The Infectious risk has shown a gradual increase over the past 12 weeks, with the most recent week notably higher than earlier in the window..
Allergy risk activity has held steady over the past 12 weeks in Cook, Illinois.
Pollution risk activity has been increasing over the past 12 weeks in Cook, Illinois.
Weather risk activity has been easing over the past 12 weeks in Cook, Illinois.
Last updated: August 24, 2026
Data refreshed weekly