Variability of organic and elemental carbon, water soluble organic carbon, and isotopes in Hong Kong

Abstract

Abstract.To determine the levels and variations of carbonaceous aerosol in Hong Kong, PM 2.5 and PM 10 samples were collected by high volume (Hi-vol) samplers at three monitoring stations (representing middle-scale roadside, urban-, and regional-scale environments) during winter (November 2000 to February 2001) and summer (June 2001 to August 2001) periods. The highest concentrations of organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC) were found at the middle-scale roadside site with the lowest at the regional-scale site. The percentages of WSOC in total carbon at these sites were inversely correlated with their concentrations (i.e., the highest percentages of WSOC were observed at the regional-scale site). A high WSOC fraction may be associated with aged aerosol because of the secondary formation by photochemical oxidation of organic precursors of anthropogenic pollutants during transport. The annual average of isotope abundances (δ 13 C) of OC and EC were -26.9±0.5‰ and -25.6±0.1‰, respectively. There were no notable differences for seasonal distributions of carbon isotopic composition, consistent with motor vehicle emissions being the main source contributors of carbonaceous aerosol in Hong Kong. OC 13 C abundances at the regional-scale site were higher than those at the middle-scale roadside and urban sites, consistent with secondary organic aerosols of biogenic origin.

Size distributions of elemental carbon and its contribution to light extinction in urban and rural locations in the pearl river delta region, China

“…The Pearl River Delta (PRD) region is a fast-developing economic zone located on the southeast coast of China. Abundance of EC and OC in bulk PM 2.5 or PM 10 aerosol samples in the PRD region have been reported in a number of studies (Ho et al, 2002(Ho et al, , 2006Cao et al, 2003Cao et al, , 2004Yu et al, 2004;Chow et al, 2005;Duan et al, 2007;Hagler et al, 2006;Andreae et al, 2008). The concentrations of EC in PM 10 were 4.7-10.4 µg m −3 in urban locations and 2.5-6.2 µg m −3 in suburban locations.…”

Source apportionment of carbonaceous aerosols in Xi'an, China: insights from a full year of measurements of radiocarbon and the stable isotope <sup>13</sup>C

“…Complementing 14 C source apportionment with 13 C measurements allows a better constraint of the contribution of different emission sources to carbonaceous aerosols (Kirillova et al, , 2014aBosch et al, 2014;Winiger et al, 2015Winiger et al, , 2016Bikkina et al, 2016Bikkina et al, , 2017Yan et al, 2017). For example, EC is inert to chemical or physical transformations; thus the δ 13 C EC preserves the signature of emission sources (L. Huang et al, 2006;Andersson et al, 2015;Winiger et al, 2015Winiger et al, , 2016. EC from fossil sources (e.g., coal combustion, liquid fossil fuel burning) can be first separated from biomass burning by F 14 C of EC.…”

Temporal variations of black carbon in Guangzhou, China, in summer 2006

“…Previous studies of anthropogenic aerosols and gaseous pollutants at Guangzhou and the surrounding urban areas mostly focused on the relationships of OC and BC and their seasonal variations (Cao et al, 2003(Cao et al, , 2004Duan et al, 2007;Ho et al, 2006;Cheung et al, 2005), mixing states of BC (Cheng et al, 2006), and formation of sulfate and organics . Some studies have also characterized aerosol chemical composition and optical properties Liu et al, 2008;Garland et al, 2008).…”