Contributions of roadside vehicle emissions to general air quality in Hong Kong

Data for 7-year from three roadside, three urban background, and one rural monitoring stations are employed to look at the contribution of roadside vehicle emissions to the general air quality in central Hong Kong. It is found that within the urban core of Hong Kong, variations in concentrations of various gaseous pollutants are heavily influenced by variations in local traffic volume. The daily patterns of NO2, NOx, and particulates concentrations at roadside and background stations are similar while no common daily concentration pattern of SO2 can be found. Concentration at nearby roadside and background stations are closely correlated for all pollutants investigated. Daily variations of NO2, NOx, and particulates concentrations at roadside and urban background stations follow the traffic pattern of the area closely. Similarities exist between traffic volume and SO2 concentration, but they are less clear. For each of the pollutants, traffic volume and concentration in the urban background are positively correlated.