LA Times: The percentage of Californians who believe air pollution is a “big problem” has dropped precipitously in recent years, especially in Los Angeles County and the Central Valley, among the nation’s dirtiest regions, according to a new survey. At the same time, the poll by the nonpartisan Public Policy Institute of California found that support for the state’s landmark 2006 law to slash greenhouse gases has declined, and fewer people think that global warming is a serious threat to the …