A sniff of peppermint or a snort of lavender appears to enhance concentration and vigilance, according to scientific findings reported yesterday. The researchers suggested that one day mood-altering fragrances could be misted into offices and factories to increase worker productivity.

Fragrance scientists meeting here report that pleasurable smells are already being tested on clerical workers in Japan, strap-hangers in the London subway and patients having to endure brain scans, which require them to lie supine and motionless in claustrophobic, tunnel-like contraptions.

"It's somewhat Orwellian, isn't it?" said Robert Baron, a psychologist at the Rensselaer Polytechnic Institute, who found that even "air fresheners" bought at the grocery store produce positive effects in the performance of clerical tasks and face-to-face negotiations.

Because fragrances such as peppermint were shown to increase people's performance on tests measuring attentiveness and vigilance, the scientists speculated that employers may want to use piped-in scents to encourage productivity, just as manipulations in lighting, climate and, in some settings, recorded music are used to increase worker output and comfort.

Indeed, the scientists who presented their findings here at the yearly meeting of the American Association for the Advancement of Science predicted that in some settings, a "spritz of peppermint" could compete with caffeine as a "benign stimulant" to improve safety and job performance.

"The fragrance effect was about the same as low-dose caffeinated beverages," said William Dember, a psychologist at the University of Cincinnati, whose studies were funded by the Fragrance Research Fund, a nonprofit research organization supported by the fragrance and perfume industry.

To measure the effects of pleasant odors, Dember and his colleagues placed volunteers in front of a computer screen and fitted them with a face mask that delivered either a puff of peppermint or fresh air every five minutes.

The subjects were tested on their performance of "vigilance tasks," which required them to pay strict attention during a 40-minute test. Those who sniffed fresh air detected only 65 percent of the signal changes on the computer screen. Those who sniffed peppermint detected the altered signal about 85 percent of the time. Overall, peppermint inhalers did about 15 to 20 percent better.

Dember said in real life, people who might benefit from such olfactory entertainment include long-distance truckers, air traffic controllers and nurses in intensive care units. Factory and clerical workers also could gain from sniffing fragrances not yet studied.

Dember and his colleagues caution that they do not yet know enough about the power of smell to advocate that every employer could benefit by pumping pleasing perfumes into office buildings. Nor are they sure how long the effect might last or whether people would grow accustomed, and therefore unaffected, by the smells over time.

"It's a dramatic effect. It's a novel effect," said Joel Warm of the University of Cincinnati. "But we can't say you should do it yet."

In some cases, fragrance enhancement could be counterproductive. For example, Baron warned that it might not be wise to mist the air with peppermint during a job evaluation because it might make the reviewer too easy on the employee.

Moreover, Baron said the improved mood brought on by fragrance enhancement might make people more inclined to take risks, something not wanted in an air traffic controller.

In his study, Baron placed "pleasant artificial fragrances" -- actually, commercially produced air fresheners -- in a room and then observed people during mock negotiations.

He found that his subjects were more likely to compromise and make concessions when sitting in the fragrant room when compared to those in the unscented room. Baron did not speculate if the subjects in the room with air "fresheners" just wanted to hurry up and get out of the room, because some people say they find air freshener odors unappealing.

In a parallel study, Raja Parasuraman of Catholic University confirmed that peppermint increased vigilance. He also learned that brain waves associated with alertness increased in the subjects who inhaled peppermint.