No worries, William. VOC stands for volatile organic compounds. The BME unit (temperature, humidity, and pressure sensor) in the Flex, the Zen, and the Touch includes a VOC sensor. As it is now, the sensor does not differentiate between types of VOCs. It reports the Static IAQ (Index for Air Quality), which is a health metric based on the VOC readings.
This VOC data is currently an experimental feature in PurpleAir sensors. We are working on fully understanding the readings and how to implement them into PurpleAir devices properly. You can read more about this at the following link: BME680 VOC Scale Change on the PurpleAir Map.
This data can be viewed by changing the data layer on the map: Environmental Data Layers.