Kourtney Kardashian has received backlash after sharing a post on social media that claims wearing disposable face masks could lead to cancer and suffocation, among other things.The oldest Kardashian sister posted the claims on Instagram Stories and though she referenced the American Cancer Society, they were unfounded.In the post, she wrote, "Those blue masks mandated at grocery stores & airplanes are made of PTFE, a carcinogen made from synthetic fluoride."According to Cancer.org it increases