The smell of commerce: How companies use scents to sell their products

Sit through a TV ad break and you'll quickly find two senses assaulted on behalf of a third: smell. Businesses looking to sniff out a commercial oppor-tunity have been aware of its power for a long time, even if this has usually focused on shifting products that cover up malodorous breath or feet.

Time reported last month that the aromas of chocolate and bread in a Brooklyn grocery are all artificial, being pumped into the store by machine. Their story generated interest in a form of marketing that has been largely overlooked.

"It seemed to hit a raw nerve with a lot of the major supermarket chains here," says Steven Semoff, the acting co-president of the Scent Marketing Institute. "Because, when you think about it, in the world of product promotion, advertising and branding, everything is about sight and sound. Our senses are basically saturated. No one has really been tapping into smell."

Although Time and some of the supermarkets are just starting to get a whiff of the idea, it's not a new one, having grown up over the past five years or so as "nebulisation technology" – through which a fragranced oil is converted into a dry vapour. This has become more commercially viable and useable on a wide scale.

Five companies in the US control 80 per cent of the world market and an estimated 10-20 per cent of retailers in the US are their customers. "It is fairly widespread here," says Mike Gatti, the executive director of marketing at the National Retail Federation. "A lot of retail companies use it, and its purpose really is to keep customers in your store."

Semoff says that a study run by Nike showed that adding scents to their stores increased intent to purchase by 80 per cent, while in another experiment at a petrol station mini-mart, pumping in the smell of coffee saw purchases of the drink increase by 300 per cent. It's thought that it works so well because the sense of smell is most directly connected to the parts of the brain responsible for processing emotions. "It goes directly to the limbic system, which is the emotional control centre of your brain, so you smell something and – bang – it triggers an emotion," says Semoff.

But is it ethical? Dispersing the scent of bread through a store implies that those smells come from the products. Surely it reeks of deceit? Maybe not, according to Alex Hiller, an expert in marketing ethics from Nottingham Business School.

"Yes, changing smells is manipulative – this is the whole point," he says. "But it is mild, and I would argue that consumers realise and accept that in all artificial, and especially retail, environments, some mild form of manipulation does take place."

Compared to, say, fast-food outlets displaying photographs that bear no resemblance at all to the limp burgers actually on sale, it comes out rather well.

"A picture should provide a visual cue to the product you receive, and if you don't receive this then some form of deception has taken place," Hiller says.

"You're basically drawing attention to particular items," says Rachel Herz, the author of The Scent of Desire. She gives the example of using the smell of cinnamon at the location where cinnamon buns are found in a store, which will make people more likely to buy.

Stores, hotels and clubs can also use artificial smells to create a more pleasant environment. "They're effectively adding a scent logo to their establishment," says Herz. Just as music played on TV adverts can become irrevocably associated with the product they're being used to sell, so too for smells – they can bring to mind the experience of, say, being in a hotel.

To work positively, the experience being recalled would need to be a good one. "Smells don't have any meaning prior to being associated with an experience," says Herz. If a lousy time was had by all, the associated smell would bring that to mind too. So the technology is predominantly used by upmarket hotels and resorts, rather than budget accommodation.

This application, rather than for specific foods, is the principal use of manufactured smell in the UK. None of the supermarkets contacted by i use scent marketing – most prefer to use natural smells of, say, their bakeries.

Meanwhile, a firm called ScentAir UK has attracted 600 clients since it set up in 2008, including developing the piña colada smell being used in Hamleys (it makes parents "linger longer"). One of their newest customers is the M&M World store in London.

Pratt says the company provides a "full service" package to its clients, from supplying and installing the machines to replenishing the fragrances. The monthly fees range from just under £100 to £250.

The right scent can depend on several factors. Research has found that it affected everything from cultural norms, gender and appropriateness to the product. "If you get it right, it's a good thing," says Herz. "If you get it wrong, it's worse than no scent at all."

For many businesses it could help provide the sweet smell of success.