Elemental characterization and source apportionment of PM₁₀ and PM_2.5 in the western coastal area of central Taiwan

This study investigated seasonal variations in PM₁₀ and PM_2.5 mass and associated trace metal concentrations in a residential area in proximity to the crude oil refinery plants and industrial parks of central Taiwan. Particle measurements were conducted during winter, spring and summer in 2013 and 2014. Twenty-six trace metals in PM₁₀ and PM_2.5 were analyzed using ICP-MS. Multiple approaches of the backward trajectory model, enrichment factor (EF), Lanthanum enrichment and positive matrix fraction (PMF) were used to identify potential sources of particulate metals. Mean concentrations of PM₁₀ in winter, spring and summer were 76.4±22.6, 33.2±9.9 and 37.4±17.0μgm^-3, respectively, while mean levels of PM_2.5 in winter, spring and summer were 47.8±20.0, 23.9±11.2 and 16.3±8.2μgm^-3, respectively. The concentrations of carcinogenic metals (Ni, As and adjusted Cr(VI)) in PM₁₀ and PM_2.5 exceeded the guideline limits published by WHO. The result of EF analysis confirmed that Mo, Sb, Cd, Zn, Mg, Cr, As, Pb, Cu, Ni and V were attributable to anthropogenic emission. PMF analysis demonstrated that trace metals in PM₁₀ and PM_2.5 were from the similar sources, such as coal combustion, oil combustion and traffic-related emission, except for soil dust and crustal element emissions only observed in PM₁₀ and secondary aluminum smelter only observed in PM_2.5. Considering health-related particulate metals, the traffic-related emission and coal combustion for PM₁₀ and PM_2.5, respectively, are important to control for reducing potential carcinogenic risk. The results could aid efforts to clarify the impact of source-specific origins on human health.