Objective To show the distribution of facial exposure to non-melanoma biologically effective UV irradiance changes by rotation angles.Methods This study selected the cheek,nose,and forehead as representative facial sites for UV irradiance measurements,which were performed using a rotating manikin and a spectroradiometer.The measured UV irradiance was weighted using action spectra to calculate the biologically effective UV irradiances that cause non-melanoma(UVBE_(non-mel))skin cancer.The biologically effective UV radiant exposure(HBE_(non-mel))was calculated by summing the UVBE_(non-mel) data collected over the exposure period.Results This study revealed the following:(1)the maximum cheek,nose and forehead exposure UVA and UVB irradiance times and solar elevation angles(SEA)differed from those of the ambient UV irradiance and were influenced by the rotation angles;(2)the UV irradiance exposure increased in the following order:cheek展开▼