We want to be able to get natural light and air into the house. I can make a safe room if I need to, but this is an always-on threat and we can't respond with whole house unhealthy environments. Grounded metal (copper or aluminum) screens should work quite well if designed for the application I would think. But that means 100% screening, no fully transparent openings. Maybe we can come up with fluid filled windows that provide the required shielding. What a PITA.