Indoor air quality and human health are of continuously growing importance. Indoor air quality may be affected by many factors excluding, but not limited to, more loosely sealed buildings, the use of air purifiers and other pollutant sources (for example, room air fresheners), the use of various chemicals for pesticide management and cleaning, and finally, the use of synthetic building materials and furnishings. In recent years, people have become more aware of potential health and comfort problems that may be associated with poor indoor air quality. It is partly due to the move to more tightly sealed buildings, the implementation of energy conservation programs, and the growing use of laser printers, photocopiers, and other sources of indoor air contamination. Greater general awareness of environmental issues may also play a part. Most IAQ complaints from building occupants are related to a respiratory headache, irritation, odours, or fatigue. These concerns may be associated with chemical vapours, dust generated in the work environment, contaminants associated with fungal growth (mould), materials infiltrating from outside sources (such as pollen or engine exhaust), or other factors such as elevated carbon dioxide levels. This handbook aims to turn the attention to these subjects and to promote methods and technologies to reduce poor indoor air quality and to distribute outdoor air throughout the building, remove contaminants and odours, and control the indoor temperature and humidity. The information in this guide will help to maintain good indoor air quality in a building, prevent indoor air quality problems, and correct issues that may arise. It will also help to understand the indoor air quality requirements. The structure of this text allows for flexibility in course content and design. It may be used equally well either as a textbook for students or a handbook for environmental consultants, mechanical engineers, building occupants, labour unions and suppliers. Furthermore, this text may be useful data for either the undergraduate or the graduate level. The author wishes to acknowledge Nova Science Publishers with special mentions to Nadya S Gotsiridze-Columbus and Carra Feagaiga for their editorial support.