Keywords: air pollution, nitrogen oxide, traffic volume, urban-rural roadways, Southeastern China, urban trunk roads, belt highways, suburban roads, forest areas, air quality
Spatial and diurnal variations in concentration of atmospheric NOx along urban-rural roadways in Nanjing, Southeastern China
Atmospheric NOx concentrations (including NO2 and NO) on the roadside environments of urban trunk, belt highway and suburban road as well as a reference in a forest area were measured. NOx concentrations on roadside environments tended to be higher than that on the reference. With the exception of suburban road, NOx concentrations over both of the urban trunk and belt highway exceeded the limited value of National Air Environmental Quality Standards. Gradient measurement of NOx on the downwind side of the belt highway shows that it declined to background level over 100 m from the road edge.