The trouble with air fresheners, incense and candles



Spring meadows, pine forests, freshly laundered linen, and the mystic Orient; heavenly scents for boosting our morale and instantly making our homes feel fresh, clean, relaxing or invigorating.

Air Fresheners are BIG business – for example, in the UK alone over £400m a year is spent on more than 225 million aerosols, plug-ins, gels, candles and incense sticks, each promising an alluringly quick, convenient and harmless way to transform the atmosphere in your home.

However, evidence has been increasing for some time that all of these products contain industrial chemicals which can, among other things, damage lungs, aggravate asthma and cause tumours.

Chemical sprays, plug-ins and gels

Chemical sprays, plug-ins and gels for home perfuming are hugely popular but investigators warn that they can include an array of hazardous substances which may cause lung damage and tumours, interfere with our hormones and aggravate conditions such as asthma.

Many air fresheners employ carcinogens, volatile organic compounds (which are characterised by their low boiling point which mean they form a gas at room temperature, and which are known to increase the risk of asthma in children) and known toxins such as phthalate esters in their formulas. 

The evidence of harm is mounting:

  • A Natural Resources Defence Council (NRDC) study of 13 common household air fresheners found that most of the surveyed products contain chemicals that can aggravate asthma and affect reproductive development. The NRDC called for more rigorous supervision of the manufacturers and their products, which are widely assumed to be safe. The study assessed scented sprays, gels, and plug-in air fresheners. Independent lab testing confirmed the presence of phthalates, or hormone-disrupting chemicals that may pose a particular health risk to babies and young children, in 12 of the 14 products—including those marked 'all natural.' None of the products had these chemicals listed on their labels. 
  • The University of Bristol's Avon Longitudinal Study of Parents and Children  (ALSPAC) found that exposure to volatile organic compounds  through frequent use of air fresheners and other aerosols in the home was found to correlate with increased earaches and diarrhea in infants, and with increased depression and headaches in their mothers. 
  • In 2008, Anne C. Steinemann of the University of Washington published a study of top-selling air fresheners and laundry products. She found that all products tested gave off chemicals regulated as toxic or hazardous under federal laws, including carcinogens with no safe exposure level, but none of these chemicals were listed on any of the product labels or Material Safety Data Sheets. Chemicals  included acetone, the active ingredient in paint thinner and nail-polish remover; chloromethane, a neurotoxicant and respiratory toxicant; and acetaldehyde and 1,4-dioxane, both carcinogens. A plug-in air freshener contained more than twenty different volatile organic compounds, with more than one-third classified as toxic or hazardous under federal laws. Even air fresheners called "organic," "green," or with "essential oils" emitted hazardous chemicals, including carcinogens.
  • In 2009, Stanley M. Caress of the University of West Georgia and Anne C. Steinemann of the University of Washington published results from two national epidemiological studies of health effects from exposure to air fresheners. They found that nearly 20 percent of the general population and 34 percent of asthmatics report headaches, breathing difficulties, or other health problems when exposed to air fresheners or deodorizers. 
  • A 2015 study involving Public Health England's Centre for Radiation, Chemical and Environmental Hazards, warned that plug-in air fresheners produce 'considerable' levels of formaldehyde: described by the US government's National Toxicology Program as a known 'human carcinogen'. It is most closely linked with cancers of the nose and throat and at the very least, it can also cause sore throats, coughs, scratchy eyes and nosebleeds.

Formaldehyde is not the only chemical to fear in air fresheners. A report issued in 2005 by the Bureau Européen des Unions de Consommateurs (BEUC) and a study in 2006 found that many air freshener products emit allergens and toxic air pollutants including benzene, formaldehyde, styrene, phthalate esters, and toluene and secondary ultrafine particles in addition to various adsorbents, oxidizers, surfactants, and disinfectants. 

Manufacturers refute such concerns

Manufacturers of air fresheners, however, maintain that their products are safe.

In June 2015, SC Johnson, which makes Glade air fresheners, published specific information on most of the ingredients in its products for the first time.

Company chairman Fisk Johnson says: 'We take great care in making ingredient choices to offer products that are both safe and effective.'

However, not all of the ingredients used in the actual perfumes are fully listed and could well be made up of many different chemicals.

SC Johnson maintains, however, that all its fragrance ingredients, even those not listed, are safe: 'While they are not disclosed, the remaining ingredients also must meet our strict standards.'

The company is at loggerheads with environmental health campaigners, however, over its use of the synthetic musks galaxolide and tonalide.


A group of tall sticks with smoke coming out of them

Description automatically generatedMillions of us burn them every day to send spiritually inspiring wafts of spiciness around our homes. Research shows that ingredients such as frankincense can cause chemical changes in our brains, lifting our moods.

However, incense's mystic allure has been clouded by new findings warning that its fumes may be more dangerous than cigarette smoke, causing cancerous mutations in our DNA.

Burning incense releases tiny chemical particles which can become trapped in our lungs, causing potentially dangerous inflammatory reactions.

The research also found that incense particles from commonly used ingredients agarwood and sandalwood are more toxic to our cells' DNA than tobacco smoke.

Scented Candles

A group of candles lit up

Description automatically generatedScented candles bring another dimension, adding that subtle hint of aromatic bliss. Scientists remain unmoved however, voicing extreme concerns about the pollution that they are bringing to our lives.

In March 2015, a team of experts tested six scented candles, with such aromas as clean cotton, strawberry and kiwi fruit.

Behind their labels, however, lay a host of potentially dangerous industrial chemicals, including formaldehyde at levels which, with long-term exposure, are known to raise the risk of respiratory problems and cancer.

The candles also gave off significant levels of VOCs. Furthermore, the study warned that you don't even need to light such candles because simple evaporation will enable them to pollute your home.

Most scented candles are made with paraffin, which brings other problems. The oil by-product gives off ultra-fine soot particles containing acetone, benzene and toluene, usually seen in diesel emissions, and known carcinogens.

How can Airora help?

Air fresheners, incense and candles are often used to mask unpleasant odours by overwhelming them with a more powerful but more pleasant fragrance. In doing so they introduce chemicals and gasses into the air which may be harmful.


Airora is unique, instead of trying to mask a smell with a chemical fragrance, Airora simply destroys the objectional smells leaving the air clean and fresh.

Airora does more, things that no air freshener can achieve, it destroys or neutralises all types of germs and allergens and most other irritants and harmful pollutants throughout entire indoor spaces.


You can find out all about Airora at

And contact us at


Copyright Airora 2024