How do coal-burning power plants contribute to acid deposition?

Coal-burning power plants contribute to acid deposition by releasing sulphur dioxide and nitrogen oxides into the atmosphere.

When coal is burned in power plants, it releases various gases and particles into the atmosphere. Among these are sulphur dioxide (SO2) and nitrogen oxides (NOx), which are the primary causes of acid deposition. These gases can react with water, oxygen, and other substances in the atmosphere to form sulphuric acid and nitric acid. These acids then mix with water vapour in the atmosphere and can be transported by wind and weather patterns. When this acidic moisture falls to the ground, it is known as acid deposition, which can take the form of rain, snow, fog, or even dry particles.

The process begins with the extraction and burning of coal. Coal is a fossil fuel that contains a significant amount of sulphur. When this coal is burned in power plants to generate electricity, the sulphur is released as sulphur dioxide. Similarly, the high-temperature combustion process also results in the formation of nitrogen oxides. These gases are then emitted from the power plant's smokestacks and enter the atmosphere.

Once in the atmosphere, these gases can undergo a series of reactions. Sulphur dioxide and nitrogen oxides react with water, oxygen, and other chemicals to form sulphuric acid and nitric acid. These reactions can take place in clouds, and the resulting acidic compounds can be carried over long distances by wind and weather patterns. This means that areas far away from the source of the pollution can still be affected by acid deposition.

When the weather conditions are right, these acidic compounds fall to the ground as acid rain, snow, or fog. However, acid deposition is not always wet. In dry conditions, these acidic compounds can also fall to the ground as dry particles, or they can react with other gases and particles in the air to form larger particles that can also fall to the ground.

Acid deposition can have serious environmental impacts. It can acidify lakes and streams, harm vegetation, and even damage buildings and monuments. It is therefore crucial to control the emissions from coal-burning power plants to reduce the occurrence of acid deposition.