Highest pollen count of the season, last three years on Friday 13th
Monday, May 16, 2011 - 10:00
in Earth & Climate
Chicagos tree pollen count reached 1,500 today, triggering a dangerous air quality warning.
Updated by artificial intelligence Fri, 18 Jul 2025, 20:07:12 UTC Learn more
- Tell your friends
- Get science news via