Hennigan Christopher J, Bergin Michael H, Weber Rodney J
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
Environ Sci Technol. 2008 Dec 15;42(24):9079-85. doi: 10.1021/es802189y.
Ground-based measurements of meteorological parameters and water-soluble organic carbon in the gas(WSOCg) and particle (WSOCp) phases were carried out in Atlanta, Georgia, from May to September 2007. Fourteen separate events were observed throughout the summer in which WSOCp and water vapor concentrations were highly correlated (average WSOCp-water vapor r = 0.92); however, for the entire summer, no well-defined relationship existed between the two. The correlation events, which lasted on average 19 h, were characterized by a wide range of WSOCp and water vapor concentrations. Several hypotheses for the correlation are explored, including heterogeneous liquid phase SOA formation and the co-emission of biogenic VOCs and water vapor. The data provide supporting evidence for contributions from both and suggest the possibility of a synergistic effect between the co-emission of water vapor and VOCs from biogenic sources on SOA formation. Median WSOCp concentrations were also correlated with elemental carbon (EC), although this correlation extended over the entire summer. Despite the emission of water vapor from anthropogenic mobile sources and the WSOCp-EC correlation, mobile sources were not considered a potential cause for the WSOCp-water vapor correlations because of their low contribution to the water vapor budget. Meteorology could perhaps have influenced the WSOCp-EC correlation, but other factors are implicated as well. Overall, the results suggest that the temperature-dependent co-emission of water vapor through evapotranspiration and SOA precursor-VOCs by vegetation may be an important process contributing to SOA in some environments.
2007年5月至9月期间，在佐治亚州的亚特兰大进行了气象参数以及气相（WSOCg）和颗粒相（WSOCp）中水溶性有机碳的地面测量。整个夏季观测到14个独立事件，其中WSOCp与水汽浓度高度相关（WSOCp与水汽的平均相关系数r = 0.92）；然而，就整个夏季而言，二者之间不存在明确的关系。这些相关事件平均持续19小时，其特点是WSOCp和水汽浓度范围广泛。探讨了几种关于这种相关性的假设，包括非均相液相二次有机气溶胶形成以及生物源挥发性有机化合物（VOCs）与水汽的共排放。数据为二者的贡献提供了支持证据，并表明生物源水汽和VOCs共排放对二次有机气溶胶形成可能存在协同效应。WSOCp浓度中位数也与元素碳（EC）相关，尽管这种相关性在整个夏季都存在。尽管人为移动源排放水汽且存在WSOCp与EC的相关性，但由于移动源对水汽收支的贡献较低，因此未被视为WSOCp与水汽相关性的潜在原因。气象条件可能影响了WSOCp与EC的相关性，但也涉及其他因素。总体而言，结果表明，植被通过蒸散作用与二次有机气溶胶前体VOCs随温度变化的共排放可能是某些环境中二次有机气溶胶形成的一个重要过程。
