Clean cars

When it comes to how much cars and other vehicles pollute, some makes are cleaner than others, according to new research.

A study using data on nearly four million cars that underwent US government-mandated emissions test in three states found that cars manufactured by German auto maker BMW were the least likely to fail these state pollution tests. Cars manufactured by Hyundai, Mitsubishi, Chrysler and GM were most likely to fail.

While other studies have analysed data from state emissions tests, this is the first time that researchers examined how different car makes compared, said Jean-Michel Guldmann, co-author of the study and professor of city and regional planning at Ohio State University.

“There are several factors that determine how much cars and trucks pollute, and vehicle make is one of the more significant,” Guldmann said.

In the case of trucks, Honda, Nissan and Toyota models were least likely to fail pollution tests, while Mitsubishi, Mazda and Chrysler were most likely to fail.