International Laboratory for Air Quality and Health, Queensland University of Technology, 2 George Street, Brisbane, Q 4001, Australia.
Environ Sci Pollut Res Int. 2010 Jul;17(6):1268-78. doi: 10.1007/s11356-010-0306-2. Epub 2010 Mar 1.
BACKGROUND, AIM AND SCOPE: The impact of air pollution on school children's health is currently one of the key foci of international and national agencies. Of particular concern are ultrafine particles which are emitted in large quantities, contain large concentrations of toxins and are deposited deeply in the respiratory tract.
In this study, an intensive sampling campaign of indoor and outdoor airborne particulate matter was carried out in a primary school in February 2006 to investigate indoor and outdoor particle number (PN) and mass concentrations (PM(2.5)), and particle size distribution, and to evaluate the influence of outdoor air pollution on the indoor air.
For outdoor PN and PM(2.5), early morning and late afternoon peaks were observed on weekdays, which are consistent with traffic rush hours, indicating the predominant effect of vehicular emissions. However, the temporal variations of outdoor PM(2.5) and PN concentrations occasionally showed extremely high peaks, mainly due to human activities such as cigarette smoking and the operation of mower near the sampling site. The indoor PM(2.5) level was mainly affected by the outdoor PM(2.5) (r = 0.68, p < 0.01), whereas the indoor PN concentration had some association with outdoor PN values (r = 0.66, p < 0.01) even though the indoor PN concentration was occasionally influenced by indoor sources, such as cooking, cleaning and floor polishing activities. Correlation analysis indicated that the outdoor PM(2.5) was inversely correlated with the indoor to outdoor PM(2.5) ratio (I/O ratio; r = -0.49, p < 0.01), while the indoor PN had a weak correlation with the I/O ratio for PN (r = 0.34, p < 0.01).
The results showed that occupancy did not cause any major changes to the modal structure of particle number and size distribution, even though the I/O ratio was different for different size classes. The I/O curves had a maximum value for particles with diameters of 100-400 nm under both occupied and unoccupied scenarios, whereas no significant difference in I/O ratio for PM(2.5) was observed between occupied and unoccupied conditions. Inspection of the size-resolved I/O ratios in the preschool centre and the classroom suggested that the I/O ratio in the preschool centre was the highest for accumulation mode particles at 600 nm after school hours, whereas the average I/O ratios of both nucleation mode and accumulation mode particles in the classroom were much lower than those of Aitken mode particles.
The findings obtained in this study are useful for epidemiological studies to estimate the total personal exposure of children, and to develop appropriate control strategies for minimising the adverse health effects on school children.
背景、目的和范围：目前，空气污染对学童健康的影响是国际和国家机构的主要关注点之一。特别令人关注的是超细颗粒，它们大量排放，含有大量毒素，并深深地沉积在呼吸道中。
本研究于 2006 年 2 月在一所小学进行了室内和室外空气传播颗粒物的密集采样活动，以调查室内和室外颗粒数（PN）和质量浓度（PM2.5）以及颗粒大小分布，并评估室外空气污染对室内空气的影响。
对于室外 PN 和 PM2.5，在工作日观察到早高峰和晚高峰，这与交通高峰时间一致，表明车辆排放的主要影响。然而，室外 PM2.5和 PN 浓度的时间变化偶尔会出现极高的峰值，主要是由于在采样点附近吸烟和操作割草机等人类活动。室内 PM2.5水平主要受室外 PM2.5的影响（r = 0.68，p < 0.01），而室内 PN 浓度与室外 PN 值有些关联（r = 0.66，p < 0.01），尽管室内 PN 浓度偶尔会受到室内来源的影响，如烹饪、清洁和地板抛光活动。相关分析表明，室外 PM2.5与室内外 PM2.5比值（I/O 比值）呈负相关（r = -0.49，p < 0.01），而室内 PN 与 PN 的 I/O 比值呈弱相关（r = 0.34，p < 0.01）。
结果表明，即使对于不同的粒径范围，占用情况也不会导致颗粒数和粒径分布的模态结构发生重大变化。在占用和未占用情况下，粒径为 100-400nm 的颗粒的 I/O 曲线均具有最大值。在占用和未占用条件下，PM2.5的 I/O 比值没有明显差异。对学龄前中心和教室的粒径分辨 I/O 比值的检查表明，放学后，学龄前中心的 600nm 处积聚模态颗粒的 I/O 比值最高，而教室中核模态和积聚模态颗粒的平均 I/O 比值均远低于爱根模态颗粒。
本研究结果有助于开展流行病学研究，以估计儿童的个人总暴露量，并制定适当的控制策略，以尽量减少对学童的健康的不良影响。
