Li Chung-Yi, Sung Fung-Chang, Chen Fu-Li, Lee Pei-Chen, Silva Michael, Mezei Gabor
Department of Public Health, College of Medicine, Fu-Jen Catholic University, 510 Chung-Cheng Road, Hsinchuang, Taipei Hsien 24205, Taiwan.
Sci Total Environ. 2007 Apr 15;376(1-3):151-9. doi: 10.1016/j.scitotenv.2007.01.058. Epub 2007 Feb 20.
Many epidemiological studies have investigated residential exposure to extremely-low-frequency magnetic field (ELF-MF) for children, but exposure at schools where children may stay up to 8 h every weekday was rarely considered. Between March and June 2004, we carried out a field study in Taipei City and County of northern Taiwan to explore ELF-MF exposure pattern among children at schools with high voltage transmission lines (HVTL) running through the campuses. One hundred and one children attending 14 schools with nearby HVTL (exposed group) and 123 children of 18 schools at least 100 m away from HVTL (unexposed group) were monitored for 24-hour personal ELF-MF exposure. Selected classrooms and playgrounds within the buffer regions (i.e., within 30 m of HVTL) and those away from the buffer regions were also assessed, using spot measurements, to determine the extent to which HVTL may contribute to the environmental exposure on campuses. Results show that the two groups didn't differ significantly for both mean exposure and proportion of exposure greater than 0.4 micro-Tesla (microT) estimated for 24 h. However, we noted that 17.8% of the exposed children had a personal mean exposure greater than 0.4 microT during school hours, significantly (p=0.011) higher than that (6.5%) estimated for the unexposed children. An even higher percentage (27.3%) was observed for 11 students with their classrooms intersecting the buffer regions. Playgrounds near buffer regions showed a significantly higher ELF-MF than the other areas of the exposed schools (0.70 vs 0.18 microT, p=0.043). The study demonstrates a wide range of exposures to ELF-MF among school children at campuses adjacent to HVTL. Children attending the exposed schools may have a higher chance of experiencing a mean exposure greater than 0.4 microT during school hours.
许多流行病学研究调查了儿童在家中暴露于极低频磁场（ELF-MF）的情况，但很少考虑儿童在学校的暴露情况，因为他们每个工作日可能在学校待长达8小时。2004年3月至6月，我们在台湾北部的台北市和台北县进行了一项实地研究，以探索校园内有高压输电线路（HVTL）穿过的学校中儿童的ELF-MF暴露模式。对14所附近有HVTL的学校的101名儿童（暴露组）和18所距离HVTL至少100米的学校的123名儿童（未暴露组）进行了24小时个人ELF-MF暴露监测。还使用现场测量对缓冲区（即HVTL 30米范围内）内和远离缓冲区的选定教室和操场进行了评估，以确定HVTL对校园环境暴露的影响程度。结果表明，两组在24小时的平均暴露量和暴露量大于0.4微特斯拉（μT）的比例方面没有显著差异。然而，我们注意到，17.8%的暴露儿童在上学时间的个人平均暴露量大于0.4μT，显著高于（p = 0.011）未暴露儿童的估计值（6.5%）。对于11名教室与缓冲区相交的学生，这一比例甚至更高（27.3%）。缓冲区附近的操场显示出的ELF-MF明显高于暴露学校的其他区域（0.70对0.18μT，p = 0.043）。该研究表明，毗邻HVTL的校园内的学童暴露于ELF-MF的范围很广。就读于暴露学校的儿童在上学时间平均暴露量大于0.4μT的可能性可能更高。
