EnviroNearby

La Crosse County, Wisconsin air quality history

Daily Air Quality Index summaries from EPA monitors in La Crosse, Wisconsin, 1980–2025.

93%
Good days in 2025
37
Median daily AQI, 2025
0
Days above 100 in 2025
198
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for La Crosse, Wisconsin on 198 days. 185 of those days (93%) were in the Good range, and the median daily AQI was 37. That median is about the same as the typical monitored county in Wisconsin (median 38 across 29 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 198 days. Across the years with fuller monitoring, the share of Good days fell: an average of 92% in 1980–1982 versus 83% in 2023–2025.

EPA did not report an AQI for every day of 2025 here (198 of 365 days). Figures describe monitored days only; seasonal monitoring (for example, ozone measured only in warmer months) can make a county look cleaner or dirtier than a full-year record would.

Years with fewer than 120 monitored days (2005, 2006) are shown in the table but left out of comparisons and trend statements.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Share of monitored days in each AQI category, by year0%25%50%75%100%1980: Good 144 of 165 days1980: Moderate 16 of 165 days1980: Unhealthy for Sensitive Groups 3 of 165 days1980: Unhealthy 2 of 165 days19801981: Good 238 of 251 days1981: Moderate 12 of 251 days1981: Unhealthy for Sensitive Groups 1 of 251 days1982: Good 275 of 293 days1982: Moderate 17 of 293 days1982: Unhealthy for Sensitive Groups 1 of 293 days1983: Good 129 of 179 days1983: Moderate 40 of 179 days1983: Unhealthy for Sensitive Groups 7 of 179 days1983: Unhealthy 3 of 179 days1984: Good 130 of 159 days1984: Moderate 24 of 159 days1984: Unhealthy for Sensitive Groups 5 of 159 days1985: Good 103 of 129 days1985: Moderate 24 of 129 days1985: Unhealthy for Sensitive Groups 2 of 129 days19851986: Good 158 of 169 days1986: Moderate 11 of 169 days1987: Good 141 of 182 days1987: Moderate 34 of 182 days1987: Unhealthy for Sensitive Groups 7 of 182 days2005: Moderate 7 of 7 days2006: Good 48 of 119 days2006: Moderate 70 of 119 days2006: Unhealthy for Sensitive Groups 1 of 119 days2007: Good 49 of 120 days2007: Moderate 70 of 120 days2007: Unhealthy for Sensitive Groups 1 of 120 days20072008: Good 238 of 324 days2008: Moderate 84 of 324 days2008: Unhealthy for Sensitive Groups 2 of 324 days2009: Good 254 of 317 days2009: Moderate 61 of 317 days2009: Unhealthy for Sensitive Groups 2 of 317 days2010: Good 216 of 310 days2010: Moderate 93 of 310 days2010: Unhealthy for Sensitive Groups 1 of 310 days2011: Good 207 of 316 days2011: Moderate 109 of 316 days2012: Good 181 of 316 days2012: Moderate 133 of 316 days2012: Unhealthy for Sensitive Groups 2 of 316 days20122013: Good 191 of 361 days2013: Moderate 170 of 361 days2014: Good 266 of 358 days2014: Moderate 92 of 358 days2015: Good 280 of 361 days2015: Moderate 81 of 361 days2016: Good 288 of 355 days2016: Moderate 67 of 355 days2017: Good 268 of 360 days2017: Moderate 92 of 360 days20172018: Good 256 of 365 days2018: Moderate 109 of 365 days2019: Good 274 of 365 days2019: Moderate 91 of 365 days2020: Good 255 of 364 days2020: Moderate 109 of 364 days2021: Good 240 of 365 days2021: Moderate 124 of 365 days2021: Unhealthy for Sensitive Groups 1 of 365 days2022: Good 271 of 365 days2022: Moderate 94 of 365 days20222023: Good 199 of 339 days2023: Moderate 130 of 339 days2023: Unhealthy for Sensitive Groups 5 of 339 days2023: Unhealthy 5 of 339 days2024: Good 197 of 205 days2024: Moderate 8 of 205 days2025: Good 185 of 198 days2025: Moderate 13 of 198 days2025
  • Good
  • Moderate
  • Unhealthy for Sensitive Groups
  • Unhealthy
  • Very Unhealthy
  • Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median and 90th-percentile daily AQI, by year0501001980: 90th percentile AQI 611981: 90th percentile AQI 461982: 90th percentile AQI 471983: 90th percentile AQI 931984: 90th percentile AQI 741985: 90th percentile AQI 611986: 90th percentile AQI 471987: 90th percentile AQI 802005: 90th percentile AQI 952006: 90th percentile AQI 742007: 90th percentile AQI 702008: 90th percentile AQI 652009: 90th percentile AQI 622010: 90th percentile AQI 642011: 90th percentile AQI 662012: 90th percentile AQI 702013: 90th percentile AQI 672014: 90th percentile AQI 602015: 90th percentile AQI 582016: 90th percentile AQI 572017: 90th percentile AQI 582018: 90th percentile AQI 632019: 90th percentile AQI 622020: 90th percentile AQI 592021: 90th percentile AQI 642022: 90th percentile AQI 572023: 90th percentile AQI 802024: 90th percentile AQI 472025: 90th percentile AQI 491980: Median AQI 331981: Median AQI 311982: Median AQI 291983: Median AQI 411984: Median AQI 421985: Median AQI 401986: Median AQI 341987: Median AQI 422005: Median AQI 682006: Median AQI 532007: Median AQI 532008: Median AQI 412009: Median AQI 372010: Median AQI 422011: Median AQI 442012: Median AQI 472013: Median AQI 492014: Median AQI 402015: Median AQI 402016: Median AQI 372017: Median AQI 412018: Median AQI 432019: Median AQI 392020: Median AQI 422021: Median AQI 432022: Median AQI 412023: Median AQI 452024: Median AQI 372025: Median AQI 371980198520072012201720222025
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2025

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

PollutantDays as main pollutantShare of monitored days
Ozone198100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025198185130000374990Ozone
202420519780000374767Ozone
202333919913055004580181PM2.5
2022365271940000415785PM2.5
202136524012410004364110PM2.5
20203642551090000425993PM2.5
2019365274910000396285PM2.5
20183652561090000436397PM2.5
2017360268920000415887PM2.5
2016355288670000375787PM2.5
2015361280810000405898Ozone
2014358266920000406098PM2.5
20133611911700000496786PM2.5
201231618113320004770105PM2.5
201131620710900004466100PM2.5
20103102169310004264110PM2.5
20093172546120003762121Ozone
20083242388420004165122Ozone
2007120497010005370147PM2.5
2006119487010005374117PM2.5
20057070000689595PM2.5
19871821413470004280122Ozone
1986169158110000344780Ozone
19851291032420004061115Ozone
19841591302450004274133Ozone
19831791294073004193154Ozone
19822932751710002947115Ozone
19812512381210003146105Ozone
19801651441632003361169Ozone

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in Wisconsin with a similar median AQI in 2025

All monitored counties in Wisconsin

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem