Asphalt is a source of smog: especially in summer, when temperatures rise and it is directly hit by the sun's rays, the road surface emits pollutants that can give rise to fine dust, in particular the dangerous PM 2.5.
This was revealed by a study published in the journal Science Advances, conducted by Peeyush Khare of Yale University and based on laboratory experiments exposed to different agents, such as temperature increase and sunlight.
It emerged that an average increase of 20 degrees, compatible with what occurs in large urban centers in summer due to summer temperatures, leads to a doubling of total asphalt emissions.
Even its direct exposure to sunlight leads to a quadrupling of asphalt emissions.
Experts warn that with the inexorable rise in temperatures predicted due to climate change, metropolitan roads will increasingly be a source of emissions, which may even exceed those of diesel and petrol vehicles in the future.