A January 2016 paper by Univeristy of Texas researchers in Environmental Science and Technology titled "Emissions of Ultrafine Particles and Volatile Organic Compounds from Commercially Available Desktop Three-Dimensional Printers with Multiple Filaments" shows that ABS filament releases at least 10-50 times as much styrene (a known carcinogen) into the atmosphere near an operating printer than does PLA.
Z-Temp, by enabling PLA printing with the M200, allows you to print with far lower levels of many potentially harmful particulates and VOC emissions, especially styrene.
