Dyson launches workplace air purifier HEPA Big+Quiet

Dyson's lead research engineer Tim Jones explains how Dyson's most effective and "quietest ever" air purifying product was designed.

Dyson has launched air purification product, the HEPA Big+Quiet, designed specifically for shared workplaces with a greater capacity, triple-layer filtration system and "imperceptible" acoustics.

As well as outdoor sources of pollution – such as car fumes, construction and allergens like pollen – there are also many indoor sources in workspaces, including cooking odours, particles from furniture and carpets, and cleaning chemicals, Dyson explains.

What most people don't know is that we are one of the main sources of pollution in shared workspaces, says Dyson's lead research engineer Tim Jones. "The concentration of CO2 in our breath is about 40,000 parts per million, with around 200 volatile organic compounds (VOCs) leaving our bodies as we breath out".

Pointing to an environmental science study suggesting that a build-up of CO2 and VOCs can affect both cognitive function and fatigue, Dyson sought to design a purifier that can "capture pollutants effectively", benefit the entire space rather than "a localised bubble of polluted air", and also be quiet, no matter its size, says Jones.

The Dyson HEPA Big+Quiet's size means it can emit 90 litres of purified air every second around a 100 square metres, says Jones, "more than twice what Dyson's current products do".

Its triple layered filtration system was designed to capture different kinds of pollution particles. The first layer is the HEPA (high-efficiency particulate absorbing) filter, comprising 21 metres of "filter media" pleated 459 times, says Jones. Working at 99.95% efficiency, this layer absorbs "ultra-fine particles", has a 21,900-hour lifespan, and is "four times larger than any previous Dyson filter", he adds.

The middle layer is an activated carbon filter that "works a bit like a sponge" to absorb gases like Nitrogen Dioxide, VOCs and odours, says Jones. He explains that its 430,000 square metre "microscopic pore structure" allows pollutant particles to "stick inside the inner pores" across its 8,600-hour lifetime.

The third inner layer is a selective catalytic oxidation filter (SCO), which serves to capture and destroy extremely small formaldehyde gas particles, and never needs replacing.

Dyson's "quietest ever product, even on max mode" has various features that make its 55.6 decibel sound level possible, says Jones. The design team's biggest challenge was increasing airflow to work effectively in a 100 square metre space while keeping it quiet.

Jones says it took seven years of development, but eventually they landed on the idea of drawing in air through the base and projecting it out at the top over "rigorously designed" surfaces, he explains.

The design of the surfaces uses the Coandă effect – also in the Dyson Air Wrap – in which air flow passes across a curved surface and "sticks" to it. In the case of the Dyson HEPA Big+Quiet, this creates two controlled jets of air that collide in the middle of the product before being projected out at an angle 50 degrees above horizontal.

Other acoustic measures include the incorporation of a Helmholtz cavity in the middle of the product compressor, which is engineered to absorb sound, an internal "soft-mounted" motor to minimise noise from vibration, and a labyrinth seal, which creates what Jones calls a "convoluted path" for noise to stop it coming out of the product.

To gauge CO2 concentration, the product's real-time photo-acoustic sensors work by passing light across CO2 molecules, while microphones within pick up on the substance's "signature response", says Jones. It then categorises the CO2 levels through a colour coding system on its small screen.

Jones claims that it is Dyson's "most energy efficient air purifier".