Bad Air Days in Benton County, Washington: 6 a Year

6 bad air days a year

More bad air days than three quarters of monitored counties. Ranked 168 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly particles: smoke and dust (71% particle days).

When the bad days come in Benton

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

Is a purifier worth it here?

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 record for Benton

In 2000 to 2009 this county averaged 3 bad days a year; in 2016 to 2025, 6. It has got worse. The worst recent year was 2017, with 14 bad days on 365 monitored days.

Date	AQI	Main pollutant
2020-09-07	954	PM10
2020-09-12	458	PM10
2020-09-14	398	PM10
2020-09-13	368	PM10
2020-09-15	340	PM10

The air on a normal day

Across 3,651 monitored days from 2016 to 2025, the air in Benton County rated Good on 77% of them, more often than the 72% typical of monitored counties, and Moderate on 22%. The median day sat at AQI 37; one day in ten went above 61.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)58%2,107 days
ozone33%1,195 days
coarse dust (PM10)10%349 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	293	70	2	0	36	113
2024	366	299	64	3	0	34	126
2023	365	262	99	4	3	41	261
2022	365	278	84	3	1	38	151
2021	365	283	73	9	3	36	180
2020	365	284	69	12	9	35	954
2019	364	273	91	0	0	39	80
2018	365	275	76	14	2	36	188
2017	365	242	109	14	5	39	204
2016	366	307	57	2	0	35	122
2015	362	269	83	10	2	37	483
2014	348	295	52	1	0	26	131
2013	362	279	80	3	1	29	517
2012	364	286	78	0	0	29	99
2011	363	306	56	1	0	27	102
2010	365	314	51	0	0	27	78

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

Elsewhere in Washington

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.