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)

Keweenaw County had the highest share of days with good air quality (US EPA AQI) of 30 counties in 2002, at 89.5%. Wayne County had the lowest, at 19.5%. The median was 60.3%. Source: EPA.

Keep it in a collection in your library.
Highest89.5Keweenaw County
Lowest19.5Wayne County
Median60.330 counties

Map of counties, 2002

Allegan County: 44.6 %Alpena County: 59.8 %Bay County: 47.6 %Benzie County: 64.5 %Berrien County: 49 %Cass County: 49.4 %Chippewa County: 64.5 %Clinton County: 68.1 %Genesee County: 53.6 %Grand Traverse County: 65.1 %Huron County: 71.6 %Ingham County: 49.4 %Kalamazoo County: 46.3 %Kent County: 35.1 %Keweenaw County: 89.5 %Lenawee County: 60.9 %Macomb County: 66.8 %Mason County: 61.7 %Missaukee County: 76.5 %Monroe County: 23.7 %Muskegon County: 52.1 %Oakland County: 67.9 %Ottawa County: 52.7 %Saginaw County: 48.1 %St. Clair County: 52.1 %Schoolcraft County: 82.3 %Tuscola County: 85.1 %Washtenaw County: 61.6 %Wayne County: 19.5 %Wexford County: 82.4 %
  • Under 47
  • 47 to 51
  • 51 to 60
  • 60 to 65
  • 65 to 72
  • 72 and over
  • No data
%, 2002. 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, 2002

Keweenaw County: 89.5 %Keweenaw County89.5Tuscola County: 85.1 %Tuscola County85.1Wexford County: 82.4 %Wexford County82.4Schoolcraft County: 82.3 %Schoolcraft County82.3Missaukee County: 76.5 %Missaukee County76.5Huron County: 71.6 %Huron County71.6Clinton County: 68.1 %Clinton County68.1Oakland County: 67.9 %Oakland County67.9Macomb County: 66.8 %Macomb County66.8Grand Traverse County: 65.1 %Grand Traverse County65.1Benzie County: 64.5 %Benzie County64.5Chippewa County: 64.5 %Chippewa County64.5Mason County: 61.7 %Mason County61.7Washtenaw County: 61.6 %Washtenaw County61.6Lenawee County: 60.9 %Lenawee County60.9Alpena County: 59.8 %Alpena County59.8Genesee County: 53.6 %Genesee County53.6Ottawa County: 52.7 %Ottawa County52.7Muskegon County: 52.1 %Muskegon County52.1St. Clair County: 52.1 %St. Clair County52.1Cass County: 49.4 %Cass County49.4Ingham County: 49.4 %Ingham County49.4Berrien County: 49 %Berrien County49Saginaw County: 48.1 %Saginaw County48.1Bay County: 47.6 %Bay County47.6Kalamazoo County: 46.3 %Kalamazoo County46.3Allegan County: 44.6 %Allegan County44.6Kent County: 35.1 %Kent County35.1Monroe County: 23.7 %Monroe County23.7Wayne County: 19.5 %Wayne County19.5Keweenaw County: 89.5 %Keweenaw County89.5Tuscola County: 85.1 %Tuscola County85.1Wexford County: 82.4 %Wexford County82.4Schoolcraft County: 82.3 %Schoolcraft County82.3Missaukee County: 76.5 %Missaukee County76.5Huron County: 71.6 %Huron County71.6Clinton County: 68.1 %Clinton County68.1Oakland County: 67.9 %Oakland County67.9Macomb County: 66.8 %Macomb County66.8Grand Traverse County: 65.1 %Grand Traverse County65.1Benzie County: 64.5 %Benzie County64.5Chippewa County: 64.5 %Chippewa County64.5Mason County: 61.7 %Mason County61.7Washtenaw County: 61.6 %Washtenaw County61.6Lenawee County: 60.9 %Lenawee County60.9Alpena County: 59.8 %Alpena County59.8Genesee County: 53.6 %Genesee County53.6Ottawa County: 52.7 %Ottawa County52.7Muskegon County: 52.1 %Muskegon County52.1St. Clair County: 52.1 %St. Clair County52.1Cass County: 49.4 %Cass County49.4Ingham County: 49.4 %Ingham County49.4Berrien County: 49 %Berrien County49Saginaw County: 48.1 %Saginaw County48.1Bay County: 47.6 %Bay County47.6Kalamazoo County: 46.3 %Kalamazoo County46.3Allegan County: 44.6 %Allegan County44.6Kent County: 35.1 %Kent County35.1Monroe County: 23.7 %Monroe County23.7Wayne County: 19.5 %Wayne County19.5
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

RankCounties2002 (%)Change on 2001
1Keweenaw County89.5+3.5 pts
2Tuscola County85.1-0.7 pts
3Wexford County82.4-2.9 pts
4Schoolcraft County82.3+4.1 pts
5Missaukee County76.5+5.6 pts
6Huron County71.6+3 pts
7Clinton County68.1-0.2 pts
8Oakland County67.9-0.2 pts
9Macomb County66.8-1.1 pts
10Grand Traverse County65.1+4.2 pts
11Benzie County64.5-6 pts
11Chippewa County64.5-3.6 pts
13Mason County61.7-8.2 pts
14Washtenaw County61.60 pts
15Lenawee County60.9-1.9 pts
16Alpena County59.8-1.5 pts
17Genesee County53.6+0.9 pts
18Ottawa County52.7+1.2 pts
19Muskegon County52.1-5.1 pts
19St. Clair County52.1-3.9 pts
21Cass County49.4-12.9 pts
21Ingham County49.4-14.3 pts
23Berrien County49-2 pts
24Saginaw County48.1-2.7 pts
25Bay County47.6-2.8 pts
26Kalamazoo County46.3-2.3 pts
27Allegan County44.6+5.9 pts
28Kent County35.1+1.1 pts
29Monroe County23.7-5.1 pts
30Wayne County19.5+0.9 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. 23 counties with data in other periods have no value for 2002 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), 2002) [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), 2002. 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=2002. 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), 2002. 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=2002.

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), 2002 [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=2002 (Accessed: 12 October 2026).

BibTeX
@misc{environmental_counties_in_michigan_by_2002,
  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), 2002}},
  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=2002. 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), 2002
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=2002
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/michigan-counties?period=2002.
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)?

Keweenaw County, with 89.5% in 2002, according to EPA.

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

Wayne County, with 19.5% in 2002.

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. 23 counties have no value for 2002 and are not ranked.

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

Counties in Michigan: more rankings