The role of glass as a barrier against the transmission of ultraviolet radiation: an experimental study.
OBJECTIVE
Excessive exposure of the skin to sunlight may cause many symptoms and skin cancer. The aim was to measure the transmission of ultraviolet (UV) A and UVB radiation through glasses of different types, according to the distance from the light source.


METHODS
The baseline radiation from UVA and UVB sources was measured at different distances from the photometers. Next, the radiation from the same sources was measured at the same distances, but transmitted by different types of glass. The baseline values were compared with the results after protection using glass.


RESULTS
Laminated glass totally blocked UVA radiation, while smooth ordinary glass transmitted the highest dose (74.3%). Greater thicknesses of glass implied less radiation transmitted, but without a significant difference. Green glass totally blocked UVA radiation, while blue glass transmitted the highest dose of radiation (56.8%). The presence of a sunlight control film totally blocked UVA radiation. All glasses totally blocked UVB radiation.


CONCLUSIONS
The main characteristics of glass that make it a photoprotective agent are its type (especially laminated glass) and color (especially green), which give rise to good performance by this material as a barrier against the transmission of radiation.
Duarte
Ida
I
Clinic of Dermatology, Santa Casa de Misericórdia de São Paulo, São Paulo, Brazil. idaduarte@terra.com.br
Rotter
Anita
A
Malvestiti
Andrey
A
Silva
Mariana
M
D005898:Glass; D008422:Materials Testing; D014466:Ultraviolet Rays