Farming in California’s Central Valley is a source of smog, a major contributor to the region’s high asthma rates. (Getty Images)

Farming in California's Central Valley is a source of smog, a major contributor to the region's high asthma rates. (Getty Images)

Farming in California’s Central Valley is a source of smog, a major contributor to the region’s high asthma rates. (Getty Images)

Download Original: 300 × 300 Temperatures, Smog Soar in Central Valley — as Statewide Track Meet Starts

Farming in California’s Central Valley is a source of smog, a major contributor to the region’s high asthma rates. (Getty Images) 1 June,2012Lisa Aliferis