When you search ‘breath of fresh air’ and every picture has people with their arms open wide. (What’s up with that?) image source
Dec 2016, phys.org
There seems to be this debate, or perhaps I should just call it confusion, over whether or not we can smell non-organic molecules like ammonia, chlorine, or sulfur. From what I can get out of people who are professionals in chemistry, smell science, or what have you – we cannot smell these things.
When we smell the ‘chlorine in the pool,’ we are actually smelling chlorine as it mixes with other organic molecules to make chloramines (and the so the smell of chlorine, which most would consider clean and disinfected, is actually the smell of a dirty pool, because the cleaning agent chlorine is mixing with all the organic garbage poop molecules in the pool). “Sulfur” is the smell of sulfur mixed with other organic molecules. Some people say we can smell ammonia, but I bet it’s the same situation.
While we’re talking about it, “metal” is not the smell of metal but the smell of something, an organic something (like our sweaty hands), interacting with the metal.* (I have a smell in my vocabulary called ‘metal mold’ and although I’m not sure what it is, its smell is powerful and unmistakable...and it's on my fire escape sometimes.)
So when I hear this – "mice can smell oxygen" – I have a feeling it’s not as it seems. And sure enough the truth reads like this:
They don’t smell oxygen itself, but the “levels of oxygen in the air.” They also don’t use odor receptor genes to do this; they are chemosensitive genes, but not odor receptor genes. And also, in humans, these genes are non-functional (called pseudogenes or junk genes), so we can’t generalize this to humans, only mice.
Can we say that mice “smell” oxygen? That’s like almost the truth, almost a fact. They can sense it. And if we consider chemosensation to fall under olfaction, just for simplicity sake, then sure, they can. That’s how almost truth works, isn’t it? And for the record, this is one of the reasons Hidden Scents is subtitled …’the age of approximation.’ The very thing that is so commonplace in studying or simply experiencing the world of olfaction is fast becoming the norm in how we interact with the Noosphere, the total collection of facts and knowledge.
*Credit to author Alexandra Horowitz; I got this from her book Being a Dog, it just came out in 2016, and is absolutely fascinating.