Abstract: An apparatus and method remove particulate matter from a gas. The apparatus has an inlet for receiving a contaminated gas having particulate matter, and for inducing a swirl to the contaminated gas. A cyclonic separation stage including a first flow-path is provided for separating a portion of the particulate matter from the swirl-induced contaminated gas by centrifugal action, to produce a partially clean gas. An ionization stage including a second flow-path is provided for ionizing the particulate matter remaining in the partially clean gas by producing a corona discharge in the second flow-path. A particle collection stage including a third flow-path is provided for separating the ionized particulate matter from the gas using an electric field across the third flow-path, to produce a clean gas. The ionization stage and the particle collection stage are arranged such that the third flow-path has an increased cross-sectional area relative to the second flow-path.