The quoted study "...assumes for all cars that present and future emission-control technologies will be more widely used in 2020, especially particulate filter

The quoted study "...assumes for all cars that present and future emission-control technologies will be more widely used in 2020, especially particulate filters which have a marked effect on cleaning diesel exhausts." Why wouldn't you assume similarly optimistic scenarios for large scale power generation. It's clearly easier to retrofit and regulate about a 100 power station to trap particulate matter etc. than assuming that millions of gasoline and diesel cars on the road will each individually have correctly functioning filters. Also, a large number of EV's on the road means that any future power plants' improved cleaner nature instantly affects the pollution impact of all the cars on the road.