While many people tend to visualize acid rain as an occurrence marked by pure acid falling from the sky, that is far from true. Basically, acid rain is a broad term which encompasses certain types of precipitation by which the chemical compounds suspended in the atmosphere come down to the Earth.
What is Acid Rain?
In geography, acid rain refers to the phenomenon of precipitation, wherein the droplets of water coming down to the Earth are characterized by unusually high acidic content.
In several cases, the concept is used as an attribute of a broader concept known as acid deposition. In this concept, the acidic compounds in the atmosphere come down to Earth in the form of rain and/or snowfall.
The acidic compounds in water are measured in terms of pH value, with low pH value signifying highly acidic nature of the liquid. While pure water has a pH value of 7, normal rainwater can have the same ranging between 5.5 to 7.
The slight increase in pH value of normal rainwater can be attributed to the presence of carbon dioxide in the atmosphere. When the pH value of rainwater goes below 5.5, it technically qualifies as acid rain. If you are fascinated by science, you will find the chemistry of acid rain equally interesting.
Causes of Acid Rain
As we mentioned earlier, acid rain occurs as a result of chemical reaction in the atmosphere. The most common chemicals that contribute to this process include nitrogen oxide and sulfur dioxide, both known for their ability of dissolving in water with ease.
These chemicals are basically the pollutants that are released in the atmosphere. Of the various human activities which contribute to this phenomenon, the most prominent one is burning of fossil fuels to produce electricity, power vehicles, and power industries.
Pollutants such as sulfur dioxide and nitrogen oxide are released in the atmosphere in form of exhaust smoke. Being light in nature, they start ascending and eventually come in contact with the rain-bearing clouds. When the clouds start precipitating, the water droplets come in contact with the chemicals suspended in the atmosphere.
The chemicals get dissolved in these water droplets wherein they react with oxygen and other chemicals, and come down in the form of acid rain. The occurrence is also recorded from areas wherein there is less air pollution, as these light chemicals are easily guided off by wind to far off places.
Acid rain can be caused by oil spills as well, and that can be attributed to the fact that the oil spilled in the ocean tends to evaporate into the atmosphere along with the ocean water. In this case, the particles in oil get suspended in the atmosphere and eventually come down in form of acidic compounds.
Other than these causes, there also exist some natural causes, such as volcanic eruptions and forest fires, which fuel this phenomenon.
In order to curb this phenomenon, we need to identify its causes and eliminate them. While natural causes of acid rain do exist, they are negligible as compared to the human-induced causes. It is but obvious that human activities play a major role in the occurrence of acid rain on the planet.
Taking into consideration its future implications, the onus is on us to ensure that we implement certain solutions and stop contributing to this natural hazard―knowingly or unknowingly.