"The San Joaquin Valley's bad air is also being exported from the Bay area as a consequence of public policies that are both willful and avoidable. For years, cities and counties in the San Francisco Bay area have been imposing "smart growth" policies such as urban growth boundaries and hefty development impact fees in an attempt to control "urban sprawl." These policies significantly raise the price of housing by rationing land, politicizing land use decisions and restricting competition in home building."
Thanks to Chris Steins