How does 62.1 address particulate matter?

• A. PM is not addressed by 62.1.
• B. PM is addressed only by filtration in 62.1.
• C. PM is addressed via filtration and ventilation strategies to limit exposure in the breathing zone.
• D. PM is controlled solely by outdoor air dilution.

Answer: (C)

Particulate matter is controlled by a combined approach, not by a single method. ASHRAE 62.1 addresses PM by using filtration of the air that occupants breathe and by implementing ventilation strategies that dilute indoor air with outdoor air. Filtration removes particles from the air as it circulates through the HVAC system, while the ventilation design brings in outdoor air and exhausts indoor air to lower the concentration of particles in the breathing zone. This dual strategy is essential because relying on filtration alone doesn’t account for particles that may enter indoors from outdoors or be generated indoors, and relying only on outdoor dilution misses the benefit of actively removing particles already present in the space. The result is a balanced approach that reduces occupant exposure to PM in the breathing zone.