Electron Microscopic Analysis of Silicate and Calcium Particles in Cigarette Smoke Tar

Abstract

Scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDS) supplies information that is complementary to those data traditionally obtained using inductively coupled plasma-mass spectrometry for analysis of inorganic tobacco and tobacco smoke constituents. The SEM-EDS approach was used to identify select inorganic constituents of mainstream cigarette smoke "tar." The nature of SEM-EDS instrumentation makes it an ideal choice for microstructural analyses as it provides information relevant to inorganic constituents that could result from exposure to combusted tobacco products. Our analyses show that aluminum silicates, silica, and calcium compounds were common constituents of cigarette mainstream smoke "tar."Identifying inorganic tobacco smoke constituents is important because inhalation of fine inorganic particles could lead to inflammatory responses in the lung and systemic inflammatory responses. As cigarette smoking causes chronic inflammation in the respiratory tract, information on inorganic particulate in mainstream smoke informs efforts to determine causative agents associated with increased morbidity and mortality from tobacco use.

Aluminum in Tobacco Products Available in the United States

“…This work resulted in a validated method for the analysis of an analytically challenging metallic element in tobacco. The new method was used to determine aluminum concentrations in various tobacco products, and complements our earlier work using SEM-EDS (17, 18). However, it must be emphasized that the route of exposure to aluminum depends on whether the tobacco product is smokeless or combustible.…”

“…We have previously shown using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), that aluminum silicate particles are present in mainstream smoke (17). Insoluble aluminum silicate particles have been described as “smokers’ inclusions,” and as the principal particles visible in pulmonary macrophages of smokers (14, 15, 16).…”

“…Tobacco smoke inhalation is another route of human exposure to aluminum (14, 15, 16). Most aluminum compounds are not volatile, but when aluminum-containing substances such as tobacco undergo combustion, inhalation of the resulting mainstream smoke results in oral and pulmonary exposure to insoluble aluminum silicates (17). When combustible tobacco products are smoked, aluminum in the mainstream smoke aerosol is derived from soil-based insoluble aluminum silicates adhered to the leaf surfaces (17, 18) and possibly soluble and insoluble forms derived from internal uptake by the plant (4, 7).…”

“…Most aluminum compounds are not volatile, but when aluminum-containing substances such as tobacco undergo combustion, inhalation of the resulting mainstream smoke results in oral and pulmonary exposure to insoluble aluminum silicates (17). When combustible tobacco products are smoked, aluminum in the mainstream smoke aerosol is derived from soil-based insoluble aluminum silicates adhered to the leaf surfaces (17, 18) and possibly soluble and insoluble forms derived from internal uptake by the plant (4, 7). It is likely that non-volatile aluminum-containing compounds are transported in mainstream smoke in a manner similar to other non-volatile compounds in particulate liberated by combustion of the matrix (19).…”

Direct imaging evidences of metal inorganic contaminants traced into cigarettes

“…[70] Potassium sulphate and chloride are evident other organic particulate in cigarettes. [71] Breathing small amounts of these particulate inorganic agglomerate for short periods of time has adversely effects on human respiratory system by irritating eyes, nose, throat, lungs with sneezing, coughing and sore throat.…”