The major function of the sinuses is to heat, humidify, and clean the air we breathe so that it arrives at the lungs ready for the rest of the body to use. The sinuses complete all of these tasks through the creation of mucus, the sticky substance we usually pay attention to only when we are sick and our bodies seem to be producing too much. In reality, the sinuses constantly produce a significant amount of mucus, whether we are sick or not.
The sinuses normally produce between 1 and 2 liters of mucus per day Mucus is made up of 95 percent water and has a slightly acidic pH. Healthy mucus is usually clear and watery, but it can become thickened and viscous when we are experiencing an infection. When we are sick or are suffering from allergies, mucus production increases. When your body produces this thicker mucus, you may experience the feeling of postnasal drip. This term is misleading, because normal, healthy mucus is always dripping down into your throat, but you are not aware of it. It is only when the mucus becomes thickened because of an infection that you notice its existence.
Mucus adds moisture to the air taken in through the nose so the lungs receive air with the proper humidity. It also lubricates the membranes of our nose. Mucus contains salts and glycoproteins, which create a barrier to infection. Each set of sinuses are lined by mucous membranes that are
covered by a mucous blanket. As air passes through the sinuses, the mucous blanket traps tiny particles, including dirt, chemicals, irritants, dust, pollution, allergens, fungi, molds, viruses, and bacteria. This mechanism allows the dirt to be separated from the air that enters the lungs. These particles attach to the mucus, which is later expelled from the body It is estimated that the mucous blanket is totally replaced in the nose every 10 to 20 minutes and in the sinuses every 10 to 15 minutes.