Shendell Derek G, Winer Arthur M, Stock Thomas H, Zhang Lin, Zhang Junfeng Jim, Maberti Silvia, Colome Steven D
Environmental Sciences and Engineering Program, UCLA School of Public Health, 650 Charles E. Young Drive South, Los Angeles, CA 90095-1772, USA.
J Expo Anal Environ Epidemiol. 2004 Jan;14(1):44-59. doi: 10.1038/sj.jea.7500297.
Recent state and federal public school class-size reduction initiatives, increased elementary and pre-K enrollment driven by population growth and immigration, and limited resources for capital projects, modernization, and maintenance at aging schools have increased the prevalence of prefabricated, portable classrooms (portables). At present, approximately one of three California students are taught in portables, whose use is especially prevalent in more populated counties such as Los Angeles, home to the nation's second largest school district. Limited data existed on chemical compound air concentrations, and thus exposures, inside American public schools. Measurements have been limited, usually performed in complaint schools, and varied in sampling protocols and analysis methods. To address a school environment and children's health issue of present concern, an assessment of public school portables was conducted in Los Angeles County. Seven schools in two school districts were recruited, from which 20 classrooms--13 portables, seven in main buildings--were randomly selected. We report indoor air concentrations of 21 target toxic and odorous volatile organic compounds (VOCs), including formaldehyde and acetaldehyde, measured with passive samplers (DNSH PAKS and 3M OVM 3500) in the cooling and heating seasons between June 2000 and June 2001. None of the measured indoor air formaldehyde concentrations exceeded the existing California Air Resources Board guideline (50 ppb, or 60 microg/m(3)). The main sources of aldehydes in classrooms, especially portables, were likely interior finish materials and furnishings made of particleboard without lamination. Indoor air VOC concentrations were generally low in this pilot study. The four most prevalent VOCs measured were toluene, m-/p-xylene, alpha-pinene, and delta-limonene; likely indoor sources were personal, teaching, and cleaning products. Future schools research should attempt larger samples over larger geographical areas.
近期，州和联邦层面发起了公立学校班级规模缩减倡议，人口增长和移民导致小学及学前教育入学人数增加，同时老旧学校在基本建设、现代化改造及维护方面资源有限，这些因素使得预制式移动教室（移动房）的使用更为普遍。目前，加利福尼亚州约三分之一的学生在移动房中上课，在人口较多的县，如拥有美国第二大校区的洛杉矶，移动房的使用尤为普遍。关于美国公立学校内化学化合物的空气浓度及相应暴露情况的数据有限。相关测量一直较为有限，通常是在有投诉的学校进行，且采样方案和分析方法各不相同。为解决当前备受关注的学校环境与儿童健康问题，在洛杉矶县对公立学校的移动房进行了评估。从两个学区招募了七所学校，从中随机选取了20间教室——13间移动房和7间主楼内的教室。我们报告了2000年6月至2001年6月制冷和制热季节期间，使用被动采样器（DNSH PAKS和3M OVM 3500）测量的21种目标有毒和有气味的挥发性有机化合物（VOCs）的室内空气浓度，包括甲醛和乙醛。所测室内空气中的甲醛浓度均未超过加利福尼亚州空气资源委员会现行标准（50 ppb，或60微克/立方米）。教室尤其是移动房内醛类的主要来源可能是未经覆膜处理的刨花板制成的室内装修材料和家具。在这项初步研究中，室内空气中VOC的浓度普遍较低。所测最常见的四种VOCs是甲苯、间/对二甲苯、α-蒎烯和δ-柠檬烯；可能的室内来源是个人用品、教学用品和清洁用品。未来关于学校的研究应尝试在更大的地理区域进行更大规模的采样。
