Your Indoor Air Quality
HVAC systems can greatly affect indoor air quality.
Filters help in this regard, but the overall system plays a large part as well. The phrase “HVAC system” refers to the equipment that provides heating, cooling, filtered air and humidity control to ensure comfortable conditions inside a building. Some buildings may rely on natural ventilation while others may not have air conditioning, which would cool the air mechanically. There are still others that operate with little to no humidity control. HVAC system features will depend on factors such as the age of the design, climate, building codes, planned use, preferences of the owner and designer, and other modifications.
These systems can be as simple as a single stand-alone unit that controls the temperature in a single room, to large, centrally-controlled systems that serve multiple zones within a building. Modern offices have large heat gains due to lighting, people, and computers, and, therefore, can require year-round cooling. Spaces at the outside of the same building (i.e. those with exterior walls) may require hourly and daily temperature control as outside weather conditions fluctuate. Buildings that are over one story in height also generally experience an influx of uncontrolled air infiltration at the ground level.
There are some buildings that do not have any kind of central heating or cooling but use natural ventilation or exhaust fans to remove odors and contaminants. In these structures, a high degree of discomfort and marginal air quality are likely, particularly when people keep the windows closed due to extreme weather conditions. Luckily though, most modern buildings use mechanical ventilation systems to bring in outside air when the building is occupied.