Methanotrophs are those microbes (bacteria) which feeds on methane or used methane as energy source for their survival. These type of microbes survive by using single carbon compound as a source of energy. So we can say that due to the presence of Methanotrophs, the level of methane decreases while there is no change occurs in oxygen saturation level.
If it goes in the nostrils the air is warmed and humidified. The tiny hairs) protect the nasal passageways and other parts of the respiratory tract, filtering out dust and other particles that enter the nose through the breathed air.