Metro area air quality · 2025
Lafayette-West Lafayette, IN
Median AQI 43 (Good). 68.5% of monitored days rated Good across this metro's EPA monitoring network.
- 43
- Median AQI
- 68.5%
- Good-air days
- 0
- Unhealthy days
- 42%
- Cleaner than US metros
Lafayette-West Lafayette, IN posted a 2025 median AQI of 43 (Good) with 68.5% Good days
According to the U.S. EPA Air Quality System, the Lafayette-West Lafayette, IN CBSA recorded a median AQI of 43 across 362 monitored days in 2025, with 68.5% 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 Lafayette-West Lafayette, IN CBSA's 68.5% Good-day share places it cleaner than 42% 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 Lafayette-West Lafayette, IN.
- 2020–2025 Good-day shift
- Lafayette-West Lafayette, IN's Good-day share moved +19.8 points from 2020 to 2025 (median AQI -8).
- Median AQI
- Median AQI: 43
Aggregated from EPA Air Quality System (2025), 362 monitored days. EPA AQS →
The verdict
Lafayette-West Lafayette, IN's Good-day share (68.5%) sits in the middle CBSA tercile on this extract. On the EPA scale the metro runs good, more polluted than the median US metro, with a median AQI of 43 and 68.5% of 362 monitored days in the Good band.
- 43
- median AQI · Good
- 68.5%
- days rated Good
- 42%
- cleaner than US metros
- 105
- 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
- Lafayette-West Lafayette, IN metro's Good-day share rose from 65.8% to 68.7% between the 2024 and 2025 EPA annual releases, a change of +2.9 percentage points.
- Lafayette-West Lafayette, IN metro's peak single-day AQI rose from 90 to 105 between the 2024 and 2025 EPA annual releases, a change of +15 points.
Lafayette-West Lafayette, IN's Good-day share (68.5%) sits in the middle CBSA tercile on this extract. Signature read: 68.5% 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 43 over 362 measured days in 2025 (Good / Moderate). The monitored-day split lands at 248 Good (69%), 113 Moderate (31%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 62; the highest single-day reading hit 105 (USG).
Across 2020–2025, Good-day share shifted +19.8 points and median AQI moved -8 (improving). No Unhealthy-tier days appear in this annual dataset. 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
68.5%
248 of 362 days
Max AQI
105
USG
Health Grade
Moderate
90th pct: 62
AQI Day Breakdown (2025)
Distribution of 362 monitored days across EPA AQI categories.
Good
248
69%
Moderate
113
31%
USG
1
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Lafayette-West Lafayette, IN metro area's air quality is rated Moderate based on 68.5% 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 Lafayette-West Lafayette, IN metro compare?
How Lafayette-West Lafayette, IN compares
5-Year Air Quality Trend
Air quality is improving in the Lafayette-West Lafayette, IN metro. Highest Good-day share: 2022 (72.9%, 266 of 365 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 179 | 187 | 0 | 51 | 100 |
| 2021 | 214 | 150 | 0 | 46 | 105 |
| 2022 | 266 | 99 | 0 | 41 | 96 |
| 2023 | 236 | 118 | 1 | 45 | 206 |
| 2024 | 241 | 125 | 0 | 44 | 90 |
| 2025 | 248 | 113 | 0 | 43 | 105 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Lafayette-West Lafayette, 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 Lafayette-West Lafayette, IN'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
Adrian, MI
0 unhealthy-or-worse days · median AQI 41
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
Frequently Asked Questions
How many unhealthy air days does Lafayette-West Lafayette, IN have? ▼
What is the air quality in the Lafayette-West Lafayette, IN metro area? ▼
Is air quality in Lafayette-West Lafayette, IN getting better or worse? ▼
What does AQI 43 mean for health? ▼
How does Lafayette-West Lafayette, IN compare to other metro areas? ▼
What is the 90th percentile AQI for Lafayette-West Lafayette, IN? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Lafayette-West Lafayette, 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, Lafayette-West Lafayette, IN · 2020–2025