title: The relationship between ambient ultraviolet radiation (UVR) and objectively measured personal UVR exposure dose is modified by season and latitude.
abstract: Despite the widespread use of ambient ultraviolet radiation (UVR) as a proxy measure of personal exposure to UVR, the relationship between the two is not well-defined. This paper examines the effects of season and latitude on the relationship between ambient UVR and personal UVR exposure. We used data from the AusD Study, a multi-centre cross-sectional study among Australian adults (18-75 years), where personal UVR exposure was objectively measured using polysulphone dosimeters. Data were analysed for 991 participants from 4 Australian cities of different latitude: Townsville (19.3°S), Brisbane (27.5°S), Canberra (35.3°S) and Hobart (42.8°S). Daily personal UVR exposure varied from 0.01 to 21 Standard Erythemal Doses (median = 1.1, IQR: 0.5-2.1), on average accounting for 5% of the total available ambient dose. There was an overall positive correlation between ambient UVR and personal UVR exposure (r = 0.23, p < 0.001). However, the correlations varied according to season and study location: from strong correlations in winter (r = 0.50) and at high latitudes (Hobart, r = 0.50; Canberra, r = 0.39), to null or even slightly negative correlations, in summer (r = 0.01) and at low latitudes (Townsville, r = -0.06; Brisbane, r = -0.16). Multiple regression models showed significant effect modification by season and location. Personal exposure fraction of total available ambient dose was highest in winter (7%) and amongst Hobart participants (7%) and lowest in summer (1%) and in Townsville (4%). These results suggest season and latitude modify the relationship between ambient UVR and personal UVR exposure. Ambient UVR may not be a good indicator for personal exposure dose under some circumstances.
authors.affiliation: AusSun Research Laboratory, School of Public Health and Social Work, Queensland University of Technology, Brisbane, Australia. j1.sun@qut.edu.au.
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.forename: R M
authors.initials: RM
authors.lastname: Lucas
authors.forename: S
authors.initials: S
authors.lastname: Harrison
authors.forename: I
authors.initials: I
authors.lastname: van der Mei
authors.forename: B K
authors.initials: BK
authors.lastname: Armstrong
authors.forename: M
authors.initials: M
authors.lastname: Nowak
authors.forename: A
authors.initials: A
authors.lastname: Brodie
authors.forename: M G
authors.initials: MG
authors.lastname: Kimlin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001315:Australia; D003430:Cross-Sectional Studies; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011834:Radiation Monitoring; D012044:Regression Analysis; D012621:Seasons; D013472:Sunlight; D014466:Ultraviolet Rays; D055815:Young Adult