ColonialWebb is a private hvac firm that installs, maintains and upgrades mechanical and electrical systems in the US. They did a prety good job of illustrating some key aspects of indoor air quality in this video. Although they focus in the end mainly on mechanical solutions, and their are other solutions available, I think this video can help viewers understand the importance of indoor air quality when on average we can spend up to 90% of our time indoors in buildings that are becoming more air tight with every renovations that makes them more energy efficient.