A portable microwave plasma discharge unit receives microwaves and a gas flow via a supply line. The portable microwave plasma discharge unit generates plasma from the gas flow and the received microwaves. The portable microwave plasma discharge unit includes a gas flow tube made of a conducting and/or dielectric material and a rod-shaped conductor that is axially disposed in the gas flow tube. The rod-shaped conductor has an end configured to contact a microwave supply conductor of the supply line to receive microwaves and a tapered tip positioned adjacent the outlet portion of the gas flow tube. The tapered tip is configured to focus the microwaves received from the microwave supply conductor to generate plasma from the gas flow.