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Scents and Sensibility

Are air fresheners polluting?


Scents and Sensibility

The chemicals in air fresheners are bad for our health. Essential oils are a safe way to infuse the air with scent, and they may even boost the immune system.

Fragrances evoke wonderful holiday memories—consider fresh home baking and real Christmas trees. But headache, fatigue, and other symptoms commonly blamed on the pressures of last-minute shopping may be due instead to seasonal scents. Something in the air may be an uninvited chemical guest.

Air care or air scare?

Many Canadians no longer celebrate the holidays on the grand scale of prior generations. Yet artificial trees and big-box store desserts can’t duplicate the memorable aromas of Christmases past.

To imitate these comforting smells, it’s tempting to turn to air freshener sprays or plug-ins. In 2009 the self-designated Canadian “air care” industry raked in a fragrant $259 million—a 7 percent jump from 2008. Along with the olfactory memories they reproduce, air sprays and scented oils produce serious revenue for the companies that sell them.

There’s a not-so-festive side to simulated scents, but marketing has managed to create a veritable smokescreen about their risks. Professor William W. Nazaroff and his team at the University of California, Berkeley, investigated what happens when commercial air freshener sprays are used indoors, and they made some startling discoveries.

A chief finding of the study, conducted in 2006 for the California Air Resources Board and California Environmental Protection Agency, was that scent molecules in the spray change when released into the air, yielding unwanted byproducts under typical household conditions. Such substances have no place in human respiratory health, yet they are finding a place, literally, in our bodies when we inhale air freshener particles.

Trade secrets

Manufacturers don’t list air freshener byproducts on their ingredient labels for two reasons. First, in Canada, there’s no legal requirement to disclose what’s going into air fresheners or perfumes. Using the words “fragrance” or “parfum” is usually done to protect trade secrets.

Second, byproducts are formed when compounds in the air fresheners, called terpenes, react with ozone in the air. Indoor ozone, a greenhouse gas, comes from outdoor air pollution, but can also come from home ozone generators, ionizers, photocopiers, and printers.

Terpenes naturally occur in various plants. Alpha- and beta-pinene are terpenes originally found in pine resin; limonene is a citrusy-smelling terpene. Their concentrations are highest indoors because the use of scented products has increased steadily over the past two decades.

According to a 2007 report published by the European Commission Joint Research Centre “they exist at concentrations five to seven times higher indoors than outdoors, typically in the low ppb (parts per billion by volume) range.”

As Canadians we are especially at risk of high terpene concentrations in the air of our homes. The European Indoor Air Monitoring and Exposure Assessment Project discovered indoor environments in southern cities contained lower amounts of alpha-pinene and limonene than northern cities sampled between 2003 and 2007.

The reason for this difference? The report blames heavy indoor use of terpene-containing products paired with tightly sealed buildings that allow very little air exchange, more common in colder climates. Southern Europeans, in contrast, lack the need for such insulation and can allow the ventilation provided by drafts and open windows. In other words, northern homes where air fresheners are used are prime candidates for sick building status—a likely precursor to sick people.

Nazaroff says he’s optimistic that better options are possible, despite his criticism of current air fresheners. In his opinion, omitting the most reactive terpenes and similar chemicals would be an excellent start. What about essential oils as alternatives? Nazaroff says he doesn’t know, but he doesn’t rule them out.


Can the holidays include lovely scents while protecting our health? “Absolutely,” says Lee Fisher, a Dartmouth, Nova Scotia, aromatherapist with 11 years of experience.

She recommends therapeutic-grade essential oils for their safety and purity. “They’re checked before they go to market to ensure they have no fillers, and actually enhance the immune system.”

Quality natural health retailers sell genuine essential oils and diffusers. Some, such as the wellness centre co-owned by Fisher, even offer aromatherapy classes. One of her best-selling seasonal blends is cinnamon-orange, which she says is suitable “for extra sensitive people. It’s fantastic and doesn’t have to be really strong.”

Her other top seasonal blend is peppermint-cocoa absolute, which, says Fisher, “smells like a peppermint patty.”

Real Christmas trees and wreaths, preferably organic, are another sensory delight. And potpourri can be made with naturally scented dry materials such as pine chips and flower petals, enhanced with just a few drops of essential oils.

“We have a lot of environmentally sensitive clients coming in,” Fisher explains, addressing a common aromatherapy concern. “We bring them back into the world of scent very, very slowly.”

She argues that air freshening products can worsen chemical sensitivities, but careful exposure to essential oil can help people enjoy scent again. “We usually start with a fruit oil. We ask them, ‘Can you eat an orange?’ because orange oil comes from the fruit peel.”

Fisher says she’s witnessed wonderful results with sensitive clients—proof, she believes, of the difference between synthetic and therapeutic-grade oils. “If [manufacturers] want millions of bottles of something to smell the same, they go to the lab. Mother Nature can’t provide a million of the same thing at all times, but when you smell the wholeness of the essential oils, that’s when the body reacts favourably.”

A breath of fresh air?

A May 2008 article in the Globe and Mail noted that January 1, 2010, was to herald new transparency about home cleaning products in Canada. Although the Canadian Consumer Specialty Products Association announced that its 47 member companies would go public with their formulations, glaring exemptions remain: ingredients need not be printed on packaging, fragrances remain proprietary secrets, and disclosure is voluntary. 

Nazaroff scoffs at the new measures: “In the interest of public health, I think that a system similar to what is used on food products should be strongly considered as mandatory; ‘fragrance’ or ‘parfum’ is not adequate, nor is voluntary practice. The ultimate alternative would be to regulate content, but I think it is much more efficient and effective to require disclosure and let consumer demand and the marketplace push the system toward safer products.”

Until the air care industry improves upon last New Year’s resolution, individuals can resolve to keep questionable products out of their breathing space.

More than just a pretty scent

In addition to adding a scent to the air, air fresheners can add the following harmful chemicals.

Formaldehyde: a well-known carcinogen already present in many homes due to the off-gassing of materials such as particle board and plywood.

Hydroxyl radical: a less familiar danger, but a potent free radical. According to a 2003 article in the Internet Journal of Advanced Nursing Practice, hydroxyl radical can cause cell damage or destruction.

Organic particulate matter: these tiny, easily inhaled molecules can travel deep into the lungs, triggering coughing and asthma attacks by suppressing the natural air-filtering action of our lungs.

The European Indoor Air Monitoring and Exposure Assessment Project concludes there are too few human-health studies that consider the full impact of air sprays and their byproducts.



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