IAQ and Emergency Preparedness
Ventilation and shading can help control indoor temperatures. Ventilation also helps remove or dilute indoor airborne pollutants coming from indoor sources. This reduces the level of contaminants and improves indoor air quality (IAQ). Carefully evaluate using ventilation to reduce indoor air pollutants where there may be outdoor sources of pollutants, such as smoke or refuse, nearby.
The introduction of outdoor air is one important factor in promoting good air quality. Air may enter a home in several different ways, including through natural ventilation, such as through windows and doors; through mechanical means, such as through outdoor air intakes associated with the heating, ventilation and air conditioning (HVAC) system; and through infiltration, a process by which outdoor air flows into the house through openings, joints, and cracks in walls, floors, and ceilings, and around windows and doors. Infiltration occurs in all homes to some extent.
Natural ventilation describes air movement through open windows and doors. If used properly natural ventilation can at times help moderate the indoor air temperature, which may become too hot in homes without air-conditioning systems or when power outages or brownouts limit or make the use of air conditioning impossible. Most residential forced air-heating systems and air-conditioning systems do not bring outdoor air into the house mechanically, and infiltration and natural ventilation are relied upon to bring outdoor air into the home. Advanced designs for new homes are starting to add a mechanical feature that brings outdoor air into the home through the HVAC system. Some of these designs include energy efficient heat recovery ventilators to mitigate the cost of cooling and heating this air during the summer and winter.