A general definition of IAQ is the quality of the air inside buildings as represented by concentrations of air contaminants and thermal conditions that affect our health and comfort. Inferring from this definition, IAQ is evaluated based on two factors, health and comfort. According to ASHRAE Standard 62.1, an acceptable IAQ is about the indoor air, in which there are no known contaminants at harmful concentration as determined by cognizant authorities, while a substantial majority – say 80% or more of the people exposed – do not express dissatisfaction.
We spend most of our time in indoor environments. Many of you may think your home is very clean, but do you know that indoor air contaminants are basically everywhere? From building construction materials, painting or coatings on walls, ceilings, gas stoves in kitchens, and even your personal care products contain contaminants that can be harmful in an indoor environment. From studies, indoor air can be several times more polluted than outdoor air.
Since we spend more time indoors than outdoors, the concern about IAQ is rising nowadays. Examples of indoor air contaminants are Radon, Indoor aerosol, VOCs, Ozone, Carbon monoxide and Nitrogen dioxide, Bioaerosols, Asbestos etc. Besides the indoor air contaminants, temperature, humidity, air movement and the quality of ventilation systems also affect IAQ.
When someone suffers from influenza, it is easy for other people in the same indoor environment to get infected. The situation is worse when staying with someone who suffer from serious infectious disease like Severe Acute Respiratory Syndrome, (SARS) and the results can be fatal. SARS spreads rapidly around the world because some SARS patients were traveling around by aircrafts, one of the typical public indoor environments.
IAQ is very important to us. In an indoor environment with good IAQ, the concentrations of indoor air contaminants are maintained at an acceptable level. Our health can then be protected. Evidence shows that the productivity is improved under a good indoor air quality environment. On the other hand, an environment with poor IAQ can lead to different issues. We simply do not feel comfortable. Besides, poor IAQ also brings negative health impacts to us. 2 common building related health issues, Sick Building Symptom and building related illness are caused by poor IAQ. Working in an environment with poor IAQ also leads to lower productivity and high absenteeism.