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The main use of dust suppressants is to minimize dust emissions from unpaved roads and unpaved shoulders of paved roads. Loss of aggregate and subsequent road surface deterioration (e.G. Ruts, potholes, and corrugations) with the loss of road surface fines results in dust generation. There are two major alternatives employed to achieve desired dust control results. The first general method to control dust generation is to apply good construction and maintenance practices on unpaved roads. The second general method is the application of chemical methods of dust suppression. Other methods of dust suppression include changes to speed limits, encouraging the use of alternative routes, restricting heavy traffic, paving roads, or changing the timing of road construction and maintenance activities (i.E., to occur during wet weather). Seven categories of dust suppressants have been identified and described in the report: chloride (e.G. Calcium chloride and magnesium chloride) salts and brines. These chemicals are either mixed in place with the top few centimeters of surface material, or they are topically sprayed. Water-attracting chemical dust suppressants are recognized for providing the best combination of application ease, durability, cost, and dust control for semi-arid, semi-humid, and humid climates. They can have significant impacts on the reduction of dust (e.G. 30 to 80%) but require frequent re-application to maintain long-term dust suppression performance. Environmental impacts of chlorides include metal corrosion, degradation to nearby vegetation, surface water, groundwater and aquatic species. Organic non-bituminous chemicals (which include lignosulfonates, sulphide pulp mill liquors, tall oil pitch, pine tar, vegetable oils, and molasses) adhere to the soil particles or physically bind the soil particles together to increase particle mass and cohesion. They tend to require frequent application. Environmental impacts include being sticky, odorous and visually unappealing. They are also slow to biodegrade, may contribute to deoxygenation of surface water (i.E. From spills) and may cause the road to become slippery when wet. Petroleum-based binders and waste oils are insoluble and create a sealed surface on the road. They can be very effective. However, there may be significant sealed surface leakages associated with hazardous components that may contaminate surface and groundwater. Electro-chemical stabilizers attract positively charged fine dust particles and bind ionically to them. They also expel adsorbed water from the soil and increase compaction. These stabilizers are considered environmentally acceptable, but vegetation does not easily establish on compacted sites where sulphonated petroleum products have been used. Polymers, most effective in lightly trafficked surfaces, are composed of long-chained molecular structures. These dust suppressants can stick to more particles and bridge greater gaps between particles. Enzyme slurries promote compaction, which reduces dust generation. They have been effective under highly specific trafficked surface and aggregate conditions. Cementitious binders work by chemically and permanently binding soil particles together.
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