Although barely detectable by the average nose, fragrance fills the air of most shopping malls. Retailers want consumers to stay a little longer and buy a little more.
Some real-estate agents supply home sellers with cinnamon rolls to pop into the oven moments before an open house.
And it does more.
Technicians at New York City's Sloan-Kettering Cancer Center disperse vanilla-scented oil into the air to help patients cope with the claustrophobic effects of magnetic resonance imaging (MRI) testing.
Scents will soon be used at the Chicago Board of Trade to lower the decibel level on the trading floor.
And Judie Bertolino, who teaches 3- and 4-year-olds at Palisades United Methodist Preschool in Capistrano Beach, uses a household plastic spray bottle to fill her classroom's air with spearmint oil twice a day.
"Odors can impact upon behavior," said Alan R. Hirsch, director of the Smell and Taste Treatment and Research Foundation in Chicago, "because the part of the brain that recognizes smell, the olfactory lobe, is part of the limbic lobe or emotional brain."
In his 1996 study on odors and learning, Hirsch discovered that people were able to complete a maze 17% faster when wearing a floral-scented mask.
Some teachers have been collecting their own data on the subject.
"It's not a Jekyll-and-Hyde kind of thing," said teacher Bertolino. "But I've really seen the difference in one little boy who's been having trouble adjusting to school.
"Most of the time he has a real problem using words instead of his hands to express himself. But when I spray the room [with scents], he seems far more able to calm down, to recognize his inappropriate behavior."
Not only does the aroma help some of her students feel at home in a strange environment, but it also fits in with the current educational philosophy of addressing the needs of the whole child.
"Teaching children through the senses of touch and smell have been underutilized," Bertolino said.
Aromatic oils, such as the spearmint oil used in Bertolino's classroom, are distilled from various parts of plants and have chemical properties affecting specific parts of the body. Some are antiseptic, antibacterial and fungicidal. Others act as stimulants, anti-inflammatories and sedatives.
Oils may be inhaled (diluted and sprayed into the air), absorbed through the skin (mixed with carrier oils such as almond oil) or combined (as in bath additives). Pure oils should not be applied directly to the skin or taken orally.
"There are some aromas that are excellent for helping people who are very uptight," said pediatrician Martin Baren of Orange. "There's no doubt in my mind that some lavenders are very helpful because they have a chemical affect on the ability to relax."
However, the 65-year-old developmental/behavioral pediatrician doesn't believe that aromatherapy, or any form of alternative medical treatment, can improve concentration or learning ability.
"If a teacher wants badly enough for her kids to do better, for a period of time they will. It's called the Hawthorne effect. It's a well-documented psychological premise that's true for diet, vitamins and minerals," he said. "There's a 35% placebo effect of anything you use, no matter what it is."
After conducting 85 studies relating to the sense of smell and how people are affected by it, Hirsch also has some unanswered questions.
Why does the effect of aroma on learning ability last for only 15 minutes? Are we seeing a nostalgic response prompted by earlier memories?
"People's cognitive processes are influenced by their emotional state. If you're in a happier mood you tend to do better," he said.
"Teachers usually spend a great deal of time decorating the blackboard and preparing visual displays to reinforce their lesson material. Using good smells in the classroom is another idea."
It was the health and emotional well-being of her students that prompted Anneliese Schimmelpfennig to use aromatherapy.
"In the [German] village where I grew up, the children were sent out into the fields to collect different kinds of herbs. We made oils from the rosemary, lavender and pine seeds," said Schimmelpfennig, who runs the three Anneliese's Schools in Laguna Beach.
After lunch each day, the youngest children at two of her schools are treated to a nap-time environment permeated with the aroma of lavender, eucalyptus and mandarin (a blend created by Isha Oils called Childhood Dreams). Oil diffusers (electrical devices that work like room vaporizers) are turned on, and the tiny scholars settle down on their miniature cots.
"In the morning all of the children, even the little ones, do a lot of learning, lots of activities in reading, math and language. By lunchtime they really need to relax. In the afternoon the children can focus better because they've had a very deep sleep, and their concentration is higher," said Schimmelpfennig.
Iris Kober, a teacher at Anneliese's Schools, says she has noticed that the children usually awake in a good mood and ready to tackle the rest of the day.
"The kids are calmer and nicer to each other," she said. "I also think that everyone is more creative when they have good smells around them. It opens their minds to different things in their surroundings."
Parents who arrive at school during nap time usually ask for advice about using essential oils at home.
Besides helping her fourth- and fifth-graders concentrate better, aromatherapy has provided some unexpected benefits in Tami Schwartz's class at the Camellia Avenue School in North Hollywood, she says.
In the beginning of the school year she sprays a dilution of lavender oil "because it has good antibacterial qualities" in the classroom and and introduces her students to the the concept of using things found in nature for health. The children are asked to bring something from home that their parents use for healing when they get sick.
"The kids bring in the most amazing things, mostly potted plants grown in their apartments. We've gotten a lot of yerba buena and a plant that is cooked and used for ear infections," said Schwartz, who has used aromatherapy in her classroom for four years.
Schwartz is convinced that when these children feel a closer connection between home and school they feel less intimidated and, ultimately, learn better.
Marilyn Nardini-Smith teaches severely handicapped middle-school-age children at an Orange County public school. Most of her students use wheelchairs, and many are blind or deaf.
"When you go through the day without being able to see or hear anything, your sense of smell becomes very important to you. It might be the only way you can understand what's going on around you," said Nardini-Smith, who, like many teachers, pays for the essential oils, spray bottles and diffusers out of her own pocket.
A believer in the value of aromatherapy, she sought a professional aromatherapist to blend three combinations of essential oils.
In the morning she sprays a blend containing orange blossoms intended to create a feeling of relaxation, happiness and alertness. After lunch the children are treated to the scent of rosemary, designed to stimulate and wake them up after eating a meal. The end of the school day is signaled by a pine smell reminscent of the outdoors.
Deciding to introduce aromatherapy in her classroom was no casual decision for Nardini-Smith. All of the parents and staff members were allowed to experience the essential oils before the students did.
"We haven't had any miraculous breakthroughs with any of our students," Nardini-Smith said. "But we have a happier, more relaxed staff. Anything that helps our staff members creates better people [to work] with our students."
Experts advise teachers who use aromatherapy in the classroom to thoroughly educate themselves first and buy only high-quality essential oils from reputable vendors.
The title "aromatherapist" may be used by only someone who has received certification by an aromatherapy school. tMany aromatherapists, like Kathy Styrcula, owner of Of the Earth in San Juan Capistrano, hope that national guidelines for certified training programs will soon be established.