I'd missed seeing this yesterday. More could follow, Use this DNR site.

Advisory for Ozone (Orange)

Start Time:	5:30PM CT Tuesday, July 9, 2019
End Time:	9:30PM CT Tuesday, July 9, 2019
Counties:	Kenosha, Racine, Walworth, Washington, Waukesha

Air Quality Index (AQI) Values	Levels of Health Concern	Colors
When the AQI is in this range:	...air quality conditions are:	...as symbolized by this color:
0 to 50	Good	Green
51 to 100	Moderate	Yellow
101 to 150	Unhealthy for Sensitive Groups	Orange
151 to 200	Unhealthy	Red
201 to 300	Very Unhealthy	Purple
301 to 500