Increasing temperatures not only increases the risk of wildfires and drought, but a new study also finds that during the hottest and sunniest periods, asphalts releases hazardous air pollutants.
Asphalt, also known as bitumen, is a primary source of pollution. In hot areas, asphalt emissions from roads and roofs combined can be more significant than petrol- and diesel-powered vehicles, the study says.
To study asphalt emissions closely, Yale University researchers placed samples of asphalt into an enclosed furnace at temperatures between 40C to 200C. Between temperatures of 40C to 60C, they find a doubling of asphalt emissions. High temperatures can make asphalt emissions a long-term source of pollution (Marshal, 2020).
According to the study, when the asphalt is exposed at temperatures of 60C for 18 hours, emissions increased at nearly 300%. Emissions continue at 30% after 18 hours.
Asphalt emissions react and transform into a pollutant particle known as PM2.5, a harmful substance when inhaled.
The increasing production of electric vehicles will likely see the decline in emissions from conventional cars. However, as cities and roading infrastructure expands, so is the use and application of asphalt.
Temperatures rise due to climate change can worsen asphalt emissions unless cities and communities living in highly paved areas apply green infrastructures to mitigate heat and prevent harmful asphalt emissions (Newburger, 2020).
To read the full study, click the link below:
Khare, P., Machesky, J., Soto, R., He, M., Presto, A., Gentner, D. (2020 September 2). Asphalt-related emissions are a major missing nontraditional source of secondary organic aerosol precursors. Science Advances. Retrieved from https://advances.sciencemag.org/content/6/36/eabb9785
Marshal, M. (2020 September 2). Asphalt on roads may soon be greater source of air pollution than cars. New Scientist. Retrieved from https://www.newscientist.com/article/2253470-asphalt-on-roads-may-soon-be-greater-source-of-air-pollution-than-cars/#ixzz6X1AEbFv6
Newburger, E. (2020 September 2). As Earth overheats, asphalt is releasing harmful air pollutants in cities. CNBC. Retrieved from https://www.cnbc.com/2020/09/02/climate-change-hot-asphalt-releases-harmful-air-pollutants-in-cities.html