1 dot = 10 people living within 1,000 feet of a freeway in 2010
An estimated 2.5 million Southern Californians live in high-pollution zones within 1,000 feet of a freeway. Nearly half live within 500 feet, where health scientists and air quality regulators say homes, schools and day cares should not be built.
Sources: Southern California Association of Governments, San Diego GIS, U.S. Census Bureau, Carto, Mapbox