The dangers of indoor tobacco smoke have been well documented, but now some researchers are turning their attention to possible health effects of concentrated outdoor smoking, such as that often found outside the doors of bars and restaurants, Medical News Today reported May 24.

In states and cities that have banned indoor smoking, it has become more common for smokers and their friends to congregate outside to indulge their habit. Researchers are now starting to study whether the trend produces health risks of its own.

"Athens is a college town, and we have thousands of college kids standing shoulder to shoulder outside bars and restaurants on weekend nights. In select areas outside certain establishments, we believe many of these young people are exposed to elevated levels of secondhand smoke," says researcher Luke Naeher, Ph.D., of the University of Georgia College of Public Health. "You can have 40 to 50 smokers in a small area -- which translates to fairly aggressive exposures to secondhand smoke, even if it's outside. We want to know what those exposures are, and if it's unhealthy, we want to tell policy makers who are making decisions about these regulations."

Naeher and colleagues presented findings from a study that found that airborne pollution levels outside bars rose with the number of smokers present; a follow-up study will collect urine and saliva samples to determine the secondhand-smoke exposure level of patrons standing outside bars.

"There's a wide range of health effects that are tied to secondhand smoke," said Naeher. "With more inside smoking bans, more people seem to be smoking outside. Are we creating zones that are potentially unhealthy? That's what we're trying to figure out."

The research was presented at the 2007 International Conference of the American Thoracic Society.