Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China; Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
Sci Total Environ. 2020 Jul 10;725:138243. doi: 10.1016/j.scitotenv.2020.138243. Epub 2020 Apr 5.
High temporal-resolution VOC concentration data can provide detailed and important temporal variations of VOC species and emission sources, which is not possible when using coarse temporal-resolution data. In this study, we utilized the positive matrix factorization (PMF) model to conduct source apportionment of hourly concentrations of nineteen VOC species and CO measured at the Mong Kok air quality monitoring station, operated by the Hong Kong Environmental Protection Department, from January 2013 to December 2014. The PMF analysis of the hourly dataset (PMF_Hourly) identified five sources, including liquefied petroleum gas (LPG) (contribution of 45%), gasoline exhaust (21%), combustion (20%), biogenic emission (9%), and paint solvents (6%). The diurnal patterns of VOC emissions from identified sources are likely to be affected by the strength of emissions, variation of the planetary boundary layer height, and photochemical reactions. In addition, the PMF analyses of hourly and 24-hour averaged data of the hourly-resolved data (PMF_Hourly and PMF_Daily) were generally comparable, but the time series of VOC emissions from PMF_Hourly could not be well captured by PMF_Daily for two local VOC sources of gasoline exhaust and LPG. This study highlights the benefit of high temporal-resolution measurement data in apportioning VOC sources, hence providing critical information on VOC emission sources (e.g., diurnal variations) for controlling VOC emissions effectively.
高时间分辨率 VOC 浓度数据可以提供 VOC 物种和排放源的详细和重要的时间变化，而使用粗时间分辨率数据则无法实现。在本研究中，我们利用正定矩阵因子 (PMF) 模型，对香港环境保护署运营的旺角空气质量监测站从 2013 年 1 月至 2014 年 12 月测量的 19 种 VOC 物种和 CO 的每小时浓度进行源解析。对每小时数据集 (PMF_Hourly) 的 PMF 分析确定了五个来源，包括液化石油气 (LPG) (占 45%)、汽油尾气 (21%)、燃烧 (20%)、生物排放 (9%)和油漆溶剂 (6%)。确定来源的 VOC 排放的日变化模式可能受到排放强度、行星边界层高度变化和光化学反应的影响。此外，对小时分辨数据的每小时和 24 小时平均数据的 PMF 分析 (PMF_Hourly 和 PMF_Daily) 通常是可比的，但 PMF_Daily 无法很好地捕捉 PMF_Hourly 的 VOC 排放时间序列，因为有两个局部 VOC 来源，即汽油尾气和 LPG。本研究强调了高时间分辨率测量数据在分配 VOC 源方面的优势，从而为有效控制 VOC 排放提供了有关 VOC 排放源 (例如，日变化) 的关键信息。
