Main Causes of Acid Rain

Sources that play a major role in acid rain

What is Acid Rain?

The extremely acidic rainfall that occurs due to environmental pollution is termed as acid rain. The main elements that influence acid rain are nitric acids and sulfur acids. When atmospheric pollution exceeds its limit, it causes acid rain spoiling the environment to a large extent.


Various reasons contribute to acid rain. Some of these are natural causing processes, whereas some others are human activities that cause acid rain. Burning of fossil fuels, industrial activities, automobiles, etc. are the major human activities that cause acid rain.

In simple terms, the increase in the acidity of water droplets makes the acid rain to happen. The pH level of the water droplets helps to determine the acidity of rain waterer. Normal water droplets of rain have a pH level of 5.3 to 6.0 which is weakly acidic.

When the pH level of water droplets goes down below the normal pH level, it becomes more acidic and causes acid rain. In this article, we will try to understand little more about acid rain. Here, we will discuss the major causes of acid rain so that is a major environmental issue and leads to harmful effects.

Also check – Causes of water pollution

How is Acid Rain Caused?

There are various sources of acid rain, some are human causing sources and some others are natural sources. However, out of these human causing sources contributes a lot to acid rain. You can go through the primary sources of acid rain as discussed here –

causes of acid rain

Acid Rain Due to Human Activities

Human activities are majorly causing acid rain. Various human activities are involved with causing acid rain such as the burning of fossil fuels, industrial activities, etc. It won’t be wrong if we say that human activities are the primary factors that cause acid rain. The acid rain causing gases emits through different activities of ours. The urban areas that are developing day by day are mainly affected by acid rain. The major cause of acid rain through human activities is as follows –

Burning of fossil fuels

Nitrogen oxide (NO2) and sulfur dioxide (SO2) are mainly two gases that are responsible for acid rain. Fossil fuels (especially coal and oil) are used in various activities of our daily lives such as to generate energy, for heating, cooking, etc. The burning of fossil fuel releases a huge amount of these two gases in the atmosphere. Coal and oil emit NO2 and SO2 on combustion polluting the environment. When these gases are released in the air, they form mild sulfuric acid and nitric acid when contact with the water molecules present in the atmosphere.

The fact is that burning coal and oil emits a large amount of SO2 and NO2 gases that are mainly causing compounds of acid rain. As the level of combustion of these fuels increases, the level of emission of these gases in the atmosphere will also be increased at a faster pace.

Industrial activities

  • There is no doubt in it that the level of pollution has increased to an optimal level after the commencement of the industrial revolution, especially power plants and manufacturing industries.
  • Fuel is the main requirement of the power plants to generate energy. Due to the combustion of fuel, sulfur dioxide and nitrogen oxide get its way into the atmosphere through power generation processes.
  • Manufacturing industries (such as cement manufacturing industry, chemical production industries, petroleum refineries, metal producing industries, plastic processing industry, pharmaceutical industries, etc.) also contribute to enhancing the level of NO2 and SO2 in the atmosphere.
  • From the past few years, these industries are using technologies to minimize the level of release of nitrogen oxides and sulfur dioxide. Even though the level of emission has reduced but still the continuous process for a long time-period will leads to sources of acid rain.
Also read about – Water treatment plant

Automobiles also cause acid rain

Automobiles have always been the source of pollution in the environment. They have been one of the major reason of acid rain through the release of nitrogen oxides and sulfur dioxide in the atmosphere. From the past few decades, the number of automobiles and other vehicles has increased a lot, and simultaneously the pollution has also increased equally. Acid rain is mostly observed in urban areas due to the high concentration of pollution.

Acid Rain Due to Natural Sources

Natural processes also contribute to acid rain. Volcanic eruptions are a very good example of natural sources of acid rain. The pollutants that release through natural processes accumulate in the atmosphere every time and later on, it enhances the chances of acid rain.


Volcanic explosions

The volcanic eruption is one of the major natural causes of acid rain. When volcanoes erupt, it releases a huge amount of acid rain causing gases in the atmosphere such as sulfur. Later on, these gases emitted through volcano eruptions cause a higher amount of acid rain. Sometimes these gases may cause precipitation forms such as fog or snow that affects the flora and fauna of the Earth’s ecosystem. Due to volcanic eruptions, various gases and other pollutants get their way into the atmosphere causing acid rain.

Decomposition of flora and other biological processes

Apart from volcanic eruptions, there are some other biological processes happens in the environment that also plays a vital role in the reasons of acid rain. Decomposition of vegetation, forest fires, etc. is some of the examples of these biological processes that generate acid rain causing gases in the atmosphere.

Dimethyl sulfide is a major component that releases in the atmosphere through biological processes that occur in the environment. This dimethyl sulfide contains sulfur which is one of the main elements that causes acid rain.

Lightning also generate acid rain

Lightning is another natural way of causing acid rain. When lightning strikes it releases nitric oxide through a natural process. When this nitric oxide reacts with water molecules present in the atmosphere via electrical mode it generates nitric acid through a chemical reaction. As a result of this, acid rain caused by a natural process of lightning.

Acid rain is dangerous and it can lead to harmful effects. If you can think of more points, do comment below.

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button