How can building materials negatively impact indoor air quality?

Building materials can negatively impact indoor air quality primarily by emitting pollutants over time. Many common materials used in construction, such as carpets, paints, adhesives, and wood products, can release volatile organic compounds (VOCs) and other harmful substances. This process is known as off-gassing, and it can contribute to various health issues, including headaches, respiratory problems, and exacerbation of allergies.

As these materials age or when they undergo changes in temperature and humidity, the rate of emission can increase, leading to higher concentrations of pollutants in the indoor environment. This is particularly concerning in poorly ventilated spaces where fresh air circulation is limited, thereby allowing pollutants to accumulate.

The other options do not accurately address the significant impact that building materials can have on indoor air quality. While blocking ventilation and increasing humidity can certainly contribute to poor IAQ, they are more indirect effects rather than direct emissions from building materials themselves. The assertion that building materials do not affect IAQ would overlook the critical role that material selection plays in maintaining healthy indoor environments.