Facts for Prelims (FFP)
Source: US EPA
Acid rain, or acid deposition, encompasses precipitation with acidic components, like sulfuric or nitric acid, falling to the ground from the atmosphere.
| Aspect | Description |
| What is acid rain and how does it form? | 1) Acid rain is rain with high levels of acidic substances like sulfuric acid or nitric acid. 2) It forms when emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) released from burning fossil fuels, industries, and human activities mix with water vapour and chemicals in the air. 3) These acidic pollutants combine with water droplets in the atmosphere and then fall to the ground as rain, snow, fog, or dry particles. 4) The pH of acid rain is usually between 4.2 and 4.4 |
| Effects of acid rain on the environment | 1) Damage to vegetation: Acid rain leaches nutrients, weakens plants, reduces water absorption, and stunts growth. It led to reduced crop yields and plant fatalities. 2) Harm to aquatic ecosystems: Acid rain lowers the pH of water bodies. It harms aquatic life by damaging gills, reducing reproduction, and altering food availability. 3) Soil degradation: Acid rain can disrupt soil chemistry by leaching away essential nutrients like calcium and magnesium, which are crucial for plant growth. It can also release toxic metals such as aluminium from the soil, further damaging plants and aquatic life. |
| Efforts to minimize the effects | 1) Coal power plants have reduced the sulfur dioxide (SO2) content in their atmospheric emissions by more than 90% using flue-gas desulfurization. 2) The Acid Deposition Monitoring Network in East Asia (EANET) operates to address this issue. |
| About EANET | It is an intergovernmental initiative (started in 2001; Secretariat: UN Environment Programme Asia Pacific) among East Asian countries to monitor and collect data on the deposition of acid substances, such as sulphur dioxide and nitrogen oxides, in the atmosphere and their subsequent impact on the environment. |
| Other programme | Monitoring programs like the National Atmospheric Deposition Program and the Clean Air Status and Trends Network track acid rain’s environmental impact, aiding policymakers and researchers |
