Feature article

Formaldehyde: the invisible indoor pollutant

From that familiar fresh paint smell to the unboxing of new furniture – odours associated with these seemingly harmless home improvements are usually an indication that a substance has been released into the air. And while the smell of new paint might fade over time, the emission of potentially harmful gases, such as formaldehyde, can persist. Pollutants like these can continuously ‘off-gas’ for a number of years – but what exactly is formaldehyde and why is it in our homes?

01 April 2021

  • What is formaldehyde?


  • Formaldehyde is a colourless gas pollutant, which can be released by furniture and wooden products containing formaldehyde-based resins, such as plywood and fibreboard, insulating materials, do-it-yourself products such as paint, wallpapers, varnishes and household cleaning products.

    Being 500 times smaller than 0.1 microns, formaldehyde is particularly difficult to capture and left undetected, can be trapped in a home for years.

    Research indicates that the main source of indoor formaldehyde pollution in China comes from the gas being released after decorating a home. If left alone, it has been reported to persist for between three to 15 years due to continuous off-gassing.1

Is exposure to formaldehyde dangerous?

The impact of formaldehyde has been widely reported by the World Health Organisation and other research bodies, with some governmental institutions setting formaldehyde safety limitations and regulating its usage.

While in-home formaldehyde readings at any given time may appear low, potential continuous exposure through off-gassing can sometimes occur over multiple years. This is particularly relevant for homes that have been recently renovated. According to the South Australian health department, formaldehyde exposure at low levels commonly found indoors can cause itchy, sore or burning sensations.2 High level exposure can have major toxic effects, causing coughing, wheezing, chest pains and bronchitis.3

Formaldehyde levels within homes can be exacerbated by how well sealed they are, as a well-sealed home can trap indoor pollutants. This can result in greater exposure over time. Formaldehyde concentrations are particularly high in portable buildings due to the higher load factor and because they are more air tight than conventional homes.4 In a 2000 study of occupied and unoccupied caravans in Australia, results show formaldehyde levels being higher in winter compared to summer which could be explained by the reduction in ventilation during the winter period allowing formaldehyde concentrations to build up.5

Observed in another Australian study in 2002, Dingle and Franklin carried out a study in 185 homes in Perth and found indoor formaldehyde concentrations of between 2.5 and 133.7 μg/m3.6 Other studies found similar findings in other countries. A 2019 report found that 50% of Chinese households have indoor formaldehyde concentrations exceeding international and local standards of 0.10mg/m3.7 A different study released in the same year, revealed that in a fifth of the 47 UK homes tested for the pollutant showed more than double the levels deemed safe.8 In fact, US authorities such as Centre for Disease Control and Prevention (CDC) claim that there are small amounts of formaldehyde in almost all homes.9

What can you do to reduce formaldehyde within your home?

As well as selecting DIY and renovation products that don’t contain formaldehyde, increasing ventilation and using purification within a space can help to remove the gas from your home. The new Dyson Hot+Cool Formaldehyde not only sense formaldehyde with their intelligent solid-state sensor, but they also destroy it, using Dyson’s Selective Catalytic Oxidisation (SCO) filter.

Some formaldehyde sensors are gel-based, so can dry out over time, causing the precision and performance of the sensor to deteriorate. Dyson’s formaldehyde sensor is solid-state, and so doesn’t dry out, lasting the lifetime of the machine. Its intelligent algorithm precisely senses formaldehyde levels without confusing it with other violent organic compounds (VOCs).

As well as sensing formaldehyde, Dyson’s SCO filter captures and destroys the pollutant at a molecular level, breaking it down into tiny amounts of water and CO2. It then regenerates from the oxygen in the air to keep destroying it continuously without ever requiring replacement.

  • Formaldehyde levels detected by the Dyson Hot+Cool Formaldehyde are reported via the LCD screen and the Dyson Link App. This helps to reassure the user that the invisible pollutant is being captured and destroyed, supporting a healthier indoor space.

  • Formaldehyde

[1] Chinese Home Indoor Formaldehyde White Paper, CHEARI, 2019.
[2] Government of South Australian, SA Health, Formaldehyde.
[3] Government of South Australian, SA Health, Formaldehyde.
[4] Sexton K, Petreas M, Liu K: Formaldehyde exposures inside mobile homes. Environ Sci Teclmol l 989;23:985-988.
[5] Dingle P, Tan R, Cheong C, 2000, Indoor Built Environment, ‘Formaldehyde in occupied and Unoccupied Caravans in Australia’.
[6] Dingle P and Franklin P, 2002, ‘Formaldehyde Levels and the Factors Affecting These Levels in Homes in Perth, Western Australia’.
[7] Chinese Home Indoor Formaldehyde White Paper, CHEARI, 2019.
[8] Airtopia, Clean Air Day, 2019.
[9] Formaldehyde in your home- what you need to know, Centre for Disease Control and Prevention.

Press Contact

Jane Zouch
Email: jane.zouch@dyson.com

Dyson Newsroom

The latest news from Dyson