Abstract: The road dust suppressant was used to reduce the dust in the air at Kandan Bridge, Fengtai District in Beijing. The sprayed area was 0.4 million square meters. Sampling points were set both at sprayed area and non-sprayed area to monitor change of PM_2.5, PM₁₀, NO_x concentrations before and after the spraying, and the water-soluble anions and elements collected in the particulates analyzed. The results showed that the air pollution situation was improved by the way of spraying dust suppressant. PM₁₀ was reduced significantly, the restrain rate is 25.0%. PM_2.5 took the second, the restrain rate is 12.0%, and NO_x was controlled only in a short term, the rate is 20.1%. In addition, the dust suppressant was efficient for controlling certain specific anions and inorganic elements in the air.