Acid rain is rain that has an acid pH due to the various polluting compounds found in the atmosphere. The acidity value of this type of rain so harmful to inert objects, animals, plants, natural resources such as water or soil, and humans varies from 4.0 to 4.2.
Now that you know what acid rain is, maybe you’re interested in knowing what acid rain consists of.
- Acid rain consists of precipitation of acidic water from clouds to earth surfaces.
- For the rain to become acidic, it has to go through a process of chemical reactions in the clouds, involving specific pollutants, water and oxygen.
How acid rain occurs
To know how acid rain is formed we must first know the precursors:
- Precursors are mainly acidic compounds from contamination. These are elsulfuric acid and nitric acid.
- Those directly responsible for acid rain are called secondary pollutants (Ac. Sululfic and A. Nitrics), which originate from chemical processes and/or photochemicals of primary pollutants.
- Primary pollutants in acid rain are sulphur oxides and nitrogen oxides.
Now that we know what contaminants are involved in the process, we need to know why acid rain occurs and how it happens:
- Primary pollutants from smoke and gases emitted from cars and industry are first produced.
- These contaminants interact with the water vapours present in the clouds of the atmosphere, and the sulfuric and nitric acids form.
- Acid rain occurs due to the interaction of sulfuric acid, nitric acid and nitrogen oxides with water vapor.
- Finally, when the precipitation of the water occurs, the droplets have a more acidic pH producing the famous acid rain.