In-vehicle airborne fine and ultra-fine particulate matter exposure: The impact of leading vehicle emissions.

Airborne particulate matter (PM) concentrations inside vehicle cabins are often extremely high compared to background levels. The present study was motivated by the fact that in the last few decades, the implementation of new emission standards has led to the reduction of vehicle particle emissions. This study addresses for the first time the relationship between leading vehicle (LV) emissions and in-cabin PM exposure levels in the immediately following vehicle (henceforth called the study vehicle - SV), with particular emphasis on the role of the LV's emission reduction technologies (e.