Data / Highest daily Air Quality Index (US EPA) / Houghton County

Highest daily Air Quality Index (US EPA) in Houghton County

Highest daily Air Quality Index (US EPA) in Houghton County was 115 in 1991, according to the U.S. Environmental Protection Agency. That is up 35 from 1990.

1991, index115
Change on 1990+35
Series high1541988
Series low501987

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Highest daily Air Quality Index (US EPA) in Houghton County, 1987 to 1991

5075100125150175198719881989199019911987: 50 index1988: 154 index1989: 143 index1990: 80 index1991: 115 index501001502001987198919911987: 50 index1988: 154 index1989: 143 index1990: 80 index1991: 115 index
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 5 values
Periodindex
1991115
199080
1989143
1988154
198750

Houghton County compared with nearby places

Allegan County: 229 indexBay County: 62 indexBenzie County: 238 indexBerrien County: 204 indexCalhoun County: 70 indexCass County: 207 indexClinton County: 185 indexDelta County: 212 indexDickinson County: 129 indexGenesee County: 192 indexGratiot County: 24 indexHoughton County: 115 indexIngham County: 166 indexKalamazoo County: 140 indexKent County: 217 indexKeweenaw County: 63 indexMacomb County: 207 indexManistee County: 177 indexMarquette County: 90 indexMason County: 222 indexMidland County: 83 indexMonroe County: 52 indexMontcalm County: 197 indexMuskegon County: 224 indexOakland County: 185 indexOceana County: 225 indexOttawa County: 238 indexSaginaw County: 72 indexSt. Clair County: 210 indexTuscola County: 179 indexVan Buren County: 154 indexWashtenaw County: 185 indexWayne County: 208 index
  • Under 76
  • 76 to 150
  • 150 to 190
  • 190 to 210
  • 210 to 220
  • 220 and over
  • No data
Highest daily Air Quality Index (US EPA), 1991, index. Houghton County is outlined. Same source and period for every area shown. Source: U.S. Environmental Protection Agency. Boundaries: U.S. Census Bureau cartographic boundary files.

Rankings

Definition

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.

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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 (Highest daily Air Quality Index (US EPA), Houghton County, 1987 to 1991) [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, Highest daily Air Quality Index (US EPA), Houghton County, 1987 to 1991. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/en/highest-daily-air-quality-index/houghton-county-michigan. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Highest daily Air Quality Index (US EPA), Houghton County, 1987 to 1991. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/en/highest-daily-air-quality-index/houghton-county-michigan.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Highest daily Air Quality Index (US EPA), Houghton County, 1987 to 1991 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/highest-daily-air-quality-index/houghton-county-michigan (Accessed: 12 October 2026).

BibTeX
@misc{environmental_highest_daily_air_quality_1991,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Highest daily Air Quality Index (US EPA), Houghton County, 1987 to 1991}},
  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/en/highest-daily-air-quality-index/houghton-county-michigan. 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: Highest daily Air Quality Index (US EPA), Houghton County, 1987 to 1991
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/en/highest-daily-air-quality-index/houghton-county-michigan
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/houghton-county-michigan.
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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Questions

What is the highest daily Air Quality Index (US EPA) in Houghton County?

Highest daily Air Quality Index (US EPA) in Houghton County was 115 in 1991, according to the U.S. Environmental Protection Agency. That is up 35 from 1990.

Where does this figure come from?

U.S. Environmental Protection Agency. EPA AirData annual AQI by county: highest daily AQI. Retrieved by Invokely on 2026-10-12.

What was the highest highest daily Air Quality Index (US EPA) in Houghton County?

154 in 1988, the highest value since 1987 in this series.

Related statistics for Houghton County

All statistics for Houghton County | Houghton County in figures