EnviroNearby

Stark County, Ohio air quality history

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

53%
Good days in 2025
49
Median daily AQI, 2025
2
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Stark, Ohio on 365 days. 194 of those days (53%) were in the Good range, and the median daily AQI was 49. That median is higher than 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 fine particles (PM2.5) on 250 days. Across the years with fuller monitoring, the share of Good days fell: an average of 70% in 1980–1982 versus 50% 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 223 of 358 days1980: Moderate 98 of 358 days1980: Unhealthy for Sensitive Groups 27 of 358 days1980: Unhealthy 10 of 358 days19801981: Good 280 of 364 days1981: Moderate 56 of 364 days1981: Unhealthy for Sensitive Groups 20 of 364 days1981: Unhealthy 5 of 364 days1981: Very Unhealthy 3 of 364 days1982: Good 255 of 365 days1982: Moderate 71 of 365 days1982: Unhealthy for Sensitive Groups 26 of 365 days1982: Unhealthy 11 of 365 days1982: Very Unhealthy 2 of 365 days1983: Good 260 of 365 days1983: Moderate 57 of 365 days1983: Unhealthy for Sensitive Groups 30 of 365 days1983: Unhealthy 16 of 365 days1983: Very Unhealthy 2 of 365 days1984: Good 281 of 366 days1984: Moderate 57 of 366 days1984: Unhealthy for Sensitive Groups 23 of 366 days1984: Unhealthy 5 of 366 days1985: Good 248 of 365 days1985: Moderate 78 of 365 days1985: Unhealthy for Sensitive Groups 33 of 365 days1985: Unhealthy 6 of 365 days19851986: Good 264 of 362 days1986: Moderate 65 of 362 days1986: Unhealthy for Sensitive Groups 29 of 362 days1986: Unhealthy 3 of 362 days1986: Very Unhealthy 1 of 362 days1987: Good 267 of 363 days1987: Moderate 59 of 363 days1987: Unhealthy for Sensitive Groups 20 of 363 days1987: Unhealthy 16 of 363 days1987: Very Unhealthy 1 of 363 days1988: Good 259 of 357 days1988: Moderate 38 of 357 days1988: Unhealthy for Sensitive Groups 28 of 357 days1988: Unhealthy 21 of 357 days1988: Very Unhealthy 11 of 357 days1989: Good 264 of 361 days1989: Moderate 69 of 361 days1989: Unhealthy for Sensitive Groups 22 of 361 days1989: Unhealthy 6 of 361 days1990: Good 286 of 365 days1990: Moderate 50 of 365 days1990: Unhealthy for Sensitive Groups 22 of 365 days1990: Unhealthy 6 of 365 days1990: Hazardous 1 of 365 days19901991: Good 246 of 365 days1991: Moderate 64 of 365 days1991: Unhealthy for Sensitive Groups 37 of 365 days1991: Unhealthy 16 of 365 days1991: Very Unhealthy 2 of 365 days1992: Good 291 of 365 days1992: Moderate 51 of 365 days1992: Unhealthy for Sensitive Groups 17 of 365 days1992: Unhealthy 6 of 365 days1993: Good 255 of 364 days1993: Moderate 70 of 364 days1993: Unhealthy for Sensitive Groups 26 of 364 days1993: Unhealthy 13 of 364 days1994: Good 275 of 365 days1994: Moderate 49 of 365 days1994: Unhealthy for Sensitive Groups 37 of 365 days1994: Unhealthy 4 of 365 days1995: Good 251 of 365 days1995: Moderate 76 of 365 days1995: Unhealthy for Sensitive Groups 25 of 365 days1995: Unhealthy 13 of 365 days19951996: Good 275 of 366 days1996: Moderate 53 of 366 days1996: Unhealthy for Sensitive Groups 33 of 366 days1996: Unhealthy 5 of 366 days1997: Good 282 of 364 days1997: Moderate 55 of 364 days1997: Unhealthy for Sensitive Groups 24 of 364 days1997: Unhealthy 3 of 364 days1998: Good 250 of 365 days1998: Moderate 64 of 365 days1998: Unhealthy for Sensitive Groups 36 of 365 days1998: Unhealthy 14 of 365 days1998: Very Unhealthy 1 of 365 days1999: Good 188 of 365 days1999: Moderate 131 of 365 days1999: Unhealthy