EnviroNearby

Madison County, Missouri air quality history

Daily Air Quality Index summaries from EPA monitors in Madison, Missouri, 1980–1984.

70%
Good days in 1983
41
Median daily AQI, 1983
40
Days above 100 in 1983
338
Days with an AQI in 1983 (of 365)

In 1983, EPA reported a daily Air Quality Index (AQI) for Madison, Missouri on 338 days. 235 of those days (70%) were in the Good range, and the median daily AQI was 41. That median is higher than the typical monitored county in Missouri (median 35 across 9 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 338 days.

The most recent year with data for this county is 1984; EPA's files for 1985–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1984) 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%1980: Good 102 of 195 days1980: Moderate 55 of 195 days1980: Unhealthy for Sensitive Groups 24 of 195 days1980: Unhealthy 12 of 195 days1980: Very Unhealthy 2 of 195 days19801981: Good 288 of 327 days1981: Moderate 32 of 327 days1981: Unhealthy for Sensitive Groups 4 of 327 days1981: Unhealthy 3 of 327 days19811982: Good 247 of 353 days1982: Moderate 91 of 353 days1982: Unhealthy for Sensitive Groups 13 of 353 days1982: Unhealthy 2 of 353 days19821983: Good 235 of 338 days1983: Moderate 63 of 338 days1983: Unhealthy for Sensitive Groups 34 of 338 days1983: Unhealthy 5 of 338 days1983: Very Unhealthy 1 of 338 days19831984: Good 2 of 2 days1984
  • 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 1401981: 90th percentile AQI 541982: 90th percentile AQI 901983: 90th percentile AQI 1081984: 90th percentile AQI 431980: Median AQI 491981: Median AQI 351982: Median AQI 411983: Median AQI 411984: Median AQI 4319801981198219831984
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 1983

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
Ozone338100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
19842200000434343Ozone
1983338235633451041108201Ozone
198235324791132004190156Ozone
19813272883243003554192Ozone
19801951025524122049140202Ozone

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 Missouri

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–1984 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem