Hot Asphalt May Increase Air Pollution in Urban Areas

A new study reports that asphalt emits significant amounts of pollutants in hot conditions. "[Researchers] observed that asphalt emissions doubled when the temperature increased from 40C to 60C — levels the material often reaches in summer," reports Rhi Storer.

When road asphalt was exposed to both solar radiation and heat, to mimic outdoor summer conditions, the researchers found a 300 percent increase in emissions. The release of secondary organic aerosols has been shown to have public health impacts, notes Storer.

While most traffic-related pollution comes from vehicle sources, the impact of cars and trucks may decrease as gross polluters are phased out. As a result, asphalt emissions may contribute more to air pollution as urban areas grow—45 percent of the surface area in the United States is paved—and temperatures rise due to climate change.