College of Architecture and Environment, Sichuan University, Chengdu, China; Chengdu Academy of Environmental Sciences, Chengdu, China.
Chengdu Academy of Environmental Sciences, Chengdu, China.
Environ Res. 2020 Jun;185:109478. doi: 10.1016/j.envres.2020.109478. Epub 2020 Apr 4.
As important pollution gases and represented precursors of both ozone and second organic aerosol (SOA), the component characteristics, source origins, environmental health and emission control of volatile organic compounds (VOCs), are gaining more and more attention in Chinese megacities. In order to understand the concentration, composition and temporal and spatial distribution characteristics of VOCs in the atmosphere of Chengdu, a megacity located in Sichuan basin in southwest China, the offline sampling measurements of VOCs were carried out at 28 different field sites covering all the districts and counties of Chengdu during special periods from May 2016 to January 2017. Speciated VOCs measurement was performed by the GC-FID/MS, and 99 species were identified. The averaged total VOC mixing ratios of each sampling site were in the range from 35.03 to 180.57 ppbv. Based on these observational data, the distribution characteristics of VOCs in different months and different regions of Chengdu were clarified. The VOCs data were used to estimate the potential amount of ozone, secondary aerosol formation and health risk assessment in Chengdu. Furthermore, the positive matrix factorization (PMF) model was used to identify the dominant emission sources and evaluate their contribution to VOCs in the city. The two main sources of VOCs in Chengdu were motor vehicle exhaust and solvent utilization. These accounted for 43% of all emission sources. In the summertime, due to higher temperatures and stronger sunlight, the contribution of natural sources and secondary emissions were also relatively high, which were supported by the regional emission inventories. Finally, the controlling direction of VOCs and O pollution in Chengdu was discussed, and the VOCs pollution control strategy was proposed for the near future.
作为重要的污染气体和臭氧及二次有机气溶胶（SOA）的代表前体物，挥发性有机化合物（VOCs）的组成特征、来源、环境健康和排放控制在中国特大城市中越来越受到关注。为了了解位于中国西南四川盆地的特大城市成都大气中 VOCs 的浓度、组成及时间和空间分布特征，于 2016 年 5 月至 2017 年 1 月在成都所有区县的 28 个不同现场站点进行了 VOCs 的离线采样测量。采用 GC-FID/MS 对 VOCs 进行了分谱测量，共鉴定出 99 种物质。每个采样点的平均总 VOC 混合比范围为 35.03-180.57 ppbv。基于这些观测数据，阐明了成都不同月份和不同区域 VOCs 的分布特征。利用 VOCs 数据估算了成都臭氧、二次气溶胶形成的潜在量和健康风险评估。此外，还采用正定矩阵因子（PMF）模型识别了主要排放源，并评估了它们对成都市 VOCs 的贡献。成都 VOCs 的两个主要来源是机动车尾气和溶剂利用。这两个来源占所有排放源的 43%。在夏季，由于气温较高和阳光较强，自然源和二次排放的贡献也相对较高，这得到了区域排放清单的支持。最后，讨论了成都 VOCs 和 O3 污染的控制方向，并提出了近期 VOCs 污染控制策略。
