A recent study from the University of York suggests that shifting car exhausts to the right side could potentially reduce harmful air pollutants on U.K. streets by up to a third. This research has been detailed in a publication from ACS ES&T Air.

According to the study, cars with exhaust pipes on the left produce pollution at levels that are 40% higher compared to those situated on the right. The research team utilized advanced techniques to analyze traffic-related air pollution (TRAP) in urban areas, allowing them to model the concentration of pollutants like nitrogen oxides (NO_x) based on exhaust positioning.

The Impact of Location

The researchers estimate that positioning the exhausts on the right for all U.K. diesel cars could lead to a one-third decrease in NO_x emissions at the roadside. Currently, only 20.1% of diesel passenger cars, which mainly contribute to NO_x emissions, have their exhausts on this side, as the U.K. follows left-hand traffic rules.

Interestingly, the study also highlights an unexpected advantage of electric vehicles (EVs). Not only do they have no tailpipe emissions, but they also help dilute the exhaust from nearby petrol and diesel vehicles. This is due to the way air turbulence from EVs mixes with and diffuses exhaust plumes, offering additional protection for pedestrians and cyclists.

Significant Findings

Professor David Carslaw, the study’s lead author, stated, “Our findings show that even minor changes in vehicle design can significantly impact air quality near roads.” He added that adjusting tailpipe placement offers a straightforward option for manufacturers to lower roadside pollution. Additionally, the surprising benefit of EVs in mitigating existing pollution further emphasizes the urgency for their increased use.

To thoroughly investigate air quality around roadways, the researchers employed a fast measurement technique that enabled detailed analysis of how exhaust emissions disperse and affect those near the road.

“This research sheds light on the intricate links between various factors that influence urban air quality,” noted Professor Carslaw. “This understanding is vital for both policymakers and car manufacturers as we look for solutions to combat health issues arising from traffic pollution.”