Odour is big business. Both producing it and eliminating it. While perfume and toiletry companies battle to churn out novel fragrances to entertain our olfactory receptors, the huge odour control industry strives to protect us from the assault of nasty scents. This is actually a greater challenge. In the perfume trade you can get away with some inventive advertising and fanciful claims, but when it comes to eliminating odours, well, it isn’t hard to tell if a product works or not.
Bad smells are not rare. Pet urine, garbage, manure, sewage, mildew, sweat and the toilet bowl all waft undesirable fragrances into the air. How do you get rid of them? There are several options. The odour can be masked by a more powerful one, which is essentially what floral scented air fresheners do. Or the smelly molecules can be removed from the air. Air purifiers pass the air through activated carbon filters which can bind smelly compounds. Zeolites (aluminosilicate minerals) have an amazing ability of adsorbing molecules to their surface and are available in various formats.
Chemical reactions can also be used. Fish odour on the hands is due to chemicals called amines. But if reacted with citric acid in lemon juice, they form salts that do not become airborne. Washing hands with lemon juice therefore eliminates fishy aromas. Many undesirable smells, such as that of spoiled food, are due to organic acids, and can be neutralized by baking soda. Fragrant molecules in the air can also be destroyed by means of a chemical reaction. Ozone generators produce ozone gas which can destroy smelly compounds in the air. The smell of smoke after a fire yields to ozone. Certain enzymes produced by bacteria can also chew up foul compounds. Most pet odour eliminators are bacterial concoctions.
Molecules can also be removed from the air by interacting with other volatile substances in such a way that the resulting complex is no longer volatile. Cyclodextrin, the active ingredient in products like Febreze, is a large molecule made of glucose units joined in a ring. Malodorous compounds are entrapped in the ring, and the cyclodextrin-smelly molecule complex, because of the extra mass, now settles out of the air. Some essential oils from plants can also interact with volatile compounds in this fashion and many smell “neutralizers” are based on this principle.
But there is more to essential oils. Some can bind to receptors in our nose without triggering any action, and in the process block other molecules from interacting with the receptor. Sort of like the wrong key fitting a lock without being able to unlock it, but preventing the right key from being inserted. There has been a great deal of research trying to find specific essential oils to block specific smells, with some success. Unfortunately the information is proprietary and companies will not reveal exactly what oils they use, but the results can be effective in controlling bad smells emanating from pig manure, landfills and sewage treatment plants.
Sometimes odour control products and perfumes can work hand in hand. The Harvey Prince Company, a New York based perfume manufacturer, claims to have come up with just such a happy union in “Ageless Fantasy,” a perfume having the “smell of youth.” I bet you sniff a scam coming up. But maybe not. At least, not a total scam. The whole idea is based on the notion that as we age our body chemistry changes, and we produce novel compounds.
Japanese researcher, Shinichiro Haze analyzed the scents emanating from shirts worn for three days by subjects ranging in age from 26 to 75. One particular compound stood out. 2-Nonenal, with an odour described as greasy, grassy, “old book,” or “old person” was more prominent in the elderly. Subsequent research revealed that it was the product of bacterial action on vaccenic and palmitoleic acids, both of which are found in sweat and increase with age.
Armed with this knowledge, Harvey Prince developed “Ageless Fantasy” with hopes of neutralizing the scent of 2-nonenal. Chemically destroying a scent is not in the realm of a perfume, however, masking one is. But the company wanted something more than just a masking smell. It wanted a youthful fragrance. Previous research had indicated that the scent of grapefruit was associated with youth. Could there be some mix of plant fragrances that both blocked 2-nonenal and optimized the youth effect? In an intriguing experiment women were anointed with different scents while a panel of men judged their age. The scents of apple, pink grapefruit, pomegranate, mango and pineapple consistently made the men underestimate the age of the wearer. Floral fragrances like jasmine and cherry blossom triggered happy emotions. Feelings of youth and excitement were attributed to musk and vanilla.
So Harvey Prince blended all these, plus more, in Ageless Fantasy and sprinkled it on women. Men were then invited for a sniff test. And the results, we’re told, were quite exciting. The testers judged the women wearing Ageless Fantasy to be eight years younger than their chronological age.
I’m not sure what we can make of all this, because the research hasn’t been published. Did they test to see if the scent of pure 2-nonenal was masked? Did they use controls? Did they determine how the men guessed ages in the absence of a perfume? Maybe men are polite when asked to judge a lady’s age. Or maybe any perfume would provoke similar results. Who knows? But for $120, you can try your own experiment. Let’s face it, getting older stinks. While a perfume can’t turn back the clock, it may trick others into believing that you had a dip in the fountain of youth.
