What method of transport should be avoided for air going into occupied spaces?

Forced air systems should be avoided for air going into occupied spaces primarily because of their potential to circulate not only conditioned air but also dust, allergens, and contaminants. These systems rely on a blower to move air through ductwork, which can lead to the movement of particles that may affect indoor air quality. In environments where cleanliness and air purity are crucial, such as in healthcare facilities or sensitive industrial applications, using forced air systems can inadvertently introduce pollutants into occupied spaces.

On the other hand, controlled ventilation and natural convection methods can be more efficient in maintaining good air quality and thermal comfort without the risk of redistributing contaminants. Controlled ventilation systems, which can include techniques such as balanced ventilation or demand-controlled ventilation, can provide fresh air while diluting indoor pollutants effectively. Natural convection leverages temperature differences to induce air movement, which typically results in less airborne particulate matter compared to forced circulation.

Therefore, while both controlled ventilation and natural convection methods have their advantages, forced air systems pose a risk that makes them less suitable for transporting air into occupied spaces.