EnviroNearby

Kewaunee County, Wisconsin air quality history

Daily Air Quality Index summaries from EPA monitors in Kewaunee, Wisconsin, 1985–2025.

85%
Good days in 2025
39
Median daily AQI, 2025
1
Days above 100 in 2025
199
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Kewaunee, Wisconsin on 199 days. 169 of those days (85%) were in the Good range, and the median daily AQI was 39. That median is about the same as the typical monitored county in Wisconsin (median 38 across 29 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 199 days. Across the years with fuller monitoring, the share of Good days rose: an average of 74% in 1985–1987 versus 80% in 2023–2025.

EPA did not report an AQI for every day of 2025 here (199 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.

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%1985: Good 113 of 154 days1985: Moderate 31 of 154 days1985: Unhealthy for Sensitive Groups 5 of 154 days1985: Unhealthy 5 of 154 days19851986: Good 149 of 180 days1986: Moderate 20 of 180 days1986: Unhealthy for Sensitive Groups 10 of 180 days1986: Unhealthy 1 of 180 days1987: Good 119 of 180 days1987: Moderate 36 of 180 days1987: Unhealthy for Sensitive Groups 12 of 180 days1987: Unhealthy 9 of 180 days1987: Very Unhealthy 4 of 180 days1988: Good 124 of 183 days1988: Moderate 23 of 183 days1988: Unhealthy for Sensitive Groups 16 of 183 days1988: Unhealthy 9 of 183 days1988: Very Unhealthy 11 of 183 days1989: Good 132 of 184 days1989: Moderate 39 of 184 days1989: Unhealthy for Sensitive Groups 10 of 184 days1989: Unhealthy 3 of 184 days1990: Good 145 of 184 days1990: Moderate 24 of 184 days1990: Unhealthy for Sensitive Groups 10 of 184 days1990: Unhealthy 4 of 184 days1990: Very Unhealthy 1 of 184 days19901991: Good 132 of 179 days1991: Moderate 23 of 179 days1991: Unhealthy for Sensitive Groups 20 of 179 days1991: Unhealthy 2 of 179 days1991: Very Unhealthy 2 of 179 days1992: Good 146 of 180 days1992: Moderate 27 of 180 days1992: Unhealthy for Sensitive Groups 7 of 180 days1993: Good 154 of 184 days1993: Moderate 25 of 184 days1993: Unhealthy for Sensitive Groups 4 of 184 days1993: Unhealthy 1 of 184 days1994: Good 140 of 179 days1994: Moderate 24 of 179 days1994: Unhealthy for Sensitive Groups 10 of 179 days1994: Unhealthy 4 of 179 days1994: Very Unhealthy 1 of 179 days1995: Good 137 of 183 days1995: Moderate 25 of 183 days1995: Unhealthy for Sensitive Groups 15 of 183 days1995: Unhealthy 5 of 183 days1995: Very Unhealthy 1 of 183 days19951996: Good 138 of 182 days1996: Moderate 31 of 182 days1996: Unhealthy for Sensitive Groups 11 of 182 days1996: Unhealthy 1 of 182 days1996: Very Unhealthy 1 of 182 days1997: Good 140 of 184 days1997: Moderate 29 of 184 days1997: Unhealthy for Sensitive Groups 10 of 184 days1997: Unhealthy 3 of 184 days1997: Very Unhealthy 2 of 184 days1998: Good 123 of 184 days1998: Moderate 40 of 184 days1998: Unhealthy for Sensitive Groups 17 of 184 days1998: Unhealthy 4 of 184 days1999: Good 130 of 183 days1999: Moderate 31 of 183 days1999: Unhealthy for Sensitive Groups 15 of 183 days1999: Unhealthy 7 of 183 days2000: Good 159 of 184 days2000: Moderate 20 of 184 days2000: Unhealthy for Sensitive Groups 2 of 184 days2000: Unhealthy 3 of 184 days20002001: Good 142 of 179 days2001: Moderate 22 of 179 days2001: Unhealthy for Sensitive Groups 10 of 179 days2001: Unhealthy 5 of 179 days2002: Good 128 of 183 days2002: Moderate 40 of 183 days2002: Unhealthy for Sensitive Groups 9 of 183 days2002: Unhealthy 5 of 183 days2002: Very Unhealthy 1 of 183 days2003: Good 137 of 184 days2003: Moderate 35 of 184 days2003: Unhealthy for Sensitive Groups 7 of 184 days2003: Unhealthy 4 of 184 days2003: Very Unhealthy 1 of 184 days2004: Good 168 of 198 days2004: Moderate 24 of 198 days2004: Unhealthy for Sensitive Groups 6 of 198 days2005: Good 138 of 192 days2005: Moderate 32 of 192 days2005: Unhealthy for Sensitive Groups 17 of 192 days2005: Unhealthy 5 of 192 days20052006: Good 145 of 182 days2006: Moderate 31 of 182 days2006: Unhealthy for Sensitive Groups 4 of 182 days2006: Unhealthy 2 of 182 days2007: Good 139 of 196 days2007: Moderate 39 of 196 days2007: Unhealthy for Sensitive Groups 15 of 196 days2007: Unhealthy 3 of 196 days2008: Good 171 of 199 days2008: Moderate 26 of 199 days2008: Unhealthy for Sensitive Groups 2 of 199 days2009: Good 168 of 194 days2009: Moderate 22 of 194 days2009: Unhealthy for Sensitive Groups 4 of 194 days2010: Good 169 of 200 days2010: Moderate 25 of 200 days2010: Unhealthy for Sensitive Groups 5 of 200 days2010: Unhealthy 1 of 200 days20102011: Good 174 of 199 days2011: Moderate 22 of 199 days2011: Unhealthy for Sensitive Groups 2 of 199 days2011: Unhealthy 1 of 199 days2012: Good 147 of 194 days2012: Moderate 33 of 194 days2012: Unhealthy for Sensitive Groups 10 of 194 days2012: Unhealthy 4 