Secondary Inorganic Ions Characteristics in PM_2.5 Along Offshore and Coastal Areas of the Megacity Shanghai

Abstract

With rapid economic development as well as dramatic population growth, the affiliations between coastal urban megacities have become increasingly thoroughly interconnected, especially through marine transportation (F. Xiao et al., 2013). Over the past several decades, lying over the broad shelf of the Northwest Pacific Ocean, the East China Sea (ECS) has played an important role in ocean transport capacity around the world (Kang et al., 2017;G. Zhang et al., 2007). The coastal urban megacity Shanghai handles more than 20% of the world's cargo throughput and is also the largest petrochemical production and fishery resource area (Harshit et al., 2009). The transportation and industrial activities in the ECS have caused both a meteoric increases in the industrialization and urbanization of Shanghai, along with significant increases in regional air pollution (Moldanová et al., 2009;F. Wang et al., 2016). In addition, influenced substantially by the East Asian monsoon, especially during the summer season, marine fine particle matters are subject to long-range transport to inland areas, and these mix with local emissions. This can change precipitation patterns and regional atmospheric stability (Fan et al., 2016;Mao et al., 2020). Therefore, more scientific attention should be paid to investigate the loadings, particle compositions, and sources of marine aerosols, especially in coastal urban megacities and offshore regions where the urban-ocean interaction is intense.Oceans cover more than 70% of the Earth's surface, and marine aerosols contribute significantly to the global aerosol load (O'Dowd et al., 2004), playing an important role in cloud albedo, atmospheric chemical reactions, global climate change, and the biogeochemical cycling of nutrients (

Aerosol high water contents favor sulfate and secondary organic aerosol formation from fossil fuel combustion emissions

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