A featured item on the website
A new study has been completed by researchers at the Harvard School of Public Health showing that levels of secondhand smoke particles in cars can reach dangerous levels, even when windows are open. Based on 45 trials, they report that peak levels with closed windows were over 500 μg m-3, on average, and peak levels with open windows were about 100 μg m-3, on average. See if you can simulate levels of this magnitude using the vehicle simulation model available on this website.
An article describing the study is appearing in the November 2006 issue of the American Journal of Preventive Medicine and can be downloaded.
Vaughan Rees, the lead author on the paper, says that “The smoke particle levels we measured are alarming and are above the threshold for what’s considered unhealthy for sensitive groups — people like children and the elderly."
The creator of this website, Dr. Neil Klepeis, is available to perform custom simulations of tobacco smoke exposure for policy or education purposes -- in most cases free of charge. This service is intended to assist those website visitors who may want to explore a specific exposure situation or who may want to compare a variety of different potential exposures, such as those taking place in sophisticated multizone environments or involving prescribed human activity patterns.
The U.S. Surgeon General has released its anticipated report "The Health Consequences of Involuntary Exposure to Tobacco Smoke".
Important findings of the report include (paraphrased):
Two new research papers on the simulation of exposure to secondhand smoke occurring in residences are being published in the journal Atmospheric Environment, authored by Dr. Neil Klepeis and Prof. William Nazaroff. (links: 1 , 2).
These papers contain detailed simulation results of likely exposures that can occur in homes for a variety of ventilation conditions and occupant behavior patterns.
This simulation is of smokers in an enclosed (indoor) bar or restaurant over a 2-hour period where there are designated smoking and nonsmoking rooms. The two rooms are well-mixed and connected by a doorway or open passage.
You may select the dimensions of each room (Length x Width x Height in feet), the overall rate of outdoor air exchange (h-1), which is apportioned to each room according to their volumes, the air flow rate between zones (m3 h-1), which is currently the same in each direction, and the total number of cigarettes smoked in the smoking room of the venue over the 2-hour period.
Multiple smokers can be active simultaneously. Each cigarette lasts 10 minutes. Cigarette starting times are assigned randomly. A given cigarette has an equal chance of being lit during any minute of the 2-hour period.
The California Air Resources Board (ARB) has just designated secondhand tobacco smoke as a toxic agent, according to an article in the San Francisco Chronicle (there is also a shorter piece):
''The designation...places secondhand smoke in the same category as the poisons arsenic and benzene.''
This simulation is of one or two smokers in a two-zone house over a 12-hour period where each zone is well-mixed.
You may select the volume of each zone (m3), the overall rate of outdoor air exchange (h-1), which is apportioned to each zone according to their volumes, the air flow rate between zones (m3 h-1), which is currently the same in each direction, and the total number of cigarettes smoked in each zone.
The cigarettes are assumed to be smoked at even intervals.
This simulation is of a smoker in a car over a 1-hour period. You may select the volume of the car (m3) and the rate of outdoor air exchange (h-1), which depends on the window and ventilation positions in the car.