Fossil and Non-fossil Fuel Sources of Organic and Elemental Carbonaceous Aerosol in Beijing, Shanghai, and Guangzhou: Seasonal Carbon Source Variation

Abstract

We measured the radiocarbon isotope signals in various fractions of carbonaceous aerosols sampled across four seasons (Oct 2013-Jul 2014) in three megacities of China, viz., Beijing, Shanghai, and Guangzhou. The contributions of fossil fuel (FF) and non-fossil fuel (NF) to the carbonaceous aerosol were estimated based on the radiocarbon content in the organic carbon (OC), water-soluble organic carbon (WSOC), water-insoluble organic carbon (WIOC), and elemental carbon (EC). Although NF generated the primary share (> 55%) during autumn in all of the cities, the seasonal contributions of the sources differed by location during the rest of the year. During winter, FF emissions constituted the majority of the carbonaceous pollution (64%) in Beijing, probably as a result of increased coal combustion for heating. On average, the EC, WSOC, and WIOC generated by FF composed ~10%, 35%, and 19% of the total carbon (TC). Overall, NF was identified as the largest source of carbonaceous aerosol in Guangzhou (63%), whereas FF was the largest source, contributing slightly more than NF, in Shanghai (54%). During spring and summer, FF played a greater role than NF in Beijing (~55%) and Guangzhou (~63%); additionally, based on our limited number of samples, it contributed 71% in Shanghai during the latter season, with a significant portion due to fuel combustion (i.e., industrial, vehicular, fishing-boat, and large-vessel emissions).

An evaluation of source apportionment of fine OC and PM2.5by multiple methods: APHH-Beijing campaigns as a case study

“…S1). Generally, non-fossil fuel sources accounted for 41% of TC, which is comparable with that in another study conducted in Beijing (45%) 42 in Fig. 1.…”

Source Apportionment of Carbonaceous Aerosols in Beijing with Radiocarbon and Organic Tracers: Insight into the Differences between Urban and Rural Sites

“…ECf contributed 7.6 ± 2.1 % and 6.0 ± 1.4 % to TC at the IAP and PG sites in winter and 6.9 ±1.6 % and 8.9 ± 2.6 % in summer. Most of the fossil fractions of EC are within the range of previous studies in urban Beijing (67-96% of EC) (Liu et al, 2020;Liu et al, 2017;Zhang et al, 2016;. Higher contributions of ECf were found on the polluted days in wintertime (Table S1), showing that the PM2.5 concentrations may be elevated due to direct emission from coal combustion and vehicle exhaust.…”

Source apportionment of carbonaceous aerosols in Beijing with radiocarbon and organic tracers: insight into the differences between urban and rural sites

“…A previous study in north-east China found a dominant fossilfuel contribution to EC (76 ± 11 %) and found that non-fossil sources are major contributors to OC (66 ± 11 %) (Zhang et al, 2016). Non-fossil sources of OC were major contributors to the fine particle pollution in Beijing during the APEC summit (Liu et al, 2016a). Moreover, clear seasonal trends of non-fossil and fossil source contributions to waterinsoluble OC (WINSOC) and water-soluble OC (WSOC) were found.…”