Abstract: Road dust is one of the sources of urban ambient PM_2.5, and urban road dust suppressants are increasingly recognized as an effective measure for road dust control. To study the application effect of road dust suppressants, this study compared and monitored the application effect of road dust suppressants on actual roads using the road dust quantity detection method (including two indicators of road dust residue and road dust load), the gravimetric method for ambient air particulate matter, and the mobile monitoring method for ambient air particulate matter. The results from all three testing methods demonstrated that road dust suppressants had a certain application effect on road dust and particulate matter (PM₁₀ and PM_2.5). Compared with the control road section with water spraying, spraying road dust suppressants reduced the residual amount of road dust and road dust load by 20.6% and 24.3%, respectively. The reduction rates of PM₁₀ and PM_2.5 mass concentration in road ambient air were 7.1%-10.1% and 0.6%-2.5%, respectively, and the reduction rate of PM_2.5 was not as good as that of PM₁₀. When evaluating the effectiveness of road dust suppressants, the road dust quantity and road ambient air particulate matter concentration could be used as evaluation indicators. By conducting comparative testing on experimental and control road sections, with a minimum of 5 days before and after the suppressant application, the effectiveness of the road dust suppressant could be assessed more accurately.