Effectiveness evaluation of water-sprinkling in controlling urban fugitive road dust based on TRAKER method: A case...

Fugitive road dust (FRD) contributes a great deal to urban rainwater and air pollution and is commonly controlled by water-sprinkling in most Chinese cities. However, there is a lack of information on its effectiveness. We used the Testing Re-entrained Aerosol Kinetic Emissions from Roads (TRAKER) method to monitor different types of roads in Baoding city before and within 1 hr after water-sprinkling and obtained the road dirtiness index (a) and PM concentration in the road environment (T_T^*), to evaluate the removal efficiency for PM deposited on the road surface (η_a) and the reduction efficiency for the PM concentration in the road environment (η_PM). The results give that the η_a for three types of roads is ranked: branch road (87%--100%) > major arterial road (80%-83%) > minor arterial road (68%-77%), and the η_PM ranked: minor arterial road (70%) > branch road (46%-58%) > major arterial road (37%-53%). The η_a and η_PM varied non-linearly with time and presented a quadratic curve. The average effective control time (η_a> 0) was 62 min on the major and minor arterial roads, and much longer than 1 hr on branch roads. The η_PM values diminished completely by 72 min on average from the end of sprinkling for the three types of roads. Water-sprinkling can remove PM₁₀ particles from the road surface and reduce their concentration in the road environment more thoroughly than PM_2.5. Our findings could be helpful for controlling urban FRD emissions more efficiently and precisely.