for Sensitive Groups 35 of 365 days1999: Unhealthy 10 of 365 days1999: Very Unhealthy 1 of 365 days2000: Good 205 of 365 days2000: Moderate 135 of 365 days2000: Unhealthy for Sensitive Groups 20 of 365 days2000: Unhealthy 5 of 365 days20002001: Good 198 of 365 days2001: Moderate 133 of 365 days2001: Unhealthy for Sensitive Groups 24 of 365 days2001: Unhealthy 10 of 365 days2002: Good 199 of 365 days2002: Moderate 117 of 365 days2002: Unhealthy for Sensitive Groups 31 of 365 days2002: Unhealthy 18 of 365 days2003: Good 216 of 365 days2003: Moderate 128 of 365 days2003: Unhealthy for Sensitive Groups 16 of 365 days2003: Unhealthy 3 of 365 days2003: Very Unhealthy 2 of 365 days2004: Good 223 of 365 days2004: Moderate 126 of 365 days2004: Unhealthy for Sensitive Groups 15 of 365 days2004: Unhealthy 1 of 365 days2005: Good 193 of 361 days2005: Moderate 134 of 361 days2005: Unhealthy for Sensitive Groups 30 of 361 days2005: Unhealthy 3 of 361 days2005: Very Unhealthy 1 of 361 days20052006: Good 174 of 342 days2006: Moderate 143 of 342 days2006: Unhealthy for Sensitive Groups 24 of 342 days2006: Unhealthy 1 of 342 days2007: Good 185 of 355 days2007: Moderate 127 of 355 days2007: Unhealthy for Sensitive Groups 36 of 355 days2007: Unhealthy 7 of 355 days2008: Good 221 of 352 days2008: Moderate 111 of 352 days2008: Unhealthy for Sensitive Groups 20 of 352 days2009: Good 138 of 365 days2009: Moderate 225 of 365 days2009: Unhealthy for Sensitive Groups 2 of 365 days2010: Good 98 of 365 days2010: Moderate 242 of 365 days2010: Unhealthy for Sensitive Groups 24 of 365 days2010: Unhealthy 1 of 365 days20102011: Good 109 of 365 days2011: Moderate 244 of 365 days2011: Unhealthy for Sensitive Groups 10 of 365 days2011: Unhealthy 2 of 365 days2012: Good 108 of 366 days2012: Moderate 237 of 366 days2012: Unhealthy for Sensitive Groups 20 of 366 days2012: Unhealthy 1 of 366 days2013: Good 130 of 365 days2013: Moderate 232 of 365 days2013: Unhealthy for Sensitive Groups 3 of 365 days2014: Good 195 of 365 days2014: Moderate 168 of 365 days2014: Unhealthy for Sensitive Groups 2 of 365 days2015: Good 207 of 365 days2015: Moderate 151 of 365 days2015: Unhealthy for Sensitive Groups 7 of 365 days20152016: Good 216 of 366 days2016: Moderate 144 of 366 days2016: Unhealthy for Sensitive Groups 6 of 366 days2017: Good 179 of 365 days2017: Moderate 184 of 365 days2017: Unhealthy for Sensitive Groups 2 of 365 days2018: Good 176 of 365 days2018: Moderate 186 of 365 days2018: Unhealthy for Sensitive Groups 3 of 365 days2019: Good 157 of 365 days2019: Moderate 208 of 365 days2020: Good 202 of 358 days2020: Moderate 152 of 358 days2020: Unhealthy for Sensitive Groups 4 of 358 days20202021: Good 154 of 365 days2021: Moderate 208 of 365 days2021: Unhealthy for Sensitive Groups 3 of 365 days2022: Good 206 of 365 days2022: Moderate 157 of 365 days2022: Unhealthy for Sensitive Groups 2 of 365 days2023: Good 163 of 365 days2023: Moderate 192 of 365 days2023: Unhealthy for Sensitive Groups 7 of 365 days2023: Unhealthy 1 of 365 days2023: Very Unhealthy 2 of 365 days2024: Good 192 of 366 days2024: Moderate 174 of 366 days2025: Good 194 of 365 days2025: Moderate 169 of 365 days2025: Unhealthy for Sensitive Groups 2 of 365 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 1011981: 90th percentile AQI 901982: 90th percentile AQI 1011983: 90th percentile AQI 1121984: 90th percentile AQI 901985: 90th percentile AQI 1011986: 90th percentile AQI 971987: 90th percentile AQI 1011988: 90th percentile AQI 1471989: 90th percentile AQI 