Ventilation of occupied buildings can best be accomplished by:

Ventilation of occupied buildings is essential for maintaining air quality and ensuring the safety and comfort of occupants, especially in emergency situations. The most effective approach to achieve this is through a combination of natural and mechanical means.

Natural ventilation involves the use of windows, doors, and other openings to allow fresh air to flow in and stale air to escape. This method can enhance circulation and is often the simplest and most efficient way to ventilate a space, particularly in situations where the outdoor air quality is good.

Mechanical ventilation utilizes fans, air conditioning systems, or specialized ventilation systems to actively move air into and out of a building. This method allows for more controlled ventilation and can be tailored to specific needs, such as removing smoke, fumes, or heat from a building during an emergency.

Combining both natural and mechanical ventilation methods offers the best results, allowing for flexibility based on the situation, building design, and environmental conditions. This approach helps maintain the health and safety of occupants by ensuring that fresh air is consistently supplied while effectively removing contaminants from the indoor environment.

Other options, such as using windows only, relying solely on air conditioning, or closing all windows and doors, would not provide an effective or safe means of ventilation. Relying on just windows limits