What can be a significant result of ineffective ventilation in a building?

Ineffective ventilation in a building can lead to the development of indoor air pollutants. Proper ventilation is crucial for maintaining air quality, as it helps to circulate fresh air and remove contaminants that can accumulate indoors. When ventilation is inadequate, the concentration of airborne pollutants—such as volatile organic compounds (VOCs), mold spores, dust mites, and carbon dioxide—increases. This buildup can lead to health issues for occupants, including respiratory problems, headaches, and allergic reactions.

The other options do not accurately reflect the consequences of poor ventilation. Improved air quality and increased energy efficiency are benefits associated with effective ventilation. Decreased humidity levels typically result from active moisture control and proper airflow, rather than ineffective ventilation, which often contributes to increased humidity and moisture problems. Therefore, the primary concern with insufficient ventilation is indeed the potential for indoor air pollutants to develop, which can significantly impact the health and comfort of the building’s occupants.