Bad Air Days in Clinton County, Michigan: 2 a Year

2 bad air days a year

About the middle of monitored US counties. Ranked 453 of 996 monitored counties, where 1 is worst.

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

When the bad days come in Clinton

Most bad days here fall in June and May and April. 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

The worst recent year was 2016, with 7 bad days on 181 monitored days.

Date	AQI	Main pollutant
2018-05-29	143	Ozone
2023-06-29	136	Ozone
2016-04-18	122	Ozone
2016-05-24	119	Ozone
2025-06-11	119	Ozone

The air on a normal day

Across 2,329 monitored days from 2016 to 2025, the air in Clinton County rated Good on 90% of them, more often than the 72% typical of monitored counties, and Moderate on 9%. The median day sat at AQI 38; one day in ten went above 54.

The pollutant setting the AQI on an ordinary day here:

ozone100%2,329 days

Clinton County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	204	184	19	1	0	39	119
2024	244	228	16	0	0	38	80
2023	240	206	31	3	0	38	136
2022	235	213	22	0	0	38	90
2021	239	217	22	0	0	37	100
2020	256	244	12	0	0	34	93
2019	248	243	5	0	0	35	67
2018	244	213	27	4	0	39	143
2017	238	211	27	0	0	38	93
2016	181	143	31	7	0	41	122
2015	182	161	21	0	0	39	100
2014	182	148	33	1	0	41	112
2013	183	148	34	1	0	41	108
2012	176	118	46	12	2	44	166
2011	183	152	28	3	0	39	122
2010	183	147	35	1	0	42	115

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

Elsewhere in Michigan

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.