Bad Air Days in Pitkin County, Colorado

Not enough data

EPA monitors in Pitkin County ran on too few days between 2016 and 2025 to give a fair yearly count (about 44% of days covered). Neighbouring counties below are a better guide.

What to buy, and what not to

EPA monitors here ran too few days to give a fair yearly count. Use AirNow for today's air.

The worst days on file

The worst recent year was 2025, with 1 bad day on 365 monitored days.

Date	AQI	Main pollutant
2025-08-10	154	PM2.5
2021-08-08	90	PM2.5
2025-08-09	88	PM2.5
2025-08-11	85	PM2.5
2025-07-16	77	PM2.5

An ordinary day in Pitkin

Across 1,596 monitored days from 2016 to 2025, the air in Pitkin County rated Good on 96% of them, more often than the 72% typical of monitored counties, and Moderate on 4%. The median day sat at AQI 15; one day in ten went above 34.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)51%819 days
coarse dust (PM10)49%777 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	337	27	1	1	19	154
2024	257	246	11	0	0	19	76
2023	121	120	1	0	0	13	51
2022	122	118	4	0	0	14	72
2021	122	115	7	0	0	14	90
2020	120	116	4	0	0	12	72
2019	121	121	0	0	0	11	46
2018	123	120	3	0	0	15	53
2017	123	123	0	0	0	14	48
2016	122	122	0	0	0	12	44
2015	124	121	3	0	0	12	60
2014	115	115	0	0	0	12	44
2013	296	235	61	0	0	44	97
2012	182	176	6	0	0	31	67
2011	363	141	207	15	0	54	119
2010	362	214	142	6	1	49	164

*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.