ENVIRONMENT Diesel pollution higher than tailpipe tests show

make sure they meet pollution limits.

Experts and the researchers don’t accuse car and truck makers of cheating, but say testing is not simulating real-world conditions.

“The paper shows how much human failure costs,” said Jens Borken-Kleefeld, a transportation scientist at the International Institute for Applied System Analysis in Austria.

The researchers included a team from the International Council on Clean Transportation, a nonprofit research and advocacy group, which arranged the testing that first showed VW diesel cars were rigged to cheat on emissions tests. They used previously published tests of pollutants coming from thousands of vehicles, all models, to calculate the extra pollution in 2015. Worldwide, three-quarters of that extra pollution is from trucks and buses.

Other research connects soot and smog to heart and lung diseases, with pollution killing more than four million people every year around the world, said lead author Susan Anenberg, a researcher at Environmental Health Analytics.

The researchers calculated that the extra nitrogen oxides were responsible for about 31,400 deaths in 2015 because of tiny soot particles in the air.

Allen Schaeffer, executive director of the US industry group Diesel Technology Forum, said it’s impossible to design a lab test that could cover all real-world driving possibilities but industry officials and regulators are working on it.

“It’s important to understand that diesel has been a technology of continuous improvement, meaning that today’s generation of new diesel technology is lower in emissions and more efficient than one built 10 or even five years ago,” Schaeffer said in a statement.