Electrostatic precipitators ( ESPs) are very efficient devices which remove 99% of particulates present in the industrial and thermal plant exhausts. There are electrode wires and a stage of collecting plates. The collecting plates are connected with ground. The electrode wires are provided with several thousand volts electric current. It creates a corona
which releases electrons. The electrons attach to the suspended particles and make them negatively charged within a fraction of a second. Air with charged particles passes slowly over collecting plates. The particulate matter settles over them and are removed.
So, the correct answer is 'Electrostatic precipitator'.