Daily personal exposure to black carbon in different microenvironments in Hanoi, Vietnam

Daily personal exposure to black carbon (BC) in different microenvironments in Hanoi, Vietnam was quantified for the first time. In this study, a portable instrument, microAethe® model AE51, was used to continuously measure BC concentrations in various microenvironments within buildings and transportation modes. Overall average daily personal exposure to BC from those microenvironments was 5.46 µg/h. The highest BC exposure was during commuting 13.48 µg/h and 5.74 µg/h for the motorcyclist and car driver, respectively. In building environments, the highest BC exposure was 3.98 µg/h in a coffee shop with smoking; the lowest BC exposure was 1.54 µg/h in a hospital department; while BC exposure in an office was 1.92 µg/h. The level of BC exposure in an apartment was strongly influenced by building ventilation modes. They were 3.58 µg/h and 2.15 µg/h with doors/windows open and closed, respectively. Our finding confirmed that commuting contributes disproportionately to the total BC exposure due to the high level of BC during traffic/travel. Building ventilation and air conditioning can significantly affect indoor BC levels and should be considered as a measure to reduce BC exposure within buildings in Hanoi.