Air Quality in Wisconsin

Wisconsin has 29 counties with EPA air quality monitoring. Air quality is generally worsening across the state, with an average of 242 "Good" days per county per year. The best air quality is in Monroe (median AQI 23) and the most polluted is Milwaukee (median AQI 43).

County	Median AQI	Max AQI	Good Days	Unhealthy Days	Trend	Top Pollutant
Ashland	34	101	331	1	→ stable	Ozone
Brown	37	87	290	0	→ stable	PM2.5
Columbia	38	93	186	0	→ stable	Ozone
Dane	42	93	264	0	→ stable	PM2.5
Dodge	38	84	297	0	→ stable	Ozone
Door	37	108	175	2	→ stable	Ozone
Eau Claire	38	142	299	1	→ stable	PM2.5
Fond du Lac	38	77	190	0	→ stable	Ozone
Forest	37	153	313	1	→ stable	Ozone
Grant	36	82	263	0	→ stable	PM2.5
Jackson	27	95	238	0	↑ worsening	PM2.5
Jefferson	39	93	183	0	→ stable	Ozone
Kenosha	41	143	267	11	→ stable	Ozone
Kewaunee	39	105	170	1	→ stable	Ozone
La Crosse	37	67	197	0	→ stable	Ozone
Manitowoc	39	129	172	6	→ stable	Ozone
Marathon	37	151	311	1	→ stable	PM2.5
Milwaukee	43	147	251	6	→ stable	PM2.5
Monroe	23	90	258	0	↑ worsening	PM2.5
Outagamie	37	99	291	0	→ stable	PM2.5
Ozaukee	37	161	296	9	→ stable	Ozone
Racine	42	151	156	11	→ stable	Ozone
Rock	41	112	171	2	→ stable	Ozone
Sauk	37	77	312	0	→ stable	PM2.5
Sheboygan	40	166	166	9	→ stable	Ozone
Taylor	34	80	357	0	→ stable	Ozone
Vilas	37	93	197	0	→ stable	Ozone
Walworth	42	100	169	0	→ stable	Ozone
Waukesha	43	101	260	1	→ stable	PM2.5