Madera, CA
- High ozone days per year: 38
- No. of days with unhealthy particle pollution: 10
- People with asthma: 11,665
- Population: 156,890
Another of California’s Central Valley agricultural hubs, Madera county produces hundreds of millions of dollars worth of almonds, grapes, and milk. Because the burning of brush and other vegetation was a major cause of agricultural pollution in the valley, a state law was enacted in 2004 to limit these emissions and reduce particulate matter.