Counties in Michigan by highest daily Air Quality Index (US EPA)

Macomb County had the highest highest daily Air Quality Index (US EPA) of 30 counties in 1994, at 218. Gratiot County had the lowest, at 11. The median was 171. Source: the U.S. Environmental Protection Agency.

Highest218Macomb County

Lowest11Gratiot County

Median17130 counties

Map of counties, 1994

Under 57
57 to 160
160 to 170
170 to 180
180 to 200
200 and over
No data

index, 1994. Hatched areas have no value for this period. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 1994

index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12.

Full ranking

Rank	Counties	1994 index	Change on 1993
1	Macomb County	218	+26
2	Kent County	215	+13
3	Wayne County	203	+6
4	St. Clair County	202	+25
5	Cass County	201	+35
6	Muskegon County	200	-4
7	Ottawa County	190	n/a
8	Huron County	187	+33
8	Oakland County	187	+18
10	Allegan County	185	-15
11	Mason County	182	-18
12	Lenawee County	177	+48
13	Tuscola County	174	-27
13	Washtenaw County	174	-16
15	Benzie County	172	+11
16	Kalamazoo County	169	+5
16	Manistee County	169	+18
18	Clinton County	166	+2
18	Genesee County	166	-40
20	Berrien County	161	+28
20	Ingham County	161	+7
22	Monroe County	76	-125
23	Sanilac County	61	+38
24	Calhoun County	60	+4
25	Van Buren County	58	+10
26	Midland County	51	-23
27	Marquette County	44	-33
27	Saginaw County	44	-7
29	Cheboygan County	13	-19
30	Gratiot County	11	-8

Other periods

About this ranking

Highest daily Air Quality Index (AQI) value recorded in a US county during the year, from the EPA AirData annual summaries. Values above 500 are beyond the AQI scale and are published as EPA computes them.

A single day decides the value, so one wildfire or dust event can set it. Dust from the dry Owens Lake bed puts Inyo and Mono counties in California in the thousands. 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 1994 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: highest 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: highest daily AQI (Counties in Michigan by highest daily Air Quality Index (US EPA), 1994) [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: highest daily AQI, Counties in Michigan by highest daily Air Quality Index (US EPA), 1994. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/michigan-counties?period=1994. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Counties in Michigan by highest daily Air Quality Index (US EPA), 1994. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/michigan-counties?period=1994.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Counties in Michigan by highest daily Air Quality Index (US EPA), 1994 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/highest-daily-air-quality-index/michigan-counties?period=1994 (Accessed: 12 October 2026).

BibTeX

@misc{environmental_counties_in_michigan_by_1994,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Counties in Michigan by highest daily Air Quality Index (US EPA), 1994}},
  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/highest-daily-air-quality-index/michigan-counties?period=1994. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest 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: highest daily AQI: Counties in Michigan by highest daily Air Quality Index (US EPA), 1994
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/highest-daily-air-quality-index/michigan-counties?period=1994
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/highest-daily-air-quality-index/michigan-counties?period=1994.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest 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 highest daily Air Quality Index (US EPA) using official data, and cite the source.

rank_places {"indicator":"aqi_max","level":"province","within":"Michigan","limit":10}
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Questions

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

Macomb County, with 218 in 1994, according to the U.S. Environmental Protection Agency.

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

Gratiot County, with 11 in 1994.

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: highest daily AQI. Retrieved 2026-10-12. 23 counties have no value for 1994 and are not ranked.