Differentiate between dry deposition and wet deposition.

Differentiate between dry deposition and wet deposition.

• A. Dry deposition is removal via surface contact without precipitation; wet deposition involves scavenging by rain, snow, or other precipitation processes.
• B. Dry deposition involves rainfall deposition with aerosols.
• C. Wet deposition is removal via surface contact without precipitation.
• D. Dry deposition tends to increase downwind concentrations.

Answer: (C)

Deposition removes pollutants from the air either by direct contact with surfaces or by being washed out by precipitation. Dry deposition is the process where pollutants deposit to surfaces such as soil, vegetation, or buildings without any precipitation, through mechanisms like diffusion, turbulent transfer, impaction, and gravitational settling. Wet deposition occurs when rain, snow, or other precipitation scavenges pollutants from the atmosphere, either inside clouds (washout) or below the clouds (rainout), delivering them to the surface. Therefore, the best way to describe the difference is: dry deposition happens without precipitation, while wet deposition involves precipitation scavenging. Descriptions that assign wet deposition to surface contact without precipitation or that dry deposition requires rainfall aren’t accurate, and the notion that dry deposition increases downwind concentrations isn’t generally correct because deposition removes material from the air.

Deposition removes pollutants from the air either by direct contact with surfaces or by being washed out by precipitation. Dry deposition is the process where pollutants deposit to surfaces such as soil, vegetation, or buildings without any precipitation, through mechanisms like diffusion, turbulent transfer, impaction, and gravitational settling. Wet deposition occurs when rain, snow, or other precipitation scavenges pollutants from the atmosphere, either inside clouds (washout) or below the clouds (rainout), delivering them to the surface. Therefore, the best way to describe the difference is: dry deposition happens without precipitation, while wet deposition involves precipitation scavenging. Descriptions that assign wet deposition to surface contact without precipitation or that dry deposition requires rainfall aren’t accurate, and the notion that dry deposition increases downwind concentrations isn’t generally correct because deposition removes material from the air.