EnviroNearby

Manitowoc County, Wisconsin air quality history

Daily Air Quality Index summaries from EPA monitors in Manitowoc, Wisconsin, 1984–2025.

87%
Good days in 2025
36
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 Manitowoc, Wisconsin on 199 days. 174 of those days (87%) were in the Good range, and the median daily AQI was 36. 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 199 days. Across the years with fuller monitoring, the share of Good days rose: an average of 71% in 1984–1986 versus 84% 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%1984: Good 124 of 177 days1984: Moderate 26 of 177 days1984: Unhealthy for Sensitive Groups 15 of 177 days1984: Unhealthy 7 of 177 days1984: Very Unhealthy 5 of 177 days19841985: Good 117 of 179 days1985: Moderate 32 of 179 days1985: Unhealthy for Sensitive Groups 20 of 179 days1985: Unhealthy 9 of 179 days1985: Very Unhealthy 1 of 179 days1986: Good 143 of 181 days1986: Moderate 23 of 181 days1986: Unhealthy for Sensitive Groups 11 of 181 days1986: Unhealthy 4 of 181 days1987: Good 111 of 183 days1987: Moderate 34 of 183 days1987: Unhealthy for Sensitive Groups 18 of 183 days1987: Unhealthy 12 of 183 days1987: Very Unhealthy 8 of 183 days1988: Good 102 of 179 days1988: Moderate 30 of 179 days1988: Unhealthy for Sensitive Groups 25 of 179 days1988: Unhealthy 8 of 179 days1988: Very Unhealthy 14 of 179 days1989: Good 119 of 180 days1989: Moderate 37 of 180 days1989: Unhealthy for Sensitive Groups 18 of 180 days1989: Unhealthy 5 of 180 days1989: Very Unhealthy 1 of 180 days19891990: Good 125 of 183 days1990: Moderate 33 of 183 days1990: Unhealthy for Sensitive Groups 16 of 183 days1990: Unhealthy 7 of 183 days1990: Very Unhealthy 2 of 183 days1991: Good 120 of 179 days1991: Moderate 30 of 179 days1991: Unhealthy for Sensitive Groups 15 of 179 days1991: Unhealthy 11 of 179 days1991: Very Unhealthy 3 of 179 days1992: Good 145 of 183 days1992: Moderate 25 of 183 days1992: Unhealthy for Sensitive Groups 13 of 183 days1993: Good 155 of 184 days1993: Moderate 23 of 184 days1993: Unhealthy for Sensitive Groups 5 of 184 days1993: Unhealthy 1 of 184 days1994: Good 136 of 184 days1994: Moderate 27 of 184 days1994: Unhealthy for Sensitive Groups 11 of 184 days1994: Unhealthy 9 of 184 days1994: Very Unhealthy 1 of 184 days19941995: Good 109 of 184 days1995: Moderate 43 of 184 days1995: Unhealthy for Sensitive Groups 17 of 184 days1995: Unhealthy 9 of 184 days1995: Very Unhealthy 6 of 184 days1996: Good 121 of 184 days1996: Moderate 42 of 184 days1996: Unhealthy for Sensitive Groups 12 of 184 days1996: Unhealthy 7 of 184 days1996: Very Unhealthy 2 of 184 days1997: Good 117 of 184 days1997: Moderate 42 of 184 days1997: Unhealthy for Sensitive Groups 17 of 184 days1997: Unhealthy 4 of 184 days1997: Very Unhealthy 4 of 184 days1998: Good 109 of 184 days1998: Moderate 50 of 184 days1998: Unhealthy for Sensitive Groups 16 of 184 days1998: Unhealthy 9 of 184 days1999: Good 149 of 237 days1999: Moderate 62 of 237 days1999: Unhealthy for Sensitive Groups 15 of 237 days1999: Unhealthy 11 of 237 days19992000: Good 162 of 242 days2000: Moderate 72 of 242 days2000: Unhealthy for Sensitive Groups 6 of 242 days2000: Unhealthy 2 of 242 days2001: Good 154 of 243 