The invention relates to a method for waste-gas purification in degasification plants using a device (16) for generating a negative pressure, in particular by means of steam jet ejector pumps or mechanical vacuum pumps. It is provided according to the invention that the waste gas passing from a vacuum chamber (15) is conducted into a cyclone separator (12), and in that the method steps of coarse separation of particles from the waste gas and fine-dust separation of particles from the waste gas and gas cooling in the cyclone separator (12) are carried out in succession in such a way that the waste gas, after coarse purification has taken place, is conducted directly via a fine dust filter (13) installed in the cyclone separator (12) and subsequently through a gas cooler (14), which follows the fine dust filter (13), into a suction line (2) which is connected to the device (16); for generating a negative pressure, and to the device (16).