| Abstract | Rapid urbanization, industrialization and modernization are the important factors causing serious air pollutions in developing countries, including Vietnam. This study is designed to assess the particulate matter (PM) air pollution in Hanoi and the contributing of various sources. Two hundred and one (201) pairs of samples were collected and analyzed. Out of that one hundred eighty six pair of 4-h PM2.5 and 4-h PM10 were collected on quartz filters and mixed cellulose ester filters by an Andersen dichotomous sampler and two MiniVol Portable Air Samplers at the mixed site (Thuong Dinh - Thanh Xuan) in Hanoi, Vietnam during the dry season (23 December 2006 - 11 February 2007). All samples were analyzed in AIT, for PM mass concentration and black carbon (BC), ion species and element composition. The composition data were prepared as the input data for receptor modeling to determine source contributions to PM10 and PM2.5. Simultaneously, carbon monoxide (CO) was also monitored. The results show that 24-h PM10 mass concentrations during the study period met the PM10 Vietnam Standard of 150pg/m3, except for one day. All 24-h PM2.5 mass concentrations exceed the currently proposed US.EPA standard of 35g/m3. The 1-h CO concentration and 24-h Pb concentration in PM were lower than Vietnam Standard (30mg/m3 or 26ppm for CO and 1.5pg/m3 for Pb). The elemental concentrations (Fe, Ni, Sr, Ti, V, Zn, Si, Al, Be, Ca, Cd, Co, Cr, Cu, Li, Mg, Mn, Mo and TI) were all lower than 0.5p.g/m3, except for Ca, which was higher than 2pg/m3. This suggests a significant contribution from paved or unpaved road and construction activity to PM levels. Normally, the CO and mass" concentration in the morning and evening hours (including rush hours) (6:00-10:00 and 18:00-22:00) are higher than the levels at other times of the day. The results of receptor modeling showed that five factors (oil, biomass, aged sea spray, industry and diesel) contribute similarly to both PM10 and PM2.5 mass in percentage (2-4%; 2-4%; 2-3%; 4-6%; 40-41%, respectively). However, contributions of secondary particles and construction activities are different. The secondary particles and construction activities contributed to PM 10 are of (16% and 40%) and to PM2.5 are of (28% and 8%). Further study is recommended for traffic, residential site, industrial site and commercial sites to provide a better picture of sources contributing to ambient PM in Hanoi, Vietnam. |