Asked by: Vincent Bradley, Canterbury
Ordinary glass absorbs 97 per cent of the UVB rays that cause sunburn and some skin cancers, and 37 per cent of the less harmful UVA radiation. This translates to a protection of about SPF30, so you can still get burned with long enough exposure. Car windscreens have a plastic layer bonded between two layers of glass and this blocks all the UVB and 80 per cent of the UVA, making sunburn very unlikely.
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