Bad Air Days in Converse County, Wyoming: 2 a Year

2 bad air days a year

Fewer bad air days than most monitored US counties. Ranked 541 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (39% particle days).

When the bad days come in Converse

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

What actually helps 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, 2. Not much has changed. The worst recent year was 2020, with 4 bad days on 366 monitored days.

Date	AQI	Main pollutant
2016-11-29	173	PM10
2020-08-23	129	Ozone
2024-07-24	126	Ozone
2017-09-03	121	PM10
2017-09-14	121	PM2.5

The air on a normal day

Across 3,653 monitored days from 2016 to 2025, the air in Converse County rated Good on 85% of them, more often than the 72% typical of monitored counties, and Moderate on 15%. The median day sat at AQI 41; one day in ten went above 56.

The pollutant setting the AQI on an ordinary day here:

ozone84%3,057 days
coarse dust (PM10)14%504 days
fine particles (PM2.5)2%79 days

Converse County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	351	14	0	0	40	63
2024	366	305	57	4	0	41	126
2023	365	331	34	0	0	42	99
2022	365	314	51	0	0	40	90
2021	365	274	87	4	0	42	119
2020	366	302	60	4	0	42	129
2019	365	314	50	1	0	41	101
2018	365	310	54	1	0	41	102
2017	365	282	80	3	0	42	121
2016	366	311	54	1	1	41	173
2015	365	288	72	5	2	43	161
2014	365	308	57	0	0	42	87
2013	365	295	68	2	0	42	108
2012	360	296	62	2	0	29	129
2011	360	335	25	0	0	22	89
2010	363	337	26	0	0	23	99

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

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