Characterization of environmental tobacco smoke by neutron activation analysis as a source of hazardous metals in indoor air pollution

The characterization of environmental tobacco smoke (ETS) as a source of heavy metals has been performed. Thirty elements were determined in 15 brands of cigarettes and their components. Five elements, Br, Cd, Cl, K, and Zn were found to be major elemental sources in the particulate phase of ETS. The elemental distribution in cigarette components was examined using a mass balance before and after cigarette smoking. The results show that most elements retain their major fraction in cigarette ash; only cadmium has a large emission (44%) in sidestream smoke, which thus makes cadmium a very important element of exposure to passive smokers. Elemental particle size distribution in ETS was measured in a room size chamber. The mass mean diameters ranged from 0.20 $\mu$m to 0.35 $\mu$m.Instrumental neutron activation analysis was improved for air filter samples by using epithermal neutrons and Compton suppression counting techniques. The detection limits have been reduced to a few nanograms for Cd and less than a half nanogram for As and Sb. The method provides a means for large scale multi-element determination.The evaluation of cadmium as a marker of ETS was carried out. Cadmium concentration in ETS free indoor air was measured to be less than 2 ng/m$\sp3.$ The cadmium source in tobacco of American cigarettes was determined to be 1.25 $\pm$ 0.18 $\mu$g/g, of which about 60% of the cadmium in consumed tobacco was released as ETS. Cadmium in ETS was found to exist in small particles (less than 1 $\mu$m), and Cd concentration in ETS was observed to decay slowly, and increase linearly with the strength of the source.The One-Compartment Model was chosen in this study for validating the experimental results. A parameter, deposition velocity, in the model was measured by the experiments, with a value of 0.04 m/h. The elemental and total suspended particulate (TSP) emission factors were measured both in sidestream smoke and in the chamber, and results show that they strongly depend on smoking conditions, except for Cd. The predictions of TSP concentrations agree with the experimental results. The amount of TSP and cadmium in ETS inhaled by a passive smoker was estimated.U of I OnlyETDs are only available to UIUC Users without author permissio