Scent is an important part of our everyday experience. It can trigger memories, set a mood, warn us of danger, or fire up an appetite. In fact, the olfactory system is the only sense that is wired directly into the brain.

It’s not surprising, then, that air fresheners, scented candles, room sprays and incense are a huge money-making industry. Even dryer sheets, laundry detergent, garbage bags, drawer liners, feminine hygiene products and toilet paper carry a variety of scents to make our bodies, clothes and living spaces more appealing.

As consumers, it is important for us to be aware of these potential hazards so that we can make informed decisions about what we bring into our homes.

We’ve put together a primer on scented products and their dangers, what to avoid, and safe alternatives to use instead.

What type of candles do you use at home?

Candles are a great way to make a home feel cozy and romantic, or to set the mood for a party. A birthday party, special dinner or holiday celebration would hardly be the same without them. The use of candles at night is even recommended to encourage melatonin production. But the type of candles you use matters.

It turns out your average paraffin wax candles are made from a byproduct of the petroleum industry. Paraffin wax starts out as a black sludge, which is treated and bleached with carcinogenic chemicals like benzene and toluene. Not only are these toxic candles detrimental to the environment, they also present some major health hazards.

Burning paraffin candles releases at least seven different toxins, two of which have been proven to cause cancer. Some of these volatile compounds are the same ones found in oil-based paint, lacquer, varnish, and chemical solvents. They also release tiny particles of petrochemical soot, which stay suspended in the air for several hours. These particles are inhaled, get trapped in the lungs, and can cause respiratory irritation.

Dangers of scented candles

Add synthetic colors and scents into the mix and you’re really in for trouble. Those overpriced boutique candles in cute packaging release almost as many toxins as cigarette smoke.

Scented candles are essentially a source of indoor air pollution because they are usually used in poorly ventilated spaces like bathrooms, and in the evening when the windows are closed. Research shows that this can raise the risk of health conditions such as asthma, eczema and skin problems. A study of asthma sufferers found that scented candles made symptoms worse for at least 25 percent of people. Experts say that people who believe they have allergies or respiratory illness may in fact simply be responding to the toxins from the candles they burn in their home.

The synthetic fragrances and dyes used in candles give off harmful particles when they are heated, as does the metal-cored wick typically used in conventional candles. Studies report that scented candles also give off harmful soot, and the wicks can release particles of heavy metals like lead and cadmium.

The occasional candle used at home, especially in a well-ventilated area, doesn’t present a huge danger. However, environments like churches, where candles are burned consistently, are a hotbed for toxins. One Dutch study found that the air inside a church contained 10 times the amount of free radicals (molecules that damage cells and tissues) as the air beside a busy highway.

Are soy candles safe?

Soy products are frequently marketed as healthy and environmentally friendly. Soy candles would therefore appear to be a good nontoxic option. In reality, they are frequently blended with paraffin wax, which, as mentioned above, is highly toxic.

If you do decide to purchase soy candles, make sure they are labeled “100% soy” since even the term “pure” only requires 51 percent of the product to be made of soy. Also, avoid soy candles made with colors or fragrances. Even essential oils added to candles are not safe. High heat exposure damages the structure of the oils, causing the release of unknown byproducts.

Ultimately, soy candles are not an ideal choice. The vast majority of soy crops in the world are genetically modified and heavily sprayed with pesticides. Therefore, purchasing soy candles supports an industry that is damaging to the planet and the well-being of its inhabitants.

Dangers of air fresheners and scented products

While air fresheners are supposed to get rid of unpleasant or embarrassing odors, the scented products themselves may be the biggest faux-pas.

Not only are they dispensed from toxic plastic containers and aerosol cans that are damaging to the environment, the contents are essentially unregulated by any government authority or consumer safety agency. Manufacturers are not required to reveal the names of the substances in their products because they are considered trade secrets. Even when they are listed, terms like “fragrance” or “parfum” can cover up the thousands of unknown chemicals that manufacturers use.

One study discovered that 86 percent of air freshener products contain phthalates, including those labeled as “all-natural” or “unscented.” Phthalates are known to interfere with hormones and cause reproductive abnormalities, including infertility and birth defects. These chemicals are released into the air when air fresheners are used, where they can be inhaled or absorbed into the bloodstream through the skin.

Natural alternatives to air fresheners

Are you convinced yet? We think that avoiding conventional scented products is a vital step toward living a long, healthy, nontoxic life.

But what if we still want a nice-smelling home or an attractive ambiance for a party? The best options to use are either 100-percent beeswax candles or essential oils in a diffuser.

Beeswax candles actually purify the air, releasing ions that can help remove indoor air pollutants. They are also said to help relieve allergies and respiratory conditions. Aesthetically, beeswax candles give off a lovely warm glow and a sweet scent of honey. They are a bit more expensive, but are certainly worth the investment. Purchasing beeswax candles also supports local farmers and apiaries.

Essential oils in a diffuser allow scents to be dispersed via micro-particles of water. This helps distribute oils not just for enjoyment and atmosphere, but also to cleanse the environment and eliminate pathogens and mold.

If you love using scents to zone out and relax, try these natural, free methods of stress relief.

—Liivi Hess