Data / Rankings / Median Air Quality Index (US EPA) / Counties in Michigan

Counties in Michigan by median Air Quality Index (US EPA)

Wayne County had the highest median Air Quality Index (US EPA) of 30 counties in 2002, at 65. Keweenaw County had the lowest, at 17. The median was 45. Source: the U.S. Environmental Protection Agency.

Keep it in a collection in your library.
Highest65Wayne County
Lowest17Keweenaw County
Median4530 counties

Map of counties, 2002

Allegan County: 53 indexAlpena County: 37 indexBay County: 53 indexBenzie County: 44 indexBerrien County: 51 indexCass County: 54 indexChippewa County: 38 indexClinton County: 42 indexGenesee County: 47 indexGrand Traverse County: 33 indexHuron County: 42 indexIngham County: 51 indexKalamazoo County: 53 indexKent County: 56 indexKeweenaw County: 17 indexLenawee County: 46 indexMacomb County: 37 indexMason County: 43 indexMissaukee County: 34 indexMonroe County: 61 indexMuskegon County: 48 indexOakland County: 34 indexOttawa County: 49 indexSaginaw County: 52 indexSt. Clair County: 48 indexSchoolcraft County: 33 indexTuscola County: 32 indexWashtenaw County: 42 indexWayne County: 65 indexWexford County: 35 index
  • Under 34
  • 34 to 41
  • 41 to 45
  • 45 to 50
  • 50 to 53
  • 53 and over
  • No data
index, 2002. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2002

Wayne County: 65 indexWayne County65Monroe County: 61 indexMonroe County61Kent County: 56 indexKent County56Cass County: 54 indexCass County54Allegan County: 53 indexAllegan County53Bay County: 53 indexBay County53Kalamazoo County: 53 indexKalamazoo County53Saginaw County: 52 indexSaginaw County52Berrien County: 51 indexBerrien County51Ingham County: 51 indexIngham County51Ottawa County: 49 indexOttawa County49Muskegon County: 48 indexMuskegon County48St. Clair County: 48 indexSt. Clair County48Genesee County: 47 indexGenesee County47Lenawee County: 46 indexLenawee County46Benzie County: 44 indexBenzie County44Mason County: 43 indexMason County43Clinton County: 42 indexClinton County42Huron County: 42 indexHuron County42Washtenaw County: 42 indexWashtenaw County42Chippewa County: 38 indexChippewa County38Alpena County: 37 indexAlpena County37Macomb County: 37 indexMacomb County37Wexford County: 35 indexWexford County35Missaukee County: 34 indexMissaukee County34Oakland County: 34 indexOakland County34Grand Traverse County: 33 indexGrand Traverse County33Schoolcraft County: 33 indexSchoolcraft County33Tuscola County: 32 indexTuscola County32Keweenaw County: 17 indexKeweenaw County17Wayne County: 65 indexWayne County65Monroe County: 61 indexMonroe County61Kent County: 56 indexKent County56Cass County: 54 indexCass County54Allegan County: 53 indexAllegan County53Bay County: 53 indexBay County53Kalamazoo County: 53 indexKalamazoo County53Saginaw County: 52 indexSaginaw County52Berrien County: 51 indexBerrien County51Ingham County: 51 indexIngham County51Ottawa County: 49 indexOttawa County49Muskegon County: 48 indexMuskegon County48St. Clair County: 48 indexSt. Clair County48Genesee County: 47 indexGenesee County47Lenawee County: 46 indexLenawee County46Benzie County: 44 indexBenzie County44Mason County: 43 indexMason County43Clinton County: 42 indexClinton County42Huron County: 42 indexHuron County42Washtenaw County: 42 indexWashtenaw County42Chippewa County: 38 indexChippewa County38Alpena County: 37 indexAlpena County37Macomb County: 37 indexMacomb County37Wexford County: 35 indexWexford County35Missaukee County: 34 indexMissaukee County34Oakland County: 34 indexOakland County34Grand Traverse County: 33 indexGrand Traverse County33Schoolcraft County: 33 indexSchoolcraft County33Tuscola County: 32 indexTuscola County32Keweenaw County: 17 indexKeweenaw County17
index. Source: EPA, EPA AirData annual AQI by county: median daily AQI. Retrieved 2026-10-12.

Full ranking

RankCounties2002
index		Change on 2001
1Wayne County65-3
2Monroe County61+3
3Kent County56-2
4Cass County54+10
5Allegan County53-2
5Bay County53+3
5Kalamazoo County530
8Saginaw County52+2
9Berrien County51+2
9Ingham County51+9
11Ottawa County490
12Muskegon County48+1
12St. Clair County48+2
14Genesee County47-2
15Lenawee County460
16Benzie County440
17Mason County43+1
18Clinton County42-1
18Huron County42-2
18Washtenaw County42-1
21Chippewa County380
22Alpena County37+1
22Macomb County37-3
24Wexford County350
25Missaukee County34-9
25Oakland County340
27Grand Traverse County33-7
27Schoolcraft County33+11
29Tuscola County32-1
30Keweenaw County17-4

Other periods

About this ranking

Median of the daily Air Quality Index (AQI) values of a US county over the days of the year with an AQI, from the EPA AirData annual summaries.

More on how it is measured
  • The daily county AQI is the highest AQI among the monitors and pollutants reported that day (ozone, PM2.5, PM10, carbon monoxide and nitrogen dioxide).
  • Lower is cleaner: 0 to 50 is good, 51 to 100 moderate and above 100 unhealthy for sensitive groups.

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: median daily AQI. 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: median daily AQI (Counties in Michigan by median Air Quality Index (US EPA), 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: median daily AQI, Counties in Michigan by median Air Quality Index (US EPA), 2002. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/median-air-quality-index/michigan-counties?period=2002. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: median daily AQI. Counties in Michigan by median Air Quality Index (US EPA), 2002. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/median-air-quality-index/michigan-counties?period=2002.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: median daily AQI, Counties in Michigan by median Air Quality Index (US EPA), 2002 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/median-air-quality-index/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: median daily AQI: Counties in Michigan by median Air Quality Index (US EPA), 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/median-air-quality-index/michigan-counties?period=2002. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. 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: median daily AQI: Counties in Michigan by median Air Quality Index (US EPA), 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/median-air-quality-index/michigan-counties?period=2002
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/median-air-quality-index/michigan-counties?period=2002.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -
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Rank Counties in Michigan by median Air Quality Index (US EPA) using official data, and cite the source.
rank_places {"indicator":"aqi_median","level":"province","within":"Michigan","limit":10}
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Questions

Which county has the highest median Air Quality Index (US EPA)?

Wayne County, with 65 in 2002, according to the U.S. Environmental Protection Agency.

Which county has the lowest median Air Quality Index (US EPA)?

Keweenaw County, with 17 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: median daily AQI. Retrieved 2026-10-12. 23 counties have no value for 2002 and are not ranked.

Median Air Quality Index (US EPA): other rankings

Counties in Michigan: more rankings