Bad Air Days in Clallam County, Washington: 3 a Year

3 bad air days a year

About the middle of monitored US counties. Ranked 422 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 Clallam

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

Is a purifier worth it here?

Bad air days are rare here. A standard furnace filter is enough; no purifier needed for outdoor air.
On the odd bad day, check AirNow and keep windows shut.

Better or worse than it was

In 2000 to 2009 this county averaged under 1 bad days a year; in 2016 to 2025, 3. It has got worse. The worst recent year was 2017, with 8 bad days on 365 monitored days.

Date	AQI	Main pollutant
2020-09-14	368	PM2.5
2020-09-12	338	PM2.5
2020-09-13	309	PM2.5
2020-09-15	255	PM2.5
2020-09-11	254	PM2.5

An ordinary day in Clallam

Across 3,653 monitored days from 2016 to 2025, the air in Clallam County rated Good on 78% of them, more often than the 72% typical of monitored counties, and Moderate on 21%. The median day sat at AQI 38; one day in ten went above 56.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)57%2,077 days
ozone43%1,576 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	312	53	0	0	29	69
2024	366	321	45	0	0	36	69
2023	365	307	57	1	0	37	101
2022	365	272	91	2	0	38	124
2021	365	298	67	0	0	37	81
2020	366	304	55	7	6	37	368
2019	365	285	80	0	0	38	73
2018	365	243	114	8	5	42	230
2017	365	246	111	8	4	41	188
2016	366	279	87	0	0	40	73
2015	364	263	101	0	0	41	80
2014	365	279	85	1	0	40	101
2013	365	297	68	0	0	37	85
2012	366	242	124	0	0	43	83
2011	365	282	83	0	0	41	78
2010	365	316	49	0	0	38	67

*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.