Environment

CNN -  Nearly 40% of people in the US live with unhealthy air pollution, according to a new report from the American Lung Association. That amounts to 131 million people living with levels of polluted air that can significantly affect their health — up from 119 million in last year's data. Extreme heat, drought and wildfires are among the factors that have contributed to the increase, especially in the Western part of the country. Several cities in the region, including Los Angeles, Phoenix and Denver also received "F" grades for ozone smog, according to the report. Ozone pollution is formed from emissions from cars, power plants and refineries.