Which of the following is an example of wet deposition?

• A. Sulfate deposition in rain.
• B. Dust on leaves.
• C. Ozone concentration.
• D. Dry deposition of methane.

Answer: (A)

Wet deposition happens when pollutants are removed from the air by precipitation such as rain, snow, or fog, with soluble substances dissolving into the raindrops and being deposited on the surface. Sulfate deposition in rain is the classic example because sulfates dissolve in rainwater and are carried to the ground as the rain falls, removing these pollutants from the atmosphere in the form of wet deposition. The other options involve processes that don’t use precipitation: dust on leaves is dry deposition, where particles settle onto surfaces without rain; ozone concentration refers to a gas in the air, not a deposited pollutant; and dry deposition of methane is methane removed through dry processes, not via rain.