Quantification of lung doses from inhaled tobacco smoke
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: This project studies two things: predicted accumulation of inhaled cigarette smoke in the lungs, and how long cigarette smoke stays in the air of a room. Because smoke is more comp-licated than most air pollutants, understanding these two health-related issues is scientifically challenging. Clouds of fresh cigarette smoke contain very large numbers of microscopic liquid drops, which are called particles. Because of this high concentration of particles, smoke clouds can behave in an unusual way, which is not seen with ordinary particles in the air, such as dust from a vacuum cleaner or water droplets from a mist sprayer. Before being diluted by the surrounding air, cigarette smoke clouds move as bodies with distinct shapes rather than as separate particles that drift apart in random directions. Persistent smoke rings blown by smokers are evidence of this cloud-type motion.
 
 
 
 
 
 The research in this project involves studies of the effects of cloud-type motion on where and how much cigarette smoke accumulates in the human lung after the smoke is inhaled, and on the rate at which secondhand smoke clears from the air of rooms in which people are smoking. It has been known for a long time that more cigarette smoke deposits in the human lung than is predicted by computers when the effects of cloud motion are ignored. In addition, since the liquid drop particles in the smoke are so tiny, scientific calculations indicate that they should deposit in the very deepest parts of the lung. However, lung cancers often occur in the upper parts of the lung. Also, computer calculations indicate that clouds of cigarette smoke will fall out of the air slower than we have observed. This project works on improving the computer calculations so that they will better describe what takes place in reality.
 
 
 
 
 
 The methods are innovative. Smoke accumulation in the lung will be studied using rubber and plastic models of lung airways which have the same sizes and shapes as airways in real human lungs. Airways in both the upper and lower parts of the lungs will be included, as will human-like breathing patterns. We will also study where one of the most likely lung cancer-causing agents in smoke deposits. The results from these experiments will be used to improve the predictions obtained using computer programs that calculate risks.
 
 
 
 
 
 The effects of air movement, air temperature, and moisture in the air on the speed that secondhand smoke clears from a room will also be studied. In addition, how the presence of the smoker (in our case, a heated mannequin) affects the speed of clearing of smoke from a room will be examined. This information can be used to design efficient smoke control techniques for homes, offices, and other environments.
 
 
 
 
 
 In summary, our project will produce needed information on the unusual behavior of clouds of cigarette smoke, and will generate new information which can be used to measure and control the risks of smoking.