title: Survey of residential extremely-low-frequency magnetic field exposure among children in Taiwan.
abstract: This survey estimated the extremely-low-frequency magnetic field (ELF-MF) exposure in households with children under the age of 7 years in Taiwan. To select a representative sample, we used the probability proportional to size sampling technique and simple random cluster sampling technique to select study districts in each city/county of Taiwan. A total of 40 districts were selected and all households with children aged less than 7 (n=4184) were visited and solicited for in-home measurements. Four trained interviewers carried out spot-measurements in rooms of each selected household during a two-year period. A questionnaire inquiring residential characteristics and nearby power facilities was also administered to a parent or caregiver. ELF-MF measurements were performed in a total of 2214 households (53% participation rate). Controlling for participation rate, the weighted overall mean magnetic field exposure was estimated at 0.121 (standard deviation 0.185) micro-Tesla (microT) (range 0.010-3.304 microT). Mean exposures were higher than 0.3 and 0.4 microT in an estimated 7.3% (n=159) and 5.4% (n=115) of the households, respectively. There was a substantial agreement between overall mean residential exposure and exposure measured in children's bedrooms. In a multivariate logistic regression model, we noted that buildings with advanced age, buildings for both residential and commercial uses, and buildings close to power facilities were more likely a to have mean exposure above 0.4 microT. Our survey results indicate that residential ELF-MF exposure is likely to be higher for children in Taiwan than for children in Europe and North America.
authors.affiliation: Department of Public Health, College of Medicine, Fu-Jen Catholic University, 510, Chung Cheng Rd., Hsinchuang 24205, Taipei Hsien, Taiwan. chungyi@mails.fju.edu.tw
authors.forename: Chung-Yi
authors.initials: CY
authors.lastname: Li
authors.forename: Gabor
authors.initials: G
authors.lastname: Mezei
authors.forename: Fung-Chang
authors.initials: FC
authors.lastname: Sung
authors.forename: Michael
authors.initials: M
authors.lastname: Silva
authors.forename: Pei-Chun
authors.initials: PC
authors.lastname: Chen
authors.forename: Pei-Chen
authors.initials: PC
authors.lastname: Lee
authors.forename: Li-Mei
authors.initials: LM
authors.lastname: Chen
mesh_terms: D002648:Child; D002675:Child, Preschool; D003625:Data Collection; D004781:Environmental Exposure; D006801:Humans; D008280:Magnetics; D012111:Residence Characteristics; D013624:Taiwan