How Your Nose Filters the Air You Breathe

Your nose does much more than help you smell your morning coffee. Every breath you take carries dust, pollen, pollution and whatever else is in the room, and the nasal passages are built to deal with it. Here is how that filtering works, and what modern life does to it.

The air filter

When you inhale, air passes through the nostrils into a system of passageways lined with a sticky mucus layer and millions of tiny hair-like structures called cilia. The mucus catches airborne particles; the cilia beat constantly, moving that mucus toward the back of the throat where it is swallowed or cleared. This happens around the clock, including while you sleep.

More than a filter

The nose also conditions the air. It warms it and adds moisture so that what reaches the lungs is closer to body temperature and comfortably humid. Cold, dry air is harder on the airways; the nose softens it on the way in. The lining of the nasal passages is also where the body produces small amounts of nitric oxide — see Nitric Oxide and Your Nose.

Moisture matters

The nasal lining works best when it is moist. When it dries out — air conditioning, central heating, cold weather, long flights — it becomes less comfortable and less efficient at moving particles along. That dry, tight feeling after a flight is the nose telling you it needs moisture back.

Modern life versus the nose

Polluted city air, long hours in climate-controlled buildings and crowded transport all add up to more particles and drier air than the nose evolved for. None of this is dramatic; it is simply a heavier daily workload.

Support, don't replace

The nose already does a remarkable job on its own. Supporting it is about small habits:

• Breathe through your nose rather than your mouth where you can.
• Stay hydrated — it affects the nasal lining too.
• Humidify dry rooms, especially bedrooms in winter.
• Cleanse daily. NOWONDER™ nasal spray (also known as Enovid) is a daily nasal cleanser used before or after crowded places — see A Daily Nasal Spray Routine.

Frequently asked questions

What does the nose do to the air you breathe?
It filters particles with mucus and tiny hairs called cilia, and it warms and humidifies air before it reaches the lungs.

What are cilia?
Microscopic hair-like structures lining the nasal passages. They move constantly, pushing trapped particles toward the back of the throat to be swallowed or cleared.

Why does a dry nose feel worse?
The nasal lining works best when it is moist. Air conditioning, heating, cold weather and long flights dry it out, which makes it less comfortable and less efficient at clearing particles.

How can I support my nose day to day?
Nasal breathing, staying hydrated, humidifying dry rooms and a daily cleansing routine such as NOWONDER nasal spray all help the nose do its ordinary job.

Looking for Enovid nasal spray? Shop all pack sizes with free worldwide shipping — now available as NOWONDER™ in the US.