Grant: Discovery Grants Program - Individual

Considerable scientific research is oriented to providing answers to the disturbing effects of the impacts of global change. There is a growing need to introduce new methodologies to explore the often very complex and interconnected chemistry of the atmosphere. Over the past 30 years spectroscopy has provided many of the answers to fundamental questions in combustion and atmospheric science, but these studies are best undertaken under single reaction conditions in controlled environments due to the difficulty of deconvolving the spectroscopic signatures of related species in complex mixtures. In addition, conventional reactors are typically incapable of observing low concentration intermediates in the thermolysis process. Thus, new approaches such as mass spectrometry are required that take advantage of increasing detection selectivity under more relevant reaction conditions. Mass spectrometry alone, though, is insufficient in the case of isomeric products as they have the same m/z ratio. Thus, we also employ the more selective imaging threshold photoelectron spectroscopy (TPES). In addition to purely gas-phase processes, the role of aerosol surfaces and water/ice droplets must be elucidated in order to create a complete picture of combustion and atmospheric chemistry. Thus, this proposal includes the experimental exploration of the interaction of the target molecules with protonated water clusters using reactive tandem mass spectrometry.  The long term goals are to provide a more concrete mechanistic basis for the atmospheric chemistry of reactive organic carbon at the molecular level.  In the short term, we are focusing on formates (used as fuel additives and pesticides), peroxyactylnitrates (PANs, long distance transporters for NO2) and terpenes (released by vegetation).  We will explore their thermal decomposition by pyrolysis, their reactivity by oxidation and their interactions with water clusters to obtain a more complete map of their atmospheric behaviour.  The Government of Canada estimates that 14,600 premature deaths per year can be linked to air pollution. The number of asthma symptom days in Canada is around 2.7 million with air pollution estimated to cost the Canadian economy $114 billion per year. With the current government's ambitious net-zero emission goals for 2050, being able to predict the air quality outcomes of reactive organic carbon is crucial to be able to target species that are key to a cleaner future.