Re-suspension of road dust: contribution, assessment and control through dust suppressants—a review

High level of particulate matter pollution in the urban areas of major cities is significantly affecting the human health due to its toxic chemical constituents. Re-suspension of road dust along with tyre and brake wear are the dominant sources of PM pollution in the urban area in both developed and developing countries. This paper mainly reviews the contribution of road dust in ambient PM level, factors affecting re-suspension of road dust and chemical reagents available for dust suppression. The emission of road dust re-suspension significantly varies based on amount of silt deposited on the road, type of road (paved and unpaved road, concrete material of the paved road), number and types of vehicles movement. The chemical reagent such as calcium magnesium acetate, magnesium chloride and calcium chloride are reported to significantly reduce the PM emissions from road dust in developed countries. Therefore, the efficacy of these chemicals in reducing the road dust from the urban road in developing countries needs to be evaluated along with the cost–benefit analysis and comparison with the conventional approach of dust control (road cleaning and washing). However, the associated factors in different countries may vary significantly as compared to Western countries.