Air Pollution: a Major Challenge for California
California has the United States’ most stringent air quality regulation. Yet cities and regions throughout the state struggle with high levels of air pollutants which the EPA recognizes as harmful- carbon monoxide, ozone, particulate matter, lead, nitrogen dioxide, and sulfur dioxide. Pictured: Smog over Los Angeles, the Coachella Valley, images from Bigstock.
Air pollution is a worldwide, and growing problem, as visible in the photos of Sao Paolo, Brazil and Wuhan, China. Recent World Health Organization studies have concluded that air pollutants, especially PM 2.5, are a major danger to global health.