Sun protection by umbrellas and walls

Abstract

Solar protection is an important public health issue because solar UV exposure can cause acute and chronic damage to the skin. Seeking shade is a convenient and commonly practiced sun avoidance measure. Shade works by physically shielding the skin from direct UV rays; however UV rays can also reach the skin from other angles. It is not clear how protective the widely-used shade structures like umbrellas and walls are under actual use conditions. In this study, a sky view model was applied to systematically assess the influence of different factors to umbrellas and walls, including the transmission of the shade materials, the reflectivity of the ground or the wall, diffused UV to total UV irradiance ratios, shade geometry, a person's positions and orientations in the shade. We measured the sunburn protection factor (SPF) with a calibrated UV meter at different positions in the shades of an umbrella at different times of the day and compared the measurement results with the modeling. We found that shade structures like umbrellas and walls are more effective when the ratios of diffused UV to total UV irradiance are smaller (mid-day). The effectiveness increases with more coverage, less surface reflectance, and more centralized positions in the shade. The SPF value for a typical umbrella is probably between 3 and 7 in real-life. The low sun protection level offered by a typical shade highlights the importance of educating the public about how to properly protect the skin from the sun and the importance of applying a combination of sun protection measures during extended sun exposures.

Validation of SEPI in German—A German Translation of the Sun Exposure and Protection Index

“…In all skin cancers, exposure to ultraviolet radiation (UVR) is the main environmental risk factor and an initiator of carcinogenic mutations [ 5 , 6 , 7 , 8 ]. Thus, skin cancer is often referred to as highly preventable, as primary preventive measures can be directed at promoting accurate sun protection to individuals, or groups of individuals, with the highest risk due to phenotypic, environmental, and behavioural factors [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. In order to be able to do so, there is a need for valid and reliable tools to measure sun exposure habits and sun protection behaviour, both in order to identify individuals with a risky behaviour with regard to skin cancer, as well as to be able to communicate individually tailored sun protection advice [ 18 , 19 , 20 ].…”

Sunlight Exposure and Protection Behavior as Prevention of Skin Cancer in Nursing Students

“…This condition can be prevented by reducing sun exposure. Typical sun protection measures include limiting time in the sun during the middle of the day, wearing long sleeved-clothes that protect your skin, and hats, and looking for shades on objects or buildings as shades serve as a physical barrier between the sun and the surface of the skin from direct UV rays, and using sunscreen are the main methods for preventing the harmful effects on the skin from ultraviolet radiation, including photo-aging, skin cancer, and skin cancer symptoms [12,13].…”

“…UV light can be scattered by atmospheric particles or reflected from the ground. Taking a cover behind a wall or umbrella does not offer full protection, so it is still necessary to wear sunscreens or protective clothing when taking cover under the shadow of objects in longer outdoor activities [12]. Using sunscreens with a higher SPF has shown a stronger preventive effect.…”