Artificial rain to clear air pollutants in Delhi
- November 23, 2018, 4:11 pm
Why in news ?
With the pollution levels in Delhi showing no sign of improvement, the Centre is planning to induce artificial rain to wash away toxic pollutants from the air, and the approval for the same has been given by the union Ministry of environment.
Similar Practice followed by Beijing to seed the clouds before public holidays, such as National Day on 1 October, to make rain, disperse pollution and ensure clear skies on the day.
What is artificial rain?
Artificial rain is the process of cloud seeding, which is a type of weather modification that aims to change the amount or type of precipitation that falls from clouds dispersing substances into the air. Artificial rain is produced by spraying clouds with substances like Silver Iodide or cheaper available options like solid carbon dioxide (dry ice) or even finely powdered Sodium Chloride.
How is artificial rain produced?
The process includes three stages,
- building-up stage
- bombardment of chemicals.
The process involves using chemicals to stimulate the air mass upwind of the target area to rise and form rain clouds. These clouds are capable of absorbing water vapour from the air mass thus stimulating the condensation process in the clouds.
During the second stage, the cloud mass is built up using chemicals like kitchen salt ammonium nitrate and occasionally calcium chloride. Then during the third stage chemicals such as super cool agents like silver iodide and dry ice are used to reach the most unbalanced status which eventually leads to the formulation of droplets and make them fall as raindrops.