days2001: Moderate 67 of 243 days2001: Unhealthy for Sensitive Groups 12 of 243 days2001: Unhealthy 9 of 243 days2001: Very Unhealthy 1 of 243 days2002: Good 156 of 246 days2002: Moderate 76 of 246 days2002: Unhealthy for Sensitive Groups 10 of 246 days2002: Unhealthy 4 of 246 days2003: Good 158 of 243 days2003: Moderate 72 of 243 days2003: Unhealthy for Sensitive Groups 7 of 243 days2003: Unhealthy 5 of 243 days2003: Very Unhealthy 1 of 243 days2004: Good 178 of 240 days2004: Moderate 55 of 240 days2004: Unhealthy for Sensitive Groups 7 of 240 days20042005: Good 145 of 239 days2005: Moderate 69 of 239 days2005: Unhealthy for Sensitive Groups 16 of 239 days2005: Unhealthy 7 of 239 days2005: Very Unhealthy 2 of 239 days2006: Good 163 of 241 days2006: Moderate 70 of 241 days2006: Unhealthy for Sensitive Groups 6 of 241 days2006: Unhealthy 2 of 241 days2007: Good 157 of 251 days2007: Moderate 76 of 251 days2007: Unhealthy for Sensitive Groups 15 of 251 days2007: Unhealthy 3 of 251 days2008: Good 161 of 239 days2008: Moderate 76 of 239 days2008: Unhealthy for Sensitive Groups 2 of 239 days2009: Good 190 of 247 days2009: Moderate 52 of 247 days2009: Unhealthy for Sensitive Groups 4 of 247 days2009: Unhealthy 1 of 247 days20092010: Good 189 of 241 days2010: Moderate 45 of 241 days2010: Unhealthy for Sensitive Groups 5 of 241 days2010: Unhealthy 2 of 241 days2011: Good 168 of 194 days2011: Moderate 19 of 194 days2011: Unhealthy for Sensitive Groups 5 of 194 days2011: Unhealthy 2 of 194 days2012: Good 142 of 192 days2012: Moderate 29 of 192 days2012: Unhealthy for Sensitive Groups 16 of 192 days2012: Unhealthy 5 of 192 days2013: Good 153 of 209 days2013: Moderate 50 of 209 days2013: Unhealthy for Sensitive Groups 6 of 209 days2014: Good 180 of 201 days2014: Moderate 20 of 201 days2014: Unhealthy for Sensitive Groups 1 of 201 days20142015: Good 159 of 191 days2015: Moderate 27 of 191 days2015: Unhealthy for Sensitive Groups 5 of 191 days2016: Good 160 of 188 days2016: Moderate 21 of 188 days2016: Unhealthy for Sensitive Groups 7 of 188 days2017: Good 216 of 237 days2017: Moderate 17 of 237 days2017: Unhealthy for Sensitive Groups 4 of 237 days2018: Good 202 of 239 days2018: Moderate 30 of 239 days2018: Unhealthy for Sensitive Groups 5 of 239 days2018: Unhealthy 2 of 239 days2019: Good 187 of 202 days2019: Moderate 15 of 202 days20192020: Good 169 of 192 days2020: Moderate 19 of 192 days2020: Unhealthy for Sensitive Groups 4 of 192 days2021: Good 174 of 207 days2021: Moderate 30 of 207 days2021: Unhealthy for Sensitive Groups 3 of 207 days2022: Good 167 of 198 days2022: Moderate 25 of 198 days2022: Unhealthy for Sensitive Groups 4 of 198 days2022: Unhealthy 2 of 198 days2023: Good 162 of 205 days2023: Moderate 40 of 205 days2023: Unhealthy for Sensitive Groups 2 of 205 days2023: Unhealthy 1 of 205 days2024: Good 172 of 204 days2024: Moderate 26 of 204 days2024: Unhealthy for Sensitive Groups 6 of 204 days20242025: Good 174 of 199 days2025: Moderate 24 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 year0501001502001984: 90th percentile AQI 1291985: 90th percentile AQI 1291986: 90th percentile AQI 871987: 90th percentile AQI 1541988: 90th percentile AQI 1851989: 90th percentile AQI 1191990: 90th percentile AQI 