Abstract
The aim of this Chapter is to provide an overview of various factors affecting indoor air quality (IAQ) and the associated challenges in its modeling and to assess, mitigate, and predict exposure to IAP. It starts by introducing the different types of indoor environments and the sources of air pollutants that affect the IAQ followed by processes and interactions that are involved. The efforts to monitor IAQ levels are discussed with the aim of understanding individual exposure levels. The methods to model the IAQ are discussed with a few case studies summarising the methodologies and instruments used to gain an understanding of practically implementing the above steps in real-world applications. Lastly, the challenges associated with the legislation concerning the IAQ are also discussed.