U.S. Cities Ranked by Worst Air Pollution (2012)

	Average Annual PM-10 Concentration (ug/m³)
Visalia, CA	60.4
Bakersfield, CA	54.8
Fresno, CA	51.7
Riverside, CA	48.1
Stockton, CA	44.8
Los Angeles, CA	43.8
Phoenix, AZ	39.5
Spokane, WA	38.7
Reno, NV	38.5
Las Vegas, NV	38.3