Reducing exposure to ultraviolet radiation (UV) is crucial for preventing UV-induced diseases of the skin and eyes. Shade may offer significant protection from UV.

A research team from Klein Buendel and Cancer Council Victoria and LaTrobe University in Australia have published a paper on UV measurements under shade structure built in public parks in International Journal of Environmental Research and Public Health. The paper expands empirical research to quantify the UV protection offered from built shade to guide disease prevention practices and confidence in investment in shade.

Specifically, the research team quantified UV levels under built shade relative to unshaded passive recreation areas (PRAs) over summer months in parks in two cities (Denver, Colorado, USA and Melbourne, Victoria, Australia). In a randomized controlled trial, 1,144 UV measurements were recorded at the center and periphery of PRAs in a total sample of 144 public parks as part of pretest and posttest measures of use of the PRAs by park visitors. UV measurements were recorded for three recruitment waves per city during 2010 to 2014. Following pretest, 36 of the PRAs received built shade structures.

Regression analyses modelled pre-post change in UV (Standard Erythemal Dose (SED) per 30 min) at PRAs; and environmental predictors. Mean UV at the center of built shade PRAs decreased from pretest to posttest, adjusting for the covariates of ambient SED, solar elevation, and cloud cover. Clouds decreased and solar elevation increased UV levels under shade. No significant differences in UV by design of the shade structure occurred. A substantial reduction in UV exposure can be achieved using built shade with shade cloth designs, offering considerable protection for shade users. Supplementary sun protection  is recommended for extended periods of shade use during clear sky days. This could include things like brimmed hats, long sleeves, sunglasses, and sunscreen.

This research was supported by a grant from the National Cancer Institute (CA140367; Dr. David Buller, PI). Collaborators on this publication also include Dr. Suzanne Dobbinson and Dr. James Chamberlain from Cancer Council Victoria; Jody Simmons from LaTrobe University; and Mary Buller from Klein Buendel.