International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, QLD 4001, Australia.
Sci Total Environ. 2013 Aug 1;458-460:81-9. doi: 10.1016/j.scitotenv.2013.04.007. Epub 2013 May 1.
Long-term exposure to vehicle emissions has been associated with detrimental health effects. Children are amongst the most susceptible group and schools represent an environment where they can experience significant exposure to vehicle emissions. However, there are limited studies on children's exposure to vehicle emissions in schools. The aim of this study was to quantify the concentration of organic aerosol (OA) and in particular, vehicle emissions that children are exposed to during school hours. Therefore an Aerodyne compact time-of-flight aerosol mass spectrometer (TOF-AMS) was deployed at five urban schools in Brisbane, Australia. TOF-AMS enabled the chemical composition of the non-refractory (NR-PM1) to be analysed with a high temporal resolution to assess the concentration of vehicle emissions and other OA components during school hours. The organic fraction at each school comprised the majority of NR-PM1. Primary emissions were found to dominate the OA at only one school which had an O:C ratio of 0.17, due to fuel powered gardening equipment used near the TOF-AMS. A significant source of the OA at two of the schools was aged vehicle emissions from nearby highways. More oxidised OA was observed at the remaining two schools, which also recorded strong biomass burning influences. In general, the diurnal cycle of the total OA concentration varied between schools and was found to be at a minimum during school hours. The major organic component that school children were exposed to during school hours was secondary OA at all schools. Peak exposure of school children to vehicle emissions occurred during school drop-off and pick-up times. Unless a school is located near major roads, children are exposed predominately to regional secondary OA as opposed to local emissions during school hours in urban environments.
长期暴露于车辆排放物与有害健康影响有关。儿童是最易受影响的群体之一，学校是他们在环境中可能会大量接触车辆排放物的地方。然而，关于儿童在学校接触车辆排放物的研究有限。本研究的目的是量化儿童在学校上课时接触的有机气溶胶（OA）浓度，特别是车辆排放物浓度。因此，在澳大利亚布里斯班的五所城市学校部署了 Aerodyne 紧凑型飞行时间气溶胶质谱仪（TOF-AMS）。TOF-AMS 能够以高时间分辨率分析不可挥发性（NR-PM1）的化学成分，以评估上课时车辆排放物和其他 OA 成分的浓度。每所学校的有机部分都构成了 NR-PM1 的主要部分。只有一所学校的 OA 主要由初级排放物组成，其 O:C 比为 0.17，这是由于靠近 TOF-AMS 使用的燃油动力园艺设备造成的。两所学校的 OA 主要来源是附近高速公路的老化车辆排放物。其余两所学校观察到更多氧化的 OA，同时也记录到强烈的生物质燃烧影响。一般来说，总 OA 浓度的日变化在学校之间有所不同，并且在上课时达到最低。在上课时，学童接触到的主要有机成分是所有学校的二次 OA。学童接触车辆排放物的峰值出现在上学和放学时间。除非学校位于主要道路附近，否则在城市环境中，儿童在上课时主要接触的是区域二次 OA，而不是当地排放物。
