EnviroNearby

Lake County, Ohio air quality history

Daily Air Quality Index summaries from EPA monitors in Lake, Ohio, 1980–2025.

67%
Good days in 2025
42
Median daily AQI, 2025
5
Days above 100 in 2025
363
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Lake, Ohio on 363 days. 244 of those days (67%) were in the Good range, and the median daily AQI was 42. That median is about the same as the typical monitored county in Ohio (median 43 across 36 counties), and about the same as 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 rose: an average of 62% in 1980–1982 versus 71% in 2023–2025.

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 208 of 364 days1980: Moderate 116 of 364 days1980: Unhealthy for Sensitive Groups 32 of 364 days1980: Unhealthy 7 of 364 days1980: Very Unhealthy 1 of 364 days19801981: Good 244 of 365 days1981: Moderate 94 of 365 days1981: Unhealthy for Sensitive Groups 20 of 365 days1981: Unhealthy 7 of 365 days1982: Good 231 of 365 days1982: Moderate 96 of 365 days1982: Unhealthy for Sensitive Groups 29 of 365 days1982: Unhealthy 7 of 365 days1982: Very Unhealthy 2 of 365 days1983: Good 209 of 365 days1983: Moderate 109 of 365 days1983: Unhealthy for Sensitive Groups 13 of 365 days1983: Unhealthy 24 of 365 days1983: Very Unhealthy 10 of 365 days1984: Good 272 of 364 days1984: Moderate 56 of 364 days1984: Unhealthy for Sensitive Groups 21 of 364 days1984: Unhealthy 13 of 364 days1984: Very Unhealthy 2 of 364 days1985: Good 241 of 364 days1985: Moderate 78 of 364 days1985: Unhealthy for Sensitive Groups 32 of 364 days1985: Unhealthy 12 of 364 days1985: Very Unhealthy 1 of 364 days19851986: Good 257 of 360 days1986: Moderate 64 of 360 days1986: Unhealthy for Sensitive Groups 29 of 360 days1986: Unhealthy 9 of 360 days1986: Very Unhealthy 1 of 360 days1987: Good 279 of 363 days1987: Moderate 52 of 363 days1987: Unhealthy for Sensitive Groups 23 of 363 days1987: Unhealthy 7 of 363 days1987: Very Unhealthy 2 of 363 days1988: Good 256 of 366 days1988: Moderate 50 of 366 days1988: Unhealthy for Sensitive Groups 16 of 366 days1988: Unhealthy 21 of 366 days1988: Very Unhealthy 23 of 366 days1989: Good 275 of 355 days1989: Moderate 40 of 355 days1989: Unhealthy for Sensitive Groups 29 of 355 days1989: Unhealthy 11 of 355 days1990: Good 313 of 365 days1990: Moderate 35 of 365 days1990: Unhealthy for Sensitive Groups 11 of 365 days1990: Unhealthy 5 of 365 days1990: Very Unhealthy 1 of 365 days19901991: Good 276 of 360 days1991: Moderate 45 of 360 days1991: Unhealthy for Sensitive Groups 25 of 360 days1991: Unhealthy 14 of 360 days1992: Good 254 of 331 days1992: Moderate 47 of 331 days1992: Unhealthy for Sensitive Groups 25 of 331 days1992: Unhealthy 5 of 331 days1993: Good 281 of 365 days1993: Moderate 47 of 365 days1993: Unhealthy for Sensitive Groups 29 of 365 days1993: Unhealthy 8 of 365 days1994: Good 273 of 365 days1994: Moderate 48 of 365 days1994: Unhealthy for Sensitive Groups 28 of 365 days1994: Unhealthy 16 of 365 days1995: Good 273 of 365 days1995: Moderate 52 of 365 days1995: Unhealthy for Sensitive Groups 20 of 365 days1995: Unhealthy 18 of 365 days1995: Very Unhealthy 2 of 365 days19951996: Good 286 of 366 days1996: Moderate 43 of 366 days1996: Unhealthy for Sensitive Groups 22 of 366 days1996: Unhealthy 13 of 366 days1996: Very Unhealthy 2 of 366 days1997: Good 297 of 365 days1997: Moderate 39 of 365 days1997: Unhealthy for Sensitive Groups 22 of 365 days1997: Unhealthy 6 of 365 days1997: Very Unhealthy 1 of 365 days1998: Good 267 of 362 days1998: Moderate 49 of 362 days1998: Unhealthy for Sensitive Groups 29 of 362 days1998: Unhealthy 16 of 362 days1998: Very Unhealthy 1 of 362 days1999: Good 185 of 323 