Data / Rankings / Share of days with good air quality (US EPA AQI) / Counties in Michigan

Counties in Michigan by share of days with good air quality (US EPA AQI)

Cheboygan County had the highest share of days with good air quality (US EPA AQI) of 32 counties in 1993, at 100%. Wayne County had the lowest, at 63.6%. The median was 86.3%. Source: EPA.

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Highest100Cheboygan County
Lowest63.6Wayne County
Median86.332 counties

Map of counties, 1993

Allegan County: 69.7 %Bay County: 96.6 %Benzie County: 81.9 %Berrien County: 70.3 %Calhoun County: 96.7 %Cass County: 65.6 %Cheboygan County: 100 %Clinton County: 81.8 %Delta County: 96.7 %Dickinson County: 92.8 %Genesee County: 81.7 %Gratiot County: 100 %Huron County: 81.8 %Ingham County: 84.2 %Kalamazoo County: 80.5 %Kent County: 86.8 %Lenawee County: 68.6 %Macomb County: 87.4 %Manistee County: 90.9 %Marquette County: 98.4 %Mason County: 69.8 %Midland County: 97.8 %Monroe County: 84.4 %Muskegon County: 75.3 %Oakland County: 90.8 %Saginaw County: 98.4 %St. Clair County: 73.8 %Sanilac County: 100 %Tuscola County: 91.5 %Van Buren County: 100 %Washtenaw County: 85.7 %Wayne County: 63.6 %
  • Under 71
  • 71 to 82
  • 82 to 86
  • 86 to 92
  • 92 to 98
  • 98 and over
  • No data
%, 1993. Hatched areas have no value for this period. Source: Invokely calculation with data from EPA. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 1993

Cheboygan County: 100 %Cheboygan County100Gratiot County: 100 %Gratiot County100Sanilac County: 100 %Sanilac County100Van Buren County: 100 %Van Buren County100Marquette County: 98.4 %Marquette County98.4Saginaw County: 98.4 %Saginaw County98.4Midland County: 97.8 %Midland County97.8Calhoun County: 96.7 %Calhoun County96.7Delta County: 96.7 %Delta County96.7Bay County: 96.6 %Bay County96.6Dickinson County: 92.8 %Dickinson County92.8Tuscola County: 91.5 %Tuscola County91.5Manistee County: 90.9 %Manistee County90.9Oakland County: 90.8 %Oakland County90.8Macomb County: 87.4 %Macomb County87.4Kent County: 86.8 %Kent County86.8Washtenaw County: 85.7 %Washtenaw County85.7Monroe County: 84.4 %Monroe County84.4Ingham County: 84.2 %Ingham County84.2Benzie County: 81.9 %Benzie County81.9Clinton County: 81.8 %Clinton County81.8Huron County: 81.8 %Huron County81.8Genesee County: 81.7 %Genesee County81.7Kalamazoo County: 80.5 %Kalamazoo County80.5Muskegon County: 75.3 %Muskegon County75.3St. Clair County: 73.8 %St. Clair County73.8Berrien County: 70.3 %Berrien County70.3Mason County: 69.8 %Mason County69.8Allegan County: 69.7 %Allegan County69.7Lenawee County: 68.6 %Lenawee County68.6Cass County: 65.6 %Cass County65.6Wayne County: 63.6 %Wayne County63.6Cheboygan County: 100 %Cheboygan County100Gratiot County: 100 %Gratiot County100Sanilac County: 100 %Sanilac County100Van Buren County: 100 %Van Buren County100Marquette County: 98.4 %Marquette County98.4Saginaw County: 98.4 %Saginaw County98.4Midland County: 97.8 %Midland County97.8Calhoun County: 96.7 %Calhoun County96.7Delta County: 96.7 %Delta County96.7Bay County: 96.6 %Bay County96.6Dickinson County: 92.8 %Dickinson County92.8Tuscola County: 91.5 %Tuscola County91.5Manistee County: 90.9 %Manistee County90.9Oakland County: 90.8 %Oakland County90.8Macomb County: 87.4 %Macomb County87.4Kent County: 86.8 %Kent County86.8Washtenaw County: 85.7 %Washtenaw County85.7Monroe County: 84.4 %Monroe County84.4Ingham County: 84.2 %Ingham County84.2Benzie County: 81.9 %Benzie County81.9Clinton County: 81.8 %Clinton County81.8Huron County: 81.8 %Huron County81.8Genesee County: 81.7 %Genesee County81.7Kalamazoo County: 80.5 %Kalamazoo County80.5Muskegon County: 75.3 %Muskegon County75.3St. Clair County: 73.8 %St. Clair County73.8Berrien County: 70.3 %Berrien County70.3Mason County: 69.8 %Mason County69.8Allegan County: 69.7 %Allegan County69.7Lenawee County: 68.6 %Lenawee County68.6Cass County: 65.6 %Cass County65.6Wayne County: 63.6 %Wayne County63.6
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties1993 (%)Change on 1992
1Cheboygan County100+2.7 pts
1Gratiot County1000 pts
1Sanilac County1000 pts
1Van Buren County100+5.5 pts
5Marquette County98.4-1.6 pts
5Saginaw County98.4+6.9 pts
7Midland County97.8-1.4 pts
8Calhoun County96.70 pts
8Delta County96.7+25.4 pts
10Bay County96.6+11.8 pts
11Dickinson County92.8+0.5 pts
12Tuscola County91.5+3.9 pts
13Manistee County90.9+4.2 pts
14Oakland County90.8-2.1 pts
15Macomb County87.4-1.9 pts
16Kent County86.8+2.6 pts
17Washtenaw County85.7+2.2 pts
18Monroe County84.4-13.9 pts
19Ingham County84.2+1.7 pts
20Benzie County81.9-2.2 pts
21Clinton County81.8+4.3 pts
21Huron County81.8n/a
23Genesee County81.7-2.8 pts
24Kalamazoo County80.5-3.4 pts
25Muskegon County75.3+2.8 pts
26St. Clair County73.8-7.1 pts
27Berrien County70.3-13.6 pts
28Mason County69.8-21.5 pts
29Allegan County69.7-21.3 pts
30Lenawee County68.6n/a
31Cass County65.6+2 pts
32Wayne County63.6-11 pts

