EnviroNearby

Ashtabula County, Ohio air quality history

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

81%
Good days in 2025
43
Median daily AQI, 2025
3
Days above 100 in 2025
245
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Ashtabula, Ohio on 245 days. 199 of those days (81%) were in the Good range, and the median daily AQI was 43. That median is about the same as the typical monitored county in Ohio (median 43 across 36 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 245 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 82% in 1980–1982 versus 83% in 2023–2025.

EPA did not report an AQI for every day of 2025 here (245 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%1980: Good 292 of 351 days1980: Moderate 32 of 351 days1980: Unhealthy for Sensitive Groups 19 of 351 days1980: Unhealthy 8 of 351 days19801981: Good 301 of 356 days1981: Moderate 26 of 356 days1981: Unhealthy for Sensitive Groups 18 of 356 days1981: Unhealthy 9 of 356 days1981: Very Unhealthy 2 of 356 days1982: Good 277 of 350 days1982: Moderate 45 of 350 days1982: Unhealthy for Sensitive Groups 19 of 350 days1982: Unhealthy 9 of 350 days1983: Good 303 of 360 days1983: Moderate 30 of 360 days1983: Unhealthy for Sensitive Groups 11 of 360 days1983: Unhealthy 13 of 360 days1983: Very Unhealthy 3 of 360 days1984: Good 297 of 338 days1984: Moderate 32 of 338 days1984: Unhealthy for Sensitive Groups 6 of 338 days1984: Unhealthy 3 of 338 days1985: Good 311 of 360 days1985: Moderate 36 of 360 days1985: Unhealthy for Sensitive Groups 12 of 360 days1985: Unhealthy 1 of 360 days19851986: Good 242 of 289 days1986: Moderate 35 of 289 days1986: Unhealthy for Sensitive Groups 11 of 289 days1986: Unhealthy 1 of 289 days1987: Good 152 of 204 days1987: Moderate 29 of 204 days1987: Unhealthy for Sensitive Groups 14 of 204 days1987: Unhealthy 8 of 204 days1987: Very Unhealthy 1 of 204 days1988: Good 146 of 214 days1988: Moderate 27 of 214 days1988: Unhealthy for Sensitive Groups 18 of 214 days1988: Unhealthy 13 of 214 days1988: Very Unhealthy 10 of 214 days1989: Good 146 of 198 days1989: Moderate 24 of 198 days1989: Unhealthy for Sensitive Groups 18 of 198 days1989: Unhealthy 10 of 198 days1990: Good 157 of 211 days1990: Moderate 39 of 211 days1990: Unhealthy for Sensitive Groups 12 of 211 days1990: Unhealthy 3 of 211 days19901991: Good 111 of 207 days1991: Moderate 54 of 207 days1991: Unhealthy for Sensitive Groups 26 of 207 days1991: Unhealthy 15 of 207 days1991: Very Unhealthy 1 of 207 days1992: Good 141 of 205 days1992: Moderate 37 of 205 days1992: Unhealthy for Sensitive Groups 23 of 205 days1992: Unhealthy 4 of 205 days1993: Good 163 of 207 days1993: Moderate 35 of 207 days1993: Unhealthy for Sensitive Groups 5 of 207 days1993: Unhealthy 4 of 207 days1994: Good 152 of 212 days1994: Moderate 42 of 212 days1994: Unhealthy for Sensitive Groups 15 of 212 days1994: Unhealthy 3 of 212 days1995: Good 133 of 209 days1995: Moderate 47 of 209 days1995: Unhealthy for Sensitive Groups 19 of 209 days1995: Unhealthy 9 of 209 days1995: Very Unhealthy 1 of 209 days19951996: Good 127 of 167 days1996: Moderate 30 of 167 days1996: Unhealthy for Sensitive Groups 7 of 167 days1996: Unhealthy 3 of 167 days1997: Good 151 of 213 days1997: Moderate 37 of 213 days1997: Unhealthy for Sensitive Groups 17 of 213 days1997: Unhealthy 8 of 213 days1998: Good 126 of 204 days1998: Moderate 38 of 204 days1998: Unhealthy for Sensitive Groups 30 of 204 days1998: Unhealthy 9 of 204 days1998: Very Unhealthy 1 of 204 