International Laboratory for Air Quality and Health, Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia; NHMRC Centre for Air Pollution, Energy and Health Research (CAR), Sydney, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, Australia.
Department of Occupational and Environmental Health, School of Public Health, Sun Yat-Sen University, Guangzhou, China.
Environ Int. 2019 Nov;132:105134. doi: 10.1016/j.envint.2019.105134. Epub 2019 Aug 31.
There is a significant lack of scientific knowledge on population exposure to ultrafine particles (UFP) in China to date. This paper quantifies and characterises school children's personal UFP exposure and exposure intensity against their indoor and outdoor activities during a school day (home, school and commuting) in the city of Heshan within the Pearl River Delta (PRD) region, southern China.
Time-series of UFP number concentrations and average size were measured over 24 h for 24 children (9-13 years old), using personal monitors over two weeks in April 2016. Time-activity diaries and a questionnaire on the general home environment and potential sources of particles at home were also collected for each participating child. The analysis included concurrently measured size distributions of ambient UFP at a nearby fixed reference site (Heshan Supersite).
Hourly average UFP concentrations exhibited three peaks in the morning, midday and evening. Time spent indoors at home was found to have the highest average exposure (1.26 × 10 cm during sleeping) and exposure intensity (2.41). While there is always infiltration of outdoor particles indoors (from nearby traffic and general urban background sources), indoor exposure at home was significantly higher than outdoor exposure. Based on the collected questionnaire data, this was considered to be driven predominantly by adults smoking and the use of mosquito repellent incense during the night. Outdoor activities at school were associated with the lowest average exposure (6.87 × 10 cm) and exposure intensity (0.52).
Despite the small sample size, this study characterised, for the first time, children's personal UFP exposure in a city downwind of major pollution sources of the PRD region in China. Particularly, the results highlighted the impact of smoking at home on children's exposure. While the study could not apportion the specific contributions of second hand-smoking and mosquito coil burning, considering the prevalence of smokers among the parents who smoke at home, smoking is a very significant factor. Exposure to second-hand smoke is avoidable, and these findings point out to the crucial role of government authorities and public health educators in engaging with the community on the role of air quality on health, and the severity of the impact of second-hand smoke on children's health.
目前，中国在人群暴露于超细颗粒（UFP）方面的科学知识还很匮乏。本文量化并描述了珠江三角洲（PRD）地区鹤山市在校儿童在上学日（家、学校和通勤）期间的个人 UFP 暴露情况和暴露强度，包括室内和室外活动。
2016 年 4 月，使用个人监测仪在两周内对 24 名（9-13 岁）儿童进行了 24 小时的 UFP 数浓度和平均粒径时间序列测量。还为每位参与儿童收集了时间活动日记和一份关于家庭一般环境和家中潜在颗粒源的问卷。分析包括同时在附近固定参考站点（鹤山超级站点）测量的环境 UFP 分布情况。
每小时平均 UFP 浓度显示出早晨、中午和傍晚三个高峰。在家中室内度过的时间被发现具有最高的平均暴露量（睡眠时为 1.26×10⁶cm³）和暴露强度（2.41）。尽管室外颗粒总是会渗透到室内（来自附近交通和一般城市背景源），但室内暴露水平仍明显高于室外。根据收集的问卷数据，这主要是由于夜间成年人吸烟和使用蚊香所致。在校外活动时，平均暴露量最低（6.87×10⁶cm³）和暴露强度（0.52）。
尽管样本量较小，但本研究首次描述了中国 PRD 地区主要污染源下风城市儿童的个人 UFP 暴露情况。特别是，研究结果强调了在家中吸烟对儿童暴露的影响。尽管研究无法分配二手烟和蚊香燃烧的具体贡献，但考虑到家中吸烟的父母中吸烟者的比例，吸烟是一个非常重要的因素。接触二手烟是可以避免的，这些发现指出了政府当局和公共卫生教育工作者在与社区就空气质量对健康的作用以及二手烟对儿童健康的影响的严重性进行接触的重要作用。
