Bans on smoking has cut secondhand smoke

Exposure rates reduced, but variances remain

According to the Journal of Occupational and Environmental Medicine, the official publication of the American College of Occupational and Environmental Medicine (ACOEM), bans on smoking in the workplace have substantially reduced on-the-job exposure to secondhand smoke for employees.

The researchers examined data on nearly 5,000 employed adults from a nationwide health study, the Third National Health and Nutrition Examination Survey (NHANES III). Only workers who did not smoke and were not exposed to secondhand smoke at home were included. The study analyzed changes in levels of the nicotine by-product cotinine, from initial blood samples obtained 1988-91 to follow-up samples taken 1991-94.

During this time, the workers’ blood cotinine levels decreased significantly, reflecting reduced exposure to secondhand smoke. Not only did the average blood cotinine level for all workers decrease, but so did the number of workers with any exposure to secondhand smoke. "In conclusion, decreases in . . . workplace exposure to secondhand smoke occurred between 1998 to 1991 and 1991 to 1994,"1 wrote the co-authors.

However, some occupational groups — including waiters and waitresses and some blue-collar laborers — are still exposed to high levels of second-hand smoke, reported Pascale Wortley, MD, MPH, and colleagues at the Centers for Disease Control and Prevention. "The lowest values were observed among farmers and nursery workers and the highest among waiters," wrote the researchers. (In a recent report, the National Institute for Occupational Safety and Health also notes discrepancies between occupations.)

Linking findings to policies

In the ACOEM study, the percentage of workers who said they could smell smoke at work decreased from 39% to 25%. This suggested that the drop in secondhand smoke exposure was related to the implementation of smoke-free workplace policies. The data also allowed the researchers to compare secondhand smoke exposure for workers in different occupational groups. In general, workers in blue-collar or service jobs had higher levels of exposure than those in white-collar jobs.

Second-hand smoke, sometimes called passive smoking, is a known cause of lung cancer and other health problems in nonsmokers. Over the last decade, many workplaces have implemented no-smoking policies; a 1999 study suggested that nearly 70% of the U.S. work force had a smoke-free workplace, according to ACOEM.

The nationwide NHANES III data suggest that the trend toward nonsmoking workplaces has successfully reduced exposure to secondhand smoke. Wortley and colleagues expect that 1999-2001 NHANES data will show further reductions in this occupational exposure. However, the findings show room for improvement in reducing exposure for all workers, especially in occupational groups with continued high rates of passive smoking.


1. Wortley PM, Caraballo RS, Pederson LL, et al. Exposure to secondhand smoke in the workplace: Serum cotinine by occupation. JOEM 44:503-509.

For more information, contact:

American College of Occupational and Environmental Medicine,

Pascale Wortley, MD, MPH, Office on Smoking and Health, Centers for Disease Control and Prevention, 4770 Buford Highway N.E., MS-K50, Atlanta, GA 30341-3717. E-mail:]