Does snow have its own flavor? The part of our brain that is responsible for logic is likely to answer in the negative. After all, snow is just frozen distilled water, and therefore it cannot have any smell.
But for those of us who have predicted a big blizzard based on the familiar tickling sensation in our nose, the answer is far from simple.
So what happens when we smell the "scent" of an impending meteorological phenomenon?
The answer has less to do with specific odor molecules than with the climate in which we smell that odor.
In one of the episodes of the Physics Central podcast, odorologist Pamela Dalton spoke about a complex of physical conditions that we interpret as the smell of snow. Indeed, when the temperature drops to frost before a snowfall, it is harder to smell the air than in milder weather. At low temperatures, the movement of molecules slows down, and due to their low activity, some odors become less pungent. This means that the sensation of the "scent of snow" corresponds in part to simply a decrease in the number of different odors in the open air, compared to what we are used to.
However, if that were all, the aroma of a blizzard would be no different from an ordinary cold, dry day. The fact is that before a snowstorm, air humidity is usually higher than usual. This leads to flocculation: when the amount of moisture in the atmosphere reaches the maximum value that the atmosphere can hold at this temperature, it reacts by giving the earth some of the moisture, in the form of rain, sleet, or, in this case, just snow. This extreme humidity has the additional effect of giving our olfactory system a quick boost. Many people associate the feeling of smell with a warm soft nose in frosty weather with an upcoming snowfall.
Since all this happens in the world around us all the time, there are mechanisms in the human body that also help to unmistakably recognize the smell of snow. We feel the cold air that we breathe in with our trigeminal nerve, thus, which recognizes the sensations caused by hot pepper or mint toothpaste (by the way, this same nerve is also responsible for the interpretation of other "facial" sensations, including making us sneeze when strong sunlight).
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This is not directly related to our olfactory system, but we nevertheless combine the information that this nerve gives us with the usual aromas, such as the aroma of coffee or pine.
So the three elements mentioned - cold weather, high humidity, and trigeminal stimulation - combine to create something that is not really a scent, but our sensory experience associates it with snow. This is why when someone is asked to describe the smell of snow, people often use words like “clean,” “fresh,” and “cold,” which are characteristics that, at first glance, have nothing to do with the smell.
Igor Abramov