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Diffuse component of solar ultraviolet radiation in tree shade
A V Parisi1, M G Kimlin, J C Wong
1Centre for Astronomy and Atmospheric Research, University of Southern Queensland, Toowoomba, Australia. parisi@usq.edu.au
Summary
Tree shade significantly contributes to UV exposure, with diffuse radiation comprising over 50% of erythemal UV and UV-A. This highlights potential risks even in shaded areas, emphasizing the need for sun protection.
Area of Science:
- Environmental Science
- Dermatology
- Physics
Background:
- UV radiation poses health risks, necessitating accurate exposure assessments.
- Understanding diffuse UV radiation in shaded environments is crucial for public health.
- Previous data on diffuse UV in shaded, sub-tropical Southern Hemisphere locations is limited.
Purpose of the Study:
- To quantify diffuse erythemal UV and UV-A radiation in tree shade.
- To compare diffuse UV percentages in tree shade versus full sun.
- To assess potential UV exposure risks in shaded environments.
Main Methods:
- Quantitative measurement of erythemal UV and UV-A radiation.
- Data collection in tree shade and full sun conditions.
- Measurements taken at a sub-tropical Southern Hemisphere latitude over summer.
Main Results:
- Diffuse radiation constitutes ~60% of erythemal UV and ~56% of UV-A in tree shade.
- Diffuse UV percentages in tree shade remained constant from morning to afternoon.
- Full sun showed a decrease in diffuse UV percentage from morning to afternoon.
- Exposure in tree shade (9:00-15:00 EST) reached ~4 MED for erythemal UV and ~14 J cm(-2) for UV-A.
Conclusions:
- Tree shade has a high diffuse UV component, contributing significantly to total UV exposure.
- High diffuse UV in shade poses risks to unprotected skin and eyes.
- Further research is needed to understand the full implications of diffuse UV in shaded environments.