Final answer:
Natural ventilation uses wind and buoyancy to deliver fresh air into buildings, maintaining air quality and reducing pollutant levels.
Step-by-step explanation:
Natural ventilation uses the natural forces of wind and buoyancy to deliver fresh air into buildings. It involves air movement through opened windows and doors, driven by temperature differences between indoors and outdoors and by wind.
This method of ventilation helps to replace indoor air with outdoor air, maintaining air quality and reducing pollutant levels.