Boogers are actually "nose garbage," she writes. "Each day, you suck in a small roomful of air. If the air was only gas, you would not even make boogers. But the air is filled with dust, smoke, grit, bacteria, tiny fungi, pollen, soot, little metal pieces, ash, fuzz, sand, and even itty bitty meteorites. One job of the nose is to clean the stuff out."
This nose-cleaning system is so effective that the nasal area is one of the cleanest parts of your body, Branzei adds. However, allergies and pollutants will trigger inflammation in the sinus lining, which creates sinus drainage, Horesh explains. "For some people, that means a runny nose, for other people, it's post-nasal drip."
Nasal sprays may help with post-nasal drip. Allergy shots and pills can control allergic reactions. "If air quality is a problem, another option is to move to Colorado," Horesh says.
Another tidbit: "The reason that smokers have more sinus and upper respiratory infections is because smoking damages the cilia, the hairs lining the sinus membranes which interfere with the natural snot mechanism," Horesh explains.