High-resolution temporal metallic elements in PM2.5 in Chengdu, Southwest China: variations, extreme events, and effects of meteorological parameters

• Published in: Air quality, atmosphere and health atmosphere and health, 2021-12, Vol.14 (12), p.1893-1909
• Main Authors: Jin, Qian, Liu, Yanmei, Feng, Miao, Huang, Chengmin
• Format: Article
• Language: English
• Subjects: Air pollution; Anthropogenic factors; Atmospheric aerosols; Atmospheric Protection/Air Quality Control/Air Pollution; Cadmium; Calcium; Chromium; Coal-fired power plants; Construction; Copper; Detection limits; Earth and Environmental Science; Efficiency; Emission measurements; Emissions; Environment; Environmental Health; Gold; Health Promotion and Disease Prevention; Health risks; Industrial plant emissions; Iron; Lead; Manganese; Megacities; Mercury (metal); Metal concentrations; Metals; Meteorological effects; Meteorological parameters; Mountains; Particulate matter; Pollutants; Rainfall; Rainfall intensity; Risk assessment; Seasonal variations; Selenium; Silver; Trends
• ISSN: 1873-9318; 1873-9326
• DOI: 10.1007/s11869-021-01065-z

Urban atmospheric metallic element in PM 2.5 is affected by multiple factors across spatial and temporal scales. Yet the coupling of metallic elements with PM 2.5 and the relationship between metallic element concentrations and influencing factors are still poorly understood, which hampers the adoption of appropriate policies and measures to mitigate emission. Therefore, an hourly resolved measurement campaign was performed from March 2017 to February 2018 to investigate the characteristics of 17 metallic elements (i.e., K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Ag, Cd, Ba, Au, Hg, and Pb) in PM 2.5 using a CES Xact 625 multi-metals monitor in Chengdu, Southwest China. The hourly concentrations of all 17 studied metallic elements ranged from the detection limits to 27,630 ng·m −3 , while the hourly PM 2.5 values varied from 1.95 to 282.7 μg·m −3 , with an average value of 51.4 ± 25.4 μg·m −3 . The change of anthropogenic emissions and meteorological parameters in Chengdu jointly resulted in the unimodal diurnal and distinct seasonal variations of most metallic elements concentrations. Furthermore, the value of total metallic mass (TMM) might be extremely high when the concentration of PM 2.5 is relatively low, indicating that the health risks of exposure to low PM 2.5 could be underestimated in previous studies, in which the health risk assessment of exposure to PM 2.5 had been dependent on PM 2.5 concentration. The removal efficiency of rainfall on metallic elements and PM 2.5 might vary depending on the rainfall intensity. Moderate rainfall has the highest removal efficiency for PM 2.5 and TMM.