What is the role of outside air in a building's ventilation system?

The role of outside air in a building's ventilation system is primarily to ensure that enough fresh air is entering the building. This is vital for maintaining indoor air quality, as fresh air helps dilute indoor pollutants, allergens, and excess humidity, creating a healthier environment for occupants. When outside air is introduced, it can replace stale air, thus improving ventilation efficacy.

Proper ventilation using outside air bolsters the overall health and comfort of a building's occupants. It contributes to the prevention of respiratory issues and helps in maintaining suitable oxygen levels indoors. Additionally, the introduction of outside air can also aid in temperature regulation, but the main emphasis is on the freshness and quality of the indoor atmosphere.

While outside air can also play a role in energy costs, pressure balance, and heat removal, those are secondary effects or functions of a properly ventilated system response and may not address the fundamental purpose of bringing fresh air into the space. Regular supply of outside air is critical in meeting health and safety standards in building design and operation.