What technical and environmental factors drive the shift from coal tar to asphalt emulsion waterproofing?

Environmental drivers include regulation of coal tar due to PAH content and concerns about runoff contamination. Technically, asphalt emulsions offer lower VOC, lower odor, and safer handling because they are water-based and often applied at lower temperatures. The trade-off is that coal tar can have strong chemical resistance to fuels and oils, so projects that need that property must compensate with system selection, film build, or alternative chemistries. Overall, asphalt emulsions align better with modern environmental compliance while still meeting many waterproofing needs when properly specified.