Bad Air Days in Uintah County, Utah: 13 a Year

13 bad air days a year

Among the worst tenth of monitored US counties. Ranked 57 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (3% particle days).

When the bad days come in Uintah

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

What to buy, and what not to

Ozone drives many bad days here. Purifiers and filters do not remove ozone, so do not buy one for that. Ozone peaks on hot afternoons: exercise outside in the morning.
Sign up for EnviroFlash ozone alerts for this area during the worst months.

The worst days on file

The worst recent year was 2023, with 37 bad days on 365 monitored days.

Date	AQI	Main pollutant
2016-02-12	216	Ozone
2023-02-05	215	Ozone
2017-02-05	206	Ozone
2017-02-01	205	Ozone
2019-03-01	205	Ozone

The air on a normal day

Across 3,653 monitored days from 2016 to 2025, the air in Uintah County rated Good on 54% of them, less often than the 72% typical of monitored counties, and Moderate on 42%. The median day sat at AQI 50; one day in ten went above 81.

The pollutant setting the AQI on an ordinary day here:

ozone92%3,350 days
fine particles (PM2.5)8%302 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	213	148	4	0	48	126
2024	366	218	141	7	0	48	133
2023	365	154	174	37	21	54	215
2022	365	242	123	0	0	47	93
2021	365	190	149	26	2	50	159
2020	366	201	160	5	0	50	133
2019	365	157	186	22	5	54	205
2018	365	181	173	11	1	51	156
2017	365	200	154	11	8	49	206
2016	366	234	121	11	7	47	216
2015	365	242	121	2	0	46	122
2014	365	229	128	8	2	48	164
2013	365	126	175	64	42	61	238
2012	366	157	193	16	1	54	167
2011	365	179	154	32	19	51	236
2010	365	156	162	47	31	54	219

*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, and on why a purifier does not touch ozone in smoke vs ozone.