Extreme Temperatures Cause Asphalt to Release Harmful Emissions

Increasing temperatures increase the risk of wildfires and drought, but a new study also finds that during the hottest and sunniest periods, asphalts release hazardous air pollutants.

Asphalt, also known as bitumen, is a primary source of pollution. In hot areas, the study says asphalt emissions from roads and roofs combined can be more significant than those from petrol—and diesel-powered vehicles.

To study asphalt emissions closely, Yale University researchers placed samples into an enclosed furnace at temperatures between 40C and 200C. Between temperatures of 40C and 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 to temperatures of 60C for 18 hours, emissions increase by 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 decrease emissions from conventional cars. However, as cities and roading infrastructure expand, so is the use and application of asphalt.

Temperatures rising due to climate change can worsen asphalt emissions unless cities and communities in highly paved areas apply green infrastructures to mitigate heat and prevent harmful asphalt emissions (Newburger, 2020).

To read the complete study, click the link below: