Uva penetration through windows
11 Jul Nevertheless, it's smart to stay in the shade when the sun's rays are high; just make sure you're also slathered with sunscreen. Myth #3: Sun can't penetrate through windows.
Reality: Glass filters out only one kind of radiation -- UVB rays. But UVA rays, which penetrate deeper, can still get through.
Does solar UV penetrate window glass?
Description:The role of glass as a barrier against the transmission of ultraviolet radiation: So you can enjoy the upsides and warmth of direct sunlight, without the dangerous downsides of UV light. In summary, typical window glass such as that found in homes will block most of the UV light from entering your house with the exception of UV-A light. If you are going to be behind the wheel for extended periods of time, consider applying sunscreen.