Researchers at Washington University are expected to announce today the results of the first study to monitor secondhand smoke exposure in St. Louis area bars and restaurants and whether ventilation systems work in purifying the air.

The study was a joint effort between the Siteman Cancer Center at Washington University School of Medicine and the Center for Tobacco Policy Research at Washington University. Researchers looked at airborne nicotine levels, nicotine levels in employees’ hair samples, employees’ health, employees’ knowledge about smoke-free policies and the effectiveness of ventilation systems.

Key players are scheduled to discuss the findings at a 1 p.m. press conference. John Postel, marketing and entertainment manager of the Highlands Brewing Co. in Kirkwood, where a smoking ban went into effect over nine months ago, is also on the list to speak.

A smoking ban in public places in St. Louis and St. Louis County takes effect Jan. 2. However, casino floors, some hotel rooms, private clubs (mainly veterans and fraternal organizations) and tobacco stores are exempt. The county also exempts bars where income from food is 25 percent or less of gross receipts.

In the city, small bars — less than 2,000 square feet where food sales are "incidental" to alcohol consumption — have five years to comply with the ban.

Bans are already in effect in Clayton, Kirkwood, Arnold, Ballwin and Lake Saint Louis and throughout the state of Illinois. Some of the municipal laws, such as one that goes into effect Jan. 1 in Brentwood, ban smoking in all bars.