Pollution is a significant problem at 401 national parks, report says

More than 96% of national parks assessed in a recent report are “plagued by significant air pollution problems,” and some of California’s most iconic parks are among the most troubled, according to one of the nation’s largest nonprofit conservation associations.

The National Parks Conservation Association said in its May “Polluted Parks” report that 401 of 417 national parks that were looked at suffered from air pollution-related problems in at least one of four areas: climate change, damage to nature, visibility and air that is unhealthy to breathe.

That report noted that in 2018, four California parks — Sequoia, Kings Canyon and Joshua Tree national parks, and Mojave National Preserve — measured “unhealthy” air conditions for visitors and park rangers more than two months out of the year. The worst days are usually in the summer.

“Much of the air pollution in these parks comes from vehicles and the agriculture industry in the San Joaquin Valley — one of the most polluted areas in the nation — where residents are frequently exposed to unsafe air,” the report reads.

Unhealthy air was measured in NPCA’s report in terms of high ozone levels. Air pollution at those four California parks is at times worse than that found in cities like Los Angeles and Houston, the report claims.

Sequoia and Kings Canyon got an F grade in healthy air in a 2015 pollution report by NPCA, which ranked them tied for the No. 1 most air-polluted national park.

The report claims that temperatures at national parks are rising at double the rate of the U.S. as a whole, “threatening the very existence of namesake features at Glacier, Joshua Tree and Saguaro National Parks.”

Climate change, the report says, is “intensifying flooding, drought and wildfires.” All...