Salt. Salt is one of the best road dust control products available. Lignin Sulfonate and Calcium Chloride are two of the most popular unpaved road dust control products. These salts are mixed in a 35% solution and applied directly on the unpaved road.
What do they spray on gravel roads for dust control?
Calcium chloride and lignin sulfonate, two salts, when mixed with water in about a 35 percent solution and sprayed over gravel roads, have been found to be very effective at keeping dust down.