中国华北地区北京-天津地区偏远农村地区和城市大气中多环芳烃（PAHs）的浓度及其气-土交换通量。
Atmospheric concentrations and air-soil gas exchange of polycyclic aromatic hydrocarbons (PAHs) in remote, rural village and urban areas of Beijing-Tianjin region, North China.
机构信息
Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
出版信息
Sci Total Environ. 2011 Jul 1;409(15):2942-50. doi: 10.1016/j.scitotenv.2011.04.021.
Forty passive air samplers were deployed to study the occurrence of gas and particulate phase PAHs in remote, rural village and urban areas of Beijing-Tianjin region, North China for four seasons (spring, summer, fall and winter) from 2007 to 2008. The influence of emissions on the spatial distribution pattern of air PAH concentrations was addressed. In addition, the air-soil gas exchange of PAHs was studied using fugacity calculations. The median gaseous and particulate phase PAH concentrations were 222 ng/m³ and 114 ng/m³, respectively, with a median total PAH concentration of 349 ng/m³. Higher PAH concentrations were measured in winter than in other seasons. Air PAH concentrations measured at the rural villages and urban sites in the northern mountain region were significantly lower than those measured at sites in the southern plain during all seasons. However, there was no significant difference in PAH concentrations between the rural villages and urban sites in the northern and southern areas. This urban-rural PAH distribution pattern was related to the location of PAH emission sources and the population distribution. The location of PAH emission sources explained 56%-77% of the spatial variation in ambient air PAH concentrations. The annual median air-soil gas exchange flux of PAHs was 42.2 ng/m²/day from soil to air. Among the 15 PAHs measured, acenaphthylene (ACY) and acenaphthene (ACE) contributed to more than half of the total exchange flux. Furthermore, the air-soil gas exchange fluxes of PAHs at the urban sites were higher than those at the remote and rural sites. In summer, more gaseous PAHs volatilized from soil to air because of higher temperatures and increased rainfall. However, in winter, more gaseous PAHs deposited from air to soil due to higher PAH emissions and lower temperatures. The soil TOC concentration had no significant influence on the air-soil gas exchange of PAHs.
四十个被动空气采样器被部署在北京-天津地区的偏远农村和城市地区进行研究，以了解 2007 年至 2008 年四个季节（春季、夏季、秋季和冬季）中气态和颗粒态多环芳烃的发生情况。研究了排放物对空气多环芳烃浓度空间分布模式的影响。此外，还通过逸度计算研究了多环芳烃的气-土气体交换。气态和颗粒态多环芳烃的中值浓度分别为 222ng/m³和 114ng/m³，总多环芳烃浓度的中值为 349ng/m³。冬季测量的多环芳烃浓度高于其他季节。山区农村和城市站点测量的空气多环芳烃浓度明显低于南部平原站点在所有季节的测量值。然而，在北部和南部地区，农村和城市站点之间的多环芳烃浓度没有显著差异。这种城乡多环芳烃分布模式与多环芳烃排放源的位置和人口分布有关。多环芳烃排放源的位置解释了环境空气多环芳烃浓度空间变化的 56%-77%。每年土壤到空气的多环芳烃气-土气体交换通量中值为 42.2ng/m²/天。在所测量的 15 种多环芳烃中，苊烯（ACY）和苊（ACE）贡献了超过总交换通量的一半。此外，城市站点的空气-土壤多环芳烃气体交换通量高于偏远和农村站点。在夏季，由于较高的温度和降雨量增加，更多的气态多环芳烃从土壤挥发到空气中。然而，在冬季，由于较高的多环芳烃排放和较低的温度，更多的气态多环芳烃从空气中沉积到土壤中。土壤 TOC 浓度对多环芳烃的气-土气体交换没有显著影响。
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