Table 2. Inventory data of plastic-based single-use masks at pre-manufacturing stage (based on 1 ton)

Category		Material	Amount	Unit
Input	Raw materials	Propylene	834.2	kg
	Auxiliary materials	Nitrogen	52.7	kg
	Auxiliary materials	Electricity	246.8	kWh
	Auxiliary materials	Natural gas	28.0	m3
	Auxiliary materials	Water for processing	2,468.0	kg
Output	Product	PP resin	822.7	kg
	Air emissions	CO2, NMVOC, particulates etc.	8.4	kg
	Waterborne emissions	BOD, COD, Zn etc.	0.03	kg