The Chemistry of Smell

We all learned about our five senses in grade school—sight, hearing, touch, taste, and smell. And as we got older, we learned more about what actually causes these senses to be activated. When light bounces off of an object, our eyes receive that light and we call it sight. When vibrations travel through the air, our eardrums vibrate too and our brain interprets the sound. Touch and taste are equally straightforward; when we brush up against something or put food in our mouth we touch and we taste. But what causes smells? We could just say aromas are in the air. But what is it that actually triggers our brain to recognize a scent?

The answer is small molecules and a little bit of chemistry.

Olfaction, A.K.A. Smell

The scientific word for smell is olfaction, and this process is facilitated by the olfactory system. You’ve probably noticed that “olfact-” is code for “has to do with smell;” we’ll keep using this code word as we talk about what triggers our sense of smell.

In any case, there are a lot of parts to the olfactory system. The most interesting of these parts are the olfactory receptors. These receptors are part of specialized brain cells that span from your nasal cavity, across your olfactory epithelium (a type of skin), and directly to your brain. Humans have about 12 million of these receptors while animals known for their sense of smell—like dogs—have 1 billion or more.

Courtesy of Rice University

These olfactory receptors are what receive smells and allow your brain to interpret them. But, this still doesn’t answer the question of what actually causes smells.

Small Molecules, Big Smells

When we sense a smell in the air, we’re actually sensing the presence of small, vaporized molecules. So, when you smell a flower, baking bread, or your smelly gym socks, you’re actually sensing molecules that have evaporated from the surface of those objects. These molecules move through the air and into your nose. Then, they bind with a specific set of olfactory receptors and generate a signal in your brain, triggering you to recognize that specific smell.

Courtesy of eSchoolToday

Not all materials can vaporize easily. That’s why materials like metal tend not to have a strong smell. There are also some molecules that humans don’t have odor receptors for. Gases like carbon monoxide and natural gas are odorless not because they’re not vapors, but because we simply don’t have the receptors to smell them.

All Molecules Are Not Created Equal

Not surprisingly, there are many, many different kinds of odor-causing molecules. There are also about 340 different types of odor receptors in humans that work together in different combinations to identify specific smells. Even in your home, there can be many different odor-causing molecules floating around. However, there are a few key molecules that when filtered out of your air can greatly improve your indoor air quality.

Ammonia

Ammonia and ammonia-related compounds have a characteristic, pungent smell. And in large quantities ammonia can be dangerous. But in homes, this gas often comes from a variety of minor sources and is an annoyance rather than a danger. Ammonia can come from cleaners, cat urine, older refrigerators, and fertilizers used near your home.

Formaldehyde

Formaldehyde levels in homes are typically low, but the smell of formaldehyde can be noticeable even at these low levels. This gas makes its way into homes through particleboard and plywood, cigarette smoke, and some dyes and preservatives. It is also a main ingredient in some insulation found in homes from the 1970s and 1980s.

Sulfur Compounds

Sulfur compounds, specifically hydrogen sulfide, are responsible for rotten egg smells in your home. If you’ve ever lived in a home that used well water you’re probably very familiar with this smell. While hydrogen sulfide is not dangerous at low levels—and the human nose can detect very low levels of this gas—it’s definitely a nuisance.

Homeowners have options when it comes to eliminating smells in their homes. Candles and air fresheners are often the first line of defense against home odors. But, now that we know that odors are actually caused by certain molecules in the air, there are some better options.

Rather than cover up odors the best option is to eliminate odor-causing molecules altogether. The easiest way to do this is to simply add odor-molecule trapping capabilities to the filters you already use in your home. Serionix manufactures filters like this, made to fit easily into your home furnace system. These filters were originally designed for cleanrooms and are incredibly effective at removing airborne chemicals. Using a filter like this gives you the cleanest possible air for your home!

Sources

1. http://www.rsc.org/education/eic/issues/2009March/smell-chemical-molecule-receptor-shape.asp
2. https://cnx.org/contents/5nOdwC6i@5/Taste-and-Smell
3. http://www.ehow.com/info_8783314_could-cause-smell-ammonia-home.html
4. http://www.idph.state.il.us/envhealth/factsheets/formaldehyde.htm
5. http://www.ehso.com/ehshome/hydrogensulfide.htm

Why a House That Smells Won’t Sell

The sense of smell brings back strong memories. These memories may be of a certain flower from childhood or the perfume your grandmother used to wear. Whatever these memories may be, smell is inherently linked to our brains.

