EnviroNearby

Sandusky County, Ohio air quality history

Daily Air Quality Index summaries from EPA monitors in Sandusky, Ohio, 1986–2001.

87%
Good days in 1994
31
Median daily AQI, 1994
0
Days above 100 in 1994
182
Days with an AQI in 1994 (of 365)

In 1994, EPA reported a daily Air Quality Index (AQI) for Sandusky, Ohio on 182 days. 159 of those days (87%) were in the Good range, and the median daily AQI was 31. That median is lower than the typical monitored county in Ohio (median 40 across 40 counties), and lower than the typical monitored U.S. county (39). The main pollutant was coarse particles (PM10) on 182 days.

EPA did not report an AQI for every day of 1994 here (182 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.

The most recent year with data for this county is 2001; EPA's files for 2002–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1996, 1997, 1998, 1999, 2000, 2001…) 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%1986: Good 22 of 23 days1986: Moderate 1 of 23 days19861987: Good 86 of 97 days1987: Moderate 11 of 97 days1988: Good 203 of 218 days1988: Moderate 10 of 218 days1988: Unhealthy for Sensitive Groups 1 of 218 days1988: Unhealthy 3 of 218 days1988: Very Unhealthy 1 of 218 days19881989: Good 19 of 20 days1989: Moderate 1 of 20 days1990: Good 107 of 117 days1990: Moderate 10 of 117 days19901991: Good 156 of 173 days1991: Moderate 17 of 173 days1992: Good 166 of 183 days1992: Moderate 17 of 183 days19921993: Good 150 of 184 days1993: Moderate 34 of 184 days1994: Good 159 of 182 days1994: Moderate 23 of 182 days19941995: Good 81 of 91 days1995: Moderate 10 of 91 days1996: Good 48 of 62 days1996: Moderate 14 of 62 days19961997: Good 46 of 62 days1997: Moderate 15 of 62 days1997: Unhealthy 1 of 62 days1998: Good 47 of 63 days1998: Moderate 16 of 63 days19981999: Good 56 of 65 days1999: Moderate 9 of 65 days2000: Good 60 of 61 days2000: Moderate 1 of 61 days20002001: Good 20 of 20 days2001
  • 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 year0501001986: 90th percentile AQI 431987: 90th percentile AQI 521988: 90th percentile AQI 451989: 90th percentile AQI 481990: 90th percentile AQI 491991: 90th percentile AQI 501992: 90th percentile AQI 501993: 90th percentile AQI 561994: 90th percentile AQI 521995: 90th percentile AQI 511996: 90th percentile AQI 581997: 90th percentile AQI 621998: 90th percentile AQI 591999: 90th percentile AQI 562000: 90th percentile AQI 372001: 90th percentile AQI 341986: Median AQI 221987: Median AQI 251988: Median AQI 141989: Median AQI 211990: Median AQI 241991: Median AQI 281992: Median AQI 281993: Median AQI 311994: Median AQI 311995: Median AQI 341996: Median AQI 361997: Median AQI 371998: Median AQI 341999: Median AQI 272000: Median AQI 222001: Median AQI 21198619881990199219941996199820002001
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 1994

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
Coarse particles (PM10)182100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2001202000000213436PM10
2000616010000223751PM10
1999655690000275670PM10
19986347160000345977PM10
199762461501003762154PM10
19966248140000365867PM10
19959181100000345167PM10
1994182159230000315268PM10
1993184150340000315669PM10
1992183166170000285069PM10
1991173156170000285065PM10
1990117107100000244970PM10
1989201910000214852PM10
19882182031013101445208Ozone
19879786110000255265PM10
1986232210000224357PM10

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 1994

All monitored counties in Ohio

Source: U.S. EPA AirData, “Annual AQI by County” files for 1986–2001 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem