Air Quality in Oregon

Oregon has 24 counties with EPA air quality monitoring. Air quality is stable across the state, with an average of 258 "Good" days per county per year. The best air quality is in Benton (median AQI 21) and the most polluted is Douglas (median AQI 53).

County	Median AQI	Max AQI	Good Days	Unhealthy Days	Trend	Top Pollutant
Baker	28	155	279	3	→ stable	PM2.5
Benton	21	68	183	0	→ stable	PM2.5
Clackamas	30	127	325	6	→ stable	PM2.5
Columbia	26	74	354	0	→ stable	PM2.5
Coos	25	63	99	0	↓ improving	PM2.5
Crook	24	173	282	8	↓ improving	PM2.5
Deschutes	39	176	258	19	→ stable	PM2.5
Douglas	53	69	21	0	↑ worsening	PM2.5
Grant	49	204	189	19	↑ worsening	PM2.5
Harney	46	271	200	26	↑ worsening	PM2.5
Jackson	41	155	262	5	→ stable	PM2.5
Jefferson	26	142	289	1	↓ improving	PM2.5
Josephine	29	146	284	8	→ stable	PM2.5
Klamath	33	207	259	16	→ stable	PM2.5
Lake	28	153	286	9	→ stable	PM2.5
Lane	44	216	219	16	→ stable	PM2.5
Linn	25	86	320	0	→ stable	PM2.5
Marion	35	129	298	4	→ stable	PM2.5
Multnomah	35	93	311	0	→ stable	Ozone
Umatilla	38	117	272	4	→ stable	PM2.5
Union	23	128	303	2	↓ improving	PM2.5
Wallowa	23	125	283	1	→ stable	PM2.5
Wasco	23	93	317	0	↓ improving	PM2.5
Washington	33	105	309	2	→ stable	Ozone