A new study found that air pollution in Joshua Tree and Sequoia and Kings Canyon National Parks rivals Los Angeles. Both parks are downwind of the most polluted air basins in the country: Los Angeles and the San Joaquin Valley. Pollution in the parks can mar scenic vistas and make it unhealthy to hike.

This story is part of Elemental: Covering Sustainability, a new multimedia collaboration between Cronkite News, Arizona PBS, KJZZ, KPCC, Rocky Mountain PBS and PBS SoCal.