Comparative analysis of atmospheric trace elements pollution in Beijing and Haikou: Sources, transport and local...

Atmospheric trace elements (ATEs) have complex pollution sources and exhibit strong spatial heterogeneity, attracting widespread attention due to their toxicity and persistence. Here, by integrating multiple methodologies including online monitoring, receptor modeling, and emission inventory analysis, we found an overall higher ATEs concentrations in Beijing (an inland city) than those in Haikou (an island city), mainly due to the relatively higher local industrial and traffic emissions in Beijing, as well as the regional transport (such as dust sources) from inland sources from North China. Notably, Haikou showed uniquely elevated V and Ni pollution levels. This anomaly may be mainly attributed to shipping emissions, which accounted for over 50 % of the total V and Ni emissions in Haikou. Additionally, the regional transport of ship emissions from the surrounding ocean, and biomass burning emissions from South Asian countries, also led to the accumulation of ATEs in this area. Seasonal variations also differed markedly in these two cities: Beijing's ATEs concentrations peaked in spring and autumn, while Haikou's concentrations were highest in autumn and winter. This study elucidates divergent patterns and driving mechanisms of ATEs pollution in northern versus southern China. The integrated methodology enhanced the reliability of source apportionment, providing a scientific basis for region-specific control strategies and collaborative governance.