Margaret E. Greenslade

Assistant Professor

Physical Chemistry
Department of Chemistry
Parsons Hall 241
University of New Hampshire
Durham, NH 03824-3598

Education and Achievements

  • B.A., 1998, Bryn Mawr College
  • Ph.D., 2005, University of Pennsylvania
  • Research Scientist, 2005 - 2007, Cooperative Institute for Research in Environmental Science (CIRES) at University of Colorado, Boulder and an affiliate of the National Oceanic and Atmospheric Administration (NOAA)

Research Interests

Physical and Atmospheric Chemistry. Chemical and physical transformations of aerosol properties. Aerosol optical properties are of specific interest.

Current Research Interests

Aerosols are ubiquitous in the atmosphere and play intriguing roles in physical and chemical processes impacting fields such as atmospheric sciences, climate change, combustion, medicine, and health. We will investigate aerosol properties using physical chemistry methods and relate the results to broader questions.

Figure 1: A coal-fired power plant in Cheshire, Ohio
Photo from

Complex aerosol mixtures are of special interest and how their optical and morphological properties change as a function of environmental influence. For example, an aerosol emitted from fossil fuel combustion may contain elemental/black carbon, aliphatic hydrocarbons and polycyclic aromatic hydrocarbons. Once emitted, such an aerosol may encounter other species in the atmosphere that can mix and/or attach to it like sea salt or ammonium sulfate. In addition, aerosols are processed by gas phase oxidants, humidity, temperature and light.

One of the main techniques we will use is cavity ring-down (CRD) spectroscopy. CRD is commonly used to measure absorption of gas phase species. It has recently been adapted for in situ measurement of aerosol extinction. Especially sensitive to small optical changes, CRD will be used to study a variety of aerosols under both controlled and ambient settings. This system will allow the interrogation of aerosols before and after processing.

Figure 2: Schematic of a typical cavity ring-down experimental set-up

Another technique that we will use is optical microscopy. Aerosol optical microscopy combines an ordinary optical microscope with a stage onto which aerosols can be deposited and observed resulting in a highly visual technique. The aerosol's morphological response to changes in environment, particularly with respect to relative humidity and temperature, will be measured.

Additional experimental and theoretical work is planned for the future.

Related Publications and Presentations

M.E. Greenslade, D. A. Lack, T. Baynard, A. R. Ravishankara, E. R. Lovejoy, "The Humidity Dependence of Aerosol Absorption Measured using Photoacoustic Spectroscopy: Capabilities and Limitations of the System for Atmospheric Measurements," manuscript in preparation.

American Geophysical Union Fall Meeting 2006 in San Francisco, CA, December 2006. Poster Presentation: "Optical Properties of Absorbing Aerosols as a Function of Relative Humidity"

University of New Hampshire, Physical/Analytical Seminar in Durham, NH, November 2006. Presentation: "Optical Properties of Absorbing Aerosols"

Boulder Laboratories Postdoctoral Poster Symposium in Boulder, CO, June 2006. Poster Presentation: "Optical Properties of Absorbing Aerosols as a Function of Relative Humidity"