Cigarettes worse than diesel cars?

The New Scientist reports that an Italian group finds cigarettes produce more respirable particulates than a diesel car.

“I was very surprised. We didn’t expect to find such a big difference in the particulate matter produced,” says Giovanni Invernizzi from the Tobacco Control Unit of Italy’s National Cancer Institute in Milan, who led the study.

This needs verification: among other little details we need to know the relative distributions of particle sizes and estimates for the total volumes of junk produced. Note that this refers to modern diesel cars: I've been around some older cars and trucks that strangled me even worse than smokers do.