days1999: Good 129 of 213 days1999: Moderate 47 of 213 days1999: Unhealthy for Sensitive Groups 29 of 213 days1999: Unhealthy 8 of 213 days2000: Good 138 of 212 days2000: Moderate 53 of 212 days2000: Unhealthy for Sensitive Groups 18 of 212 days2000: Unhealthy 2 of 212 days2000: Very Unhealthy 1 of 212 days20002001: Good 140 of 214 days2001: Moderate 33 of 214 days2001: Unhealthy for Sensitive Groups 30 of 214 days2001: Unhealthy 11 of 214 days2002: Good 126 of 214 days2002: Moderate 46 of 214 days2002: Unhealthy for Sensitive Groups 17 of 214 days2002: Unhealthy 22 of 214 days2002: Very Unhealthy 3 of 214 days2003: Good 145 of 214 days2003: Moderate 50 of 214 days2003: Unhealthy for Sensitive Groups 14 of 214 days2003: Unhealthy 3 of 214 days2003: Very Unhealthy 2 of 214 days2004: Good 162 of 213 days2004: Moderate 35 of 213 days2004: Unhealthy for Sensitive Groups 14 of 213 days2004: Unhealthy 2 of 213 days2005: Good 135 of 213 days2005: Moderate 49 of 213 days2005: Unhealthy for Sensitive Groups 22 of 213 days2005: Unhealthy 7 of 213 days20052006: Good 145 of 213 days2006: Moderate 55 of 213 days2006: Unhealthy for Sensitive Groups 9 of 213 days2006: Unhealthy 4 of 213 days2007: Good 146 of 214 days2007: Moderate 44 of 214 days2007: Unhealthy for Sensitive Groups 18 of 214 days2007: Unhealthy 6 of 214 days2008: Good 151 of 212 days2008: Moderate 51 of 212 days2008: Unhealthy for Sensitive Groups 10 of 212 days2009: Good 175 of 214 days2009: Moderate 34 of 214 days2009: Unhealthy for Sensitive Groups 5 of 214 days2010: Good 146 of 214 days2010: Moderate 50 of 214 days2010: Unhealthy for Sensitive Groups 17 of 214 days2010: Unhealthy 1 of 214 days20102011: Good 153 of 211 days2011: Moderate 50 of 211 days2011: Unhealthy for Sensitive Groups 7 of 211 days2011: Unhealthy 1 of 211 days2012: Good 150 of 213 days2012: Moderate 54 of 213 days2012: Unhealthy for Sensitive Groups 7 of 213 days2012: Unhealthy 2 of 213 days2013: Good 178 of 213 days2013: Moderate 33 of 213 days2013: Unhealthy for Sensitive Groups 2 of 213 days2014: Good 176 of 213 days2014: Moderate 35 of 213 days2014: Unhealthy for Sensitive Groups 2 of 213 days2015: Good 168 of 210 days2015: Moderate 39 of 210 days2015: Unhealthy for Sensitive Groups 3 of 210 days20152016: Good 171 of 213 days2016: Moderate 36 of 213 days2016: Unhealthy for Sensitive Groups 6 of 213 days2017: Good 212 of 245 days2017: Moderate 31 of 245 days2017: Unhealthy for Sensitive Groups 2 of 245 days2018: Good 208 of 244 days2018: Moderate 33 of 244 days2018: Unhealthy for Sensitive Groups 3 of 244 days2019: Good 221 of 245 days2019: Moderate 23 of 245 days2019: Unhealthy for Sensitive Groups 1 of 245 days2020: Good 224 of 241 days2020: Moderate 17 of 241 days20202021: Good 213 of 243 days2021: Moderate 28 of 243 days2021: Unhealthy for Sensitive Groups 2 of 243 days2022: Good 211 of 239 days2022: Moderate 23 of 239 days2022: Unhealthy for Sensitive Groups 5 of 239 days2023: Good 208 of 245 days2023: Moderate 35 of 245 days2023: Unhealthy for Sensitive Groups 2 of 245 days2024: Good 205 of 245 days2024: Moderate 38 of 245 days2024: Unhealthy for Sensitive Groups 2 of 245 days2025: Good 199 of 245 days2025: Moderate 43 of 245 days2025: Unhealthy for Sensitive Groups 3 of 245 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 771981: 90th percentile AQI 841982: 90th percentile AQI 901983: 90th percentile AQI 871984: 90th percentile AQI 611985: 90th percentile AQI 611986: 90th percentile AQI 741987: 90th percentile AQI 1151988: 90th