SCIE 1P51 Lecture Notes - Lecture 6: Titanium Dioxide, Zinc Oxide, Ozone Layer
18 May 2017
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Document Summary
Ozone layer protects from the uv radiation but because the layer is depleating, more and more radiation is entering the earth and causes more damage. Active ingredients physical agents zinc oxide: protects body from 250-400nm titanium dioxide, protects from 260 360. Skin type 1 always burns easily: never tans. Skin type 2 always burns easily: tans minimally. Skin type 6 never burns: deeply pigmented. Water/sweat/perspiration resistant: manages to stay on for 20 minutes, but are never water proof. It stays on for up to 40 minutes. Spf numbered rating (sun protection factor: uvb/a. Testing protocols: the test on hairless mice, expose them to uv radiation, they use a solar simulator. Testing protocols: they recruit human subjects with skin type 1 and 2. 81% expect products to prevent cancer: cancer related problems is due to improper use of the product. 19 mins of unprotected sin exposure to uva and uvb can induce skin cell cancer due to dna damage.
