Improvements in energy efficiency
Improvements in energy efficiency can have a negative impact on indoor air quality. In some instances, overly tight buildings have been shown to have indoor air quality concerns simply because there is a lack of adequate fresh air ventilation. Other conditions can also contribute to poor air quality. These may be related to activities occurring inside the building (or in the case of a past building renovation, activities which previously occurred in the building), such as improperly vented combustion sources, poor dust control or cleaning practices, smoking, the release of volatile organic compounds from building materials (including furnishings, carpet, paints, woods, and other substances), improper storage or use of chemicals, personal hygiene, or pesticide applications. Other problem conditions may arise in a building from other concerns, including moisture intrusion, sewage backflow, and excessive humidity.