Ventilation: What you need to know

There is growing evidence that, in some instances, air inside buildings and homes is more polluted than the outdoor air in some larger, industrialized cities. This should be a significant concern considering that research has shown that people spend an overwhelming majority of their time indoors and exposed to indoor air pollution that may pose health risks.

A growing emphasis on energy efficiency has resulted in buildings that sealed much tighter to limit the infiltration of outdoor air. This, along with deferring maintenance to save money and the increasing number of consumer products that contain harmful chemicals, has led to deteriorating indoor air quality and more frequent complaints from building occupants.

The response of the occupants to the indoor air pollutants and other factors, such as climate, noise, light, etc., can be classified into one of the following categories:

• Acute effects. Acute effects occur immediately (e.g., within 24 hours) after exposure. The effects typically do not last long and disappear quickly once the occupant is no longer exposed. However, it is possible that exposure to certain microorganisms and other biological contaminants can cause serious, potentially life threatening respiratory diseases that may lead to chronic respiratory ailments.
• Chronic effects. Chronic effects are long-lasting responses to long-term or frequently repeated exposures. Cancer is the most well-known chronic effect of long-term exposure to certain air pollutants.
• Discomfort. Discomfort is typically associated with climatic conditions in the building. Occupants may feel too hot or too cold or ...