Illinois Ozone 8-hour Exceedance Summary
8-hour Exceedances Summary
Values in each column is 8-hour concentration - standard of 70 parts per billion;
| Region | County | Site | 6/16/25 | 6/12/25 | 6/11/25 | 6/7/25 | 6/5/25 |
| Chicago Metropolitan | Cook | Alsip | 71 | 71 | |||
| Cook | Chicago - Com Ed | 71 | |||||
| Cook | Chicago - SWFP | 78 | 77 | ||||
| Cook | Chicago - Taft | 74 | 74 | ||||
| Cook | Cicero | 73 | 73 | ||||
| Cook | Des Plaines | ||||||
| Cook | Evanston | 73 | 72 | ||||
| Cook | Lemont | ||||||
| Cook | Northbrook | ||||||
| Cook | Schiller Park | ||||||
| DuPage | Lisle | ||||||
| Kane | Elgin | 81 | 75 | 72 | |||
| Lake | Zion | 73 | 71 | ||||
| McHenry | Cary | 80 | 72 | 72 | |||
| Will | Braidwood | ||||||
| Metro-East | Jersey | Jerseyville | 76 | ||||
| Madison | Alton | ||||||
| Madison | Maryville | ||||||
| Madison | Wood River | ||||||
| Randolph | Houston | ||||||
| St. Clair | East St. Louis | ||||||
| Northern Illinois | Rock Island | Rock Island | |||||
| Winnebago | Loves Park | 73 | |||||
| West Central Illinois | Adams | Quincy | |||||
| Macoupin | Nilwood | ||||||
| Peoria | Peoria | 73 | |||||
| Peoria | Peoria Heights | 73 | |||||
| Sangamon | Springfield | ||||||
| East Central Illinois | Champaign | Thomasboro | |||||
| McLean | Normal | 74 | |||||
| Macon | Decatur | ||||||
| Southeast Illinois | Effingham | Effingham | |||||
| Hamilton | Knight Prairie Township |