or-worse days · median AQI 46

46

Frequently Asked Questions

How many unhealthy air days does Indianapolis-Carmel-Anderson, IN have? ▼
In 2025, the Indianapolis-Carmel-Anderson, IN metro area recorded 2 unhealthy air days (2 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 170.
What is the air quality in the Indianapolis-Carmel-Anderson, IN metro area? ▼
The Indianapolis-Carmel-Anderson, IN metro area has a median Air Quality Index (AQI) of 54, rated "Moderate." 37.5% of monitored days (137 out of 365) had good air quality in 2025.
Is air quality in Indianapolis-Carmel-Anderson, IN getting better or worse? ▼
Air quality in the Indianapolis-Carmel-Anderson, IN metro is improving across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2025 at 38.2% (137 of 359 days). Lowest qualifying Good-day share: 2021 at 22.3% (80 of 358 days).
What does AQI 54 mean for health? ▼
An AQI of 54 is "Moderate", air quality is acceptable, but some pollutants may pose a moderate health concern for a small number of sensitive individuals.
How does Indianapolis-Carmel-Anderson, IN compare to other metro areas? ▼
The Indianapolis-Carmel-Anderson, IN metro has 37.5% good air days. Similar metros: Baton Rouge, LA (35.6% good), Cleveland-Elyria, OH (42.5% good), Columbus, OH (39.7% good).
What is the 90th percentile AQI for Indianapolis-Carmel-Anderson, IN? ▼
The 90th percentile AQI for the Indianapolis-Carmel-Anderson, IN metro area is 74, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 170 (Unhealthy).

Data Sources

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