- "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids, organic chemicals, metals, and soil or dust particles. - EPA
Generally, smaller particulate is more dangerous than larger particles
- "Inhalable coarse particles" such as those found near roadways and dusty industries, are larger than 2.5 micrometers and smaller than 10 micrometers in diameter.
"Fine particles," such as those found in smoke and haze, are 2.5 micrometers in diameter and smaller. These particles can be directly emitted from sources such as forest fires, or they can form when gases emitted from power plants, industries and automobiles react in the air. - National Ambient Air Quality Standards (NAAQS)
- "The smaller the particles are, the deeper they can be inhaled. Coarse particles generally pass nose and throat and enter into the lungs. Fine particles tend to penetrate into the gas exchange regions of the lung and some may even enter into the bloodstream." - Gerber et. al., 2015
Cigarette smoke contains significant amount of fine Particulate Matter or PM2.5.
Scientists found that the amount of particulate matter coming out from cigarettes is much greater than that from diesel engines.
- "The air pollution emitted by cigarettes is 10 times greater than diesel car exhaust, suggests a controlled experiment, reported in Tobacco Control."
- Medical News Today, August 25, 2004
- "According to the Center for Disease Control (CDC), smoking leads to 440k deaths a year in the US. However, smoking is less frequently viewed in terms of environmental health. In its tally, the CDC includes nearly 50,000 deaths from second-hand smoke, a risk associated with proximity to a smoker and a form of air pollution."
- Rachel Lipstein, 2015 Environmental Performance Index
1. Gerber et al., Tobacco smoke particles and indoor air quality (ToPIQ-II) – a modified study protocol and first results, Journal of Occupational Medicine and Toxicology (2015)
2. Invernizzi et. al. Particulate matter from tobacco versus diesel car exhaust: an educational perspective. Tobacco Control 13: 219-221. (2004)