What is the role of filtration in ASHRAE 62.1?

• A. To remove particulates and contaminants from supply air, contributing to IAQ.
• B. To increase ventilation rate.
• C. To humidify air.
• D. To cool supply air only.

Answer: (A)

Filtration in ASHRAE 62.1 is about cleaning the air that is supplied to occupied spaces. By removing particulates and some contaminants from the supply air, filters help lower what occupants inhale, directly contributing to indoor air quality. This makes filtration a key control measure alongside ventilation and source control, working to reduce contaminant levels before air reaches occupants. It isn’t meant to increase the ventilation rate, humidify, or cool the air—that’s handled by other parts of the system. Filtration also has practical side effects, like pressure drop and energy use, but its primary role is to remove particulates from the supply air to improve IAQ.