Department of Environmental Protection, Taipei City Government, 6 Floor, No. 1, City Hall Road, Taipei 110, Taiwan.
College of Public Health, National Taiwan University, No. 17, Xu-Zhou Road, Taipei 100, Taiwan.
Int J Environ Res Public Health. 2018 Jun 21;15(7):1305. doi: 10.3390/ijerph15071305.
Fine particulate matter (PM) has a small particle size, which allows it to directly enter the respiratory mucosa and reach the alveoli and even the blood. Many countries are already aware of the adverse effects of PM, and determination of the sources of PM is a critical step in reducing its concentration to protect public health. This study monitored PM in the summer (during the southwest monsoon season) of 2017. Three online monitoring systems were used to continuously collect hourly concentrations of key chemical components of PM, including anions, cations, carbon, heavy metals, and precursor gases, for 24 h per day. The sum of the concentrations of each compound obtained from the online monitoring systems is similar to the actual PM concentration (98.75%). This result suggests that the on-line monitoring system of this study covers relatively complete chemical compounds. Positive matrix factorization (PMF) was adopted to explore and examine the proportion of each source that contributed to the total PM concentration. According to the source contribution analysis, 55% of PM can be attributed to local pollutant sources, and the remaining 45% can be attributed to pollutants emitted outside Taipei City. During the high-PM-concentration (episode) period, the pollutant conversion rates were higher than usual due to the occurrence of vigorous photochemical reactions. Moreover, once pollutants are emitted by external stationary pollutant sources, they move with pollution air masses and undergo photochemical reactions, resulting in increases in the secondary pollutant concentrations of PM. The vertical monitoring data indicate that there is a significant increase in PM concentration at high altitudes. High-altitude PM will descend to the ground and thereby affect the ground-level PM concentration.
细颗粒物（PM）粒径小，可直接进入呼吸道黏膜，到达肺泡甚至血液。许多国家已经意识到 PM 的不良影响，而确定 PM 的来源是降低其浓度以保护公众健康的关键步骤。本研究于 2017 年夏季（西南季风季节）监测 PM。使用三个在线监测系统连续 24 小时每小时采集 PM 关键化学成分（包括阴离子、阳离子、碳、重金属和前体气体）的浓度。从在线监测系统获得的每个化合物的浓度总和与实际 PM 浓度（98.75%）相似。这一结果表明，本研究的在线监测系统涵盖了相对完整的化学化合物。采用正定矩阵因子分解（PMF）方法来探索和检查每个源对总 PM 浓度的贡献比例。根据源贡献分析，55%的 PM 可归因于本地污染源，其余 45%可归因于台北市以外排放的污染物。在高 PM 浓度（爆发）期间，由于剧烈的光化学反应的发生，污染物转化率高于平时。此外，一旦外部固定污染源排放污染物，它们就会随污染空气团移动并发生光化学反应，导致 PM 的二次污染物浓度增加。垂直监测数据表明，高海拔地区的 PM 浓度显著增加。高空 PM 会下降到地面，从而影响地面 PM 浓度。