So why is smell so important in selling a home? Research suggests that one of the first impressions someone has walking into your home may be of the smell. Maybe they get a whiff of your cat’s litter box or the Indian curry you were cooking last night. Overpowering smells make a home difficult to sell, according to Eric Spangenberg, Dean of the College of Business at Washington State University who has extensively studied the science of smell on consumer behavior.

Realtors suggest a few simple methods to reduce or eliminate the smell in your home.

  1. Clean your home thoroughly, but not with cleaning products that leave strong odors such as bleach. Lightly scented cleaners are best–and if possible, use organic smells such as lemon or orange to give a hint of scent.
  2. Roast coffee beans in the oven.
  3. Boil a pot of water with lemon or orange peels, to give a hint of organic smell.
  4. If you love to bake, avoid chocolate chip cookies prior to an open house. Instead, opt for baking something such as cinnamon rolls which leave the scent of cinnamon instead of the heavy scent of chocolate.

A more permanent solution to your smell problem may be found in Serionix filters. Our revolutionary color changing filters have been proven to eliminate odors that come from pets, especially cat litter odors, and cooking odors. Whether or not you are selling your home, having a clean smelling home may increase your confidence in having guests over and your overall satisfaction with your home.

Serionix has both portable air purifier units and furnace filters available. We are in the process of beginning our beta trial and looking for customers interested in testing out our product. Got a house that smells? We can help. Sign up here to test our product.

 

Sources: http://www.homesandland.com/real-tips/smell-can-help-sell-your-home/

http://www.fifthsense.org.uk/psychology-and-smell/

http://www.zillow.com/advice-thread/How-to-get-rid-of-cooking-smell-while-selling-your-home/352355/

What is Adsorption?

We know that the air in our homes can have unwanted contaminants in it; that’s why we use filters. But not all filters were created equally. High efficiency furnace filters and portable air purifiers do a great job removing things like pollen and pet dander from the air. Unfortunately, even though pollen and pet dander are small from our perspective, in terms of air quality they are actually rather big when compared to other air contaminants. Other hazards like bacteria, viruses, and irritating chemicals are much, much smaller. Trying to capture them with conventional filters is the microscopic equivalent of trying to catch minnows with a tuna net.  The chemicals we can’t capture using filters are often the most noticeable indicators of air quality in the form of malicious odors. When Zipper the cat pees on the carpet or your collard greens go bad it’s easy to notice that your air quality is suffering.

When air passes through a filter, big particles like dust and pet hair get caught in the filter fibers. But, small chemicals pass through the filters and into the ‘clean’ air.

There is a solution, though. Some filters can trap these small bacteria, viruses, and chemicals. But what does it mean for a filter to trap these tiny chemical molecules?  What traps them? And do they stay trapped? The answer to all of these questions is adsorption.

Molecular Velcro

Adsorption is a process where a substance in a gas or liquid becomes attached to a solid surface. Of course, if you’re not a chemist this doesn’t mean much. Instead of thinking about the scientific definition, think about Velcro. Some things stick to Velcro and some don’t—and the things that do stick tend to stay stuck.

Courtesy of Amazon.com

Adsorption works kind of like Velcro. The surface of a solid acts as the Velcro, and the tiny chemical molecules in the air act as the things that get stuck in Velcro. So, when air passes over the right kind of solid surface, chemical molecules in the air get stuck to that surface and the cleaned air passes over. And once the molecules are stuck to the surface, they don’t come back off.

When molecules in the air pass over an adsorptive surface, they get stuck to the surface and cleaned air passes over the surface.

There are lots of materials with this special, molecular-Velcro surface. The most common one is activated carbon. Activated carbon is similar to charcoal and naturally has this molecular-Velcro surface, which makes it really good at removing chemicals from the air. But, no one wants piles of charcoal sitting in their home to remove chemicals. So what can the average homeowner use instead to make sure they’re removing unwanted chemicals from their air?

Coated Filters

The answer to this question is a coated filter. Think about a typical home furnace filter. These filters are really good at removing ‘big’ particles like dust and pet dander, but not so good at removing chemicals. But, with the addition of a coating that gives the filter the same molecular-Velcro surface that occurs naturally in activated carbon, a standard filter can remove chemicals, too.

