EnviroNearby

Ohio County, West Virginia air quality history

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

81%
Good days in 2025
40
Median daily AQI, 2025
0
Days above 100 in 2025
278
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Ohio, West Virginia on 278 days. 225 of those days (81%) were in the Good range, and the median daily AQI was 40. That median is about the same as the typical monitored county in West Virginia (median 39 across 12 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 196 days. Across the years with fuller monitoring, the share of Good days fell: an average of 86% in 1980–1982 versus 80% in 2023–2025.

EPA did not report an AQI for every day of 2025 here (278 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 319 of 348 days1980: Moderate 27 of 348 days1980: Unhealthy for Sensitive Groups 2 of 348 days19801981: Good 284 of 297 days1981: Moderate 10 of 297 days1981: Unhealthy for Sensitive Groups 3 of 297 days1982: Good 256 of 365 days1982: Moderate 91 of 365 days1982: Unhealthy for Sensitive Groups 14 of 365 days1982: Unhealthy 4 of 365 days1983: Good 258 of 365 days1983: Moderate 74 of 365 days1983: Unhealthy for Sensitive Groups 27 of 365 days1983: Unhealthy 6 of 365 days1984: Good 287 of 366 days1984: Moderate 61 of 366 days1984: Unhealthy for Sensitive Groups 18 of 366 days1985: Good 261 of 365 days1985: Moderate 81 of 365 days1985: Unhealthy for Sensitive Groups 21 of 365 days1985: Unhealthy 2 of 365 days19851986: Good 283 of 365 days1986: Moderate 70 of 365 days1986: Unhealthy for Sensitive Groups 12 of 365 days1987: Good 289 of 365 days1987: Moderate 48 of 365 days1987: Unhealthy for Sensitive Groups 22 of 365 days1987: Unhealthy 5 of 365 days1987: Very Unhealthy 1 of 365 days1988: Good 284 of 366 days1988: Moderate 47 of 366 days1988: Unhealthy for Sensitive Groups 16 of 366 days1988: Unhealthy 17 of 366 days1988: Very Unhealthy 2 of 366 days1989: Good 298 of 365 days1989: Moderate 52 of 365 days1989: Unhealthy for Sensitive Groups 12 of 365 days1989: Unhealthy 3 of 365 days1990: Good 308 of 355 days1990: Moderate 35 of 355 days1990: Unhealthy for Sensitive Groups 9 of 355 days1990: Unhealthy 3 of 355 days19901991: Good 283 of 364 days1991: Moderate 51 of 364 days1991: Unhealthy for Sensitive Groups 25 of 364 days1991: Unhealthy 5 of 364 days1992: Good 309 of 366 days1992: Moderate 47 of 366 days1992: Unhealthy for Sensitive Groups 10 of 366 days1993: Good 307 of 364 days1993: Moderate 43 of 364 days1993: Unhealthy for Sensitive Groups 13 of 364 days1993: Unhealthy 1 of 364 days1994: Good 296 of 362 days1994: Moderate 44 of 362 days1994: Unhealthy for Sensitive Groups 21 of 362 days1994: Unhealthy 1 of 362 days1995: Good 295 of 365 days1995: Moderate 52 of 365 days1995: Unhealthy for Sensitive Groups 13 of 365 days1995: Unhealthy 5 of 365 days19951996: Good 296 of 366 days1996: Moderate 50 of 366 days1996: Unhealthy for Sensitive Groups 16 of 366 days1996: Unhealthy 4 of 366 days1997: Good 298 of 362 days1997: Moderate 49 of 362 days1997: Unhealthy for Sensitive Groups 12 of 362 days1997: Unhealthy 3 of 362 days1998: Good 280 of 365 days1998: Moderate 55 of 365 days1998: Unhealthy for Sensitive Groups 25 of 365 days1998: Unhealthy 5 of 365 days1999: Good 212 of 363 days1999: Moderate 127 of 363 days1999: Unhealthy for Sensitive Groups 18 of 363 