How Scent Works: From Airborne Molecules to Human Emotion

You head to the movie theater excited to watch your favorite superheroes save the day. You’ve already spent too much money on the ticket, and you’re determined NOT to spend any more on refreshments. But when you walk in, the smell of fresh-popped, buttery popcorn hits you full in the face, your stomach grumbles, your willpower wilts, and you sigh as you dig out your wallet.

Sounds familiar, right? This kind of experience illustrates the way scent influences our decisions, guiding our choices for what to eat, what to wear, where to shop, and more. To understand how a smell is taken in as an inhalation of airborne molecules and transformed into a mood or emotion powerful enough to affect us, we need to dig into the science. And that starts with how aromas fill the air around us.

You may have heard the term “diffusion.” In the science of scent, it refers to the way a fragrance permeates the air, moving from its point of origin, where the smell is strong, to areas with little aroma, gradually spreading out to fill the space. Diffusion is what, slowly but surely, turns the simple act of “lighting a candle” into a fragrant experience for everyone in the room. Think of how a drop of blue food coloring dropped into water will slowly spread out, going from deep blue to light blue as the molecules spread out. Scent molecules act in much the same way.

The science behind this process is fascinating. On a basic level, everything is made of molecules. Our definitions for the three states of matter—solids, liquids, and gases—are based on the density of the molecules each contains. Gases are the least dense, meaning they have more space for new molecules to enter and mingle. The air around us, for instance, contains all kinds of different molecules that are always on the move, swirling and whirling and making way for new molecules to join the mix.

But how do the vanilla-scented molecules from a just-lit candle travel through a room to be breathed in by someone sitting several feet away? Three important factors play a role in taking scent-laden molecules from their source to the scent receptors in our noses:

• Temperature: Adding heat is a powerful way to release scent. The higher the temperature, the more the molecules move.
• Airflow: Via natural wind or manmade ventilation, air currents carry scent molecules over varied distances. Even a simple fan can help disperse scent through a space.
• Surface Materials: Density affects scent absorption. Porous substances are capable of absorbing and releasing scents.

Other factors, like the molecular weight of the molecules, can affect the way smells travel. The lighter a molecule is, the faster and farther it can travel. The heavier a molecule, the more likely it stays close to its source. The amount of water in the air affects dispersion and diffusion, too.

It’s a bit strange to think about, but with every sniff you take, you inhale tiny bits of the world around you. That’s because smells are particle-based. The particles that enter your olfactory system, however, are very small. And with millions of molecules in every breath, your nose has its work cut out for it trying to identify the aromas it smells.

Inside our bodies, the inhalation of an odor kicks off an amazingly complex series of reactions, with the real possibility that one of the scented odors will spark a memory or an emotion. But before that can happen, the molecules breathed in must pass through an identification process. With every inhalation, new particles come in contact with nasal receptors in the olfactory epithelium.

The olfactory epithelium includes an important type of cell called the olfactory receptor neuron. According to the National Institutes of Health, it’s a “bipolar cell that gives rise to a small-diameter, unmyelinated axon at its basal surface that transmits olfactory information centrally.” [SOURCE]

In other words, these specialized neurons are able to sort through incoming “scent data” featuring a huge range of chemical compounds and identify ones they recognize. But how do the scents inhaled turn into meaningful information transmitted to the brain?

We take for granted the ability to inhale through our noses, smell freshly cut grass, and identify it. But there’s a complex process underlying that experience, all unfolding behind the scenes. As our oldest but perhaps least-understood sense, our sense of smell holds many mysteries. And every day, scientists work to unravel them. Let’s take a close look at what current science tells us about how our brains interpret scents.

Scientists believe there are about 400 different receptors, and these allow us to detect hundreds of thousands of scents! That’s because each complex scent is made of a mixture of different scent molecules. If the molecules can find a 1-to-1 match—a perfect fit between themselves and a receptor cell—your brain has an “aha moment,” making a connection and identifying the smell.

That info is relayed to our olfactory bulbs, which serve as the main gates through which scent info is processed. As scents are inhaled and analyzed, the information our brain picks up is passed into the limbic system, where it is interpreted and linked to scent memories and emotions.

Without our sense of smell, the world would be a much duller place—we can all agree on that. But how can businesses use the science of scent to enhance the customer experience AND increase profits? The answer lies in the special relationship between scent and emotion.

This is exactly why scent branding is so important for modern businesses looking for an edge. Tapping into customers’ positive memories with certain scents allows brands to create emotional connections that enhance the customer experience. By diffusing pleasing scents into the air, stores make their locations more welcoming, encouraging customers to stay longer, make a few more purchases, and leave with that warm, fuzzy feeling all brands hope to cultivate!

Now that you understand more about the power of scent branding, you may be ready to work it into your marketing strategy. That’s where Aire-Master comes in. From providing ready-made scent solutions to helping design signature scents, Aire-Master does it all.  

When you’re ready to put scent to work for your business, Aire-Master can help.