title: The enhancement of biological ocular UV radiation on beaches compared to the radiation on grass.
abstract: BACKGROUND
  The influence of albedo on ocular UV exposure has seldom been reported. This paper aimed to explore the enhancement effect on measured ocular UV radiation due to a sand surface compared to measured ocular UV radiation due to a grass surface.
  
  
  METHODS
  We measured ambient and ocular UV radiation over the beach and grass surface in Sanya City of China (18.4°N, 109.7°E). The experimental apparatus was composed of a manikin and a dual-detector spectrometer. Integration of both UVA and UVB radiation was used to denote UV radiation. Then biologically effective ocular UVB radiation (UVBE) and the ratios of UVBE of two surfaces were calculated.
  
  
  RESULTS
  Maximum of ocular UV radiation versus time over the two surfaces is bimodal. UVBE on the beach is significantly larger than UVBE on the sand, and UVBE peaked at different solar elevation angle (SEA) over the two surfaces (about 53° and 40° on the beach and grass, respectively, according to Bayesian regression). The maximum of ocular UVBE ratios is greater than two, which peaked SEA was about 50°. One hour's cumulative radiation under sunny weather exceeds thresholds for photokeratitis, conjunctivitis and lens damage.
  
  
  CONCLUSIONS
  Higher albedo significantly increased biological ocular UV radiation. Tourists on tropical beaches should take protective measures and avoid facing the sun directly, especially when SEA is around 50°.
authors.affiliation: School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China.
authors.forename: Guang-Cong
authors.initials: GC
authors.lastname: Liu
authors.affiliation: School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.affiliation: School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China.
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Gao
authors.affiliation: School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Yang
authors.affiliation: School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China.
authors.forename: Li-Wen
authors.initials: LW
authors.lastname: Hu
authors.affiliation: School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Gao
authors.affiliation: School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China.
authors.forename: Jun-Chol
authors.initials: JC
authors.lastname: Ri
authors.affiliation: School of Public Health, China Medical University, No. 92 Bei'er Road, Heping District, Shenyang 110001, Liaoning, PR China. Electronic address: cmu_liuyang@163.com.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
mesh_terms: D001493:Bathing Beaches; D005123:Eye / Q000528:radiation effects*; D006801:Humans; D008348:Manikins; D006109:Poaceae / Q000737:chemistry; D013053:Spectrophotometry; D013997:Time Factors; D014466:Ultraviolet Rays