Story at-a-glance

• Unfortunately, these products pollute the air inside your home with chemicals that are dangerous for your pets
• Studies have found harmful chemicals in air fresheners (all types), scented candles and incense
• Most of the effects of these products aren’t immediately obvious and may not even manifest as respiratory issues
• Safe, natural alternatives that freshen the air in your home include pet-safe indoor plants, an air purifier and diffusing diluted pet-safe essential oils

By Dr. Karen Shaw Becker

A whopping 75 percent of U.S. households these days use a variety of products to scent the air in their homes, including air freshener sprays, upholstery sprays, plug-ins, gels, candles and incense. Some people who use these products are trying to mask odors, while others just want to walk into a home that smells like a beautiful meadow or a pine forest after a rain shower.

TV commercials and other advertising for air-scenting products are everywhere, sending a not-so-subliminal message that most homes stink, and fixing the problem with a vanilla-scented candle or air freshener is a harmless solution to an embarrassing problem.

Why I Never Recommend Chemical Air-Scenting Products

Unfortunately, as appealing as all of these scented products are, they also produce dangerous indoor pollutants that dramatically affect our pets. Over the past decade, scientific research has shown that many household air fresheners contain chemicals that may be harmful.

I don't recommend using these types of products, especially if you have any type of pet in your home. Birds and cats in particular are highly sensitive to airborne toxins, but if you have any animals in the home at all, I recommend you not use these products. Studies show that children can have as much as 30 times greater exposure to indoor pollutants than adults due to their smaller size and greater activity level. Now, consider these facts:

• Most pets are even smaller than kids
• They tend to spend a lot of time near the floor where all indoor air pollutants eventually wind up
• They groom themselves and each other, which means they're ingesting the pollutant particles that have accumulated on their fur and in the environment
• Many pets spend up to 100 percent of their time indoors, and are living with very high levels of airborne toxins

These factors combine to put pets at the highest risk of anyone in the household for health conditions related to indoor air pollution. Even if neither you nor your pets are having symptoms, it's still possible the air fresheners in your home are harming your health. Most of the effects of these products aren't immediately obvious and may not even manifest as respiratory issues. Some people say, "If I was having a problem, my pets or I would have watery eyes. We'd be coughing or wheezing." But that's not always the case.

Harmful Chemicals Found in Air Fresheners

Air fresheners in both aerosol sprays and plug-ins contain a number of toxic chemicals that are dangerous to your pet's health and yours, including:

•Volatile organic compounds, or VOCs, such as acetone, ethanol, pinene and acetate, some of which are inherently toxic. When these substances react with the ozone in the air, they generate a range of secondary pollutants such as formaldehyde and ultrafine particles. Ultrafine particles have been linked to heart and lung disease and respiratory problems.

In fact, a 2011 news report released by the American College of Allergy, Asthma and Immunology (ACAAI) linked the VOCs in air fresheners with a 34 percent increase in health problems in people with asthma.1

•Formaldehyde is a known carcinogen that has been definitively linked to cancers of the nose and throat. It is also known to cause ongoing irritation of the throat and airways, potentially leading to secondary infection, nosebleeds, asthma and other respiratory ailments.

•Naphthalene has been shown to cause inflammation, but as well as tissue damage and cancer in the lungs of rodents.

•Phthalates are linked to a disruption in hormone levels, poor semen quality, birth defects and reproductive harm.

•1,4-Dichlorobenzene (1,4-DCB) has been linked to compromised lung function and liver cancer in mice.

Harmful Substances in Scented Candles and Incense

A 2001 EPA study concluded that candles containing fragrance produce more soot. It's possible organic compounds in poor-quality candle wax may increase cancer risk.2 A 2009 study warns that the chemicals emitted into the air by burning candles can have a harmful effect on human health.3 Paraffin candles produce potentially toxic chemicals, including alkanes, alkenes and toluene.

Like air fresheners, scented candles can also contain dangerous chemicals such as formaldehyde and VOCs. Cheaply made candles can contain toxic levels of heavy metals in the wicks. When one of these candles burns, the lead particles are released into the air. Frequent use of these candles could contribute to the development of health conditions such as asthma, allergies and cancer.

Research shows that burning incense can be dangerous to human health, and a 2015 study even suggested it's much worse that inhaling cigarette smoke.4 Incense smoke is mutagenic, meaning it can cause mutations in DNA that can lead to cancer. In the 2015 study, incense was found to be more toxic to cells and DNA than cigarette smoke. Of the 65 compounds identified in incense smoke, two were determined to be highly toxic.

Natural Alternatives to Keep Your Home Smelling Fresh

One of the best ways to freshen up the air in your home is to simply open the windows when weather allows. Also consider adding some pet-safe indoor plants. Common houseplants can help clean the air by using their natural ability to absorb toxins through their leaves and roots and turn them into nutrients. I also strongly recommend investing in an indoor air purifier, which can provide long-term benefits to both you and your pets.

To add a natural scent to your home, you can simmer some mint tea or cinnamon in water in a saucepan on the stove, or grind up a fresh orange. Or you can do what I do — I dilute and diffuse pet-safe essential oils. They smell wonderful and are nontoxic. It's a nice all-natural way to keep your home smelling fresh and clean while eliminating toxic products from your life.