WHO has guidelines for air quality, including pollutants and something about dampness and mold. I attach the link to the latest one, there you can search for the pollutants such as bencene, etc...
Follow through chapter 4 Comfort and Health—Indoor Environmental Quality from the book: "Heating, Ventilating, and Air Conditioning Analysis and Design Sixth Edition by Faye C. McQuiston". You will find most of the answers there.