CAREER: Laboratory Studies on the Chemical Characterization of Atmospheric Emission Sources and their Oxidative Evolution using Novel Instrumentation

Washington University, Saint Louis MO

Investigators

Abstract

1554061 Williams Pollutants emitted to the atmosphere have a wide array of natural and anthropogenic origins. These pollutants almost immediately undergo oxidative aging processes that transform their molecular composition, ultimately influencing their fate. Vapor and particle pollutants, either emitted directly or formed from atmospheric photochemistry, have detrimental health impacts and can alter the climate. This proposed project will specifically look at organic compounds which comprise a major fraction of air and particulate pollution. To understand the health and climate impacts of specific emission sources, it is necessary to assign these pollutants to their sources of origin. This project will address improved measurement methods and focused laboratory studies to obtain detailed chemical composition of source-specific gases and particles as they undergo oxidative evolution in the atmosphere. The primary goal of this project is to advance the understanding of the sources and transformation of organics emitted to the atmosphere through (1) creation of new in-situ instrumentation for chemical characterization of gases and particles, (2) controlled laboratory studies of the emissions and gas-to-particle formation pathways/potential from simple precursor vapors to realistic complex sources, (3) development of an open-access and searchable mass spectral and source profile database, and (4) integrated education and outreach activities including an academia/industry research experience program for undergraduates and direct research involvement from grade 6-12 students as part of a Peer Mentoring Pipeline Program. The current understanding of the chemicals released from natural and anthropogenic emission sources is limited, and the knowledge of the subsequent chemical transformations of these chemicals that occur while in the atmosphere is even more limited. At the conclusion of this project, metrics will be available for incorporation in model simulations and for field observation interpretation on volatility- and polarity-resolved source-specific chemical composition at the molecular and compound-class level. Additionally, new parameterizations, reaction mechanisms, and gas-to-particle aerosol production yields will be provided for a variety atmospheric oxidants (e.g., OH, O3, NO3) at different concentrations, for a variety of sources (e.g., single gases of differing volatilities and chemical functionality, simple mixtures, complex real sources), with consideration of other atmospheric variables (e.g., NOx and SO2 additions, seed particle types, and humidity levels). New instrumentation will be produced that extends chemical characterization of these emissions across a range of volatilities (from the most volatile gases to the least volatile condensed-phase material), offering new insights on specific atmospheric transformation pathways and fates of these materials. A new academia/industry research experience program in Atmospheric Science and Technology will offer undergraduate students an opportunity to work in both settings, helping to guide their career paths through first-hand experience. This will strengthen academic/industry connections and advance the field. In addition, grade 6-12 students will play a direct role in laboratory studies through the Peer Mentoring Pipeline Program.