Do the terms "washout" and "rainout" refer to a cleansing process of pollutants in the atmosphere?

The terms "washout" and "rainout" indeed refer to processes through which pollutants in the atmosphere are cleansed, mainly through precipitation.

Washout occurs during a rain event, where existing particles and aerosols that are already suspended in the air are removed from the atmosphere as rain falls. This process can significantly reduce the concentration of pollutants in the air, as the falling rain droplets capture and bring these particles down to the ground.

Rainout, on the other hand, refers to the introduction of new particles or pollutants into the atmosphere that subsequently become removed once precipitation occurs. For instance, compounds can be released into the air from natural events or human activities, and when rain begins, these new pollutants can be incorporated into the precipitation process, thus reducing their presence in the atmosphere.

Both processes are important in understanding atmospheric chemistry and air quality management since they demonstrate how precipitation can act as a natural mechanism for cleansing the atmosphere of various pollutants, contributing to better air quality.