Research Overview
Atmospheric nanoparticles (aerosols) adversely affect human health by damaging the respiratory and cardiovascular systems, and they are implicated in 30,000 or more deaths per year in the United States alone. Our research focuses on better understanding the formation, transformation and properties of aerosols, helping to develop effective policy actions aimed at mitigating aerosol concentrations and their adverse effects.
We conduct laboratory chamber experiments simulating the atmosphere as well as ambient measurements. We utilize newly developed, state-of-the art instruments and techniques to probe the chemical and physical properties of aerosols. We will use our experimental results in chemical transport models which can help inform policy makers
Instrumentation
We use several instruments to identify and quantify species in the gas and particle-phase. The main instrument central to our work is a High-Resolution Time of Flight Chemical Ionization Mass Spectrometer Coupled to a Micro-Orifice Volatilization Impactor (MOVI-HRToF-CIMS) from Aerodyne Research, Inc. The Micro-Orifice Volatilization Impactor (MOVI), originally developed at the University of Washington, is an inertial impactor specifically designed for coupling to a chemical ionization (CI) mass spectrometer. Data acquisition with the MOVI includes two main steps: (1) Particle collection and simultaneous mass-spectral identification and quantification of gas-phase species and (2) temperature programmed thermal desorption with synchronized mass-spectral analysis of vaporized aerosol species. Thus, the unique MOVI-CI design makes possible semi-continuous mass spectrometric analysis of both gas and condensed-phase composition.
The MOVI-CIMS utilizes a High Resolution Time-of-Flight Mass Spectrometer (ToFMS) from Tofwerk AG (Thun, Switzerland). In contrast to the scanning procedures used by quadrupole mass spectrometers (QMS), ToFMS is a technique which simultaneously measures the concentrations of all mass-to-charge (m/z) values of interest. The high resolution of this ToFMS makes possible the determination of molecular formulas based on the exact m/z.
List of externally funded projects
"Interactions Between Organic Aerosol and NOy: Influence on Oxidant Production"
Funded by: Texas Air Quality Research Program
PI: Lea Hildebrandt Ruiz, UT-Austin; Co-PI: Greg Yarwood, ENVIRON
"Environmental Chamber Experiments to Evaluate NOx Sinks, NOx Recycling"
Funded by: Texas Air Research Council
PI: Lea Hildebrandt Ruiz
"Atmospheric Chlorine Chemistry in the Dallas-Fort Worth Region"
Funded by: Texas Air Research Council
PI: David Allen, UT-Austin; Co-PI: Lea Hildebrandt Ruiz, UT-Austin
Hildebrandt Ruiz Research Group