Metro area air quality · 2025
Michigan City-La Porte, IN
Median AQI 43 (Good). 63.0% of monitored days rated Good across this metro's EPA monitoring network.
- 43
- Median AQI
- 63.0%
- Good-air days
- 1
- Unhealthy days
- 31%
- Cleaner than US metros
Michigan City-La Porte, IN posted a 2025 median AQI of 43 (Good) with 63.0% Good days
According to the U.S. EPA Air Quality System, the Michigan City-La Porte, IN CBSA recorded a median AQI of 43 across 365 monitored days in 2025, with 63.0% rated Good and 1 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 Michigan City-La Porte, IN CBSA's 63.0% Good-day share places it cleaner than 31% of US metros in 2025.
- Closest median-AQI peer
- Ashtabula, OH (81.2% Good, median AQI 43) is the closest nationwide median-AQI peer to Michigan City-La Porte, IN.
- 2020–2025 Good-day shift
- Michigan City-La Porte, IN's Good-day share moved -15.9 points from 2020 to 2025 (median AQI +5).
- Median AQI
- Median AQI: 43
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
Michigan City-La Porte, IN lands in the lower Good-day tercile (63.0% Good), a thinner clean-air share than most CBSA peers here. On the EPA scale the metro runs good, more polluted than the median US metro, with a median AQI of 43 and 63.0% of 365 monitored days in the Good band.
- 43
- median AQI · Good
- 63.0%
- days rated Good
- 31%
- cleaner than US metros
- 153
- worst single reading
1 day reached Unhealthy or worse across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- Michigan City-La Porte, IN metro's Good-day share fell from 70.6% to 65.0% between the 2024 and 2025 EPA annual releases, a change of -5.6 percentage points.
- Michigan City-La Porte, IN metro's peak single-day AQI rose from 115 to 153 between the 2024 and 2025 EPA annual releases, a change of +38 points.
- Michigan City-La Porte, IN metro's Unhealthy-category days rose from 0 to 1 between the 2024 and 2025 EPA annual releases, a change of +1 days.
Michigan City-La Porte, IN lands in the lower Good-day tercile (63.0% Good), a thinner clean-air share than most CBSA peers here. Signature read: 63.0% 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 43 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 230 Good (63%), 123 Moderate (34%), and 11 Unhealthy-for-Sensitive-Groups (3%). The 90th-percentile AQI finished at 72; the highest single-day reading hit 153 (Unhealthy).
Across 2020–2025, Good-day share shifted -15.9 points and median AQI moved +5 (worsening). The annual record contains 1 day at Unhealthy or worse. Metros with comparable AQI profiles include Ashtabula, OH (81.2% good, AQI 43); Bloomington, IN (67.7% good, AQI 43); Champaign-Urbana, IL (65.8% good, AQI 43).
Air Quality Summary
Median AQI
43
Good
Good Days
63.0%
230 of 365 days
Max AQI
153
Unhealthy
Health Grade
Moderate
90th pct: 72
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
230
63%
Moderate
123
34%
USG
11
3%
Unhealthy
1
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Michigan City-La Porte, IN metro area's air quality is rated Moderate based on 63.0% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 11 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 153. Sensitive groups should monitor real-time conditions at AirNow.gov.
How does the Michigan City-La Porte, IN metro compare?
How Michigan City-La Porte, IN compares
5-Year Air Quality Trend
Air quality is worsening in the Michigan City-La Porte, IN metro. Highest Good-day share: 2022 (83.4%, 302 of 362 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 291 | 68 | 1 | 38 | 154 |
| 2021 | 282 | 78 | 0 | 37 | 143 |
| 2022 | 302 | 60 | 0 | 36 | 133 |
| 2023 | 277 | 76 | 0 | 39 | 133 |
| 2024 | 257 | 107 | 0 | 41 | 115 |
| 2025 | 230 | 123 | 1 | 43 | 153 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Michigan City-La Porte, IN (43).
Ashtabula, OH
Median AQI 43 · 81.2% Good-day share
Bloomington, IN
Median AQI 43 · 67.7% Good-day share
Champaign-Urbana, IL
Median AQI 43 · 65.8% Good-day share
Cleveland, MS
Median AQI 43 · 71.9% Good-day share
Columbus, IN
Median AQI 43 · 72.6% Good-day share
Durham-Chapel Hill, NC
Median AQI 43 · 71.5% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Michigan City-La Porte, IN's 1 (independent of median AQI).
Ann Arbor, MI
1 unhealthy-or-worse days · median AQI 41
Bangor, ME
1 unhealthy-or-worse days · median AQI 33
Baraboo, WI
1 unhealthy-or-worse days · median AQI 35
Bartlesville, OK
1 unhealthy-or-worse days · median AQI 44
Beaumont-Port Arthur, TX
1 unhealthy-or-worse days · median AQI 52
Beaver Dam, WI
1 unhealthy-or-worse days · median AQI 40
Frequently Asked Questions
How many unhealthy air days does Michigan City-La Porte, IN have? ▼
What is the air quality in the Michigan City-La Porte, IN metro area? ▼
Is air quality in Michigan City-La Porte, IN getting better or worse? ▼
What does AQI 43 mean for health? ▼
How does Michigan City-La Porte, IN compare to other metro areas? ▼
What is the 90th percentile AQI for Michigan City-La Porte, IN? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Michigan City-La Porte, 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, Michigan City-La Porte, IN · 2020–2025