Basic and Clinical Sciences (BCSE) Practice Exam

In the context of cigarette smoke, sidestream smoke refers to the smoke that emanates from the burning tobacco product, while mainstream smoke is the smoke inhaled by the smoker. Sidestream smoke often contains higher concentrations of certain harmful chemicals due to the lower combustion temperatures and incomplete burning of tobacco when compared to mainstream smoke.

The reason nicotine, ammonia, and nitrosamines are more prevalent in sidestream smoke is that these components are released during the combustion process. Sidestream smoke has a higher proportion of these toxic substances because they are byproducts of the incomplete combustion occurring when the smoldering end of a cigarette is producing smoke without being actively puffed.

Nicotine is a well-known addictive substance, while ammonia contributes to the irritant properties of smoke, and nitrosamines are recognized carcinogens associated with tobacco use. These compounds can pose significant health risks to both smokers and non-smokers exposed to secondhand smoke, making their prevalence in sidestream smoke particularly concerning.