Titre : Modeling the Atmospheric Chemistry of Pollution Emitted from Alberta Oil Sands
Endroit : Pavillon Roger-Gaudry, salle G-415 à 11 h 00.
Cette conférence sera prononcée par Monsieur Jacob Sommers, étudiant au doctorat du laboratoire de Patrick Hayes, professeur au Département de chimie de l'Université de Montréal.
RÉSUMÉ: Organic aerosols (OA) are a major component of regional and global pollution. Along with other particulate matter (PM), OA has a complex effect on climate and health, at all geographic scales. Global and regional air quality models underestimate the formation of OA, largely due to poorly constrained parameterizations for secondary OA (SOA), which is formed by oxidation of gaseous species in the atmosphere. In this work, a customized box model is developed to evaluate commonly used SOA formation parameters. While most box model evaluations are compared to urban regions, the Athabasca Oil Sands (OS) are a unique source of SOA which provide a rare opportunity to evaluated models against a large and isolated source of SOA.
This work compares two methods for improving predictions of SOA that are typically biased low in traditional SOA models. The first approach incorporates multi-generational oxidation to increase SOA mass. The second approach adjusts calculated SOA yields to correct for precursor losses to experimental chamber walls. This work also compares two previously proposed volatility distributions which may describe intermediate and semi-volatile precursor emissions from bitumen with the goal of assigning emission sources. Each case is evaluated by comparing to measurements of OA concentration and the oxygen-to-carbon ratios (O:C). Finally, by using O:C ratios of individual OA components, the model is further elaborated to allow two phases representing non-polar OA and polar OA.