of 194 days2013: Good 163 of 208 days2013: Moderate 44 of 208 days2013: Unhealthy for Sensitive Groups 1 of 208 days2014: Good 176 of 202 days2014: Moderate 25 of 202 days2014: Unhealthy for Sensitive Groups 1 of 202 days2015: Good 170 of 200 days2015: Moderate 27 of 200 days2015: Unhealthy for Sensitive Groups 3 of 200 days20152016: Good 162 of 188 days2016: Moderate 21 of 188 days2016: Unhealthy for Sensitive Groups 5 of 188 days2017: Good 209 of 235 days2017: Moderate 24 of 235 days2017: Unhealthy for Sensitive Groups 2 of 235 days2018: Good 200 of 240 days2018: Moderate 35 of 240 days2018: Unhealthy for Sensitive Groups 4 of 240 days2018: Unhealthy 1 of 240 days2019: Good 199 of 210 days2019: Moderate 11 of 210 days2020: Good 195 of 207 days2020: Moderate 12 of 207 days20202021: Good 170 of 207 days2021: Moderate 35 of 207 days2021: Unhealthy for Sensitive Groups 2 of 207 days2022: Good 172 of 201 days2022: Moderate 25 of 201 days2022: Unhealthy for Sensitive Groups 3 of 201 days2022: Unhealthy 1 of 201 days2023: Good 142 of 203 days2023: Moderate 53 of 203 days2023: Unhealthy for Sensitive Groups 6 of 203 days2023: Unhealthy 2 of 203 days2024: Good 170 of 197 days2024: Moderate 26 of 197 days2024: Unhealthy for Sensitive Groups 1 of 197 days2025: Good 169 of 199 days2025: Moderate 29 of 199 days2025: Unhealthy for Sensitive Groups 1 of 199 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 year0501001502001985: 90th percentile AQI 901986: 90th percentile AQI 841987: 90th percentile AQI 1261988: 90th percentile AQI 1541989: 90th percentile AQI 931990: 90th percentile AQI 1001991: 90th percentile AQI 1081992: 90th percentile AQI 801993: 90th percentile AQI 641994: 90th percentile AQI 901995: 90th percentile AQI 1051996: 90th percentile AQI 801997: 90th percentile AQI 901998: 90th percentile AQI 1051999: 90th percentile AQI 1152000: 90th percentile AQI 582001: 90th percentile AQI 972002: 90th percentile AQI 872003: 90th percentile AQI 902004: 90th percentile AQI 642005: 90th percentile AQI 1082006: 90th percentile AQI 742007: 90th percentile AQI 972008: 90th percentile AQI 542009: 90th percentile AQI 542010: 90th percentile AQI 612011: 90th percentile AQI 512012: 90th percentile AQI 972013: 90th percentile AQI 642014: 90th percentile AQI 542015: 90th percentile AQI 582016: 90th percentile AQI 712017: 90th percentile AQI 512018: 90th percentile AQI 642019: 90th percentile AQI 452020: 90th percentile AQI 472021: 90th percentile AQI 612022: 90th percentile AQI 612023: 90th percentile AQI 872024: 90th percentile AQI 612025: 90th percentile AQI 671985: Median AQI 401986: Median AQI 341987: Median AQI 411988: Median AQI 411989: Median AQI 431990: Median AQI 401991: Median AQI 371992: Median AQI 351993: Median AQI 371994: Median AQI 391995: Median AQI 411996: Median AQI 441997: Median AQI 421998: Median AQI 441999: Median AQI 422000: Median AQI 412001: Median AQI 422002: Median AQI 422003: Median AQI 442004: Median AQI 382005: Median AQI 402006: Median AQI 402007: Median AQI 442008: Median AQI 392009: Median AQI 382010: Median AQI 392011: Median AQI 382012: Median AQI 412013: Median AQI 412014: Median AQI 392015: Median AQI 402016: Median AQI 372017: Median AQI 392018: Median AQI 422019: Median AQI 362020: Median AQI 342021: Median AQI 402022: Median AQI 392023: Median AQI 432024: Median AQI 392025: Median AQI 39198519901995200020052010201520202025
  • 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
Ozone199100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20251991692910003967105Ozone
20241971702610003961105Ozone
20232031425362004387182Ozone
20222011722531003961161Ozone
20212071703520004061108Ozone
2020207195120000344797Ozone
2019210199110000364590Ozone
20182402003541004264151Ozone
20172352092420003951112Ozone
20161881622150003771136Ozone
20152001702730004058119Ozone
20142021762510003954129Ozone
20132081634410004164119Ozone
201219414733104004197172Ozone
20111991742221003851195Ozone
20102001692551003961159Ozone
20091941682240003854140Ozone
20081991712620003954112Ozone
200719613939153004497164Ozone
20061821453142004074174Ozone
2005192138321750040108192Ozone
20041981682460003864143Ozone
20031841373574104490206Ozone
20021831284095104287201Ozone
200117914222105004297187Ozone
20001841592023004158156Ozone
1999183130311570042115192Ozone
1998184123401740044105195Ozone
199718414029103204290204Ozone
199618213831111104480202Ozone
1995183137251551041105204Ozone
199417914024104103990218Ozone
19931841542541003764151Ozone
19921801462770003580129Ozone
1991179132232022037108218Ozone
1990184145241041040100202Ozone
198918413239103004393187Ozone
19881831242316911041154229Ozone
1987180119361294041126218Ozone
198618014920101003484164Ozone
19851541133155004090182Ozone

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 1985–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem