Bad Air Days in Anchorage, Alaska: 1 a Year

1 bad air day a year

Fewer bad air days than most monitored US counties. Ranked 606 of 996 monitored counties, where 1 is worst.

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

The bad-air season here

Most bad days here fall in August and January and June and July. 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 1 bad days a year; in 2016 to 2025, 1. Not much has changed. The worst recent year was 2019, with 9 bad days on 365 monitored days.

Date	AQI	Main pollutant
2019-08-20	163	PM2.5
2019-08-19	158	PM2.5
2019-08-30	157	PM2.5
2019-08-29	152	PM2.5
2019-08-23	138	PM2.5

The air on a normal day

Across 3,648 monitored days from 2016 to 2025, the air in Anchorage rated Good on 79% of them, more often than the 72% typical of monitored counties, and Moderate on 21%. The median day sat at AQI 28; one day in ten went above 59.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)68%2,485 days
coarse dust (PM10)31%1,116 days
carbon monoxide1%47 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	289	75	1	0	26	110
2024	366	297	69	0	0	24	90
2023	365	319	46	0	0	21	71
2022	365	302	62	1	0	24	125
2021	365	289	74	2	0	28	132
2020	366	294	72	0	0	27	92
2019	365	254	102	9	4	32	163
2018	365	288	77	0	0	30	87
2017	365	299	65	1	0	28	105
2016	361	252	109	0	0	40	91
2015	361	261	100	0	0	34	79
2014	360	250	107	3	1	33	153
2013	365	286	78	1	1	31	151
2012	366	264	102	0	0	34	100
2011	365	300	65	0	0	33	88
2010	365	270	93	2	0	36	127

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

Alaska 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.