Air Pollution Kills Millions Each Year. Here’s How Cities Can Fight It.

Los Angeles is the poster child for a city that has worked hard to dramatically reduce its air pollution levels. Over the past 50 years, most pollution levels are down more than 75 percent compared to their highs, and that’s despite massive population and economic growth, according to Paulson.

‘No other city comes close,’ she said.

Los Angeles saw tremendous economic development over the past century. But as more people moved in, the city’s blanket of smog grew thicker and thicker. The main culprits were, and still are, vehicle emissions, fumes from industrial plants and the city’s proximity to two of the country’s largest ports.