Bad Air Days in Powell County, Montana

Not enough data

EPA monitors in Powell County ran on too few days between 2016 and 2025 to give a fair yearly count (about 28% of days covered). Neighbouring counties below are a better guide.

What actually helps here

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

The record for Powell

The worst recent year was 2021, with 3 bad days on 117 monitored days.

Date	AQI	Main pollutant
2024-11-20	144	PM2.5
2017-08-23	143	PM2.5
2021-09-10	133	PM2.5
2021-08-14	126	PM2.5
2024-09-09	117	PM2.5

Most days, not the worst ones

Across 1,028 monitored days from 2016 to 2025, the air in Powell County rated Good on 92% of them, more often than the 72% typical of monitored counties, and Moderate on 7%. The median day sat at AQI 11; one day in ten went above 44.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)100%1,028 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	95	90	5	0	0	13	75
2024	114	101	11	2	0	12	144
2023	109	100	7	2	0	14	115
2022	114	105	8	1	0	12	104
2021	117	101	13	3	0	12	133
2020	33	33	0	0	0	3	14
2019	109	105	4	0	0	12	84
2018	113	104	9	0	0	12	93
2017	105	91	13	1	0	9	143
2016	119	116	3	0	0	10	58
2015	120	111	7	2	2	11	178
2014	118	110	7	1	0	10	119
2013	119	113	6	0	0	9	69
2012	118	101	16	1	0	12	108
2011	108	103	5	0	0	11	72
2010	111	106	5	0	0	13	76

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

Montana compared

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.