Bad Air Days in Benewah County, Idaho: 10 a Year

10 bad air days a year

Among the worst tenth of monitored US counties. Ranked 81 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly particles: smoke and dust (100% particle days).

When the bad days come in Benewah

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

What to buy, and what not to

Particles (wildfire smoke, dust) cause enough bad days here to matter. A HEPA purifier sized to your bedroom removes them; run it with windows shut on bad days.
Upgrade the furnace or AC filter to MERV 13 so the whole house is filtered, not just one room.

The worst days on file

In 2000 to 2009 this county averaged 3 bad days a year; in 2016 to 2025, 10. It has got worse. The worst recent year was 2017, with 30 bad days on 365 monitored days.

Date	AQI	Main pollutant
2020-09-13	492	PM2.5
2017-09-05	362	PM2.5
2017-09-04	258	PM2.5
2020-09-14	244	PM2.5
2020-09-12	232	PM2.5

The air on a normal day

Across 3,644 monitored days from 2016 to 2025, the air in Benewah County rated Good on 54% of them, less often than the 72% typical of monitored counties, and Moderate on 43%. The median day sat at AQI 47; one day in ten went above 74.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)100%3,644 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	363	230	133	0	0	41	92
2024	365	225	136	4	0	43	112
2023	365	201	160	4	2	48	164
2022	365	187	167	11	3	49	177
2021	364	182	168	14	7	51	197
2020	366	218	139	9	7	42	492
2019	364	188	165	11	2	49	155
2018	361	156	192	13	2	53	164
2017	365	158	177	30	10	53	362
2016	366	214	144	8	1	43	177
2015	365	123	219	23	5	55	190
2014	362	199	150	13	0	46	136
2013	359	233	125	1	1	41	163
2012	360	260	99	1	0	34	105
2011	361	282	79	0	0	32	99
2010	363	214	147	2	0	43	131

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

Idaho 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.