Relationship between concentration of pyrene and aerosol size distribution in traffic exhausts in Taipei, Taiwan.

Variations in pyrene concentrations in motor-vehicle emissions were assessed on the basis of aerodynamic particle size and by the type of vehicle (i.e., car, truck, or bus) that passed through a Taipei, Taiwan, highway toll station. Airborne particles were collected with 8-stage cascade samplers equipped with 34-mm polyvinyl chloride filters and located in the breathing zones of toll-station workers. The authors used gas chromatography/mass spectrometry to analyze 22 polycyclic aromatic hydrocarbons that were collected. The absolute concentration of pyrene was highest in the fine-particle emission fraction for trucks, buses, and passenger cars; however, fine particles in truck and bus exhausts contained higher pyrene concentrations than the corresponding size fraction of particles emitted from passenger cars. Truck and bus emissions contained a higher concentration of pyrene than car emissions because trucks and buses produced greater amounts of fine and coarse particles, and their fine particles contained higher concentrations of pyrene.