1221991: 90th percentile AQI 1361992: 90th percentile AQI 931993: 90th percentile AQI 711994: 90th percentile AQI 1051995: 90th percentile AQI 1431996: 90th percentile AQI 1121997: 90th percentile AQI 1121998: 90th percentile AQI 1151999: 90th percentile AQI 1012000: 90th percentile AQI 742001: 90th percentile AQI 882002: 90th percentile AQI 872003: 90th percentile AQI 842004: 90th percentile AQI 702005: 90th percentile AQI 1032006: 90th percentile AQI 732007: 90th percentile AQI 842008: 90th percentile AQI 672009: 90th percentile AQI 712010: 90th percentile AQI 712011: 90th percentile AQI 612012: 90th percentile AQI 1012013: 90th percentile AQI 712014: 90th percentile AQI 512015: 90th percentile AQI 672016: 90th percentile AQI 672017: 90th percentile AQI 502018: 90th percentile AQI 642019: 90th percentile AQI 482020: 90th percentile AQI 582021: 90th percentile AQI 642022: 90th percentile AQI 712023: 90th percentile AQI 712024: 90th percentile AQI 642025: 90th percentile AQI 581984: Median AQI 421985: Median AQI 441986: Median AQI 361987: Median AQI 431988: Median AQI 451989: Median AQI 441990: Median AQI 421991: Median AQI 421992: Median AQI 351993: Median AQI 371994: Median AQI 421995: Median AQI 451996: Median AQI 451997: Median AQI 461998: Median AQI 461999: Median AQI 442000: Median AQI 432001: Median AQI 442002: Median AQI 432003: Median AQI 452004: Median AQI 402005: Median AQI 442006: Median AQI 422007: Median AQI 452008: Median AQI 422009: Median AQI 392010: Median AQI 382011: Median AQI 372012: Median AQI 392013: Median AQI 412014: Median AQI 382015: Median AQI 382016: Median AQI 372017: Median AQI 382018: Median AQI 402019: Median AQI 362020: Median AQI 362021: Median AQI 392022: Median AQI 382023: Median AQI 402024: Median AQI 392025: Median AQI 361984198919941999200420092014201920242025
  • 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
20251991742410003658115Ozone
20242041722660003964129Ozone
20232051624021004071177Ozone
20221981672542003871182Ozone
20212071743030003964119Ozone
20201921691940003658136Ozone
20192021871500003648100Ozone
20182392023052004064169Ozone
20172372161740003850126Ozone
20161881602170003767147Ozone
20151911592750003867133Ozone
20142011802010003851119Ozone
20132091535060004171126Ozone
2012192142291650039101177Ozone
20111941681952003761187Ozone
20102411894552003871174Ozone
20092471905241003971156Ozone
20082391617620004267118Ozone
200725115776153004584166Ozone
20062411637062004273197Ozone
2005239145691672044103205Ozone
20042401785570004070143Ozone
20032431587275104584208Ozone
200224615676104004387172Ozone
200124315467129104488202Ozone
20002421627262004374197Ozone
19992371496215110044101190Ozone
1998184109501690046115195Ozone
1997184117421744046112222Ozone
1996184121421272045112232Ozone
1995184109431796045143232Ozone
1994184136271191042105251Ozone
19931841552351003771151Ozone
199218314525130003593150Ozone
19911791203015113042136229Ozone
1990183125331672042122213Ozone
1989180119371851044119207Ozone
19881791023025814045185234Ozone
19871831113418128043154240Ozone
198618114323114003687182Ozone
1985179117322091044129209Ozone
1984177124261575042129216Ozone

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 1984–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem