research

One of our primary aims 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, and their determinants, of the mainstream smoke aerosol. 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, as well as a portable high-flow topography unit which can record the way people smoke in their normal environments. We are currently developing a closed-loop 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.

In addition to characterizing the properties of mainstream waterpipe smoke, we are conducting a chamber-based study of second-hand waterpipe smoke, including the exhaled and sidestream smoke components. This work involves quantifying toxicants such as volatile aldehydes, polyaromatic hydrocarbons, carbon monoxide, and respirable particulate matter emitted by the smoker+waterpipe system, as well as measuring the evolution of the particle size distribution over time.

A second major aim of our work is to investigate by computational and experimental means the problem of growth and evaporation of hygroscopic aerosol particles in bounded flows with wall heat and mass transfer. This problem is fundamental to predicting-based on breathing patterns and particle properties-the fraction and location inhaled particles deposit in the human respiratory system. This is of use in studies of inhalation toxicology as well as drug delivery from medical nebulizers.

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