When the filter fibers are coated to make their surface adsorptive, airborne chemicals stick to the fibers. That way, all of the contaminants—including small chemicals—are trapped.

Serionix makes filters like this. At Serionix, we’ve created a ‘special sauce’ that we add to typical home air filters. That way, our filters not only filter out the big stuff that typical filters handle but also the tiny chemicals that cause odors and irritation. With this combination of features, our filters ensure fresh, clean air in your home.

Is Green Air Filtration Possible?

Air filtration is all about making the air cleaner. And what could be greener than removing contaminants from the air? In this post, we’ll take a look at why that may not necessarily be the case, depending how the air is filtered.

Activated Carbon: A Dirty Solution for Cleaning Air

Activated carbon is one of the most common materials used for cleaning chemicals from air. In 2016, 577 million tonnes of activated carbon will be used for air purification purposes, mostly for the industrial market. And especially in this industrial market, it is certainly very green to remove contaminants from air used in polluting processes. However, producing the activated carbon itself is not a particularly green process.

Activated carbon is derived from elemental carbon or some kind of other carbon-rich precursor.  This precursor is then either given a high-temperature chemical treatment, or is treated via pyrolysis and then oxidation. After the activation process, the activated carbon may be further treated with a polymer coating or impregnation with other elements to increase its functionality.

A summary of the activated carbon production process. There are a number of high-temperature and resource-intensive steps throughout the process.

 

 

Wired In: James Langer

Story courtesy of the News Gazette’s Paul Wood.

On Sundays, staff writer Paul Wood spotlights a high-tech difference maker. This week, meet JAMES LANGER, 36, president of Serionix, which makes high-performance filtration materials for removal of toxic chemicals from air and water, with a large number of customers — from the Army to an appliance maker.

The team

My co-founders are Weihua Zheng and James Economy. Dr. Zheng and I both graduated from Dr. Economy’s research group in the Materials Science and Engineering Department at the University of Illinois. Weihua and I met in 2008 when he joined the group, and we just clicked right from the beginning. Our friendship and mutual respect grew over the next several years and eventually led us to start Serionix together. Since starting the company, we have expanded the team to include several additional engineers each with ties to UIUC. Tim Hoerr of Serra Ventures has been a great help to us — influential as both an investor and adviser since the advent of the company.

Photo by: Robin Scholz/The News-Gazette
Entrepreneur James Langer, president of Serionix, which makes high-performance filtration technologies to remove toxic or unwanted chemicals, with a purple (new) and a yellow (used) filter that can be reused in the Serionix lab at EnterpriseWorks in Champaign on Tuesday, Dec. 1, 2015.

How did you become an entrepreneur?

I think I have been intrigued by the idea of starting a company ever since I saw my dad start one when I was in middle school. His startup never took off like he’d hoped, but his experience inspired me to see entrepreneurship as a possibility.

To that end, I came to graduate school in 2006 with a vague idea of working with a startup or starting a technology company, but lost that vision somewhere along the way — mostly because I didn’t really know where to start. In January 2011, Weihua and I entered into the Cozad business plan competition on campus and instantly got hooked on entrepreneurship! Through extensive networking and pitching our business concept, we became more connected to the local entrepreneurial community and received a lot of support and feedback to refine our business concept. Over the next year, we generated significant financial support for the business through Small Business Innovation Research grants and extensions of those same grants that have provided over $2 million in total funding that we have used to bring our air filtration technology to a commercial-ready state.

What does your product do that nothing else does?

Our filtration product removes toxic and smelly compounds from air, far more efficiently than conventional products, at a price point three times cheaper. As an added kicker, the filter changes color when it runs out of life to remind a user to replace it.

What’s in the future for Serionix?

We are preparing to bring our product to market in the next year, in applications ranging from electronics cleanrooms to vehicle cabin air filters, residential pet odor removal and beyond. We are currently working with a major appliance manufacturer to design an odor filter for one of their products, and are on the cusp of getting sales and development agreements with several corporate partners.

Tech tidbits …

from JAMES LANGER

Twitter handle? None, yet

Favorite app? Cooks Illustrated — the recipes always work!

Book or Kindle? Book for sure. I retain information better and enjoy the feel of a book in my hand.

Wearable electronics? Just my watch!

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