Bad Air Days in Keweenaw County, Michigan

Not enough data

EPA monitors in Keweenaw County ran on too few days between 2016 and 2025 to give a fair yearly count (about 30% of days covered). Neighbouring counties below are a better guide.

What to buy, and what not to

EPA monitors here ran too few days to give a fair yearly count. Use AirNow for today's air.

The record for Keweenaw

The worst recent year was 2023, with 2 bad days on 119 monitored days.

Date	AQI	Main pollutant
2023-06-26	141	PM2.5
2020-12-20	124	PM2.5
2023-06-29	114	PM2.5
2019-07-08	73	PM2.5
2021-08-02	67	PM2.5

Most days, not the worst ones

Across 1,108 monitored days from 2016 to 2025, the air in Keweenaw County rated Good on 96% of them, more often than the 72% typical of monitored counties, and Moderate on 4%. The median day sat at AQI 13; one day in ten went above 35.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)100%1,108 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Median AQI	Highest AQI
2025*	41	41	0	0	8	31
2024	120	118	2	0	12	66
2023	119	105	12	2	16	141
2022	122	119	3	0	12	58
2021	117	109	8	0	14	67
2020	117	116	0	1	13	124
2019	117	114	3	0	12	73
2018	114	108	6	0	12	66
2017	121	116	5	0	13	64
2016	120	118	2	0	12	55
2015	118	111	7	0	17	63
2014	115	107	8	0	15	65
2013	122	115	7	0	12	63
2012	121	115	6	0	15	57
2011	121	112	9	0	17	88
2010	112	102	10	0	14	61

*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.