Bad Air Days in Garfield County, Colorado: 5 a Year

5 bad air days a year

More bad air days than three quarters of monitored counties. Ranked 235 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (9% particle days).

The bad-air season here

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

What actually helps here

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.

The record for Garfield

The worst recent year was 2018, with 16 bad days on 365 monitored days.

Date	AQI	Main pollutant
2021-08-07	158	PM2.5
2018-06-11	151	Ozone
2018-06-12	150	Ozone
2020-08-22	150	Ozone
2020-08-21	143	Ozone

An ordinary day in Garfield

Across 3,653 monitored days from 2016 to 2025, the air in Garfield County rated Good on 62% of them, less often than the 72% typical of monitored counties, and Moderate on 37%. The median day sat at AQI 49; one day in ten went above 75.

The pollutant setting the AQI on an ordinary day here:

ozone98%3,578 days
fine particles (PM2.5)2%74 days

Garfield County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	252	112	1	0	47	131
2024	366	216	145	5	0	49	133
2023	365	166	196	3	0	54	126
2022	365	221	142	2	0	49	108
2021	365	198	156	11	1	49	158
2020	366	232	129	5	0	48	150
2019	365	248	115	2	0	48	105
2018	365	214	135	16	1	48	151
2017	365	240	124	1	0	47	108
2016	366	263	102	1	0	47	126
2015	365	260	95	10	0	45	133
2014	365	299	64	2	0	44	108
2013	365	243	121	1	0	46	101
2012	366	142	171	53	0	61	150
2011	365	134	202	29	0	58	133
2010	365	167	188	10	0	51	150

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

Elsewhere in Colorado

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.