Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)
Tione Grant - University of the Virgin Islands
Co-Author(s): Antonio Brathwaite, Emory University, Atlanta Georgia
It is well-known that motor vehicles produce significant amounts of polycyclic aromatic hydrocarbons. These mutagenic and carcinogenic compounds are products of the combustion process and are present in vehicular emissions, in both the gas and particle phases.1 Traditionally, particle-phase PAH emissions have been studied by collecting cumulative emission samples from tunnels and analyzing them via high performance liquid chromatography (HPLC).1,2 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 was used to identify PAH’s in the particle-phase exhaust of two vehicles. Mass spectra of pure PAH samples were collected by compressing samples into disc-shaped targets 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, dissolved in benzene and analyzed via mass spectrometry. The results show that perylene and pyrene were present in the emissions of both vehicles, whereas, coronene and phenanthrene were found exclusively in the 2016 and 2006 models respectively. This data is interesting because it suggests a vehicle-dependent PAH presence in vehicular emissions, even between vehicles of the same make and model. Future work on this project will aim to expand the number and variety of vehicles sampled in an effort to reveal trends in PAH production.
(1) Marr, Linsey C., Thomas W. Kirchstetter, Robert A. Harley, Antonio H. Miguel, Susanne V. Hering, and S. Katharine Hammond. ‘Characterization of Polycyclic Aromatic Hydrocarbons in Motor Vehicle Fuels and Exhaust Emissions.’ Environmental Science & Technology 33.18 (1999): 3091-3099.
(2) Miguel, Antonio H., Thomas W. Kirchstetter, Robert A. Harley, and Susanne V. Hering. ‘On-Road Emissions of Particulate Polycyclic Aromatic Hydrocarbons and Black Carbon from Gasoline and Diesel Vehicles.’ Environmental Science & Technology 32.4 (1998): 450-455.
(3) Ravindra, Khaiwal., Sokhi, Ranjeet., and Van Grieken, Rene. ‘Atmospheric Polycyclic Aromatic Hydrocarbons: Source Attribution, Emission Factors and Regulations.’ Atmospheric Environment 42 (2008): 2895-2921.Not Submitted
Funder Acknowledgement(s): Funding for this project was provided by National Science Foundation HBCU-UP RIA.
Faculty Advisor: Dr. Antonio Brathwaite, firstname.lastname@example.org
Role: I conducted this research with some outside assistance from members of the UGA chemistry department, working under Dr. Michael Duncan. I collected and prepared the numerous samples for analysis, both of the pure hydrocarbon samples and the vehicular emissions. I operated the mass spectrometer and compiled all the data for this study. I also researched the necessary background information and papers to validate my work.