days1999: Moderate 101 of 323 days1999: Unhealthy for Sensitive Groups 23 of 323 days1999: Unhealthy 12 of 323 days1999: Very Unhealthy 2 of 323 days2000: Good 245 of 366 days2000: Moderate 102 of 366 days2000: Unhealthy for Sensitive Groups 16 of 366 days2000: Unhealthy 3 of 366 days20002001: Good 228 of 365 days2001: Moderate 105 of 365 days2001: Unhealthy for Sensitive Groups 24 of 365 days2001: Unhealthy 8 of 365 days2002: Good 228 of 365 days2002: Moderate 98 of 365 days2002: Unhealthy for Sensitive Groups 14 of 365 days2002: Unhealthy 22 of 365 days2002: Very Unhealthy 3 of 365 days2003: Good 234 of 365 days2003: Moderate 105 of 365 days2003: Unhealthy for Sensitive Groups 22 of 365 days2003: Unhealthy 2 of 365 days2003: Very Unhealthy 2 of 365 days2004: Good 264 of 366 days2004: Moderate 86 of 366 days2004: Unhealthy for Sensitive Groups 16 of 366 days2005: Good 214 of 365 days2005: Moderate 114 of 365 days2005: Unhealthy for Sensitive Groups 25 of 365 days2005: Unhealthy 11 of 365 days2005: Very Unhealthy 1 of 365 days20052006: Good 258 of 365 days2006: Moderate 94 of 365 days2006: Unhealthy for Sensitive Groups 12 of 365 days2006: Unhealthy 1 of 365 days2007: Good 247 of 365 days2007: Moderate 104 of 365 days2007: Unhealthy for Sensitive Groups 13 of 365 days2007: Unhealthy 1 of 365 days2008: Good 250 of 366 days2008: Moderate 97 of 366 days2008: Unhealthy for Sensitive Groups 19 of 366 days2009: Good 264 of 365 days2009: Moderate 92 of 365 days2009: Unhealthy for Sensitive Groups 7 of 365 days2009: Unhealthy 2 of 365 days2010: Good 169 of 365 days2010: Moderate 180 of 365 days2010: Unhealthy for Sensitive Groups 15 of 365 days2010: Unhealthy 1 of 365 days20102011: Good 180 of 365 days2011: Moderate 172 of 365 days2011: Unhealthy for Sensitive Groups 11 of 365 days2011: Unhealthy 2 of 365 days2012: Good 158 of 366 days2012: Moderate 174 of 366 days2012: Unhealthy for Sensitive Groups 27 of 366 days2012: Unhealthy 6 of 366 days2012: Very Unhealthy 1 of 366 days2013: Good 167 of 365 days2013: Moderate 195 of 365 days2013: Unhealthy for Sensitive Groups 3 of 365 days2014: Good 172 of 365 days2014: Moderate 187 of 365 days2014: Unhealthy for Sensitive Groups 6 of 365 days2015: Good 181 of 365 days2015: Moderate 176 of 365 days2015: Unhealthy for Sensitive Groups 8 of 365 days20152016: Good 225 of 366 days2016: Moderate 132 of 366 days2016: Unhealthy for Sensitive Groups 9 of 366 days2017: Good 244 of 365 days2017: Moderate 115 of 365 days2017: Unhealthy for Sensitive Groups 6 of 365 days2018: Good 258 of 365 days2018: Moderate 98 of 365 days2018: Unhealthy for Sensitive Groups 9 of 365 days2019: Good 292 of 365 days2019: Moderate 68 of 365 days2019: Unhealthy for Sensitive Groups 5 of 365 days2020: Good 296 of 366 days2020: Moderate 64 of 366 days2020: Unhealthy for Sensitive Groups 6 of 366 days20202021: Good 251 of 365 days2021: Moderate 107 of 365 days2021: Unhealthy for Sensitive Groups 7 of 365 days2022: Good 281 of 365 days2022: Moderate 80 of 365 days2022: Unhealthy for Sensitive Groups 4 of 365 days2023: Good 259 of 365 days2023: Moderate 96 of 365 days2023: Unhealthy for Sensitive Groups 7 of 365 days2023: Unhealthy 3 of 365 days2024: Good 272 of 365 days2024: Moderate 89 of 365 days2024: Unhealthy for Sensitive Groups 4 of 365 days2025: Good 244 of 363 days2025: Moderate 114 of 363 days2025: Unhealthy for Sensitive Groups 5 of 363 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 year0501001502001980: 90th percentile AQI 1051981: 90th percentile AQI 851982: 90th percentile AQI 1011983: 90th percentile AQI 1401984: 90th percentile AQI 1001985: 90th percentile AQI 1081986: 90th percentile AQI 1011987: 90th percentile AQI 931988: 90th