What is dry deposition?

Dry deposition refers to the process through which fine particulate matter and gaseous pollutants settle from the atmosphere onto surfaces like soil, water bodies, and vegetation without the aid of precipitation. This typically occurs when airborne particles such as dust, smoke, and other contaminants fall to the ground due to gravitational forces, offering a critical pathway for pollutants to enter ecosystems.

Understanding this concept is essential in the context of water quality because dry deposition can contribute significantly to the accumulation of harmful substances in water bodies, leading to impacts on aquatic life and overall water quality. It highlights the importance of air quality on water quality, as contaminants can impact ecosystems even in the absence of rain. For instance, when these particulates settle onto lakes or rivers, they can introduce nutrients and toxic substances that alter the chemical composition of the water.

The other options describe processes related to the hydrological cycle and pollutant transport, but they do not capture the specific mechanism of dry deposition, which is characterized by the absence of rain or other forms of precipitation.