Air-filtration systems remove more haze than hazardous chemicals, but British American Tobacco (BAT) ignored its own research and pitched filters as an alternative to bans on indoor smoking, The Australian reported Jan. 28.

BAT researchers reported in 1993 that the filters only removed about 34 percent of airborne toxins like carbon monoxide, but the company persisted in urging hotels, bars, and others to use the units. "When entering into deals with restaurant/club owners we try to first convince them of the filters' capability by demonstrating a 'mini' unit which we fill with smoke, switch on, and watch the smoke disappear in a few seconds -- an attention grabber," wrote BAT scientist Nigel Warren in 1996. "We point out that by imposing a smoking ban in their outlet they may suffer a loss of (smoking) customers and maybe their non-smoking friends, too."

BAT also developed "smoking tables" that drew smoke down into filters but then recirculated the partially cleansed air back into the room.

"Even if the technology was improved from that in the 1990 filtration units, the tables would be ineffective because isolation of the sources or the worker are the only control measures that yield air quality that is safe to breathe," said Richard Hurt, director of the Mayo Clinic's Nicotine Dependence Center.

Experts said that smoking bans were the only way to prevent harm from indoor smoking.

The findings were reported in the Jan. 28, 2006 issue of the British Medical Journal.