Mosses as Biomonitors of Atmospheric Trace Metal and Nitrogen Deposition: Spatial Distribution and Temporal Trend in Yancheng, China

This study assessed air quality in Yancheng, China, using moss biomonitoring. The moss species, Haplocladium microphyllum was chosen, and mosses were collected from 67 sites across Yancheng during July and August 2022. The concentrations of Al, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn, V, and nitrogen in mosses were determined, and the spatial distribution and temporal trends of atmospheric trace metals and nitrogen deposition in Yancheng were explored by comparing the current data with that of a similar study conducted in 2017. In 2022, high concentrations of metals and nitrogen in mosses were found in northern and southwestern Yancheng, whereas lower concentrations were observed in southern and southeastern Yancheng for metals and central Yancheng for nitrogen. Since 2017, the moss concentrations of Zn, Cu, Ni, and Cr have increased, while that of V has declined, with no notable changes observed in other metals and nitrogen. Contamination factor analysis indicated that Pb and Cu contamination levels escalated from moderate and slight (2017) to severe and moderate (2022), respectively. The Positive Matrix Factorization (PMF) model identified five dominant contamination sources of metals and nitrogen in 2022 mosses: natural source (21.4%), traffic emission (17.84%), fuel combustion derived from coal and heavy oil (22.71%), agricultural activities (19.37%), and industrial activities (18.68%). This study highlights the significance of moss biomonitoring, along with data analysis and emission source inventories, as essential tools for evaluating air quality in Yancheng.