Determination of Silt Loading Distribution Characteristics Using a Rapid Silt Loading Testing System in Tianjin, China

ABSTRACT

Silt loading (sL) is an important parameter in the fugitive road dust (FRD) emission inventory because it can indicate the cleaning degree of roads. In this study, we combined Testing Re-entrained Aerosol Kinetic Emissions from Roads (TRAKER) with the AP-42 method to measure the sL values of paved roads in Tianjin, China, and we developed a rapid silt loading testing system for the period from January to October in 2015. This allowed us to establish the FRD sL reservoir in a more feasible manner on a larger urban scale compared with sL measurements alone. We found that the background-corrected TRAKER signals tended to increase slightly as the speed of the mobile monitoring system increased, and the sL values increased exponentially with the speed-corrected TRAKER signals. The sL values determined by TRAKER were quite different, where branch roads > minor arterials > major arterials > outer ring > expressway, due to differences in the average speed and traffic volume. Furthermore, the sL values determined using TRAKER were higher in the slow lanes than the other lanes (except for the outer ring), whereas the sL values produced by TRAKER in the express lanes of the outer ring were the highest among all the vehicle lanes. The frequency distribution of the sL values obtained by TRAKER for various types of roads differed significantly from each other in terms of magnitude, especially on the branch roads and minor arterials. In terms of the temporal distribution, the sL values obtained by TRAKER were substantially higher in summer, followed by spring and autumn, and lowest in winter.