Assessing pollution characteristics and human health risk of exposure to PM2.5-bound trace metals in a suburban area in Hanoi, Vietnam

Fine particles (PM2.5) in the atmosphere, especially PM2.5 bounded with trace metals, pose potentially adverse human health risks. This study aimed to characterize the trace elements in PM2.5 in a suburban area of Hanoi from November 2019 to December 2020. The study area represented a mixture of industrial, agricultural, and residential areas. The results revealed that PM2.5 mass was highest in winter due to the stable meteorological conditions, which disfavor the particulate matter dispersion in the atmosphere. Fe, Mg, Zn, K, and Al were the most abundant elements in PM2.5, accounting for 29.6, 19.0, 16.3, 15.8, and 11.3% of the total concentration of metals, respectively. PM2.5-bound trace metals were highest in winter, followed by autumn and spring. Principal component analysis with multiple linear regression (PCA/MLR) illustrated that crustal dust, pesticide, and industrial emissions contributed to 73.6% of the total contribution sources, while vehicle exhaust mixed with coal combustion accounted for 64.1% of the total contribution sources. The health risk assessments suggested that As (HQ = 4.7) and Cd (HQ = 3.1) had non-carcinogenic risks for adults. The cumulative carcinogenic risk of elements was within the acceptable range for both children and adults. Notably, the source of As should be paid attention to as the As high concentration exceeding the safe level for non-carcinogenic risks in the study area.