days1999: Unhealthy 6 of 363 days2000: Good 256 of 366 days2000: Moderate 102 of 366 days2000: Unhealthy for Sensitive Groups 6 of 366 days2000: Unhealthy 2 of 366 days20002001: Good 211 of 365 days2001: Moderate 117 of 365 days2001: Unhealthy for Sensitive Groups 32 of 365 days2001: Unhealthy 5 of 365 days2002: Good 219 of 364 days2002: Moderate 111 of 364 days2002: Unhealthy for Sensitive Groups 25 of 364 days2002: Unhealthy 9 of 364 days2003: Good 242 of 365 days2003: Moderate 113 of 365 days2003: Unhealthy for Sensitive Groups 7 of 365 days2003: Unhealthy 2 of 365 days2003: Very Unhealthy 1 of 365 days2004: Good 240 of 343 days2004: Moderate 99 of 343 days2004: Unhealthy for Sensitive Groups 4 of 343 days2005: Good 102 of 264 days2005: Moderate 129 of 264 days2005: Unhealthy for Sensitive Groups 28 of 264 days2005: Unhealthy 5 of 264 days20052006: Good 116 of 262 days2006: Moderate 132 of 262 days2006: Unhealthy for Sensitive Groups 14 of 262 days2007: Good 107 of 264 days2007: Moderate 125 of 264 days2007: Unhealthy for Sensitive Groups 32 of 264 days2008: Good 140 of 265 days2008: Moderate 121 of 265 days2008: Unhealthy for Sensitive Groups 4 of 265 days2009: Good 145 of 262 days2009: Moderate 112 of 262 days2009: Unhealthy for Sensitive Groups 5 of 262 days2010: Good 115 of 258 days2010: Moderate 136 of 258 days2010: Unhealthy for Sensitive Groups 7 of 258 days20102011: Good 148 of 264 days2011: Moderate 109 of 264 days2011: Unhealthy for Sensitive Groups 7 of 264 days2012: Good 142 of 265 days2012: Moderate 112 of 265 days2012: Unhealthy for Sensitive Groups 10 of 265 days2012: Unhealthy 1 of 265 days2013: Good 188 of 264 days2013: Moderate 74 of 264 days2013: Unhealthy for Sensitive Groups 2 of 264 days2014: Good 176 of 258 days2014: Moderate 81 of 258 days2014: Unhealthy for Sensitive Groups 1 of 258 days2015: Good 165 of 251 days2015: Moderate 84 of 251 days2015: Unhealthy for Sensitive Groups 2 of 251 days20152016: Good 176 of 261 days2016: Moderate 82 of 261 days2016: Unhealthy for Sensitive Groups 3 of 261 days2017: Good 218 of 283 days2017: Moderate 65 of 283 days2018: Good 225 of 283 days2018: Moderate 57 of 283 days2018: Unhealthy for Sensitive Groups 1 of 283 days2019: Good 226 of 283 days2019: Moderate 57 of 283 days2020: Good 232 of 274 days2020: Moderate 41 of 274 days2020: Unhealthy for Sensitive Groups 1 of 274 days20202021: Good 223 of 285 days2021: Moderate 62 of 285 days2022: Good 247 of 283 days2022: Moderate 36 of 283 days2023: Good 224 of 280 days2023: Moderate 52 of 280 days2023: Unhealthy for Sensitive Groups 3 of 280 days2023: Unhealthy 1 of 280 days2024: Good 219 of 272 days2024: Moderate 53 of 272 days2025: Good 225 of 278 days2025: Moderate 53 of 278 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 year0501001501980: 90th percentile AQI 491981: 90th percentile AQI 391982: 90th percentile AQI 691983: 90th percentile AQI 971984: 90th percentile AQI 681985: 90th percentile AQI 901986: 90th percentile AQI 711987: 90th percentile AQI 901988: 90th percentile AQI 1001989: 90th percentile AQI 671990: 90th percentile AQI 611991: 90th percentile AQI 901992: 90th percentile AQI 581993: 90th percentile AQI 671994: 90th percentile AQI 871995: 90th percentile AQI 741996: 90th percentile AQI 801997: 90th percentile AQI 711998: 90th percentile AQI 901999: 90th percentile