EnviroNearby

Dickinson County, Michigan air quality history

Daily Air Quality Index summaries from EPA monitors in Dickinson, Michigan, 1984–2006.

93%
Good days in 1993
35
Median daily AQI, 1993
4
Days above 100 in 1993
265
Days with an AQI in 1993 (of 365)

In 1993, EPA reported a daily Air Quality Index (AQI) for Dickinson, Michigan on 265 days. 246 of those days (93%) were in the Good range, and the median daily AQI was 35. That median is about the same as the typical monitored county in Michigan (median 35 across 25 counties), and lower than the typical monitored U.S. county (38). The main pollutant was ozone on 248 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 90% in 1985–1987 versus 93% in 1991–1993.

EPA did not report an AQI for every day of 1993 here (265 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 2006; EPA's files for 2007–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1984, 2005, 2006) 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%1984: Good 61 of 61 days19841985: Good 335 of 364 days1985: Moderate 24 of 364 days1985: Unhealthy for Sensitive Groups 5 of 364 days19851986: Good 334 of 365 days1986: Moderate 28 of 365 days1986: Unhealthy for Sensitive Groups 3 of 365 days19861987: Good 320 of 365 days1987: Moderate 38 of 365 days1987: Unhealthy for Sensitive Groups 4 of 365 days1987: Unhealthy 3 of 365 days19871988: Good 311 of 365 days1988: Moderate 43 of 365 days1988: Unhealthy for Sensitive Groups 9 of 365 days1988: Unhealthy 2 of 365 days19881989: Good 311 of 365 days1989: Moderate 44 of 365 days1989: Unhealthy for Sensitive Groups 8 of 365 days1989: Unhealthy 2 of 365 days19891990: Good 344 of 365 days1990: Moderate 16 of 365 days1990: Unhealthy for Sensitive Groups 5 of 365 days19901991: Good 297 of 319 days1991: Moderate 16 of 319 days1991: Unhealthy for Sensitive Groups 6 of 319 days19911992: Good 338 of 366 days1992: Moderate 20 of 366 days1992: Unhealthy for Sensitive Groups 7 of 366 days1992: Unhealthy 1 of 366 days19921993: Good 246 of 265 days1993: Moderate 15 of 265 days1993: Unhealthy for Sensitive Groups 3 of 265 days1993: Unhealthy 1 of 265 days19932005: Good 20 of 25 days2005: Moderate 5 of 25 days20052006: Good 39 of 67 days2006: Moderate 28 of 67 days2006
  • 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 year0501001984: 90th percentile AQI 291985: 90th percentile AQI 481986: 90th percentile AQI 481987: 90th percentile AQI 541988: 90th percentile AQI 671989: 90th percentile AQI 641990: 90th percentile AQI 471991: 90th percentile AQI 471992: 90th percentile AQI 471993: 90th percentile AQI 492005: 90th percentile AQI 572006: 90th percentile AQI 621984: Median AQI 191985: Median AQI 341986: Median AQI 341987: Median AQI 331988: Median AQI 351989: Median AQI 371990: Median AQI 341991: Median AQI 321992: Median AQI 311993: Median AQI 352005: Median AQI 382006: Median AQI 44198419851986198719881989199019911992199320052006
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 1993

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
Ozone24894%
Nitrogen dioxide (NO₂)176%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20066739280000446280PM2.5
2005252050000385768PM2.5
19932652461531003549154Ozone
19923663382071003147151Ozone
19913192971660003247129Ozone
19903653441650003447136Ozone
19893653114482003764156Ozone
19883653114392003567172Ozone
19873653203843003354179Ozone
19863653342830003448133Ozone
19853643352450003448136Ozone
1984616100000192933NO2

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 Michigan with a similar median AQI in 1993

All monitored counties in Michigan

Source: U.S. EPA AirData, “Annual AQI by County” files for 1984–2006 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem