Air Quality in Utah

Utah has 17 counties with EPA air quality monitoring. Air quality is stable across the state, with an average of 218 "Good" days per county per year. The best air quality is in Garfield (median AQI 9) and the most polluted is Salt Lake (median AQI 54).

County	Median AQI	Max AQI	Good Days	Unhealthy Days	Trend	Top Pollutant
Box Elder	47	133	214	5	→ stable	Ozone
Cache	44	101	238	1	→ stable	Ozone
Carbon	44	112	278	1	→ stable	Ozone
Davis	46	133	234	15	→ stable	Ozone
Duchesne	47	165	225	5	→ stable	Ozone
Garfield	9	61	116	0	↓ improving	PM2.5
Grand	47	105	246	2	↑ worsening	Ozone
Iron	43	100	303	0	→ stable	Ozone
Salt Lake	54	230	150	43	→ stable	Ozone
San Juan	44	126	276	3	→ stable	Ozone
Tooele	46	143	227	12	→ stable	Ozone
Uintah	48	133	218	7	→ stable	Ozone
Utah	47	151	210	9	→ stable	Ozone
Wasatch	37	108	138	1	↑ worsening	Ozone
Washington	44	108	278	2	→ stable	Ozone
Wayne	11	56	116	0	→ stable	PM2.5
Weber	45	122	243	6	→ stable	Ozone