Bad Air Days in Churchill County, Nevada: 2 a Year

2 bad air days a year

About the middle of monitored US counties. Ranked 461 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (0% particle days).

Which months to watch

Most bad days here fall in August 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 3 bad days a year; in 2016 to 2025, 2. Not much has changed. The worst recent year was 2021, with 10 bad days on 362 monitored days.

Date	AQI	Main pollutant
2021-08-08	159	Ozone
2020-08-20	147	Ozone
2021-08-23	136	Ozone
2021-08-21	133	Ozone
2017-07-03	129	Ozone

An ordinary day in Churchill

Across 3,516 monitored days from 2016 to 2025, the air in Churchill County rated Good on 84% of them, more often than the 72% typical of monitored counties, and Moderate on 15%. The median day sat at AQI 42; one day in ten went above 58.

The pollutant setting the AQI on an ordinary day here:

ozone100%3,516 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	344	293	51	0	0	40	77
2024	358	280	77	1	0	44	105
2023	354	295	59	0	0	43	90
2022	349	330	19	0	0	39	100
2021	362	271	81	10	1	44	159
2020	363	336	25	2	0	40	147
2019	353	323	30	0	0	41	80
2018	332	256	71	5	0	44	129
2017	350	283	64	3	0	43	129
2016	351	284	66	1	0	41	108
2015	261	209	50	2	0	44	133
2014	211	153	58	0	0	46	100
2013	210	153	57	0	0	46	87
2012	206	205	1	0	0	32	51
2011	210	208	2	0	0	33	77
2010	207	186	21	0	0	40	80

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

Nearby counties on file

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, and on why a purifier does not touch ozone in smoke vs ozone.