Frequently Asked Questions

Here are some answers to common questions about this website.

What is secondhand tobacco smoke?

Secondhand tobacco smoke, sometimes referred to by its acronym SHS, is the material that is emitted from a burning cigarette, cigar, or pipe -- and then mixed in the air. Secondhand tobacco smoke consists of both the smoke that comes from the butt end of the cigarette or cigar, or the pipe bowl, and smoke that is inhaled by the smoker and subsequently exhaled. Secondhand tobacco smoke contains many dangerous chemicals and has been associated with a variety of health problems, including lung cancer, asthma, and heart disease mortality. You can find out more about secondhand tobacco smoke in the scientific literature, in general news articles, or on various web pages.

What do you mean by "exposure"?

Human exposure to an environmental air pollutant is defined as contact between molecules of the pollutant and a given biological boundary, such as the breathing zone or the human lung. For the purposes of this website, we consider exposure as the concentration of airborne particles from secondhand smoke in the breathing zone of a person. We DO NOT consider any uptake or dose of the chemical components of secondhand smoke. You can learn more about the science of exposure on various websites and in scientific articles.

Is secondhand smoke really bad for you?

In a word "yes". The weight of evidence shows that exposure to secondhand tobacco smoke (SHS) can lead to a variety of maladies some very severe, such as lung cancer and heart disease mortality.

See this description of the 2006 US Surgeon General's Report on the health effects of secondhand smoke.

The U.S. Environmental Protection Agency published a seminal report on respiratory illnesses due to SHS exposure in 1993. You may want to read an updated assessment of that report.

Is there a glossary for the scientific terms?

In describing and interpreting results from the simulation of exposure to secondhand tobacco smoke (SHS), we make use of common scientific terms. Below is a list of some of these terms and their explanation.


Simulation
The artificial depiction of events with the intention of closely mimicking reality.

Steady State
The condition that is reached when material entering a system is balanced by material leaving a system. When this happens the concentrations in the system do not vary over time, i.e., they reach a "steady state concentration".

Micrograms per Cubic Meter, μg m-3
The units of air pollutant concentration commonly used for particulate matter. Micrograms are a millionth of a gram. A cubic meter is the volume of a 3D space that has dimensions of 1 meter along each side. Micrograms per cubic meter is usually abbreviated as μg m-3.

Concentration
A quantity equal to the mass of suspended material that is mixed in a given volume of air. Concentration is typically reported in units of micrograms per cubic meter (μg m-3) for air pollutants.

Particulate Matter (PM)
Material in the air that is in the particle (condensed) phase. Also called "airborne particles" or "aerosol".