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

Highest daily Air Quality Index (US EPA) in Lake County was 79 in 2025, according to the U.S. Environmental Protection Agency. That is up 2 from 2024. That is the 20th highest of 23 counties in 2025.

2025, index79
Change on 2024+2
Series high1952017
Series low492009

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

Get an email when a new figure is out or this one is revised.
Keep it in a collection in your library.

Highest daily Air Quality Index (US EPA) in Lake County, 1985 to 2025

05010015020019851991199720032009201520251985: 66 index1986: 119 index1987: 95 index1988: 67 index1989: 119 index1990: 135 index1991: 131 index1992: 133 index1993: 69 index1994: 91 index1995: 87 index1996: 85 index1997: 59 index1998: 104 index1999: 107 index2000: 161 index2001: 156 index2002: 99 index2003: 188 index2004: 120 index2005: 98 index2006: 82 index2007: 162 index2008: 84 index2009: 49 index2010: 62 index2011: 102 index2012: 87 index2013: 56 index2014: 90 index2015: 172 index2016: 130 index2017: 195 index2018: 117 index2019: 53 index2020: 183 index2021: 152 index2022: 120 index2023: 157 index2024: 77 index2025: 79 index05010015020019851999201320251985: 66 index1986: 119 index1987: 95 index1988: 67 index1989: 119 index1990: 135 index1991: 131 index1992: 133 index1993: 69 index1994: 91 index1995: 87 index1996: 85 index1997: 59 index1998: 104 index1999: 107 index2000: 161 index2001: 156 index2002: 99 index2003: 188 index2004: 120 index2005: 98 index2006: 82 index2007: 162 index2008: 84 index2009: 49 index2010: 62 index2011: 102 index2012: 87 index2013: 56 index2014: 90 index2015: 172 index2016: 130 index2017: 195 index2018: 117 index2019: 53 index2020: 183 index2021: 152 index2022: 120 index2023: 157 index2024: 77 index2025: 79 index
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 41 values
Periodindex
202579
202477
2023157
2022120
2021152
2020183
201953
2018117
2017195
2016130
2015172
201490
201356
201287
2011102
201062
200949
200884
2007162
200682
200598
2004120
2003188
200299
2001156
2000161
1999107
1998104
199759
199685
199587
199491
199369
1992133
1991131
1990135
1989119
198867
198795
1986119
198566

Lake County compared with nearby places

Beaverhead County: 95 indexCuster County: 127 indexDawson County: 165 indexFergus County: 131 indexFlathead County: 103 indexGallatin County: 70 indexGlacier County: 117 indexHill County: 157 indexLake County: 79 indexLewis and Clark County: 93 indexLincoln County: 118 indexMissoula County: 98 indexPhillips County: 168 indexPowell County: 75 indexRavalli County: 123 indexRichland County: 165 indexRoosevelt County: 196 indexRosebud County: 68 indexSanders County: 85 indexSheridan County: 197 indexSilver Bow County: 96 indexTeton County: 92 indexYellowstone County: 91 index
  • Under 87
  • 87 to 96
  • 96 to 120
  • 120 to 160
  • 160 and over
  • No data
Highest daily Air Quality Index (US EPA), 2025, index. Lake 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.

Report a problem with this figure

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), Lake County, 1985 to 2025) [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), Lake County, 1985 to 2025. 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/lake-county-montana. 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), Lake County, 1985 to 2025. 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/lake-county-montana.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Highest daily Air Quality Index (US EPA), Lake County, 1985 to 2025 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/highest-daily-air-quality-index/lake-county-montana (Accessed: 12 October 2026).

BibTeX
@misc{environmental_highest_daily_air_quality_2025,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Highest daily Air Quality Index (US EPA), Lake County, 1985 to 2025}},
  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/lake-county-montana. 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), Lake County, 1985 to 2025
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/lake-county-montana
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/lake-county-montana.
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  - 
Embed this chart

Paste this code into a web page or a blog post. The chart shows the latest figures as they are published, with the source and a link back to this page.

Sites that read oEmbed links, such as WordPress, can show the chart when you paste the link to this page.

Use this data in your AI agent

Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:

What is the latest highest daily Air Quality Index (US EPA) in Lake County? Cite the source.
get_value {"indicator":"aqi_max","place":"us-county-30047"}
GET https://invokely.ai/api/v1/value?indicator=aqi_max&place=us-county-30047

Connect Claude, ChatGPT or Cursor in one step. The trial answers 25 calls a day without an account.

Questions

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

Highest daily Air Quality Index (US EPA) in Lake County was 79 in 2025, according to the U.S. Environmental Protection Agency. That is up 2 from 2024. That is the 20th highest of 23 counties in 2025.

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 Lake County?

195 in 2017, the highest value since 1985 in this series.

Related statistics for Lake County

All statistics for Lake County | Lake County in figures