Bad Air Days in Linn County, Oregon: 3 a Year

3 bad air days a year

About the middle of monitored US counties. Ranked 322 of 996 monitored counties, where 1 is worst.

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

Which months to watch

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

What actually helps 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.

Better or worse than it was

In 2000 to 2009 this county averaged 5 bad days a year; in 2016 to 2025, 3. Not much has changed. The worst recent year was 2020, with 11 bad days on 366 monitored days.

Date	AQI	Main pollutant
2020-09-08	853	PM2.5
2020-09-13	824	PM2.5
2020-09-09	810	PM2.5
2020-09-11	789	PM2.5
2020-09-12	780	PM2.5

An ordinary day in Linn

Across 3,653 monitored days from 2016 to 2025, the air in Linn County rated Good on 74% of them, close to the 72% typical of monitored counties, and Moderate on 25%. The median day sat at AQI 32; one day in ten went above 62.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)100%3,653 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	292	72	1	0	27	122
2024	366	320	46	0	0	25	86
2023	365	278	83	4	0	34	125
2022	365	254	109	2	0	33	127
2021	365	268	96	1	0	34	136
2020	366	245	110	11	11	36	853
2019	365	233	130	2	0	37	104
2018	365	254	106	5	0	36	122
2017	365	254	102	9	5	32	186
2016	366	298	68	0	0	26	80
2015	365	272	88	5	3	31	189
2014	365	276	87	2	0	33	130
2013	365	253	107	5	0	31	111
2012	366	285	81	0	0	31	92
2011	363	228	129	6	3	34	212
2010	365	225	140	0	0	34	89

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

Elsewhere in Oregon

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.