The Advertising Standards Authority (ASA) has banned an ad from Dyson for implying that indoor pollution was more damaging to health than outdoor pollutants.
The spot in question was designed to promote the Dyson Purifier Heater, an air filtration device.
Three members of the public believed the ad exaggerated the health risks posed by pollution levels in a typical domestic kitchen, including by drawing a comparison with a car exhaust, and challenged whether the ad’s claims were misleading and could be substantiated.
The opening scene of the ad showed a car exhaust producing vapour, before depicting a number of appliances inside a woman's home letting off purple and green vapour, including household cleaning products next to a fridge, three potted plants and a hob.
Text appeared above those items that indicated which pollutants they released – including benzene gas, pollen particles, formaldehyde gas and allergens.
The woman was then shown using a mobile app stated the word 'poor' in reference to the air quality in her home. The ad cut to a shot of Dyson's product which sucked in the coloured vapour, as a voice-over said: 'But Dyson's Purifier Heater uses a HEPA filter to capture particles and activated carbon to capture gases while warming or cooling you.'
The ASA agreed with audiences that the ad was "misleading" despite Dyson's protests that specific health risks were not mentioned in the ad. The engineering giant said that the intention of the film was to increase public awareness concerning indoor pollution.
The brand said its claims regarding awareness were supported by a paper from the European Respiratory Journal.
However, the advertising watchdog said the colour of the indoor and outdoor fumes would be understood by consumers as a comparison.
It added: "We considered that the [European Respiratory Journal] reports were not relevant in determining the comparative damage of indoor and outdoor pollutants and that the evidence was therefore not sufficient to demonstrate that indoor pollution was more damaging than outdoor pollution.
The ad must not be shown again in its current form.
This isn't the first time Dyson has landed itself in hot water with the watchdog. In 2014 an ad for its vacuum cleaner was banned for making "misleading and exaggerated" claims.