971990: 90th percentile AQI 901991: 90th percentile AQI 1261992: 90th percentile AQI 801993: 90th percentile AQI 1051994: 90th percentile AQI 1051995: 90th percentile AQI 1011996: 90th percentile AQI 1011997: 90th percentile AQI 901998: 90th percentile AQI 1191999: 90th percentile AQI 1122000: 90th percentile AQI 902001: 90th percentile AQI 992002: 90th percentile AQI 1192003: 90th percentile AQI 842004: 90th percentile AQI 822005: 90th percentile AQI 972006: 90th percentile AQI 932007: 90th percentile AQI 1082008: 90th percentile AQI 842009: 90th percentile AQI 762010: 90th percentile AQI 932011: 90th percentile AQI 802012: 90th percentile AQI 852013: 90th percentile AQI 702014: 90th percentile AQI 672015: 90th percentile AQI 672016: 90th percentile AQI 692017: 90th percentile AQI 692018: 90th percentile AQI 712019: 90th percentile AQI 712020: 90th percentile AQI 652021: 90th percentile AQI 742022: 90th percentile AQI 662023: 90th percentile AQI 782024: 90th percentile AQI 672025: 90th percentile AQI 701980: Median AQI 431981: Median AQI 361982: Median AQI 401983: Median AQI 401984: Median AQI 371985: Median AQI 421986: Median AQI 401987: Median AQI 321988: Median AQI 311989: Median AQI 351990: Median AQI 321991: Median AQI 361992: Median AQI 331993: Median AQI 351994: Median AQI 341995: Median AQI 351996: Median AQI 331997: Median AQI 321998: Median AQI 331999: Median AQI 492000: Median AQI 452001: Median AQI 472002: Median AQI 472003: Median AQI 442004: Median AQI 422005: Median AQI 492006: Median AQI 502007: Median AQI 492008: Median AQI 442009: Median AQI 552010: Median AQI 602011: Median AQI 572012: Median AQI 572013: Median AQI 532014: Median AQI 492015: Median AQI 462016: Median AQI 452017: Median AQI 512018: Median AQI 512019: Median AQI 522020: Median AQI 472021: Median AQI 532022: Median AQI 492023: Median AQI 522024: Median AQI 482025: Median AQI 491980198519901995200020052010201520202025
  • 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
Fine particles (PM2.5)25068%
Ozone11532%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536519416920004970124PM2.5
20243661921740000486793PM2.5
202336516319271205278283PM2.5
202236520615720004966136PM2.5
202136515420830005374127PM2.5
202035820215240004765119PM2.5
201936515720800005271100PM2.5
201836517618630005171108PM2.5
201736517918420005169119PM2.5
201636621614460004569119PM2.5
201536520715170004667108PM2.5
201436519516820004967108PM2.5
201336513023230005370112PM2.5
2012366108237201005785192PM2.5
2011365109244102005780154PM2.5
201036598242241006093156PM2.5
200936513822520005576126PM2.5
2008352221111200004484140Ozone
20073551851273670049108182Ozone
2006342174143241005093180Ozone
2005361193134303104997201Ozone
2004365223126151004282151Ozone
2003365216128163204484212Ozone
200236519911731180047119195Ozone
20013651981332410004799187Ozone
2000365205135205004590190Ozone
199936518813135101049112207Ozone
19983652506436141033119209Ozone
199736428255243003290179Ozone
1996366275533350033101169Ozone
19953652517625130035101200Ozone
1994365275493740034105166Ozone
19933642557026130035105179Ozone
199236529151176003380177Ozone
19913652466437162036126228Ozone
199036528650226013290304Ozone
198936126469226003597197Ozone
198835725938282111031147242Ozone
19873632675920161032101214Ozone
198636226465293104097201Ozone
1985365248783360042101169Ozone
198436628157235003790190Ozone
19833652605730162040112215Ozone
19823652557126112040101203Ozone
198136428056205303690204Ozone
19803582239827100043101197NO2

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