Air Quality in South Dakota

South Dakota has 11 counties with EPA air quality monitoring. Air quality is stable across the state, with an average of 275 "Good" days per county per year. The best air quality is in Hughes (median AQI 8) and the most polluted is Meade (median AQI 45).

County	Median AQI	Max AQI	Good Days	Unhealthy Days	Trend	Top Pollutant
Brookings	36	111	292	2	→ stable	Ozone
Brown	24	118	306	4	↓ improving	PM2.5
Clay	39	137	289	2	↑ worsening	Ozone
Codington	37	102	269	1	↑ worsening	PM2.5
Custer	44	126	276	9	→ stable	Ozone
Hughes	8	69	340	0	↓ improving	PM2.5
Jackson	44	129	269	7	→ stable	Ozone
Meade	45	154	266	7	↑ worsening	Ozone
Minnehaha	34	145	297	2	→ stable	Ozone
Pennington	36	111	248	4	→ stable	PM2.5
Union	44	167	179	4	→ stable	Ozone