Identification of Polycyclic Aromatic Hydrocarbons in the Particle-Phase Vehicle Emissions  
Tione Grant  
Undergraduate Student  
University of the Virgin Islands, College of Science and Mathematics 
 
Motor vehicles are well-known producers of polycyclic aromatic hydrocarbons. These mutagenic 
and carcinogenic compounds are products of the combustion process and are present in both gas 
and particle phases. Traditionally, particle-phase PAH emissions have been studied by collecting 
cumulative emission samples from tunnels and analyzing them via high performance liquid 
chromatography (HPLC). To our knowledge, there has been no investigation of vehicle-specific 
emissions to ascertain the dependence of PAH formation on vehicle model, age and fuel type. In 
this study, laser desorption time-of-flight mass spectrometry identified PAH’s in the particle-phase 
exhaust of two vehicles. Mass spectra of pure PAH samples were collected by compressing 
samples and ablating them with a Nd: YAG laser in a mass spectrometer. Samples of particulate 
matter were collected from the tailpipes of a 2006 and 2016 Toyota 4Runner and analyzed. The 
results showed a presence of perylene and pyrene in both vehicular emissions, whereas, coronene 
and phenanthrene were found exclusively in the 2016 and 2006 models respectively. This data is 
interesting because it suggests vehicle-dependent PAH presence in vehicular emissions, even 
between vehicles of similar make and model. Future work on this project aims to expand the 
number and variety of vehicles sampled to reveal trends in PAH production.  
 
Keywords: Polycyclic Aromatic Hydrocarbons , Mass Spectrometer.