What are VOCs and why does the air purifier monitor them?

Volatile Organic Compounds (VOCs) are gases emitted from various household products such as paints, cleaning supplies, building materials, permanent markers, and home improvement products. Some compounds have higher concentrations indoors than outdoors. When Auto Mode is activated on compatible models, the air purifier automatically adjusts to the appropriate cleaning level to reduce detected VOCs in the room. (Pages 6, 9)