Effect of fuel reformulation (aromatics from 35 to 20 vol-%, sulfur from 0.05 to 0.005 wt-%) on exhaust emissions was measured from a car using ECE/EUDC tests. 14 PAHs, mutagenicity by Ames test and DNA adducts by using 32P-postlabeling were measured from the particulate soluble organic fraction (SOF). PAH-derived DNA adducts were measured in calf thymus DNA and human breast cancer MCF-7 cell line. Ames test and DNA adduct test measure the genotoxicity and metabolically activated PAHs in exhaust particulate SOF. PAHs, mutagenicity and DNA adducts were clearly reduced in SOF, which is a benefit caused by fuel reformulation.