AQI 932000: 90th percentile AQI 772001: 90th percentile AQI 1012002: 90th percentile AQI 1002003: 90th percentile AQI 732004: 90th percentile AQI 692005: 90th percentile AQI 1082006: 90th percentile AQI 852007: 90th percentile AQI 1052008: 90th percentile AQI 802009: 90th percentile AQI 742010: 90th percentile AQI 872011: 90th percentile AQI 802012: 90th percentile AQI 902013: 90th percentile AQI 632014: 90th percentile AQI 642015: 90th percentile AQI 662016: 90th percentile AQI 612017: 90th percentile AQI 582018: 90th percentile AQI 612019: 90th percentile AQI 572020: 90th percentile AQI 542021: 90th percentile AQI 582022: 90th percentile AQI 522023: 90th percentile AQI 612024: 90th percentile AQI 552025: 90th percentile AQI 561980: Median AQI 281981: Median AQI 141982: Median AQI 431983: Median AQI 411984: Median AQI 391985: Median AQI 421986: Median AQI 401987: Median AQI 391988: Median AQI 381989: Median AQI 361990: Median AQI 341991: Median AQI 331992: Median AQI 321993: Median AQI 291994: Median AQI 321995: Median AQI 281996: Median AQI 301997: Median AQI 301998: Median AQI 291999: Median AQI 442000: Median AQI 382001: Median AQI 452002: Median AQI 442003: Median AQI 402004: Median AQI 382005: Median AQI 572006: Median AQI 542007: Median AQI 562008: Median AQI 492009: Median AQI 482010: Median AQI 532011: Median AQI 482012: Median AQI 492013: Median AQI 432014: Median AQI 442015: Median AQI 442016: Median AQI 442017: Median AQI 432018: Median AQI 412019: Median AQI 422020: Median AQI 402021: Median AQI 392022: Median AQI 372023: Median AQI 412024: Median AQI 412025: Median AQI 401980198519901995200020052010201520202025
  • 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
Ozone19671%
Fine particles (PM2.5)8229%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025278225530000405697Ozone
2024272219530000415584Ozone
20232802245231004161184Ozone
2022283247360000375270Ozone
2021285223620000395878Ozone
20202742324110004054101Ozone
2019283226570000425771Ozone
20182832255710004161105Ozone
2017283218650000435887Ozone
20162611768230004461108Ozone
20152511658420004466112Ozone
20142581768110004464120Ozone
20132641887420004363112Ozone
2012265142112101004990154Ozone
201126414810970004880126Ozone
201025811513670005387140Ozone
200926214511250004874115Ozone
200826514012140004980115Ozone
20072641071253200056105138Ozone
2006262116132140005485150Ozone
20052641021292850057108179Ozone
20043432409940003869130Ozone
200336524211372104073206Ozone
20023642191112590044100185Ozone
20013652111173250045101182Ozone
200036625610262003877156Ozone
1999363212127186004493177Ozone
199836528055255002990169Ozone
199736229849123003071172Ozone
199636629650164003080182Ozone
199536529552135002874166Ozone
199436229644211003287154Ozone
199336430743131002967159Ozone
199236630947100003258150Ozone
199136428351255003390172Ozone
19903553083593003461179Ozone
198936529852123003667156Ozone
19883662844716172038100206NO2
198736528948225103990217Ozone
198636528370120004071143Ozone
198536526181212004290190Ozone
198436628761180003968142CO
198336525874276004197177Ozone
198236525691144004369179CO
19812972841030001439118CO
19803483192720002849105Ozone

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 West Virginia with a similar median AQI in 2025

All monitored counties in West Virginia

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