Abstract
To explore the mass concentration levels and health risks of heavy metals in the air in dense traffic environments, PM2.5 samples were collected at three sites in the city of Kunming in April and October 2013, and January and May 2014. Ten heavy metals––V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd and Pb––were analyzed by ICP–MS, and the results showed PM2.5 concentrations significantly higher in spring and winter than in summer and autumn, especially for Zn and Pb. The concentration of heavy metals on working days is significantly higher, indicating that vehicle emissions are significant contributors. An enrichment factor analysis showed that Cr, Mn, Ni, Cu, Zn, As, Cd and Pb come mainly from anthropogenic sources, while V and Co may be both anthropogenic and natural. The correlation and principal component analysis (PCA) showed that Ni, Cu, Zn, Cd and Pb mainly come from vehicles emissions and metallurgical industries; Cr and Mn, from vehicles emissions and road dust; and As, mainly from coal combustion. The health risk assessment shows that the non-carcinogenic risk thresholds of the heavy metals in PM2.5 to children and adult men and women are all less than 1. The carcinogenic risk of Cr for men and women in traffic-intensive areas exceeds 10−4, reaching 1.64 × 10−4 and 1.4 × 10−4, respectively.
Highlights
In recent decades, the number of motor vehicles and total energy consumption have increased in China, as a result of rapid economic development and urbanization
Because the heavy metals in PM2.5 enter the body through the respiratory system, this study focused on assessing the health risks of inhalation exposure, and the dose of this route was calculated by the following formula: ADD(LADD)Inhale = (C × IRi × Enrichment Factor (EF) × ED × CF)/(BW × AT)
These industries were in a continuous operation, which shows that the concentrations of discharged heavy metals may not have fluctuated much between working days and rest days
Summary
The number of motor vehicles and total energy consumption have increased in China, as a result of rapid economic development and urbanization. Studies have shown the adverse health effects from exposure to PM and heavy metals [6,7,8,9], and epidemiological studies over the past few decades identified a close relationship between increased atmospheric heavy metals and increased mortality and morbidity [10,11,12]. The heavy metals come from natural and anthropogenic sources, including coal combustion, traffic emissions, and smelting. Because of their high toxicity, persistence and bioaccumulation, research into the health effects of long or short-term exposure to traffic-related air pollutants has become the focus of attention [13,14,15,16]. Fang et al [17]
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