A couple of questions

Why does it smell different at night?

Temperature is one of them, perhaps the most important. Cooler temperatures reduce the concentration of volatile compounds, thus night air smells generally purer/cleaner. In cities, less traffic and less pollution change the smell of the air.

Why does it smell weird outside at night?

Essentially, the air doesn't rise the way it is suppose to, causing smog, pollution or other odors from nearby farms, feed lots and other stinky areas to get trapped at the Earth's surface. The warmer air on top of the cooler air acts as a lid, trapping these scents and causing a stink at the ground level.

Why does it smell different when cold?

Dalton explains to Discovery News that as a protective response against cold, dry air, the olfactory receptors that lie inside all of our noses bury down in the winter. So the lack of smells plus the lesser ability to smell makes winter have a different odor than summer.

Does sense of smell change throughout the day?

A person's ability to smell may vary throughout the day in accordance with their circadian rhythm, according to new evidence in a small study by Brown University researchers who are looking at how sleep may influence eating patterns in teens.

Why does cold air smell so good?

"The reason that people like cold air and the way it smells is really a combination of not just smell but also the feel of it. "It is refreshing, you breathe it in and it's like if you put menthol in your nose, you get that evaporative cooling affect."

Is it normal to smell yourself through pants?

Smelling yourself through your pants is rarely a medical emergency, but it's also not typical. If you've bathed recently and are wearing clean, dry clothing, it's likely worth a visit to a doctor to talk about potential underlying causes.

Why do I smell sewage at night?

If you smell a noxious sewer-like odor inside your home, chances are it is sewer gas escaping from the drainage system. Not only does it smell gross, but the methane and bacteria it contains can be dangerous to your health, causing headaches or even more serious ailments.

Do you lose your sense of smell while sleeping?

Her research and experiments indicate people do not respond to odours while they are in the dreaming phase of sleep (REM) or deep sleep. "You cannot smell while you are asleep," she says. "You don't smell the coffee and wake up; rather you wake up and then smell the coffee."