by Patricia McBroom
Tobacco smoke in the workplace is creating a health risk for non-smokers that is as great or greater than the hazard of living with a smoker at home, according to an unusually large study of many different work environments.
Particularly in open offices that allowed smoking, ambient nicotine levels averaged more than twice as high as in homes with a smoker present, found S. Katharine Hammond, associate professor of public health, and colleagues in the study published Sept. 26 by the Journal of the American Medical Association.
By comparison, levels in shop or factory environments that allowed smoking were roughly comparable to those found in studies of home exposure, Hammond discovered.
Such high levels of environmental smoke mean that non-smokers are being exposed to a significant health risk at work if their employers allow smoking on the job, said Hammond.
In work environments as a whole, that risk is about one death per thousand individuals, a level at which safety and health administrators often consider taking action, she said.
Hammond also found that smoking policies that restrict or ban on-site smoking work very well, reducing the average pollution exposures by 80 to 95 percent depending on the degree of restriction.
"It would be wise to have policies that restrict smoking to enclosed, separately ventilated areas or ban it entirely in the workplace. There is no need to expose people to this hazard," she said.
Hammond's study is one of the largest ever done of occupational exposure to cigarette smoke. Some 25 worksites in Massachusetts were tested, including firehouses, textile industries, manufacturing plants of various kinds, newspapers and offices.
The sample came from an on-going cancer prevention study called the WellWorks project funded by the National Cancer Institute and carried out while Hammond was with the University of Massachusetts Medical School in Worcester. An earlier study by Hammond, published by JAMA in 1989, helped bring about smoking restrictions on airlines.
In this study, researchers took measures of average weekly concentrations of nicotine levels with monitors placed on the site. They discovered that, depending on the smoking policy in effect and the kind of work environment, nicotine levels covered a very wide range.
"ETS (environmental tobacco smoke) does not build up as much in workspaces that are large, with high ceilings and good ventilation," the article said.
Smoking policy had dramatic effects on exposure levels. Offices that allowed smoking showed average nicotine concentrations of 8.6 micrograms per cubic meter, compared to 1.3 micrograms in sites that restricted smoking and .3 micrograms in sites that banned it. Average concentrations in shop environments that allowed smoking were 2.3 micrograms per cubic meter, falling to .7 micrograms and .2 micrograms in the restrictive and banned conditions.