兰州市小学生家庭室内空气甲苯浓度及其影响因素
Indoor air toluene exposure and its influencing factors in family houses of primary school students in Lanzhou
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摘要:
背景 室内环境安全关系着人群健康。近年来室内苯系物的污染逐渐严重，甲苯作为常见的室内污染苯系物，对人体危害较大。但是，关于室内甲苯浓度的影响因素研究较少。
目的 探讨兰州市住宅内甲苯污染状况及其影响因素。
方法 选取两个兰州市的环境监测站点，以距离这两个站点最近的两所小学作为被调查小学，两所小学中共60户学生家庭作为被调查家庭，在2018年8-11月（非采暖季）对其进行室内环境问卷调查，并于2018年8-11月（非采暖季，
n =60）与2019年1-3月（采暖季，n =57）对其居室内苯、甲苯以及二甲苯（合称三苯）浓度进行测定。利用配对t 检验比较采暖季和非采暖季室内三苯浓度的差异，对不同居室特征下采暖季和非采暖季室内甲苯浓度的差异分别进行单因素分析，利用多重线性回归对室内污染物甲苯的影响因素进行多因素分析。结果 非采暖季：苯、甲苯、二甲苯平均质量浓度（后简称浓度）分别为0.009、0.009、0.003 mg·m-3，三苯浓度均未超标。采暖季：甲苯平均浓度为0.283 mg·m-3，苯和二甲苯平均浓度分别为0.008、0.001 mg·m-3；有2户住宅甲苯浓度超标，超标率为3.5%，苯和二甲苯均未超标。配对
t 检验结果显示采暖季和非采暖季室内甲苯和二甲苯浓度之间的差异均有统计学意义（t =5.283，P =0.023；t =12.700，P =0.001），室内苯浓度差异无统计学意义（t =0.213，P >0.05）。单因素分析结果显示，在采暖季，房屋所在楼层≤ 7、房屋近五年内无装修、房屋出现发霉的居室室内甲苯浓度高于房屋楼层>7、有装修、无发霉者（P < 0.05）；但房屋累计使用时间、房屋与机动车道的距离、室内是否有地毯、室内是否使用空调、开窗通风频率、平均每周在家做饭次数不同与室内甲苯浓度的关系均无统计学意义（P >0.05）。多重线性回归分析结果显示房屋出现发霉现象与采暖季室内甲苯浓度呈正相关关系（b =2.968，P =0.003）；其他变量与室内甲苯浓度的关系均没有统计学意义（P >0.05）；在非采暖季，单因素和多因素分析结果显示，以上各变量与室内甲苯浓度的关系均无统计学意义（P >0.05）。结论 兰州市住宅内苯系物污染较轻，室内甲苯浓度升高与房屋发霉相关。
Abstract:Background Indoor environment safety is related to people's health. In recent years, indoor pollution of benzenes has been increasingly serious. Toluene, a common indoor benzenes pollutant, is very harmful to human health. However, there are few studies on the influencing factors of indoor toluene concentration.
Objective This study investigates toluene contamination in residences in Lanzhou City and its influencing factors.
Methods Two primary schools nearest to the two environmental monitoring stations in Lanzhou were selected as study sites, and 60 students from the two schools were selected as study subjects and completed a questionnaire on indoor environment from August to November 2018 (non-heating season). The indoor benzene, toluene, and xylene concentrations in their residences were measured from August to November 2018 (non-heating season) and from January to March 2019 (heating season). Paired
t -test was employed to compare the differences in indoor benzene, toluene, and xylene concentrations between heating and non-heating periods, single factor analysis for the differences in indoor toluene concentrations under different room characteristics between heating and non-heating periods, and multiple linear regression analysis for potential influencing factors of indoor toluene.Results The mean concentrations of benzene, toluene, and xylene in non-heating period were 0.009, 0.009, and 0.003 mg·m-3, respectively, and all were qualified according to the national indoor air quality limits. The mean concentrations of these chemicals in heating period were 0.008, 0.283, and 0.001 mg·m-3, respectively; the indoor toluene concentration of two residences exceeded relevant national limit, and the unqualified rate was 3.5%; benzene and xylene were both qualified. The paired
t -test results showed significant differences in indoor toluene and xylene concentrations between heating and non-heating seasons (t =5.283,P =0.023;t =12.700,P =0.001), except indoor benzene (t =0.213,P >0.05). The results of single factor analysis showed that the indoor toluene concentrations in heating period were higher in residences on floor ≤ 7, renovated in recent five years, and with indoor molds than those on floor >7, not renovated, and without molds (P < 0.05), but not different among those categorized by cumulative time of residence in use, residence proximity to driveway, indoor carpet, air conditioning, frequency of opening windows, and frequency of home cooking per week (P >0.05). The results of multiple linear analysis showed a positive correlation between indoor molds and indoor toluene concentration in heating season (b =2.968,P =0.003); the relationships between other variables and indoor toluene concentration were not significant (P >0.05). In non-heating season, both single factor and multiple linear analyses revealed no relationships between the above indicators and indoor toluene concentration (P >0.05).Conclusion Slight residential benzenes pollution in Lanzhou is found in the study, and the increase of indoor toluene concentration is related to a moldy house.
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