CHEMICAL AND BIOLOGICAL CHARACTERIZATION OF PARTICULATE-PHASE-ASSOCIATED, SEMIVOLATILE-PHASE-ASSOCIATED AND GAS-PHASE-ASSOCIATED COMPOUNDS IN DILUTED HEAVY-DUTY DIESEL EXHAUSTS - A COMPARISON OF 3 DIFFERENT SEMIVOLATILE-PHASE SAMPLERS

Exhaust emissions from a heavy-duty diesel vehicle during transient driving conditions have been characterized chemically and tested for mutagenicity. Both the particulate phase and the semivolatile phase were investigated chemically and by the Ames test. Three different sampling techniques, i.e., cryocondensation and two adsorbents XAD-2 and polyurethane foam (PUF), were used for collection of the semivolatile phase together with a particulate filter situated upstream. The cryogenic technique was the least efficient type and the PUF technique gave the highest recovery of polycyclic aromatic hydrocarbons (PAH) and mutagenic activity. The amount of PAH, mainly three-ringed PAH, emitted in the semivolatile phase was approximately 3 times higher than that emitted in the particulate phase. The contribution of the semivolatile phase to the total mutagenicity was approximately 20% in strain TA100+/-S9, 10% in strain TA98-S9, and 37% in strain TA98+/-S9. The results thus show the importance of both particulate- and semivolatile-phase-associated compounds when possible health effects from diesel engine exhausts are being considered.