Bad Air Days in Wayne County, Michigan: 11 a Year

11 bad air days a year

Among the worst tenth of monitored US counties. Ranked 70 of 996 monitored counties, where 1 is worst.

What makes them bad: a mix of particles and ozone (52% particle days).

Which months to watch

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

What actually helps here

Particles (wildfire smoke, dust) cause enough bad days here to matter. A HEPA purifier sized to your bedroom removes them; run it with windows shut on bad days.
Ozone drives many bad days here. Purifiers and filters do not remove ozone, so do not buy one for that. Ozone peaks on hot afternoons: exercise outside in the morning.

The worst days on file

In 2000 to 2009 this county averaged 29 bad days a year; in 2016 to 2025, 11. The air has improved. The worst recent year was 2023, with 23 bad days on 365 monitored days.

Date	AQI	Main pollutant
2023-06-28	226	PM2.5
2020-07-05	188	PM2.5
2023-06-29	188	PM2.5
2023-06-27	186	PM2.5
2024-07-05	181	PM2.5

An ordinary day in Wayne

Across 3,653 monitored days from 2016 to 2025, the air in Wayne County rated Good on 27% of them, less often than the 72% typical of monitored counties, and Moderate on 70%. The median day sat at AQI 57; one day in ten went above 80.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)83%3,023 days
ozone14%506 days
coarse dust (PM10)2%91 days
nitrogen dioxide1%33 days

Wayne County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	132	222	11	3	54	156
2024	366	120	238	8	1	55	181
2023	365	70	272	23	4	61	226
2022	365	63	287	15	0	58	131
2021	365	86	275	4	0	58	118
2020	366	118	238	10	2	55	188
2019	365	81	275	9	0	58	142
2018	365	105	253	7	0	57	133
2017	365	103	251	11	0	57	147
2016	366	99	250	17	0	57	133
2015	365	88	270	7	0	57	133
2014	365	77	280	8	0	58	147
2013	365	116	246	3	0	55	129
2012	366	107	225	34	3	58	208
2011	365	113	234	18	2	56	154
2010	365	131	219	15	0	56	140

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

Michigan 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.