Air quality in the middle and lower reaches of the Yangtze River channel: a cruise campaign

Abstract

Abstract. The Yangtze River is the longest river in China; nearly one-third of the national population lives along the river. Air quality over the Yangtze River is important as it may have significant influences on the aquatic ecosystem, the health of everyone living along the Yangtze River, and regional climate change. Chemical compositions of ambient aerosol were determined during a comprehensive cruise campaign carried out along the mid–lower reaches of the Yangtze River (MLYR) in winter of 2015. The total average concentration of PM2.5 was 119.29±33.67 µg m−3, and the dominant ionic composition in PM2.5 was SO42- with an average concentration of 15.21±6.69 µg m−3, followed by NO3- (13.76±4.99 µg m−3), NH4+ (9.38±4.35 µg m−3), and Ca2+ (2.23±1.24 µg m−3) in this cruise. Based on the filter samples, the concentration and chemical composition of PM2.5 were remarkably varied or fluctuated from coastal areas to inland over the MLYR region. Crustal elements (Ca, Mg, Al, and K) from floating dust showed peak concentrations in the Yangtze River Delta (YRD) region, while secondary inorganic species (SO42-, NO3-, and NH4+) and some of the most enriched elements (Pb, As, Se, and Cd) presented high levels in central China (Wuhan region). The significant correlation between Se and SO42- suggested that coal combustion may play an important role in secondary inorganic aerosol formation. The relatively high enrichment factors (EFs) of Ca (EFs >100) suggested the crustal elements may derive from anthropogenic sources. Furthermore, the concentration of levoglucosan in PM2.5 and the CO column level from satellite observation were greatly enhanced in the rural areas (Anhui and Jiangxi), indicating that biomass burning may make a remarkable contribution to rural areas. The concentrations of typical tracer for heavy oil (V and Ni) significantly increased in the Shanghai port, which was mainly ascribed to ship emissions, based on the air mass source analysis and the relatively high ratio of V ∕ Ni as well. The results shown herein portray a good picture of air pollution along the Yangtze River.

Chemical Characteristics and Brown Carbon Chromophores of Atmospheric Organic Aerosols Over the Yangtze River Channel: A Cruise Campaign

“…We note that the sampling duration for the 1201M, 1201A, and 1201N samples corresponds to episode #5 in an overview paper of the cruise campaign (Li et al, 2018), whereas that for the 1202M and 1202N samples overlaps episode #6, and the 1203A sample coincides with episode #7. Based on the concentrations of carbon monoxide, and trace elements and levoglucosan in particulate matters, episode #5 and episodes #6-7 are cases strongly influenced by coal combustion and biomass burning, respectively (Li et al, 2018). The larger numbers and higher abundances of sulfur-containing compounds in the 1201M and 1201A samples (Figure 2 and Table 1) are probably caused by coal combustion, which is in agreement with Li et al (2018).…”

“…Atmospheric aerosol samples were collected onto 90-mm prebaked quartz-fiber filters (Whatman Company, UK) using a middle-flow aerosol sampler (Qingdao Hengyuan Tech Co., Ltd., HY-100) for 6 h at a flow rate of 100 L min −1 , from 22 November to 5 December 2015 along the Yangtze River channel between Shanghai and Wuhan (Figure 1). Details about the YRC can be found in a previous study (Li et al, 2018). In order to avoid the possible contaminations from self-emission of the ship, the sampler was placed on the bow of the research vessel.…”

“…These results suggest that anthropogenic emissions made important contributions to the atmospheric OAs over the MLYR channel. Li et al (2018) classified the air pollution during the cruise campaign into eight distinct episodes based on sampling locations, backward trajectories, and photochemical processes. We note that the sampling duration for the 1201M, 1201A, and 1201N samples corresponds to episode #5 in an overview paper of the cruise campaign (Li et al, 2018), whereas that for the 1202M and 1202N samples overlaps episode #6, and the 1203A sample coincides with episode #7.…”

“…Li et al (2018) classified the air pollution during the cruise campaign into eight distinct episodes based on sampling locations, backward trajectories, and photochemical processes. We note that the sampling duration for the 1201M, 1201A, and 1201N samples corresponds to episode #5 in an overview paper of the cruise campaign (Li et al, 2018), whereas that for the 1202M and 1202N samples overlaps episode #6, and the 1203A sample coincides with episode #7. Based on the concentrations of carbon monoxide, and trace elements and levoglucosan in particulate matters, episode #5 and episodes #6-7 are cases strongly influenced by coal combustion and biomass burning, respectively (Li et al, 2018).…”

“…The Yangtze River is the longest river in China and passes by several highly developed economic megacities with major petrochemical complexes and/or steel industries (Li et al, 2018), leading to high emissions of anthropogenic pollutants including particulate matters, VOCs, sulfur dioxide, and nitrogen oxides (Huang et al, 2011). Meanwhile, the Yangtze River also plays an important role in shipping of goods and leisure cruising.…”