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

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

Share of days with good air quality (US EPA AQI) in Custer County was 99.6% in 2019, according to EPA. That is up 2.1 pts from 2018.

201999.6%
Change on 2018+2.1 pts
Series high1001997
Series low57.91999

Next release: Tuesday, 13 July 2027, estimated by Invokely from past publication dates (low confidence), not announced by the publisher. Release calendar

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Share of days with good air quality (US EPA AQI) in Custer County, 1997 to 2019

506070809010019971999200120032005201620191997: 100 %1998: 100 %1999: 57.9 %2000: 61.3 %2001: 70.3 %2002: 65.7 %2003: 100 %2004: 100 %2005: 96 %2015: 100 %2016: 99.2 %2017: 99 %2018: 97.5 %2019: 99.6 %4060801001997200220191997: 100 %1998: 100 %1999: 57.9 %2000: 61.3 %2001: 70.3 %2002: 65.7 %2003: 100 %2004: 100 %2005: 96 %2015: 100 %2016: 99.2 %2017: 99 %2018: 97.5 %2019: 99.6 %
%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12, published 2026-07-13.
All 14 values
Period%
201999.6
201897.5
201799
201699.2
2015100
200596
2004100
2003100
200265.7
200170.3
200061.3
199957.9
1998100
1997100

Custer County compared with nearby places

Adair County: 80.8 %Canadian County: 86.2 %Carter County: 62.5 %Choctaw County: 94.4 %Cleveland County: 43.8 %Comanche County: 60.3 %Creek County: 93 %Custer County: 99.6 %Dewey County: 63 %Grant County: 100 %Johnston County: 90.8 %Kay County: 56.4 %Le Flore County: 81.6 %Mayes County: 95.3 %Muskogee County: 87.3 %Nowata County: 62.5 %Oklahoma County: 42.7 %Osage County: 87.9 %Ottawa County: 61.2 %Pittsburg County: 60.3 %Sequoyah County: 77.3 %Tulsa County: 51.5 %
  • Under 60
  • 60 to 63
  • 63 to 84
  • 84 to 93
  • 93 and over
  • No data
Share of days with good air quality (US EPA AQI), 2019, %. Custer 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), Custer County, 1997 to 2019) [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), Custer County, 1997 to 2019. 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/custer-county-oklahoma. 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), Custer County, 1997 to 2019. 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/custer-county-oklahoma.

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), Custer County, 1997 to 2019 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/good-air-quality-days-share/custer-county-oklahoma (Accessed: 12 October 2026).

BibTeX
@misc{environmental_share_of_days_with_2019,
  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), Custer County, 1997 to 2019}},
  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/custer-county-oklahoma. 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), Custer County, 1997 to 2019
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/custer-county-oklahoma
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/good-air-quality-days-share/custer-county-oklahoma.
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 Custer County?

Share of days with good air quality (US EPA AQI) in Custer County was 99.6% in 2019, according to EPA. That is up 2.1 pts from 2018.

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 Custer County?

100% in 1997, the highest value since 1997 in this series.

Related statistics for Custer County

All statistics for Custer County | Custer County in figures