Bad Air Days in Teton County, Wyoming: 3 a Year

3 bad air days a year

About the middle of monitored US counties. Ranked 423 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly particles: smoke and dust (92% particle days).

Which months to watch

Most bad days here fall in August and September. Averaged over 2016 to 2025.

What to buy, and what not to

Bad air days are rare here. A standard furnace filter is enough; no purifier needed for outdoor air.
On the odd bad day, check AirNow and keep windows shut.

The worst days on file

In 2000 to 2009 this county averaged under 1 bad days a year; in 2016 to 2025, 3. It has got worse. The worst recent year was 2020, with 12 bad days on 366 monitored days.

Date	AQI	Main pollutant
2020-09-16	165	PM2.5
2020-09-17	163	PM2.5
2020-09-13	161	PM2.5
2020-08-24	156	PM2.5
2020-09-18	151	PM2.5

Most days, not the worst ones

Across 3,653 monitored days from 2016 to 2025, the air in Teton County rated Good on 83% of them, more often than the 72% typical of monitored counties, and Moderate on 16%. The median day sat at AQI 43; one day in ten went above 58.

The pollutant setting the AQI on an ordinary day here:

ozone91%3,340 days
fine particles (PM2.5)8%304 days

Teton County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	310	55	0	0	44	90
2024	366	276	88	2	0	44	138
2023	365	321	44	0	0	43	75
2022	365	332	33	0	0	43	100
2021	365	277	78	10	0	44	131
2020	366	312	42	12	5	43	165
2019	365	323	42	0	0	44	87
2018	365	273	91	1	0	44	106
2017	365	289	75	1	0	44	118
2016	366	324	42	0	0	42	99
2015	365	322	42	1	0	42	107
2014	365	317	48	0	0	42	97
2013	365	303	62	0	0	44	80
2012	366	252	111	3	0	45	110
2011	365	269	96	0	0	45	90
2010	365	279	86	0	0	44	90

*2025 may be a partial year in EPA's file.

Nearby counties on file

How this is counted

A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day.