Bad Air Days in Cochise County, Arizona: 3 a Year

3 bad air days a year

About the middle of monitored US counties. Ranked 391 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (34% particle days).

Which months to watch

Most bad days here fall in July and May and June and April. Averaged over 2016 to 2025.

What to buy, and what not to

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.

The worst days on file

In 2000 to 2009 this county averaged 4 bad days a year; in 2016 to 2025, 3. Not much has changed. The worst recent year was 2024, with 13 bad days on 366 monitored days.

Date	AQI	Main pollutant
2025-01-08	328	PM10
2024-07-11	307	PM10
2025-02-27	171	PM10
2024-06-15	161	Ozone
2025-04-01	144	PM10

Most days, not the worst ones

Across 3,653 monitored days from 2016 to 2025, the air in Cochise County rated Good on 72% of them, close to the 72% typical of monitored counties, and Moderate on 28%. The median day sat at AQI 45; one day in ten went above 66.

The pollutant setting the AQI on an ordinary day here:

ozone85%3,092 days
coarse dust (PM10)11%410 days
fine particles (PM2.5)4%151 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	255	106	4	2	45	328
2024	366	225	128	13	2	48	307
2023	365	272	90	3	0	44	108
2022	365	291	73	1	0	44	101
2021	365	259	104	2	0	45	105
2020	366	271	93	2	0	45	108
2019	365	253	112	0	0	46	97
2018	365	266	99	0	0	45	90
2017	365	248	115	2	0	45	111
2016	366	278	86	2	0	44	141
2015	365	272	93	0	0	44	90
2014	365	201	159	5	0	48	137
2013	365	201	157	7	0	49	149
2012	360	189	162	9	0	50	120
2011	352	200	141	11	0	48	119
2010	363	244	115	4	0	45	112

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

Elsewhere in Arizona

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.