Scented Candles

Scented candles are a staple in many living rooms and bedrooms, but new research has shown they can actually pollute the air inside our homes. When burned, many candles—especially those made from paraffin wax—release volatile organic compounds (VOCs) like benzene and toluene, which are also found in car exhaust.

A 2024 study published in Environmental Science & Technology found that burning a scented candle for just one hour can raise formaldehyde levels above World Health Organization safety limits. These chemicals are known to irritate the lungs and may even increase cancer risk with long-term exposure.

Some candles also emit fine particulate matter, which can worsen asthma and allergies. Even when unlit, candles can release phthalates from their fragrance oils, which have been linked to hormone disruption.

It’s surprising, but the cozy glow comes with a hidden cost to indoor air quality.

Air Freshener Sprays

Air freshener sprays are marketed as a quick fix for bad smells, but scientific reports suggest they often make indoor air worse. In 2023, the U.S.

Environmental Protection Agency highlighted that common air fresheners emit more than 100 different chemicals, including limonene, formaldehyde, and acetaldehyde. These substances react with ozone in the air to form secondary pollutants like formaldehyde, a known carcinogen.

According to a 2024 Consumer Reports investigation, regular use of air fresheners can double the amount of indoor VOCs compared to homes that don’t use them. People with sensitive airways or respiratory conditions may experience coughing, headaches, and irritation.

The irony is, they don’t really “clean” the air—they just mask odors with potentially harmful chemicals.

Plug-In Scent Warmers

Plug-in scent warmers have surged in popularity for their convenience, but they continuously emit chemicals into the air as long as they are plugged in. Data from a 2023 Harvard public health review revealed that these devices commonly release phthalates and synthetic musks, which accumulate in dust and can disrupt hormones.

The fragrances are often made up of numerous unlisted chemicals, some of which are classified as allergens in the European Union. A 2024 indoor air quality study showed that homes with active plug-in warmers had 30-50% higher VOC concentrations than those without.

Children and pets are especially vulnerable because they spend more time close to the floor, where these chemicals settle. Despite their pleasant aroma, plug-in warmers can quietly degrade indoor air quality day after day.

Laundry Scent Boosters

Laundry scent boosters promise fresh-smelling clothes, but they can be a sneaky source of indoor pollution. According to a 2023 University of Washington analysis, these products emit over 25 VOCs during both washing and drying cycles, including carcinogens like acetaldehyde and styrene.

The chemicals can linger on fabric and be released gradually into the air as clothes are worn or stored indoors. The U.S.

Centers for Disease Control and Prevention warns that these emissions are especially problematic in small, poorly ventilated spaces like bedrooms and closets. Users often report headaches and skin irritation, which are signs of chemical sensitivity.

While the idea of fresh laundry is comforting, the reality is these boosters may be introducing harmful pollutants into your home environment.

Reed Diffusers

Reed diffusers are often seen as a safer alternative to candles, but evidence suggests they’re not as harmless as they appear. Research published in 2024 by the International Journal of Indoor Air Quality found that many reed diffusers release significant amounts of synthetic fragrance chemicals, including benzyl acetate and linalool, which can trigger allergies and respiratory symptoms.

Unlike candles, diffusers work continuously, which means low-level exposure all day and night. The carrier oils used to dilute the scents can also react with air, forming secondary pollutants like formaldehyde.

In homes with little ventilation, these emissions can quickly accumulate, especially in bathrooms and entryways. Even “natural” or “green” labeled diffusers often contain synthetic ingredients that contribute to toxic indoor air.

Room Sprays and Mist Diffusers

Room sprays and mist diffusers are popular for their instant scent effect, but they can pack a surprising chemical punch. A 2023 study by the American Lung Association highlighted that many sprays contain terpenes, which easily react with ozone to form formaldehyde and ultrafine particles.

When inhaled, these particles can penetrate deep into the lungs, raising the risk of respiratory diseases. Mist diffusers that use synthetic oils add to the problem by dispersing these chemicals evenly throughout a room.

The effects are even stronger in children, the elderly, and people with preexisting conditions, as their immune systems are more sensitive to airborne toxins. Despite the soothing effect of a quick spritz or a gentle mist, the reality is that these products are quietly polluting indoor air.

Scented Trash Bags

Scented trash bags might seem like a small detail, but recent investigations show they are a source of indoor air pollution. In 2024, Consumer Watchdog reported that these bags often contain high levels of synthetic fragrances, including limonene and alpha-pinene, both of which can react with other indoor chemicals to form irritants.

When the bags are moved, tied, or thrown out, the fragrance chemicals are released into the air and can linger for hours. These emissions are especially pronounced in kitchens, where trash bags are commonly stored in closed cabinets with poor ventilation.

People with allergies or asthma may notice worsening symptoms when using scented bags. The convenience of odor-masking trash bags comes with the hidden cost of more VOCs in your home.

Scented Cleaning Products

Scented cleaning products are everywhere—from floor cleaners to disinfectant wipes—but they can be a surprising source of indoor air pollution. The Environmental Working Group’s 2024 Guide to Healthy Cleaning found that more than half of scented cleaners tested released hazardous air pollutants, including chloroform and formaldehyde.

These chemicals can linger in the air for hours after cleaning, especially in bathrooms and kitchens with limited airflow. Many of the fragrances used are proprietary blends, making it tough for consumers to know what they’re breathing.

People often assume cleaning equals health, but in reality, scented products can aggravate asthma, cause headaches, and even trigger chemical sensitivities. The fresh smell after cleaning isn’t always a sign of a cleaner home—it might be a sign of more pollutants in the air.