National parks have been called “America’s best idea.” But a recent study says these parks are increasingly threatened by human-caused air pollution. The parks with the biggest risk are all here in California. Reporter: Joshua Yeager, KVPR Shuttered Madera Community Hospital has cleared yet another hurdle in the path to reopening. It’s been approved for a $57 million interest-free loan. Reporter: Kerry Klein, KVPR A community in Red Bluff was recently notified that their water had high concentrations of chemicals called PFAS. Data shows that the site has had high levels of contamination for several years. Reporter: Justin Higginbottom, Jefferson Public Radio Learn more about your ad choices. Visit megaphone.fm/adchoices