The Centers for Disease Control and Prevention (CDC) estimates that the majority of Americans spend 90 percent of their time indoors. On average, office workers spend approximately 40 hours each week in office buildings. These workers also study, eat, and drink in enclosed environments where make-up air, or fresh air added to recirculated air, may be compromised. In fact, some experts believe that more people may suffer from the effects of indoor air pollution than outdoor air pollution.
Indoor environmental quality, as the name implies, refers to the quality of air inside a building environment. Indoor environments are highly complex and occupants may be exposed to a variety of contaminants in the form of gases and particles from machines, cleaning products, construction activities, carpets, furnishings, perfumes, smoke, microbial growth, insects, outdoor pollutants, and more. Other factors such as indoor temperatures, relative humidity, and ventilation levels impact how individuals respond to indoor environments.