Is there a link between bad smells and mood?

Are bad smells linked to unpleasant thoughts?

Smell sense and the brain

Smell is a powerful sense, it is connected right in the middle of the brain.  The two main areas that the sense of smell is processed is in the Amygdala (the area in charge of memories and emotional responses) and the Hippocampus (responsible for the fight or flight mechanism).  That means smell has the ability to affect people’s emotions.  Part of the reason that the sense of smell is so powerful is that it cannot be turned off.  You can close your eyes, not eat things, not touch things and cover your ears, but you always have to smell.  This is why making sure there aren’t nuisance smells is important. People can feel trapped by smell if they are in a small area and cannot escape it. After all, if you are breathing, you are smelling.

We hear about the link between good smells and feelings, but what about bad smells like garbage?

What people smell has a direct impact on mood, even if people are not aware of the change. In an urban study researchers looked at people’s social media posts and their locations.  They discovered that in areas that smelled “nice” people were using happier words and showed more joy, whereas in areas that smelled of garbage people created negative posts. This happened even though test participants were not necessarily aware of the changes in their texts. In addition, researchers found that people anticipate where bad smells will be if they are always in the same place.

When in parks, people post happy thoughts
When smelling garbage, people send angry texts

Is smell related to stress?

Another study done in 2015 showed that the more stress someone is under, the more smell bothers them.  This study asked participants to rate how much common causes of stress in their homes made them angry. They compared noise, bad odours, light and vibration. When only one type of stress existed, 27% of people found bad odours to be ‘annoying”, about half as many as those who found noise that way. The study then increased the number of stress factors participants were under. When the stress factors were increased to over six factors, 85% of people rated bad odours as “annoying”.  We’ve asked managers about complaints from residents and have heard similar answers – noise is clearly a problem, particularly when it travels between units. However, smell can be annoying enough to cause complaints as well. We live in a dense city with lots of stress factors, therefore odours are likely to make people madder than ever.

Smell and memories

The sense of smell is very powerful.  It is strongly linked to memories, like grandmas cooking when you are a kid. As a community, we’ve cleaned up our air, both indoor and outdoor; condo common areas are cleaned and polished every day. Now, smells that would not have been noticed 50 years ago are becoming more obvious.  This can be positive and also negative. If bad smells are in the same location on a regular basis, people anticipate them and even worse we’ve heard many concerns from residents that bad odours may be harmful. This is not the case due to regular garbage removal. However, the very fact that people are worried enough to ask management these questions shows the fear bad odors create.

If residents anticipate bad smells, are annoyed by them and they cause negative thoughts and posts, they clearly affect everyday life. If you picture residents’ either frustrated working from home or rushing to get out the door, add in waiting for an elevator and then breathing in wafting chute room odours and you can see how it could subconsciously impact interactions with others.  Not having bad smells can reduce stress and make life just a bit more peaceful.  

Want to read more? Check out the studies:

Pedersen, E. City Dweller Responses to Multiple Stressors Intruding into Their Homes: Noise, Light, Odour, and Vibration. Int. J. Environ. Res. Public Health 2015, 12, 3246-3263.

Quercia, D., Aiello, L. M., & Schifanella, R. (2016). The Emotional and Chromatic Layers of Urban Smells. Proceedings of the International AAAI Conference on Web and Social Media10(1). Retrieved from

Pro-Active Odor Control