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

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 interesting as it may have significant influences on aquatic ecosystem, public health onboard and coastal areas. A comprehensive 15-days cruise campaign has been performed in the Mid-Lower Reaches Yangtze River (MLYR) in winter of 2015. Based on the filter samples, the concentration and chemical composition of PM 2.5 were greatly varied or fluctuated in different regions. Crustal elements (Ca, Mg, Al and K) from floating dust showed peak concentrations in the Yangtze River Delta (YRD) regions, while secondary species (SO 4 2− , NO 3 − and NH 4 + ) and some most enriched elements (Pb, As, Se and Cd) presented high levels in the central China (Wuhan). The significant correlation between Se and SO 4 2− suggested that coal combustion may play a key role on the secondary inorganic formation. The relative high enrichment factors (EFs) of Ca (EFs > 100) suggested the crustal elements may derive from anthropogenic sources. Furthermore, the concentration of levoglucosan in PM 2.5 and CO column level from satellite data greatly enhanced in the rural area (Anhui and Jiangxi), indicating that biomass burning may make remarkable contribution to rural area. The concentrations of V and Ni were found to evidently elevate in the Shanghai port, which were mainly ascribed to the ship emission through the air mass source analysis and the relatively high ratio of V / Ni as well. This result shown herein portrayed a good picture of air pollution along the Yangtze River.