Around the world, cities plagued by smog have tried to clear up the skies among the skyscrapers. Discover their successes by comparing photos from before and after changes were made by local governments
By Erica R. Hendry
Los Angeles had experienced poor air quality since the early 1900s, but the 1952 London incident gave then-California Governor Goodwin J. Knight even more reason to worry. The city had poor public transportation, which meant its roadways were packed with vehicles emitting hazardous chemicals. Backyard trash incinerators, which sprinkled black soot across the city, made the problem even worse. Knight appointed a committee to study ways the city could improve air quality and reduce pollution. It came up with several suggestions, which would later be called one of the foundations for today's pollution policies. They included reducing hydrocarbon emissions by "cutting vapor leaks from refineries and fueling operations," creating a standard for car exhaust, requiring trucks and busses to burn propane instead of diesel, banning trash burning and improving public transportation, among others. Today, the city's air is cleaner but it has yet to consistently achieve good results. The Environmental Protection Agency listed it as one of the most improved sites for ground-level ozone concentrations in an ozone report based on data from 2006 to 2008, but it was still among the worst sites in the country for exceeding the Environmental Protection Agency's ozone standard.