Share of days with good air quality (US EPA AQI) in Modoc County
Share of days with good air quality (US EPA AQI) in Modoc County was 50% in 2003, according to EPA. That is down 50 pts from 2002.
Share of days with good air quality (US EPA AQI) in Modoc County, 1994 to 2003
All 10 values
| Period | % |
|---|---|
| 2003 | 50 |
| 2002 | 100 |
| 2001 | 77.4 |
| 2000 | 75.7 |
| 1999 | 78.7 |
| 1998 | 95.3 |
| 1997 | 97.7 |
| 1996 | 95 |
| 1995 | 85.2 |
| 1994 | 95.3 |
Modoc County compared with nearby places
- Under 24
- 24 to 49
- 49 to 57
- 57 to 71
- 71 to 86
- 86 and over
- No data
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.
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
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), Modoc County, 1994 to 2003) [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), Modoc County, 1994 to 2003. 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/modoc-county-california. 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), Modoc County, 1994 to 2003. 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/modoc-county-california.
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), Modoc County, 1994 to 2003 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/good-air-quality-days-share/modoc-county-california (Accessed: 12 October 2026).
BibTeX
@misc{environmental_share_of_days_with_2003,
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), Modoc County, 1994 to 2003}},
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/modoc-county-california. 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), Modoc County, 1994 to 2003
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/modoc-county-california
Y2 - 2026/10/12
N1 - Accessed via Invokely, https://invokely.ai/en/good-air-quality-days-share/modoc-county-california.
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 -
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 share of days with good air quality (US EPA AQI) in Modoc County? Cite the source.
get_value {"indicator":"aqi_good_days_share","place":"us-county-06049"}
GET https://invokely.ai/api/v1/value?indicator=aqi_good_days_share&place=us-county-06049Questions
What is the share of days with good air quality (US EPA AQI) in Modoc County?
Share of days with good air quality (US EPA AQI) in Modoc County was 50% in 2003, according to EPA. That is down 50 pts from 2002.
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 Modoc County?
100% in 2002, the highest value since 1994 in this series.