The Road Hits Back!

 

Researchers at Yale and Carnegie Mellon Universities, along with the Max Planck Institute of Chemistry, have studied the impact of temperature on asphalts from roads in a range of locations (https://www.theguardian.com/environment/2020/sep/02/asphalt-roads-make-city-air-pollution-worse-in-summer-study-finds). They found, that the emissions of secondary organic aerosols (SOAs), an air-polluting particulate, doubled as the temperature was raised from 40 to 60⁰C. SOAs have been shown to negatively impact on human health (as do other particulates from diesel cars). The temperatures of road surfaces (the black asphalt surface effectively absorbs solar radiation) can easily reach 60⁰C on a hot summer day. Consequently, SOAs may be major causes of poor air quality, especially in busy urban centres. We also will not entirely rid ourselves of harmful particulates, simply by replacing diesel cars with electric vehicles.