Exposure to Non-Extreme Solar UV Daylight: Spectral Characterization, Effects on Skin and Photoprotection

Abstract

The link between chronic sun exposure of human skin and harmful clinical consequences such as photo-aging and skin cancers is now indisputable. These effects are mostly due to ultraviolet (UV) rays (UVA, 320–400 nm and UVB, 280–320 nm). The UVA/UVB ratio can vary with latitude, season, hour, meteorology and ozone layer, leading to different exposure conditions. Zenithal sun exposure (for example on a beach around noon under a clear sky) can rapidly induce visible and well-characterized clinical consequences such as sunburn, predominantly induced by UVB. However, a limited part of the global population is exposed daily to such intense irradiance and until recently little attention has been paid to solar exposure that does not induce any short term clinical impact. This paper will review different studies on non-extreme daily UV exposures with: (1) the characterization and the definition of the standard UV daylight and its simulation in the laboratory; (2) description of the biological and clinical effects of such UV exposure in an in vitro reconstructed human skin model and in human skin in vivo, emphasizing the contribution of UVA rays and (3) analysis of photoprotection approaches dedicated to prevent the harmful impact of such UV exposure.

Infrared and skin: Friend or foe

“…In order to experimentally assess the effects of solar UV, standard UV spectra have been defined, particularly in the sunscreen industry. These emission spectra represent extreme solar UV exposure conditions with a quasi zenithal sun irradiance, representative of a high UVB level [54]. However, the solar spectrum reaching Earth depends on many parameters including latitude, season, meteorological conditions, ozone layer thickness, and particularly on time of day.…”

Relationship between cumulative ultraviolet exposure and cognitive function in a rural elderly Chinese population

“…25,26 Therefore, in the present study, skin aging was applied as an indicator of cumulative UV exposure, and it was further used to explore the relationship between UV exposure and cognitive function. 25,26 Therefore, in the present study, skin aging was applied as an indicator of cumulative UV exposure, and it was further used to explore the relationship between UV exposure and cognitive function.…”

A Combination of Soybean and Haematococcus Extract Alleviates Ultraviolet B-Induced Photoaging

“…These UVB doses represent reasonable exposure to the sun for approximately two hours in mid-April in New York City [46]. …”