percentile AQI 1641989: 90th percentile AQI 1081990: 90th percentile AQI 711991: 90th percentile AQI 1051992: 90th percentile AQI 901993: 90th percentile AQI 1011994: 90th percentile AQI 1121995: 90th percentile AQI 1051996: 90th percentile AQI 1011997: 90th percentile AQI 901998: 90th percentile AQI 1121999: 90th percentile AQI 1082000: 90th percentile AQI 842001: 90th percentile AQI 972002: 90th percentile AQI 1052003: 90th percentile AQI 872004: 90th percentile AQI 802005: 90th percentile AQI 1012006: 90th percentile AQI 762007: 90th percentile AQI 772008: 90th percentile AQI 722009: 90th percentile AQI 662010: 90th percentile AQI 842011: 90th percentile AQI 772012: 90th percentile AQI 972013: 90th percentile AQI 692014: 90th percentile AQI 702015: 90th percentile AQI 712016: 90th percentile AQI 672017: 90th percentile AQI 642018: 90th percentile AQI 662019: 90th percentile AQI 582020: 90th percentile AQI 572021: 90th percentile AQI 662022: 90th percentile AQI 602023: 90th percentile AQI 772024: 90th percentile AQI 612025: 90th percentile AQI 711980: Median AQI 461981: Median AQI 431982: Median AQI 441983: Median AQI 461984: Median AQI 381985: Median AQI 431986: Median AQI 411987: Median AQI 361988: Median AQI 401989: Median AQI 361990: Median AQI 311991: Median AQI 331992: Median AQI 351993: Median AQI 311994: Median AQI 331995: Median AQI 311996: Median AQI 321997: Median AQI 311998: Median AQI 321999: Median AQI 452000: Median AQI 402001: Median AQI 412002: Median AQI 412003: Median AQI 422004: Median AQI 382005: Median AQI 442006: Median AQI 372007: Median AQI 392008: Median AQI 382009: Median AQI 382010: Median AQI 522011: Median AQI 512012: Median AQI 532013: Median AQI 522014: Median AQI 522015: Median AQI 512016: Median AQI 442017: Median AQI 432018: Median AQI 422019: Median AQI 402020: Median AQI 402021: Median AQI 412022: Median AQI 412023: Median AQI 422024: Median AQI 412025: Median AQI 421980198519901995200020052010201520202025
  • 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
Ozone19855%
Fine particles (PM2.5)16545%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536324411450004271133Ozone
20243652728940004161136Ozone
20233652599673004277170PM2.5
20223652818040004160150Ozone
202136525110770004166122PM2.5
20203662966460004057140PM2.5
20193652926850004058115Ozone
20183652589890004266126PM2.5
201736524411560004364147PM2.5
201636622513290004467143PM2.5
201536518117680005171126PM2.5
201436517218760005270129PM2.5
201336516719530005269150PM2.5
2012366158174276105397203PM2.5
2011365180172112005177161PM2.5
2010365169180151005284159PM2.5
20093652649272003866156Ozone
200836625097190003872147Ozone
2007365247104131003977169Ozone
200636525894121003776156Ozone
200536521411425111044101214Ozone
200436626486160003880140Ozone
2003365234105222204287207Ozone
20023652289814223041105210Ozone
2001365228105248004197190Ozone
2000366245102163004084187Ozone
199932318510123122045108214Ozone
19983622674929161032112213Ozone
199736529739226103190202Ozone
19963662864322132032101203Ozone
19953652735220182031105206Ozone
19943652734828160033112192Ozone
1993365281472980031101200Ozone
199233125447255003590179Ozone
19913602764525140033105197Ozone
199036531335115103171219Ozone
19893552754029110036108185Ozone
198836625650162123040164239Ozone
198736327952237203693235CO
1986360257642991041101205Ozone
19853642417832121043108203Ozone
19843642725621132038100216Ozone
1983365209109132410046140232Ozone
1982365231962972044101205Ozone
198136524494207004385190CO
19803642081163271046105217CO

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 Ohio with a similar median AQI in 2025

All monitored counties in Ohio

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