Data / Share of days with good air quality (US EPA AQI) / Deer Lodge County

Share of days with good air quality (US EPA AQI) in Deer Lodge County

Share of days with good air quality (US EPA AQI) in Deer Lodge County was 100% in 1992, according to EPA. That is up 0.6 pts from 1991.

1992100%
Change on 1991+0.6 pts
Series high1001980
Series low80.21985

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Share of days with good air quality (US EPA AQI) in Deer Lodge County, 1980 to 1992

8085909510019801984198519891990199119921980: 100 %1984: 83.8 %1985: 80.2 %1989: 100 %1990: 100 %1991: 99.4 %1992: 100 %808590951001980198919921980: 100 %1984: 83.8 %1985: 80.2 %1989: 100 %1990: 100 %1991: 99.4 %1992: 100 %
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12, published 2026-07-13.
All 7 values
Period%
1992100
199199.4
1990100
1989100
198580.2
198483.8
1980100

Deer Lodge County compared with nearby places

Big Horn County: 86.9 %Blaine County: 90 %Broadwater County: 95.3 %Cascade County: 96.3 %Deer Lodge County: 100 %Fergus County: 94.3 %Flathead County: 77.2 %Gallatin County: 78.9 %Jefferson County: 93.6 %Lake County: 85.5 %Lewis and Clark County: 87.2 %Lincoln County: 64.9 %Madison County: 96.6 %Missoula County: 72.2 %Park County: 95.7 %Phillips County: 98 %Roosevelt County: 100 %Rosebud County: 95.4 %Sanders County: 86.2 %Silver Bow County: 85.3 %Stillwater County: 100 %Yellowstone County: 94.9 %
  • Under 85
  • 85 to 88
  • 88 to 95
  • 95 to 97
  • 97 and over
  • No data
Share of days with good air quality (US EPA AQI), 1992, %. Deer Lodge 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

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.

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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 (Share of days with good air quality (US EPA AQI), Deer Lodge County, 1980 to 1992) [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, Share of days with good air quality (US EPA AQI), Deer Lodge County, 1980 to 1992. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/en/good-air-quality-days-share/deer-lodge-county-montana. 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. Share of days with good air quality (US EPA AQI), Deer Lodge County, 1980 to 1992. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/en/good-air-quality-days-share/deer-lodge-county-montana.

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, Share of days with good air quality (US EPA AQI), Deer Lodge County, 1980 to 1992 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/good-air-quality-days-share/deer-lodge-county-montana (Accessed: 12 October 2026).

BibTeX
@misc{environmental_share_of_days_with_1992,
  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: Share of days with good air quality (US EPA AQI), Deer Lodge County, 1980 to 1992}},
  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/good-air-quality-days-share/deer-lodge-county-montana. 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: Share of days with good air quality (US EPA AQI), Deer Lodge County, 1980 to 1992
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/good-air-quality-days-share/deer-lodge-county-montana
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/good-air-quality-days-share/deer-lodge-county-montana.
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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Questions

What is the share of days with good air quality (US EPA AQI) in Deer Lodge County?

Share of days with good air quality (US EPA AQI) in Deer Lodge County was 100% in 1992, according to EPA. That is up 0.6 pts from 1991.

Where does this figure come from?

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 by Invokely on 2026-10-12.

What was the highest share of days with good air quality (US EPA AQI) in Deer Lodge County?

100% in 1980, the highest value since 1980 in this series.

Related statistics for Deer Lodge County

All statistics for Deer Lodge County | Deer Lodge County in figures