Introduction As a result of modern life style, people spend 90% of their time in indoor environments and this is why, each day, sustaining acceptable indoor air quality (IAQ) becomes more important.
IAQ is a major concern to business, schools, building mangers, tenants and workers because it can impact the health, comfort well-being and productivity of the building's occupants. OSHA recognized that poor IAQ can be hazardous to workers' health, and that it is in the best interest of everyone that building owners, managers, and employers take a proactive approach to address IAQ concerns.
The indoor environment of any building is the result of the interaction of its localization, climate, HVAC systems (original design and modifications), contamination sources (building materials, furniture, equipment, activities, indoor activities and process and exterior sources), and building occupants. The Environmental Protection Agency has included IAQ among the top five environmental risks to public health.
We define Indoor Air Quality as the effect that contaminants that are generated or trapped in the building's indoor environment have on the health and wellbeing (comfort) of its occupants. The term "indoor air" is usually applied to non-industrial indoor environments, such as office buildings, public buildings (school, hospitals, theaters, restaurants, etc.), and individual homes.
We must point out that recent studies attribute 15% labor absenteeism to respiratory conditions. The natural composition of air is 21% oxygen, 78% nitrogen, and other traces of gases, such as 0.96% argon, and 0.04% carbon dioxide, helium, and water.
Technically, we define an acceptable IAQ as air in which there are no known contaminants at harmful concentrations, as determined by cognizant authorities, and with which a substantial majority (80% or more) of the people exposed do not express dissatisfaction. This definition is used by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) in their standard 62.1-2007.