Which standard defines the particle size for the purposes of indoor air quality assessment?

The correct response is rooted in the definition of particle size relevant to indoor air quality assessment. ISO 7708 specifically addresses the classification of air quality by defining particle size fractions for airborne particulate matter. These classifications are crucial for measuring and assessing indoor air contaminants, ensuring that the standards used are aligned with international benchmarks.

ISO 13964, on the other hand, pertains more to the measurement of airborne particulate matter in ambient air rather than specifying particle sizes for indoor environments. ASHRAE 55 focuses on thermal environmental conditions for human occupancy, rather than air quality standards. ISO/CEN Standards refer to a broad range of standards developed by both ISO and the European Committee for Standardization but do not specifically hone in on the particle size definitions necessary for indoor air quality assessment.

Thus, ISO 7708 stands out as the relevant standard that articulates the particle sizes critical for assessing indoor air quality, making it the correct choice.