What is the main function of the natural ventilation procedure?

The primary function of the natural ventilation procedure is to supply outdoor air into indoor spaces, typically through openings like windows, doors, or vents. This method relies on natural forces such as wind and temperature differences to facilitate the flow of fresh air. Implementing natural ventilation helps improve indoor air quality by reducing the concentration of pollutants and bringing in oxygen-rich air, which can be particularly beneficial in residential and commercial buildings.

While other options may be related to the environment and indoor conditions, they don't capture the essence of natural ventilation as effectively. Indoor air circulation management is important but focuses mainly on the movement of air once it’s inside, rather than the intake of fresh air from outside. Controlled temperature regulation relates to HVAC systems that actively manage air temperature, and humidity reduction is typically more connected to dehumidification processes rather than natural airflow. Natural ventilation specifically emphasizes the introduction of outdoor air, making it the most relevant choice for this question.