According to the ventilation standard for indoor air quality, which statement correctly identifies sources of contaminants for indoor air requirements?

According to the ventilation standard for indoor air quality, which statement correctly identifies sources of contaminants for indoor air requirements?

• A. exact occupancy numbers are difficult to predict
• B. the floor area component ensures a minimum ventilation rate
• C. contaminants originate both from the population and from the floor
• D. modern buildings are more 'tight' and ventilation cannot be counted on

Answer: (C)

Contaminants in indoor air come from two main sources: the people in the space and the materials and surfaces inside the space, including flooring. Occupants emit carbon dioxide, moisture, odors, and other bioeffluents, while building materials, adhesives, finishes, carpets, and flooring can off-gas volatile organic compounds and shed dust. Because these different sources affect air quality, ventilation standards set requirements that address emissions from both the population and the floor materials. The idea is to dilute both occupant-generated pollutants and material-emitted pollutants to maintain acceptable indoor air quality. The other statements don’t capture this dual-source perspective. Predicting exact occupancy numbers isn’t about where contaminants come from, and basing minimum ventilation strictly on floor area misses the need to account for occupant-generated pollutants. While tighter buildings raise ventilation considerations, it’s not accurate to say ventilation can’t be relied on at all.

Contaminants in indoor air come from two main sources: the people in the space and the materials and surfaces inside the space, including flooring. Occupants emit carbon dioxide, moisture, odors, and other bioeffluents, while building materials, adhesives, finishes, carpets, and flooring can off-gas volatile organic compounds and shed dust. Because these different sources affect air quality, ventilation standards set requirements that address emissions from both the population and the floor materials. The idea is to dilute both occupant-generated pollutants and material-emitted pollutants to maintain acceptable indoor air quality.

The other statements don’t capture this dual-source perspective. Predicting exact occupancy numbers isn’t about where contaminants come from, and basing minimum ventilation strictly on floor area misses the need to account for occupant-generated pollutants. While tighter buildings raise ventilation considerations, it’s not accurate to say ventilation can’t be relied on at all.