AQS Indoor Air Quality Flashcards

Which ASHRAE filter efficiency rating system replaced the older ASHRAE 52.1 dust spot efficiency ratings?

Answer: Minimum Efficiency Reporting Value (MERV)

ASHRAE Standard 52.2 introduced the MERV (Minimum Efficiency Reporting Value) scale (1–16) to replace the dust spot test, rating filters on particle capture efficiency across specific size ranges.

Volatile Organic Compounds (VOCs) in indoor environments are best controlled through:

Answer: Source elimination or substitution plus increased ventilation

The most effective VOC control hierarchy is to eliminate or substitute the source (low-VOC products), followed by engineering controls such as local exhaust and increased general ventilation dilution.

Environmental tobacco smoke (ETS) is classified as a Group A human carcinogen by the EPA and contains which class of pollutants?

Answer: Both gaseous pollutants (CO, formaldehyde, benzene) and fine particles (PM2.5)

ETS is a complex mixture of over 7,000 chemicals including CO, formaldehyde, benzene, and respirable fine particles (PM2.5), earning its Group A (known human carcinogen) EPA classification.

What does ACH (Air Changes per Hour) measure in indoor air quality assessments?

Answer: The rate at which the total volume of air in a space is replaced with fresh air per hour

ACH indicates how many times per hour the entire air volume of a space is exchanged with outdoor or filtered air, directly reflecting dilution ventilation effectiveness.

Under the Toxic Substances Control Act (TSCA) Formaldehyde Standards for Composite Wood Products, which agency enforces limits on formaldehyde emissions from pressed-wood products sold in the US?

Answer: EPA

The EPA enforces TSCA Title VI formaldehyde emission limits for composite wood products (hardwood plywood, particleboard, MDF) sold or distributed in the United States.

A demand-controlled ventilation (DCV) system uses which sensor to modulate outdoor air supply rates based on occupancy?

Answer: CO2 sensor

DCV systems use CO2 sensors as a proxy for occupancy — rising CO2 indicates more occupants exhaling, triggering increased outdoor air supply to maintain acceptable indoor air quality at minimum energy use.