How does flue gas desulfurization reduce sulfur dioxide emissions from power plants?

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New York City skyline tinted orange from wildfire smoke. — air pollution control Even something as simple as breathing can get complicated.

Flue gas desulfurization (FGD) reduces sulfur dioxide emissions from power plants by using absorption processes to trap the gas before it is released into the atmosphere.1

These systems are categorized by their method of operation:

Wet Scrubbing: Flue gases are brought into contact with a liquid or slurry absorbent. The sulfur dioxide dissolves or reacts with the absorbent, becoming trapped within it.1
Dry Scrubbing: Dry pulverized lime or limestone is used as an absorbent. Once the sulfur dioxide is absorbed, the resulting solid particles are captured using baghouse filters.1

In common chemical processes using lime or limestone slurries, sulfur dioxide reacts to form calcium sulfite or calcium sulfate (gypsum). These compounds are then precipitated out of the system. While FGD is essential for mitigating acid rain, nonregenerable systems produce significant amounts of sludge that require careful disposal. Regenerable systems, conversely, allow for the recovery of sulfur to create useful by-products like sulfuric acid.1