Bad Air Days in Yakima County, Washington: 13 a Year

13 bad air days a year

Among the worst tenth of monitored US counties. Ranked 59 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 Yakima

Most bad days here fall in August and September. 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.

Better or worse than it was

In 2000 to 2009 this county averaged 9 bad days a year; in 2016 to 2025, 13. It has got worse. The worst recent year was 2017, with 29 bad days on 365 monitored days.

Date	AQI	Main pollutant
2020-09-14	743	PM2.5
2020-09-15	605	PM2.5
2020-09-12	524	PM2.5
2020-09-13	506	PM2.5
2017-09-07	317	PM2.5

Most days, not the worst ones

Across 3,653 monitored days from 2016 to 2025, the air in Yakima County rated Good on 54% of them, less often than the 72% typical of monitored counties, and Moderate on 42%. The median day sat at AQI 47; one day in ten went above 78.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)100%3,639 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	226	136	3	1	41	154
2024	366	248	111	7	1	37	153
2023	365	203	158	4	3	46	233
2022	365	178	181	6	1	51	158
2021	365	175	163	27	15	52	210
2020	366	198	153	15	9	46	743
2019	365	178	177	10	0	51	127
2018	365	173	176	16	9	52	239
2017	365	193	143	29	8	48	317
2016	366	211	143	12	4	44	199
2015	363	190	153	20	4	48	192
2014	365	227	129	9	2	39	158
2013	365	174	173	18	4	52	158
2012	366	196	162	8	5	48	177
2011	364	236	118	10	2	36	158
2010	365	244	117	4	0	34	140

*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.