Most plastics are transparent to UVA, which is like 90% of UV that reaches earth's surface. They only start absorbing at higher UV frequencies. That's why sungl

Most plastics are transparent to UVA, which is like 90% of UV that reaches earth's surface. They only start absorbing at higher UV frequencies. That's why sunglasses have dedicated UV ratings. You can bring your sunglasses to basically any optometrist and test how well they block UV. It takes 20 seconds and they'll probably do it for free.