percentile AQI 1561989: 90th percentile AQI 1121990: 90th percentile AQI 971991: 90th percentile AQI 1361992: 90th percentile AQI 1081993: 90th percentile AQI 711994: 90th percentile AQI 871995: 90th percentile AQI 1121996: 90th percentile AQI 801997: 90th percentile AQI 1011998: 90th percentile AQI 1331999: 90th percentile AQI 1222000: 90th percentile AQI 1002001: 90th percentile AQI 1292002: 90th percentile AQI 1562003: 90th percentile AQI 972004: 90th percentile AQI 932005: 90th percentile AQI 1122006: 90th percentile AQI 972007: 90th percentile AQI 1122008: 90th percentile AQI 842009: 90th percentile AQI 612010: 90th percentile AQI 932011: 90th percentile AQI 842012: 90th percentile AQI 872013: 90th percentile AQI 642014: 90th percentile AQI 642015: 90th percentile AQI 672016: 90th percentile AQI 642017: 90th percentile AQI 582018: 90th percentile AQI 612019: 90th percentile AQI 502020: 90th percentile AQI 472021: 90th percentile AQI 582022: 90th percentile AQI 542023: 90th percentile AQI 642024: 90th percentile AQI 612025: 90th percentile AQI 611980: Median AQI 341981: Median AQI 311982: Median AQI 351983: Median AQI 311984: Median AQI 301985: Median AQI 311986: Median AQI 321987: Median AQI 391988: Median AQI 391989: Median AQI 421990: Median AQI 391991: Median AQI 461992: Median AQI 421993: Median AQI 391994: Median AQI 431995: Median AQI 451996: Median AQI 401997: Median AQI 421998: Median AQI 441999: Median AQI 462000: Median AQI 442001: Median AQI 452002: Median AQI 452003: Median AQI 442004: Median AQI 422005: Median AQI 452006: Median AQI 422007: Median AQI 442008: Median AQI 442009: Median AQI 402010: Median AQI 442011: Median AQI 422012: Median AQI 442013: Median AQI 392014: Median AQI 412015: Median AQI 412016: Median AQI 412017: Median AQI 392018: Median AQI 392019: Median AQI 392020: Median AQI 372021: Median AQI 382022: Median AQI 382023: Median AQI 422024: Median AQI 412025: Median AQI 431980198519901995200020052010201520202025
  • 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
Ozone245100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20252451994330004361122Ozone
20242452053820004161108Ozone
20232452083520004264147Ozone
20222392112350003854133Ozone
20212432132820003858112Ozone
2020241224170000374793Ozone
20192452212310003950112Ozone
20182442083330003961129Ozone
20172452123120003958143Ozone
20162131713660004164126Ozone
20152101683930004167143Ozone
20142131763520004164119Ozone
20132131783320003964108Ozone
20122131505472004487179Ozone
20112111535071004284154Ozone
201021414650171004493156Ozone
20092141753450004061150Ozone
200821215151100004484136Ozone
2007214146441860044112182Ozone
20062131455594004297185Ozone
2005213135492270045112197Ozone
200421316235142004293156Ozone
200321414550143204497204Ozone
20022141264617223045156203Ozone
20012141403330110045129200Ozone
2000212138531821044100201Ozone
1999213129472980046122197Ozone
1998204126383091044133208Ozone
1997213151371780042101174Ozone
19961671273073004080179Ozone
1995209133471991045112215Ozone
199421215242153004387154Ozone
19932071633554003971174Ozone
1992205141372340042108190Ozone
19912071115426151046136202Ozone
199021115739123003997172Ozone
19891981462418100042112200Ozone
198821414627181310039156242Ozone
1987204152291481039115218Ozone
198628924235111003274169Ozone
198536031136121003161154Ozone
19843382973263003061164Ozone
1983360303301113303187216Ozone
198235027745199003590200Ozone
198135630126189203184230Ozone
198035129232198003477190Ozone

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