Characterization of 210 Po activity and trace heavy metals in aerosols from traffic-dominated areas in urban, Hanoi, Vietnam: implications for air pollution sources and human health risks

Air pollution has become a serious problem in densely populated urban areas in recent years. The 210Po activity (a toxic radionuclide) and trace heavy element concentrations in 24 aerosol samples from Hanoi, Vietnam, were measured . 210Po activity ranged from 92.2 to 3500 μBq.m−3. Notably,210Po activity in roadside samples was much higher compared to global reference values. Among the trace heavy metals analyzed, Co showed the lowest concentrations, while Al had the highest. Most metal levels in roadside areas were higher than those in residential areas. Enrichment factor analysis indicated that metals such as Li, Al, Ti, V, Mn, Fe, Co, and Ba mainly came from crustal sources. In contrast, Cr, Ni, Cu, Zn, Cd, Sb, and Pb were linked to vehicle emissions such as fossil fuel combustion. The relationship between 210Po and these metals revealed factors affecting its presence in urban air. In residential areas,210Po negatively correlated with Ni and positively with Al, indicating a crustal origin. By contrast, its strong positive correlation with Cr and Ni in roadside areas suggests fossil fuel combustion as main source. Despite the diverse 210Po sources in Hanoi, the findings suggest that its presence in aerosols is largely determined by local characteristics and supply on-site.