EnviroNearby

Scioto County, Ohio air quality history

Daily Air Quality Index summaries from EPA monitors in Scioto, Ohio, 1988–2025.

56%
Good days in 2025
46
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 Scioto, Ohio on 365 days. 204 of those days (56%) were in the Good range, and the median daily AQI was 46. 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 346 days. Across the years with fuller monitoring, the share of Good days fell: an average of 89% in 1989–1991 versus 62% in 2023–2025.

Years with fewer than 120 monitored days (1988) are shown in the table but left out of comparisons and trend statements.

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%1988: Good 100 of 118 days1988: Moderate 18 of 118 days19881989: Good 262 of 301 days1989: Moderate 39 of 301 days1990: Good 268 of 302 days1990: Moderate 34 of 302 days1991: Good 272 of 296 days1991: Moderate 23 of 296 days1991: Unhealthy for Sensitive Groups 1 of 296 days1992: Good 281 of 301 days1992: Moderate 20 of 301 days1993: Good 275 of 300 days1993: Moderate 25 of 300 days19931994: Good 284 of 310 days1994: Moderate 26 of 310 days1995: Good 337 of 347 days1995: Moderate 10 of 347 days1996: Good 258 of 262 days1996: Moderate 4 of 262 days1997: Good 251 of 256 days1997: Moderate 5 of 256 days1998: Good 267 of 268 days1998: Moderate 1 of 268 days19981999: Good 185 of 284 days1999: Moderate 84 of 284 days1999: Unhealthy for Sensitive Groups 14 of 284 days1999: Unhealthy 1 of 284 days2000: Good 213 of 274 days2000: Moderate 57 of 274 days2000: Unhealthy for Sensitive Groups 3 of 274 days2000: Unhealthy 1 of 274 days2001: Good 128 of 232 days2001: Moderate 92 of 232 days2001: Unhealthy for Sensitive Groups 10 of 232 days2001: Unhealthy 2 of 232 days2002: Good 25 of 120 days2002: Moderate 91 of 120 days2002: Unhealthy for Sensitive Groups 4 of 120 days2003: Good 29 of 122 days2003: Moderate 92 of 122 days2003: Unhealthy for Sensitive Groups 1 of 122 days20032004: Good 65 of 147 days2004: Moderate 79 of 147 days2004: Unhealthy for Sensitive Groups 3 of 147 days2005: Good 238 of 365 days2005: Moderate 123 of 365 days2005: Unhealthy for Sensitive Groups 4 of 365 days2006: Good 276 of 365 days2006: Moderate 87 of 365 days2006: Unhealthy for Sensitive Groups 2 of 365 days2007: Good 263 of 365 days2007: Moderate 99 of 365 days2007: Unhealthy for Sensitive Groups 3 of 365 days2008: Good 125 of 366 days2008: Moderate 241 of 366 days20082009: Good 289 of 365 days2009: Moderate 76 of 365 days2010: Good 287 of 365 days2010: Moderate 78 of 365 days2011: Good 296 of 365 days2011: Moderate 69 of 365 days2012: Good 300 of 366 days2012: Moderate 66 of 366 days2013: Good 307 of 365 days2013: Moderate 58 of 365 days20132014: Good 315 of 365 days2014: Moderate 50 of 365 days2015: Good 319 of 365 days2015: Moderate 46 of 365 days2016: Good 321 of 366 days2016: Moderate 44 of 366 days2016: Unhealthy for Sensitive Groups 1 of 366 days2017: Good 344 of 365 days2017: Moderate 21 of 365 days2018: Good 338 of 365 days2018: Moderate 27 of 365 days20182019: Good 337 of 365 days2019: Moderate 28 of 365 days2020: Good 347 of 366 days2020: Moderate 19 of 366 days2021: Good 333 of 365 days2021: Moderate 32 of 365 days2022: Good 340 of 365 days2022: Moderate 25 of 365 days2023: Good 223 of 365 days2023: Moderate 135 of 365 days2023: Unhealthy for Sensitive Groups 5 of 365 days2023: Unhealthy 2 of 365 days20232024: Good 248 of 366 days2024: Moderate 118 of 366 days2025: Good 204 of 365 days2025: Moderate 159 of 365 days2025: Unhealthy for Sensitive Groups 1 of 365 days2025: Very Unhealthy 1 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 year0501001988: 90th percentile AQI 521989: 90th percentile AQI 531990: 90th percentile AQI 531991: 90th percentile AQI 481992: 90th percentile AQI 471993: 90th percentile AQI 481994: 90th percentile AQI 471995: 90th percentile AQI 401996: 90th percentile AQI 381997: 90th percentile AQI 361998: 90th percentile AQI 371999: 90th percentile AQI 902000: 90th percentile AQI 742001: 90th percentile AQI 872002: 90th percentile AQI 832003: 90th percentile AQI 792004: 90th percentile AQI 742005: 90th percentile AQI 722006: 90th percentile AQI 642007: 90th percentile AQI 632008: 90th percentile AQI 692009: 90th percentile AQI 582010: 90th percentile AQI 592011: 90th percentile AQI 562012: 90th percentile AQI 562013: 90th percentile AQI 552014: 90th percentile AQI 532015: 90th percentile AQI 532016: 90th percentile AQI 522017: 90th percentile AQI 412018: 90th percentile AQI 432019: 90th percentile AQI 442020: 90th percentile AQI 392021: 90th percentile AQI 482022: 90th percentile AQI 462023: 90th percentile AQI 642024: 90th percentile AQI 602025: 90th percentile AQI 641988: Median AQI 311989: Median AQI 311990: Median AQI 291991: Median AQI 301992: Median AQI 281993: Median AQI 291994: Median AQI 271995: Median AQI 221996: Median AQI 221997: Median AQI 201998: Median AQI 201999: Median AQI 292000: Median AQI 212001: Median AQI 442002: Median AQI 622003: Median AQI 592004: Median AQI 542005: Median AQI 362006: Median AQI 262007: Median AQI 302008: Median AQI 542009: Median AQI 232010: Median AQI 242011: Median AQI 222012: Median AQI 202013: Median AQI 192014: Median AQI 192015: Median AQI 162016: Median AQI 152017: Median AQI 132018: Median AQI 132019: Median AQI 142020: Median AQI 142021: Median AQI 162022: Median AQI 172023: Median AQI 442024: Median AQI 402025: Median AQI 46198819931998200320082013201820232025
  • 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)34695%
Coarse particles (PM10)195%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536520415910104664238PM2.5
20243662481180000406080PM2.5
202336522313552004464172PM2.5
2022365340250000174674PM10
2021365333320000164886PM10
2020366347190000143993PM10
2019365337280000144478PM10
2018365338270000134384PM10
2017365344210000134170PM10
20163663214410001552129PM10
2015365319460000165393PM10
2014365315500000195389PM10
2013365307580000195578PM10
2012366300660000205673PM10
2011365296690000225694PM10
2010365287780000245984PM10
2009365289760000235879PM10
20083661252410000546993PM2.5
20073652639930003063117PM10
20063652768720002664143PM10
200536523812340003672133PM10
2004147657930005474128PM2.5
2003122299210005979102PM2.5
2002120259140006283139PM2.5
200123212892102004487160PM2.5
20002742135731002174151PM10
199928418584141002990163PM10
199826826710000203757PM10
199725625150000203658PM10
199626225840000223860PM10
1995347337100000224059PM10
1994310284260000274773PM10
1993300275250000294875PM10
1992301281200000284767PM10
19912962722310003048110PM10
1990302268340000295374PM10
1989301262390000315375PM10
1988118100180000315269PM10

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 1988–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem