EnviroNearby

Wyandot County, Ohio air quality history

Daily Air Quality Index summaries from EPA monitors in Wyandot, Ohio, 1989–2007.

98%
Good days in 2005
23
Median daily AQI, 2005
0
Days above 100 in 2005
146
Days with an AQI in 2005 (of 365)

In 2005, EPA reported a daily Air Quality Index (AQI) for Wyandot, Ohio on 146 days. 143 of those days (98%) were in the Good range, and the median daily AQI was 23. That median is lower than the typical monitored county in Ohio (median 49 across 37 counties), and lower than the typical monitored U.S. county (44). The main pollutant was coarse particles (PM10) on 146 days. Across the years with fuller monitoring, the share of Good days rose: an average of 95% in 1991–1993 versus 99% in 2003–2005.

EPA did not report an AQI for every day of 2005 here (146 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 2007; EPA's files for 2008–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1989, 1990, 1996, 1997, 2006, 2007) 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%1989: Good 17 of 17 days19891990: Good 70 of 75 days1990: Moderate 5 of 75 days1991: Good 133 of 136 days1991: Moderate 3 of 136 days19911992: Good 138 of 148 days1992: Moderate 10 of 148 days1993: Good 142 of 152 days1993: Moderate 10 of 152 days19931994: Good 132 of 140 days1994: Moderate 8 of 140 days1995: Good 119 of 127 days1995: Moderate 8 of 127 days19951996: Good 112 of 118 days1996: Moderate 6 of 118 days1997: Good 112 of 118 days1997: Moderate 6 of 118 days19971998: Good 158 of 168 days1998: Moderate 10 of 168 days1999: Good 166 of 169 days1999: Moderate 3 of 169 days19992000: Good 165 of 169 days2000: Moderate 4 of 169 days2001: Good 164 of 168 days2001: Moderate 4 of 168 days20012002: Good 154 of 162 days2002: Moderate 8 of 162 days2003: Good 154 of 154 days20032004: Good 167 of 171 days2004: Moderate 4 of 171 days2005: Good 143 of 146 days2005: Moderate 3 of 146 days20052006: Good 64 of 68 days2006: Moderate 4 of 68 days2007: Good 42 of 55 days2007: Moderate 12 of 55 days2007: Unhealthy for Sensitive Groups 1 of 55 days2007
  • 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 year0501001989: 90th percentile AQI 391990: 90th percentile AQI 441991: 90th percentile AQI 421992: 90th percentile AQI 411993: 90th percentile AQI 481994: 90th percentile AQI 451995: 90th percentile AQI 431996: 90th percentile AQI 441997: 90th percentile AQI 411998: 90th percentile AQI 431999: 90th percentile AQI 422000: 90th percentile AQI 392001: 90th percentile AQI 362002: 90th percentile AQI 432003: 90th percentile AQI 402004: 90th percentile AQI 402005: 90th percentile AQI 382006: 90th percentile AQI 492007: 90th percentile AQI 561989: Median AQI 261990: Median AQI 211991: Median AQI 211992: Median AQI 211993: Median AQI 221994: Median AQI 231995: Median AQI 241996: Median AQI 211997: Median AQI 211998: Median AQI 211999: Median AQI 192000: Median AQI 192001: Median AQI 202002: Median AQI 232003: Median AQI 252004: Median AQI 222005: Median AQI 232006: Median AQI 262007: Median AQI 301989199119931995199719992001200320052007
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2005

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)146100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
200755421210003056107PM10
2006686440000264956PM10
200514614330000233852PM10
200417116740000224070PM10
200315415400000254048PM10
200216215480000234358PM10
200116816440000203658PM10
200016916540000193964PM10
199916916630000194267PM10
1998168158100000214370PM10
199711811260000214163PM10
199611811260000214461PM10
199512711980000244359PM10
199414013280000234569PM10
1993152142100000224873PM10
1992148138100000214173PM10
199113613330000214264PM10
1990757050000214460PM10
1989171700000263940PM10

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.

All monitored counties in Ohio

Source: U.S. EPA AirData, “Annual AQI by County” files for 1989–2007 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem