Collaborative Research: Photochemical Silicon Aerosols: Establishing Atmospheric Sources and Significance

This research is focused on improving the understanding of the chemical and physical transformations of volatile methyl siloxanes (VMS) in the atmosphere. Volatile methyl siloxanes (VMS) are high production chemicals used in many personal care products such as deodorants and lotions. The results of this research are expected to lead to a better assessment of the fate and transport issues important for understanding the environmental and health consequences of the increasing use of VMS.

The objective of this project is to assess the chemical speciation and abundance of oxidized VMS in the laboratory and in ambient atmospheric aerosols. This research is expected to confirm the presence of particles formed from ambient organosilicon compounds, establish aerosol yields at near-ambient conditions under urban and remote oxidation conditions, determine the best aerosol tracer compounds for this class of secondary organic aerosols, and integrate the results of this effort into a state-of-science photochemical grid model that will enable the prediction of the fate of VMS upon oxidation at scales ranging from urban airshed to continental.

This research includes laboratory studies at the University of Iowa using an oxidative flow reactor (OFR) and experiments in the University of Colorado environmental chambers to probe the oxidation chemistry of VMS. Outdoor ambient sampling for VMS and its gas- and condensed-phase oxidation products will be conducted during a four-week summertime deployment in the New York City metropolitan area.

The scientific insights gained from this research will be incorporated into the Community Multiscale Air Quality (CMAQ) modeling system that will lead to better predictions of aerosol formation from personal care products.

This project is jointly funded by the NSF Atmospheric Chemistry Program and the Established Program to Stimulate Competitive Research (EPSCoR).

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.