Air quality inside buildings is often three to four times worse than the air outside. This is the opposite of what most people think when it comes to air quality, which is that air pollution is what occurs outside.
The concern with indoor air quality is severe when it comes to commercial buildings. Equipment and processes in a commercial facility create a large number of airborne contaminants: carbon monoxide, volatile organic compounds, smoke, chemicals, even bacteria and mold spores. Proper ventilation is a necessity to remove as many of these pollutants as possible, but facilities often need other IAQ measures.