What filters humidifies and warms air in the body?

The respiratory system's primary filters that humidify and warm air are the nasal passages and the upper respiratory tract, particularly the nasal cavity. The mucous membranes lining these areas produce mucus, which traps particles and pathogens, while the rich blood supply warms the incoming air. Additionally, the cilia help move mucus and trapped particles out of the airways, ensuring that the air reaching the lungs is clean, warm, and moist.