research

One of our primary goals is to elucidate the potential health consequences of smoking the narghile waterpipe (aka shisha, hooka), a tobacco smoking device used widely in Southwest Asia and North Africa, and increasingly around the world. We are approaching this problem by studying the chemical and physical properties of mainstream and sidestream smoke, as well as “second-hand smoke”. This work has involved developing new instruments for the as-yet sparsely researched waterpipe such as the "playback smoking machine" which can replicate in detail real smoker puffing behavior, a portable smoking topography unit which can record the way people smoke, and an automatic control isokinetic sampling device that attaches to the mouthpiece of the waterpipe and samples a small fraction of the smoke generated by real smokers in their natural settings. Some of these instruments are being used by our collaborators at the Clinical Behavioral Pharmacology Lab at Virginia Commonwealth University and the Syrian Center for Tobacco Studies.

We are also conducting a chamber-based study of second-hand waterpipe smoke, including the exhaled and sidestream smoke components. Using a novel artificial lung waterpipe smoking machine developed at the Aerosol Lab, this work involves quantifying toxicants such as volatile aldehydes, polyaromatic hydrocarbons, carbon monoxide, and respirable particulate matter emitted by the smoker-waterpipe system. The characteristics of the emitted particle size distribution and its evolution over time are also being measured in near real-time.

Another major research focus in the Aerosol Lab is characterizing growth and evaporation of aerosol particles in the continuum and near-continuum regimes. Using computational and experimental means we have studied the problem of growth and evaporation of hygroscopic aerosol particles in bounded flows with wall heat and mass transfer, a problem fundamental to predicting the fraction and location inhaled particles deposit in the human respiratory system. This is relevant to understanding health effects of inhaled pollutants and to designing respiratory drug delivery devices.

Most recently, we have begun work with the Khlystov Aerosol Research Lab at Duke University on measuring thermodynamic and physical properties of organic aerosols, with relevance to cloud formation, air pollution, and climate modeling studies. Properties being measured include molecular evaporation coefficient, surface free energy, heat of vaporization, and vapor pressure.

We gratefully acknowledge the sponsorship of this work by the Research for International Tobacco Control Secretariat of the International Development Research Centre (Canada), the US National Cancer Institute (R01 CA120142), as well as the University Research Board of the American University of Beirut.