ChE Seminar – “Studying how particles evolve in the atmosphere by trapping them in an outdoor cage” by Dr. Don Collins (Texas A&M University)
Host: Drs. Lea Hildebrandt Ruiz and David Allen
I will present results from the first field use of a pair of portable chambers we developed to study processing and growth of aerosol particles as they are exposed to gas phase composition and solar intensity that mirror that just outside. The chambers were located in a clearing within a state forest just north of Houston during a pair of experiments that together spanned the period from June, 2015 to October, 2016. I will focus on the results from 2016 when steps taken to improve automation resulted in nearly continuous measurement of the growth of captive particles in response to production of secondary aerosol, which is simply the aerosol material that forms in the atmosphere from reactions of gas phase precursors. At this site we were most interested in production of secondary organic aerosol (SOA) from nighttime reactions involving nitrate radical originating from NOx emissions from the Houston area and biogenic hydrocarbons emitted by trees in the surrounding forested area.
Don Collins is a professor of Atmospheric Sciences at Texas A&M University. He received his B.S. in Civil Engineering from Virginia Tech in 1994 and his Ph.D. in Environmental Engineering Science from Caltech in 2000. He is currently the director of the Center for Atmospheric Chemistry and the Environment that serves to connect the research and researchers that are spread out among several departments across the university. His research is focused on examination of the properties, effects, and atmospheric processing of aerosol particles. He and his group spend most of their time in the lab and in the field using instruments that they design and build, with a current emphasis on environmental chambers. His current research activities are largely motivated by the need to better constrain i) the growth and transformation of aerosols in various environments, ii) the impact of aerosols on clouds and of clouds on aerosols, and iii) the controls and impacts of aerosol-phase water.