Question

Explain the circumstances leading to acid rain. How does acid rain affect us?

Answer 1

Hint – You can start by describing how the formation of rain takes place including evaporation, condensation and the falling of rain. Then describe how sulfur dioxide and nitrogen oxide gathers in the atmosphere and mix with the rain and make acid rain. Then follow up by describing how acid rains affect us.

Complete step by step solution:

Let’s start with how rain is formed.
- Rise of water vapor - There is water vapor in the air. The air is said to be saturated with water vapor, when it becomes unable to hold more water vapor. Cooler air contains less water vapor than warmer air before becoming fully saturated. So heat from the sun heats the water in the water bodies like oceans, seas, lakes, etc. and converts the water in the water bodies to water bodies. The same heat from the sun heats up the air molecules increasing its saturation limit. So air now contains more water vapor than before. We also know that warmer air is much lighter than cooler air, so warm air with high moisture content rises up in the atmosphere and is replaced by cool air. The warm air carries this water vapor high in the atmosphere.
- Condensation – Water vapor after rising up begins to condense. Water vapor normally begins to condense after finding a particle that it can use as a condensation nuclei. Some examples of condensation nuclei are dust particles, ice, etc. Condensing water vapor aggregate together to form larger water droplets and ultimately forms clouds.
Rain – When water droplets become too heavy they collapse due their own weight and begin to fall towards the ground.
- Acid rains are rains that are mixed with compounds like sulfur dioxide and nitrogen oxide. These gases are released in the atmosphere due to various industrial and human activities. After rising up in the atmosphere to the level where clouds are formed, these gases combine the water present in the clouds. Sulfur dioxide and nitrogen oxide dissolve readily in water and it becomes acidic in nature. When this water falls down as rain it is called acid rain.
- Acid rain affects us in the following ways –
- The acidic water of the acid rain is very harmful to the vegetation as it can corrode their outer surface.
- The lakes, ocean and seas when contaminated by this water, becomes potentially dangerous for aquatic life.
- Acid rains corrodes metals, stones potentially damaging bridges, monuments, etc.

Note – When the water condenses and aggregates, it has two different routes it can take. The temperature in the atmosphere is usually very cold. So, if the temperature is below the freezing temperature of water it turns to ice and falls down as snow and if it is above the freezing temperature of water it falls as rain.