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Size-segregated Chemical Composition of Tobacco Smoke

Institution: University of California, Irvine
Investigator(s): Neha Gowadia, M.Pharm.
Award Cycle: 2007 (Cycle 16) Grant #: 16DT-0001 Award: $16,652
Subject Area: General Biomedical Science
Award Type: Dissertation Awards

Initial Award Abstract
The purpose of this study is to help estimate dose of inhaled toxicants in the lung from cigarette and hookah smoking. Estimation of dose of inhaled toxicants is necessary to compare risks posed by tobacco smoking products that are perceived or claimed as less harmful than cigarettes. Hookah smoking, a growing smoking trend in California is perceived less harmful than cigarette smoking. However, the chemical composition of hookah smoke has only begun to be investigated and little is known about the health risks associated with hookah smoking. Therefore, in the proposed work we measure selected toxicants (including few carcinogens) like N-nitrosamines and polycyclic aromatic hydrocarbons in hookah smoke that will help provide dosimetric estimate of these toxicants. This estimation will offer a dosimetric basis for comparative health effects of cigarette and hookah smoking, helping to predict their comparative risk. The dose of inhaled toxicants to the lung consists of local, regional and total dose. This dose distribution of toxicants present in the particulate phase of smoke is controlled by its particle size. In this proposal we hypothesize that different chemicals in tobacco smoke speciate in different particle sizes based on their boiling point, vapor pressure and time for coagulation. Therefore, we expect that chemical speciation of toxicants in specific particle sizes will change their doses to the lung. To test our hypothesis, we measure size-separated chemical composition of mainstream cigarette and hookah smoke for selected toxicants including few carcinogens. Our work will utilize selected research cigarettes and commercial cigarettes for comparison with the hookah. The selected chemical constituents of major toxicological significance in smoke will be measured. These chemicals include nicotine; N-nitrosamines - NNK, NNN, NAT, NAB, NDEA, NDMA; Polycyclic aromatic hydrocarbons - benzo(a)pyrene, benzo(h)fluroanthene, benzo(k)fluoranthene, chrysene, phenanthrene and fluoroanthene. To emulate the effect of various inhalation patterns by smokers, these chemical constituents will also be analyzed using three different puffing regimens. Based upon the experimental results, a mathematical model will be proposed to predict the particle size specific chemical speciation. This data can be used to predict the deposition of these specific chemicals in the lung, estimate their doses, which can be used in the risk assessment of these toxicants.