Illinois PM2.5 24-hour Exceedance Summary
Value in each column is 24-hour concentration - standard of 35 micrograms per cubic meter
(values in micrograms per cubic meter)
| Region | County | Site | 7/20/26 | 7/19/26 | 7/18/26 | 7/17/26 | 7/16/26 |
| Chicago Metropolitan | Cook | Alsip | 51.8 | 63.8 | 38.9 | 120.7 | 247.3 |
| Cook | Chicago-Com Ed | 42.5 | 52.3 | 97.1 | 223.6 | ||
| Cook | Chicago-Mayfair | 46.2 | 51.0 | 37.0 | 118.9 | 275.4 | |
| Cook | Chicago-Springfield Pump | 45.7 | 50.1 | 35.9 | 116.8 | 275.2 | |
| Cook | Chicago-Washington HS | 46.0 | 51.9 | 107.7 | 249.8 | ||
| Cook | Cicero | 42.3 | 47.9 | 101.3 | 242.8 | ||
| Cook | Des Plaines | 41.3 | 46.4 | 111.7 | 261.7 | ||
| Cook | Kingery Near-Road | 43.5 | 52.0 | 98.7 | 186.8 | ||
| Cook | McCook | 46.3 | 50.7 | 104.7 | 234.9 | ||
| Cook | Northbrook | 47.7 | 52.9 | 42.3 | 144.8 | 330.9 | |
| Cook | Schiller Park | 48.2 | 52.1 | 37.6 | 121.7 | 283.6 | |
| Cook | Summit | 45.3 | 52.5 | 110.3 | 241.1 | ||
| Du Page | Naperville | 47.6 | 56.8 | 143.0 | 210.4 | ||
| Kane | Aurora | 41.2 | 51.3 | 131.0 | 148.3 | ||
| Kane | Elgin | ||||||
| McHenry | Cary | 41.0 | 52.2 | 102.1 | 257.9 | ||
| Will | Braidwood | 37.8 | 56.7 | 105.8 | 56.4 | ||
| Will | Joliet | 40.6 | 51.1 | 116.1 | 102.8 | ||
| Northern Illinois | Rock Island | Rock Island | 76.1 | ||||
| Winnebago | Rockford | 39.9 | 71.2 | 131.5 | 176.2 | ||
| Central Illinois | Champaign | Bondville | |||||
| Champaign | Champaign | 45.1 | 65.6 | ||||
| McLean | Normal | 40.7 | 64.3 | ||||
| Macon | Decatur | 49.0 | 66.6 | ||||
| Peoria | Peoria | 44.8 | 74.8 | ||||
| Sangamon | Springfield | 45.3 | 54.0 | ||||
| Metro-East | Jersey | Jerseyville | |||||
| Madison | Alton | ||||||
| Madison | Granite City Fire Station | 39.3 | |||||
| Madison | Granite City-Gateway Medical | 43.1 | |||||
| Madison | Wood River | 44.1 | |||||
| Randolph | Houston | ||||||
| St Clair | E St. Louis | 35.6 | |||||
| Southern Illinois | Hamilton | Knight Prairie | |||||
| Values Preliminary | Not Quality Assured |