|
County
|
State
|
Population
|
Days "very unhealthy" or worse
|
|---|---|---|---|
| Pierce County | Wash. | 904,980 | 5 |
| Snohomish County | Wash. | 822,083 | 4 |
| Multnomah County | Ore. | 812,855 | 7 |
| Washington County | Ore. | 601,592 | 7 |
| Clark County | Wash. | 488,241 | 7 |
| Tulare County | Calif. | 466,195 | 1 |
| Monterey County | Calif. | 434,061 | 2 |
| Clackamas County | Ore. | 418,187 | 3 |
| Marion County | Ore. | 347,818 | 8 |
| Thurston County | Wash. | 290,536 | 1 |
| San Luis Obispo County | Calif. | 283,111 | 2 |
| Santa Cruz County | Calif. | 273,213 | 4 |
| Kitsap County | Wash. | 271,473 | 3 |
| Whatcom County | Wash. | 229,247 | 1 |
| Benton County | Wash. | 204,390 | 3 |
| Linn County | Ore. | 129,749 | 9 |
| Douglas County | Ore. | 110,980 | 7 |
| Cowlitz County | Wash. | 110,593 | 3 |
| Franklin County | Wash. | 95,222 | 2 |
| Benton County | Ore. | 93,053 | 7 |
| Polk County | Ore. | 86,085 | 5 |
| Lewis County | Wash. | 80,707 | 2 |
| Grays Harbor County | Wash. | 75,061 | 5 |
| Mason County | Wash. | 66,768 | 5 |
| Columbia County | Ore. | 52,354 | 4 |
| Whitman County | Wash. | 50,104 | 1 |
| Stevens County | Wash. | 45,723 | 4 |
| Siskiyou County | Calif. | 43,539 | 2 |
| Union County | Ore. | 26,835 | 3 |
| Crook County | Ore. | 24,404 | 6 |
| Hood River County | Ore. | 23,382 | 7 |
| Adams County | Wash. | 19,983 | 2 |
| Plumas County | Calif. | 18,807 | 7 |
| Harney County | Ore. | 7,393 | 1 |
| Grant County | Ore. | 7,199 | 1 |
| Columbia County | Wash. | 3,985 | 2 |