Most of us think nothing of lighting a scented candle when we take a bath, burning some incense next to our yoga mat, or spritzing room spray when our homes need freshening up. But depending on the products we’re using, we may be inadvertently exposing ourselves to harmful chemicals, and decreasing the air quality in our living space.

The global home fragrance market, worth $7.6bn in 2023 and projected to grow to almost $20bn by 2030, is booming. But environmental and health watchdogs, including the Environmental Working Group and Women’s Voices for the Earth, have long criticized the industry for a lack of transparency about ingredients.

Before 2022, no US laws required companies to reveal ingredients used in fragrance formulas. Then California’s Fragrance and Flavors Right to Know Act came into effect. It requires companies to disclose their ingredients in California’s Safe Cosmetics Program database, and to reformulate any products that contain certain harmful fragrance chemicals and allergens.

Outside California, it’s a different story. “Products can contain dozens of chemicals, and all it shows up as is one word on the ingredient list: fragrance,” says Ryan Sullivan, an associate professor of chemistry at Carnegie Mellon University and associate director of the Institute for Green Science.

Lax chemical regulations and low transparency can lead to people being unknowingly exposed to potentially harmful compounds in fragrance products, many of which have been banned or strictly regulated by the more vigilant European Commission. These include the skin-sensitizing allergen HICC; lilial, a floral fragrance compound linked to sperm damage; and parabens and phthalates, additives commonly found in synthetic fragrances that can disrupt hormones by mimicking estrogen. “You don’t have to be exposed to a large amount of an endocrine-disrupting chemical for it to have its effect,” says Sullivan.

Additionally, when aerosol air freshener emissions react with chemicals that are already in the air, like ozone, they can create certain harmful volatile organic compounds (VOCs), such as benzene, toluene and formaldehyde.

Fortunately, there are many safe ways to help your home smell fresh and inviting. Here’s what experts suggest.

Clean thoroughly to prevent bad odors

The first step is to identify and manage the source of any bad odors. Regular cleaning with environmentally friendly products is important, but there’s no need to sterilize your entire home just because you associate the tang of industrial disinfectants with cleanliness, Sullivan notes. He also says using chemicals that provide a “clean” smell is actually antithetical to what a chemist would consider truly clean, “which is no chemicals”.

Instead, ensure you’re taking out your garbage regularly and that your bin has a well-fitting lid. Activated charcoal pouches are non-toxic and effective at absorbing moisture and bad smells in dank niches like shoe closets, under the kitchen sink and near pet habitats. A bowl of baking soda or white vinegar on your countertop reduces cooking odors. Sullivan’s top recommendation is to invest in Hepa air filters, especially if poor outdoor air quality restricts your ability to leave windows open for air circulation.

Choose and use scented candles carefully

Any time you burn candles or incense, you “create a little bit of pollution”, including nitrogen oxides, carbon monoxide and polycyclic aromatic hydrocarbons (PAHs), says Sullivan. Still, Sullivan does use candles at home. The few thorough studies on the health effects of burning scented candles claim the emissions are fairly negligible, but many variables can factor into your air quality, such as the size of the room or the number of candles you’re burning.

Consumers should keep an eye out for candle brands that clearly communicate their adherence to standards such as the safety and labeling regulations of California’s comprehensive Prop 65. The ecological non-profit Green America recommends candles made with renewable sources such as 100% plant-based wax or beeswax rather than petroleum-based paraffin. Many eco-conscious brands use wood or cotton wicks rather than zinc-core wicks, which can contain traces of lead; and phthalate-free natural fragrance oils and pure essential oils, which release lower concentrations of VOCs and other contaminants than synthetic fragrances when burned.

It is good practice to ensure your home is well-ventilated when you’re burning a candle, and to burn in moderation.

Caylen Baker, founder of the eco- and health-conscious candle brand Canvas Candle Co, makes a case for trimming your wick before every burn. “If you trim the wick there’s less carbon buildup causing black smoke when the candle is burning,” and therefore less particulate matter to inhale, says Baker.

Try a simmer pot

Simmer pots are an easy, DIY way to infuse your home with pleasant aromas. Toss citrus rinds, spices and vanilla extract into a pot of simmering water and voilà: cozy, cottagecore aromas. Use culinary ingredients and you can even enjoy the resulting potion as a hot drink.

Use a hot plate, slow cooker or rice cooker rather than your gas stove, which is “a much larger source of indoor air pollution than we realized until recently”, says Sullivan. Keep an eye on water levels to prevent your simmer pot ingredients from drying out and burning.

Use essential oils

​​Although some environmentalists criticize the production of essential oils for requiring substantial amounts of raw plant materials, they are generally safe to use in small quantities for fragrance purposes.

They are used to make non-toxic scented plug-ins, such as Enviroscent’s refillable paper scent warmers, or you can add them to water for use in electric diffusers or DIY room sprays. For a little aura of scent, try putting a few drops on an adhesive felt furniture pad and sticking it someplace discreet, like under a desk or in a closet.

However, individuals with respiratory conditions such as asthma might find them irritating, and pet owners should use essential oils with care since some, like clove, eucalyptus and geranium, can be harmful to animals.

Grow fragrant plants indoors

It’s a myth that houseplants clean contaminants from our air, but fragrant plants provide beauty as well as sweet smells.

Consider growing culinary herbs like basil, dwarf rosemary and oregano; flowering houseplants like jasmine, gardenia, paperwhite and stephanotis; or small citrus trees. Geranium and heliotrope thrive in window boxes, and if you have access to larger outdoor spaces, planting lilac, bay or sarcococca shrubs near windows or doors will allow their scents to waft inside.

• The main picture of this article was changed on 2 March to better reflect the content.