Air. It’s not the first thing that comes to mind when you’re searching for a gripping article topic. And yet, the lungs do so enjoy a deep breath of clean air, and the nose delights in a pleasantly scented room. There may be more to air than meets the eye. . . .
As it turns out, olfaction, or the sense of smell, is quite intriguing. Olfaction is based on chemosensation, or the detection of environmental chemicals. As such, it is the oldest of the senses. It was the very first sense to evolve, and even single-cell organisms are capable of chemosensation.
How does the sense of smell function in advanced multicellular organisms such as humans? The human nasal cavity contains special chemical detectors known as olfactory receptors. Airborne molecules known as odorants interact with the olfactory receptors. These receptors in turn activate neurons that connect directly to the brain. The activation of a specific set of receptors and neurons allows our brain to identify a specific odor. Volatile chemicals from blue cheese, for example, trigger one set of receptors, while volatile chemicals from a tiger lily trigger a different set. In this way, humans can detect more than one trillion distinct scents.
Odors in the Air
Pure, clean air shouldn’t smell. Pure air is 78 percent nitrogen, 21 percent oxygen, and 1 percent various other odorless gases such as argon and carbon dioxide. Our living environments, however, contain additional chemicals and particulate matter. These may be harmless and enjoyable, like the volatile oils of an orange peel that stimulate the salivary glands, or dangerous and off-putting, such as the volatile organic compounds in cheap carpets that can cause headaches and cancer.
We tend to take air for granted, but we shouldn’t. Poor air quality can have serious consequences. The World Health Organization estimates that air pollution causes 7 million premature deaths each year. Common outdoor air pollutants in the United States include ozone, particulate matter, carbon monoxide, nitrogen oxides, sulfur dioxide, and lead. There may be many other pollutants in your outdoor air, depending on where you live. Common indoor pollutants include smoke, mold, asbestos, bacteria, household cleaners, dust, volatile organic compounds such as formaldehyde and benzene, pet dander, and radon. All of these may be lurking in your air.
Bad Smells Gone Good
Air pollutants might be odorless, or they might really stink! Bad smells function as a warning system, and a bad smell can be a good thing if it leads you to the source of a dangerous air pollutant, such as a basement full of mold. Before reaching for a scented spray to cover up a bad odor, first try to find and eliminate the source of the odor.
Other measures for optimizing indoor air quality are to ban indoor smoking, test for radon, keep humidity levels below 50 percent, seal all water leaks and eliminate any standing water, remove and treat any mold or mildew, fully vent gas- or wood-burning appliances, put food away immediately after eating, take garbage out regularly, choose nontoxic cleaning and household products, and store hazardous chemicals out of the home.
The Rise of Modern Fresh Air
People have been burning incense to mask unpleasant odors for thousands of years. The first modern air freshener appeared in 1948 and was born out of war technology. Modern air fresheners use chemicals rather than fragrant smoke to mask unwanted odors. Some air fresheners go one step further to neutralize odors via absorption or oxidation.
As it turns out, many of the chemicals used in modern air fresheners could themselves be considered air pollutants. Several studies have found that most modern commercial air fresheners contain toxic and carcinogenic chemicals, such as phthalates and volatile organic compounds. What’s more, air fresheners are not required to put their trademarked secret ingredients on their labels. So when you use such a freshener, you’ll never know what particular chemical slew you’re spraying into your indoor air.
Home Sweet Home Fresheners
Happily, there are many healthy alternatives to modern chemical air fresheners. Essential oils are a natural and potentially therapeutic way to freshen a home. You can use these in a diffuser or ring burner, or you can make your own essential oil air freshener: In an 8-oz. glass spray bottle, mix 3/4 cup distilled water, 2 tablespoons vodka, and 20 to 30 drops of essential oil. You can use whichever scents strike your fancy. A favorite combination of mine is 6 drops tea tree oil, 10 drops lemon oil, and 8 drops lavender oil. Tea tree is a good mold preventer, lavender is naturally antibacterial, and lemon adds a clean scent that makes me think of my childhood home. If you’re mixing up a freshener for the office, try peppermint and lavender; this combination is said to promote mental alertness.
Like their chemical counterparts, natural odor absorbers eliminate airborne odor molecules. Natural absorbers include sodium bicarbonate, diatomaceous earth, and coffee grounds. You’re probably already familiar with sodium bicarbonate, a.k.a. that box of baking soda lurking in the back of your fridge. Baking soda has been used as a safe odor absorber for years. Diatomaceous earth is a naturally occurring soft, siliceous sedimentary rock that absorbs odors and also excess moisture. You can often find it at gardening centers.
Coffee grounds, either fresh or used, are also good at removing unwanted odors. Try placing these natural absorbers in a bowl near the source of your smell and see what happens!
Another cool way to clean your air is to get a plant. In 1989, NASA published findings from its Clean Air Study, including a list of plants capable of eliminating air pollutants such as benzene and formaldehyde. Popular NASA-approved air-filtering plants include Boston ferns, palm trees, rubber plants, English ivy, peace lilies, golden pothos, florists’ mum, Gerbera daisies, and spider plants. You can find the full list of NASA-approved household plants online. For best results, NASA recommends placing at least one air-purifying plant per every 100 square feet of home.
Air. Guess it’s interesting after all!
Jocelyn Engman is the proprietor of Pickle Creek Herbs, which makes of herb-infused oils, vinegars, soaps, salves, and lip balms.