Other periods

About this ranking

Days with a daily Air Quality Index of 0 to 50 (good) as a percentage of the days of the year with an AQI in a US county. Calculated by Invokely from the day counts in the EPA AirData annual summaries; both counts are stored with each value.

United States counties with air quality monitors only, about 1,000 of some 3,100 in recent years; a county without monitors has no value. The number of days with an AQI differs between counties because some monitors run only in the ozone season.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 21 counties with data in other periods have no value for 1993 and are left out rather than filled from another source. Equal values share a rank.

How to cite

U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Environmental Protection Agency. (2026). EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts (Counties in Michigan by share of days with good air quality (US EPA AQI), 1993) [Data set]. Retrieved October 12, 2026, from https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual

MLA 9

EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Counties in Michigan by share of days with good air quality (US EPA AQI), 1993. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/good-air-quality-days-share/michigan-counties?period=1993. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Counties in Michigan by share of days with good air quality (US EPA AQI), 1993. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/good-air-quality-days-share/michigan-counties?period=1993.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Counties in Michigan by share of days with good air quality (US EPA AQI), 1993 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/michigan-counties?period=1993 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_michigan_by_1993,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Counties in Michigan by share of days with good air quality (US EPA AQI), 1993}},
  year = {2026},
  howpublished = {Data set},
  url = {https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/michigan-counties?period=1993. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download\_files.html\#Annual. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Environmental Protection Agency
TI  - EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Counties in Michigan by share of days with good air quality (US EPA AQI), 1993
PY  - 2026
DA  - 2026/07/13
PB  - U.S. Environmental Protection Agency
DB  - Invokely
UR  - https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual
L2  - https://invokely.ai/rankings/good-air-quality-days-share/michigan-counties?period=1993
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/michigan-counties?period=1993.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -
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Rank Counties in Michigan by share of days with good air quality (US EPA AQI) using official data, and cite the source.
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Questions

Which county has the highest share of days with good air quality (US EPA AQI)?

Cheboygan County, with 100% in 1993, according to EPA.

Which county has the lowest share of days with good air quality (US EPA AQI)?

Wayne County, with 63.6% in 1993.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 21 counties have no value for 1993 and are not ranked.

Share of days with good air quality (US EPA AQI): other rankings

Counties in Michigan: more rankings