The U.S. Environmental Protection Agency is preparing to reject California's plan to curb air pollution in Los Angeles ... the region's smog remains the worst in the country.

The Los Angeles-Long Beach area is the country’s worst city for ozone pollution, or smog. A combination of factors, including heavy traffic, industry and wildfires have contributed to high ...

It would take years for scientists to piece together the puzzle of this Los Angeles smog and decades to implement policies to improve the air we all breathe. Today, scientists are able to monitor the ...

In a controversial new study, scientists are claiming that trees in Los Angeles are contributing to the city's air pollution ... measured as the cause of the worst emissions even in places ...

Environmental and public-health groups filed a lawsuit today against the Environmental Protection Agency for failing to ensure that Los Angeles, Sacramento and New Hampshire have effective plans to ...

Los Angeles — infamous for its smog, which is mainly composed of ozone — ranked as the worst city for ozone pollution in the ...