What are VOCs and how does the VOC Auto Sensing mode work?

Volatile Organic Compounds (VOCs) are gases emitted from household cleaning supplies, building materials, and similar products that can be harmful if inhaled. When VOC Auto Sensing mode is selected, the AirGenius 6 automatically detects VOC levels and operates at the appropriate cleaning level, displaying green (low), amber (moderate), or red (high) to indicate the detected level. (Page 3)