It is a fundamental task of HVAC to provide occupants a healthy and comfort environment. By far more and more attention has been paid to indoor air quality(IAQ). Excellent indoor air ensures health of occupants. It has become a worldwide problem and caused many sick building syndromes(SBS) and building related illness(BRI) which can not be ignored. Indoor air quality would be one of the most important problems which developers owners proprietors care more about before entering 21st
