Name and briefly describe two technologies used to reduce PM and SO2 emissions from coal-fired power plants.

• A. Biomass co-firing and selective catalytic reduction.
• B. Flue gas desulfurization (scrubbers) remove SO2; Electrostatic precipitators or baghouses capture PM before release.
• C. Catalytic cracking and hydroprocessing remove PM and SO2.
• D. Membrane separation removes both PM and SO2.

Answer: (B)

Two pollutants from coal-fired power plants are often tackled with separate, dedicated control technologies: one cleans sulfur dioxide (SO2) from the exhaust, and the other removes particulate matter (PM) before gases go to the atmosphere.

Flue gas desulfurization, or scrubbers, are designed to remove SO2. In a typical wet scrubber, the hot exhaust gas is brought into contact with a slurry of limestone or lime. The SO2 reacts with the slurry to form gypsum or other sulfate compounds, dramatically reducing SO2 emissions. This is a standard method specifically aimed at cutting sulfur pollutants that contribute to acid rain and respiratory problems.

To reduce PM, plants use electrostatic precipitators or baghouses. An electrostatic precipitator charges inhaled particles so they are attracted to and collected on plates, removing most of the fine dust and soot from the gas stream. A baghouse uses fabric filters that trap particles as the gas passes through, capturing PM before the gas is released. Both methods target solid or liquid particles suspended in the flue gas and are separate from the chemical scrubber that handles SO2.

This pairing directly addresses the two pollutants named—SO2 with scrubbing and PM with particulate collectors—making it the best-fit approach. Other technologies mentioned are oriented toward different pollutants (for example, NOx control) or are not standard methods for removing PM and SO2 from coal plant emissions.