Organic composition in the dry season rainwater of Guangzhou, China

Abstract

This paper reports the results from a study of the organic composition of rainwater collected at Tianhe district of Guangzhou city, P.R. China, during the dry season. Several special setups of a pyrex bottle with a glass funnel were used for the collection of the rainwater. Three fractions (aliphatics, PAHs and fatty acids) were separated from the total extracted organic compounds and identified with GC-MS. The molecular diagnostic ratios were utilized for the source reconciliation. The aliphatic hydrocarbon and the biomarkers (triterpanes and steranes) distribution show a characteristic of the petrochemical source in the rainwater samples. The PAHs diagnostic ratios [e.g. MP/P, MPI, Fl/ (Fl + Py)] indicated vehicular emissions. The fatty acids ratios (e.g. C(18:1)/C(18:0) and C(18:2)/C(18:0)) reflect the contribution of cooking emissions, while the higher plant waxes play little part. Moreover, the values of MP/P, MPI, BaA/(BaA + CT) and BeP/(BeP + BaP) reflected the origin of the long-distance transportation to some extent. On the whole, for the dry season rainwater, all molecular diagnostic ratios indicated the complexity of the organic composition of the rain, which have the characteristics of both a local emission contribution and a long-distance transportation contribution.

Significance of wet deposition to removal of atmospheric particulate matter and polycyclic aromatic hydrocarbons: A case study in Guangzhou, China

“…Temporally, the concentration levels of TOC and PAHs in wet deposition from the present study were lower than those from previous studies also conducted in Guangzhou, i.e., the level of TOC in 2010 (2.5 mg L À1 ) was lower than those in 2004 (7.1 mg L À1 ) (Xu et al, 2008) and levels of PAHs in 2010 (170 ng L À1 ) were lower than those in 2005 (1910 ng L À1 ). On the other hand, the relative abundance of the low molecular weight (3 þ 4-ring) PAHs, mainly derived from low-efficient combustion of domestic coal and biomass (Liu et al, 2012b), was reduced from 86% in 2005 to 61% in 2010 (Huang et al, 2009 or > 0.5 and in the range of 0.2e0.35 or 0.2e0.5 indicate coal or wood burning and petroleum combustion, respectively (Yunker et al, 1996(Yunker et al, , 2002.…”

“…The annual C VWM of POC (1.3 mg L À1 ) was higher than the levels obtained from forestry and semi-rural regions in the United States, i.e., 0.20 mg L À1 in Hubbard Brook of New York (Likens et al, 1983) and 0.73 mg L À1 in Wilmington of North Carolina (Kieber et al, 2006). Similarly, the annual C VWM of DOC (1.4 mg L À1 ) in the present study was lower than other measurements conducted in urban and forest regions in North America and Asia, i.e., 1.9 mg L À1 in Ithaca of New York (Likens et al, 1983), 3.0 mg L À1 in North China (Pan et al, 2010), 3.6 mg L À1 in Guangzhou (Xu et al, 2008), 6.7 mg L À1 in Los Angeles (Kawamura et al, 2001), and 6.8 and 2.1 mg L À1 (spring and summer) in Xi'an of China (Tian et al, 2011), but higher than those in coastal areas in north America (1.1 mg L À1 ) (Likens et al, 1983).…”

Confirming anthropogenic influences on the major organic and inorganic constituents of rainwater in an urban area

“…This is in agreement with previous work (Kawamura and Kaplan, 1986), where lower molecular fatty acids (C 12 -C 19 ) are major compounds while higher molecular weight fatty acids (C 20 -C 30 ) are minor. A major source of fatty acids (C < 20) is known to come from cooking and biomass combustion in urban areas (Rogge et al, 1991;Xu et al, 2008). All results in the present study indicate that anthropogenic sources were significant contributors to the organic compounds present in rainwater.…”

Content and composition of dissolved organic carbon in precipitation at the southern part of Mexico City

“…Studies of OC in precipitation are scarce compared to those for other atmospheric substrates, but results indicate that OC in rainwater is lower compared to concentrations observed in snow and fog (Iavorivska et al, 2016 and references therein). Some of the previous reports have focused on the measurement of total WSOC concentrations (Coehlo et al, 2008;Pan et al, 2010;Yan and Kim, 2012;Siudek et al, 2015) and others have characterized the different fractions by using gas, liquid, and UV-visible chromatographies; molecular fluorescence; FTIR-ATR, and 1 H NMR spectroscopies (Santos et al, 2009;Xu et al, 2008;Guidotti et al, 2000;Ćosović et al, 2007;Chon et al, 2015).…”