What does the VOC sensor do and what do the indicator light colors mean?

The built-in VOC sensor detects Volatile Organic Compounds (gases emitted from cleaning products, home improvement materials, and décor items) and automatically adjusts the cleaning level. A green light means a low VOC level and the unit runs on LOW; amber means a moderate level and the unit runs on MEDIUM; red means a high level and the unit runs on HIGH. (Page 6)