EnviroNearby

Florence County, Wisconsin air quality history

Daily Air Quality Index summaries from EPA monitors in Florence, Wisconsin, 1987–2010.

92%
Good days in 2010
34
Median daily AQI, 2010
0
Days above 100 in 2010
177
Days with an AQI in 2010 (of 365)

In 2010, EPA reported a daily Air Quality Index (AQI) for Florence, Wisconsin on 177 days. 163 of those days (92%) were in the Good range, and the median daily AQI was 34. That median is lower than the typical monitored county in Wisconsin (median 40 across 31 counties), and lower than the typical monitored U.S. county (44). The main pollutant was ozone on 177 days. Across the years with fuller monitoring, the share of Good days rose: an average of 81% in 1987–1989 versus 93% in 2008–2010.

EPA did not report an AQI for every day of 2010 here (177 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.

The most recent year with data for this county is 2010; EPA's files for 2011–2025 contain no row for it, which usually means its monitors stopped reporting.

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%1987: Good 157 of 184 days1987: Moderate 23 of 184 days1987: Unhealthy for Sensitive Groups 3 of 184 days1987: Unhealthy 1 of 184 days19871988: Good 207 of 260 days1988: Moderate 36 of 260 days1988: Unhealthy for Sensitive Groups 13 of 260 days1988: Unhealthy 4 of 260 days1989: Good 217 of 275 days1989: Moderate 49 of 275 days1989: Unhealthy for Sensitive Groups 8 of 275 days1989: Unhealthy 1 of 275 days19891990: Good 251 of 268 days1990: Moderate 16 of 268 days1990: Unhealthy for Sensitive Groups 1 of 268 days1991: Good 222 of 254 days1991: Moderate 24 of 254 days1991: Unhealthy for Sensitive Groups 8 of 254 days19911992: Good 247 of 265 days1992: Moderate 15 of 265 days1992: Unhealthy for Sensitive Groups 3 of 265 days1993: Good 215 of 225 days1993: Moderate 8 of 225 days1993: Unhealthy for Sensitive Groups 2 of 225 days19931994: Good 191 of 206 days1994: Moderate 14 of 206 days1994: Unhealthy for Sensitive Groups 1 of 206 days1995: Good 163 of 181 days1995: Moderate 16 of 181 days1995: Unhealthy for Sensitive Groups 2 of 181 days19951996: Good 157 of 175 days1996: Moderate 15 of 175 days1996: Unhealthy for Sensitive Groups 2 of 175 days1996: Unhealthy 1 of 175 days1997: Good 143 of 161 days1997: Moderate 16 of 161 days1997: Unhealthy for Sensitive Groups 2 of 161 days19971998: Good 146 of 184 days1998: Moderate 32 of 184 days1998: Unhealthy for Sensitive Groups 5 of 184 days1998: Unhealthy 1 of 184 days1999: Good 149 of 182 days1999: Moderate 23 of 182 days1999: Unhealthy for Sensitive Groups 6 of 182 days1999: Unhealthy 4 of 182 days19992000: Good 146 of 173 days2000: Moderate 25 of 173 days2000: Unhealthy for Sensitive Groups 2 of 173 days2001: Good 149 of 179 days2001: Moderate 23 of 179 days2001: Unhealthy for Sensitive Groups 6 of 179 days2001: Unhealthy 1 of 179 days20012002: Good 150 of 182 days2002: Moderate 30 of 182 days2002: Unhealthy for Sensitive Groups 2 of 182 days2003: Good 152 of 183 days2003: Moderate 30 of 183 days2003: Unhealthy for Sensitive Groups 1 of 183 days20032004: Good 166 of 182 days2004: Moderate 15 of 182 days2004: Unhealthy for Sensitive Groups 1 of 182 days2005: Good 140 of 176 days2005: Moderate 33 of 176 days2005: Unhealthy for Sensitive Groups 3 of 176 days20052006: Good 169 of 189 days2006: Moderate 19 of 189 days2006: Unhealthy for Sensitive Groups 1 of 189 days2007: Good 185 of 208 days2007: Moderate 20 of 208 days2007: Unhealthy for Sensitive Groups 3 of 208 days20072008: Good 186 of 207 days2008: Moderate 21 of 207 days2009: Good 167 of 173 days2009: Moderate 6 of 173 days20092010: Good 163 of 177 days2010: Moderate 14 of 177 days2010
  • 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 year0501001987: 90th percentile AQI 581988: 90th percentile AQI 901989: 90th percentile AQI 741990: 90th percentile AQI 471991: 90th percentile AQI 611992: 90th percentile AQI 461993: 90th percentile AQI 451994: 90th percentile AQI 481995: 90th percentile AQI 501996: 90th percentile AQI 511997: 90th percentile AQI 511998: 90th percentile AQI 801999: 90th percentile AQI 742000: 90th percentile AQI 612001: 90th percentile AQI 642002: 90th percentile AQI 672003: 90th percentile AQI 612004: 90th percentile AQI 492005: 90th percentile AQI 772006: 90th percentile AQI 512007: 90th percentile AQI 542008: 90th percentile AQI 512009: 90th percentile AQI 472010: 90th percentile AQI 501987: Median AQI 331988: Median AQI 391989: Median AQI 401990: Median AQI 331991: Median AQI 341992: Median AQI 301993: Median AQI 311994: Median AQI 361995: Median AQI 341996: Median AQI 381997: Median AQI 331998: Median AQI 411999: Median AQI 382000: Median AQI 372001: Median AQI 392002: Median AQI 382003: Median AQI 412004: Median AQI 372005: Median AQI 392006: Median AQI 372007: Median AQI 372008: Median AQI 372009: Median AQI 362010: Median AQI 341987198919911993199519971999200120032005200720092010
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2010

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
Ozone177100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2010177163140000345093Ozone
200917316760000364780Ozone
2008207186210000375190Ozone
20072081852030003754143Ozone
20061891691910003751101Ozone
20051761403330003977133Ozone
20041821661510003749112Ozone
20031831523010004161105Ozone
20021821503020003867122Ozone
20011791492361003964172Ozone
20001731462520003761122Ozone
19991821492364003874161Ozone
19981841463251004180182Ozone
19971611431620003351126Ozone
19961751571521003851151Ozone
19951811631620003450122Ozone
19942061911410003648108Ozone
1993225215820003145119Ozone
19922652471530003046140Ozone
19912542222480003461119Ozone
19902682511610003347105Ozone
19892752174981004074169Ozone
198826020736134003990166Ozone
19871841572331003358159Ozone

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 2010

All monitored counties in Wisconsin

Source: U.S. EPA AirData, “Annual AQI by County” files for 1987–2010 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem