You know that acid rain is a result of air pollution. Acid rain is a form of precipitation of high nitric and sulfuric acid levels from human activities and fossil fuel combustion. Acid deposition refers to the movement of acidity from the atmosphere to the Earth’s surface. Average rain is slightly acidic, with a pH of 5.6, while acid rain generally has a pH range of 4.2 and 4.4.

• At high temperatures, molecular nitrogen and molecular oxygen coming from the internal combustion engine and lightning discharges react to nitric oxide.

                                                     N2 + O2 → 2NO

• Nitric oxide then reacts with the excess oxygen in the atmosphere to give nitrogen dioxide. It is responsible for the brown colour of the smog.

                                                     2NO + O2 → 2NO2

• When nitrogen dioxide combines with rainwater, it forms a mixture of nitrous acid and nitric acid.

                                              2NO2 + H2O → HNO2 + HNO

• Excess amounts of Sulfur dioxide are released by various natural sources, such as volcanoes, forest fires, the microbial decay of organic materials, and fuel-burning.

                                                             S + O2 → SO2

                                                           2SO2 + O2 → SO3

                                     SO2 + ½ O2 soot dust or metal oxide → SO3

• The sulfur oxides react with rainwater to give sulfuric acid.

                                                       SO3 + H2O → H2SO4

• Most of the acid rain results from human activities upon burning fossil fuels, improper waste disposal. When the Sulphur and Nitrogen particles mix with the rainwater to form acids, they spread through the atmosphere, reach the Earth, and flow across the water bodies.
• Power plants, factories, automobiles burn fuels that produce polluting gases.
• Vegetable decay, pesticides and fertilisers, wildfires, and emission from volcanoes release some chemicals that cause acid rain.

• Soil Chemistry
• Soil contains minerals such as Mercury and Aluminum, which are usually not absorbed by plants and animals.
• But due to acid rain, the minerals undergo reaction with the acids and affect the food chain. Nutrients and minerals are washed off from the soil.
• Water Bodies
• Acid rain has many ecological effects, primarily on lakes, streams, wetlands, and other aquatic environments.
• As the acidity of a lake increases, the water becomes more apparent. The numbers of fish and other water animals decline, resulting in the depletion of oxygen levels in the water.

The greenhouse effect is a naturally occurring phenomenon responsible for heating of Earth’s surface and atmosphere. The Earth has an optimum climate that supports life, unlike other planets. It is because of the presence of a thin layer of greenhouse gases.

Greenhouse gas has the property of absorbing infrared radiation emitted from Earth’s surface and reradiating it back to Earth’s surface. Some examples of greenhouse gases: carbon dioxide, methane, water vapour, Nitrous oxide, and fluorinated gases.

Source: Energy Education

Effects of Greenhouse Gases

• Higher temperatures, global warming, damage to aquatic life.
• Melting of glaciers, rise in sea levels and ice caps, climate change, reduction in crop yield, decrease in rainfall—disruption of habitats such as coral reefs.

Global warming is one of the Greenhouse effects that increase Earth’s average surface temperature due to the impact of greenhouse gases, such as carbon dioxide emissions from burning fossil fuels or deforestation.

Ways to Reduce the Greenhouse Effect and Global Warming

• Public transportation: The various modes of transport emit about 30% of greenhouse gases. So, to cut out, you can use a carpool or public transport. Adopt a healthier lifestyle, and one can use a bicycle.
• Conservation of Energy: Use renewable energy sources and alternative energy sources like solar energy, hydro energy, or ocean thermal energy.
• Afforestation: You should Plant trees on a large scale. Do not burn leaves, wood, paper, etc.
• Awareness: Educating and creating awareness among people about greenhouse effects and global warming.

• Ozone gas is formed in the atmosphere by the action of UV rays. UV radiation strikes an oxygen molecule, splitting off the oxygen atoms.

                                                                O2 + UV → O + O

• Each oxygen atom collides with an O2 and another third molecule to produce two O3 molecules. The third molecule is necessary to remove excess energy associated with the collision.

                                                         O + O2 + third molecule → 2O3

                                                          Net reaction: 3O2 + UV → 2O3

Source: APOZA

• UV radiation is involved in the destruction of O3.
• Ozone depletion occurs when chlorofluorocarbons (CFCs) and halons, gases formerly found in aerosol spray, propellants, and refrigerants, are released into the atmosphere.
• The CFCs move upward and reach the stratosphere. In the stratosphere, CFCs are dissociated by UV light to produce chlorine atoms.
• The destruction of O3 occurs when these gases react with the ozone and break them into oxygen and chlorine monoxide.
• It results in the depletion of the ozone layer and the formation of an ozone hole. UV radiation can enter the Earth’s atmosphere through the ozone hole and cause several harmful effects.
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Source: Public Health

Climate changes due to the release of harmful gases and contaminants into the atmosphere result in acid rain, global warming, and ozone depletion. One should be practical and look for ways to reduce atmospheric pollution.

1. What are some of the greenhouse gases and their sources?
2. Greenhouse gases SourcesCarbon DioxideIt is released when fossil fuels like natural gas, coal, and oil are burnt. Soil degradation and deforestation add carbon dioxide to the atmosphere.MethaneIt results from fossil fuel production and transportation, agriculture, livestock, and organic waste decay.Nitrous OxideIt is produced from fertiliser application, fossil fuel, and biomass combustion.
3.  
4. What is the function of the ozone layer?
5. The layer absorbs the radiations and prohibits them from entering the outer surface of the Earth. The ozone layer occupies the lower part of the atmosphere to remove the unwanted pollutants from the Earth’s surface.
6. The ozone layer shields the Earth from UV rays. UV radiation can cause skin pigmentation, abnormalities in a growing fetus and even skin cancer.
7. What are the benefits of global warming?
8. Crops and plants grow better in the presence of high levels of CO2 and become drought tolerant.
9. Some of the frozen regions of the Earth experience more plant growth.
10. How to reduce acid rain?
11. Use alternative energy sources like wind or solar power as they produce fewer emissions.
12. Should limit the release of sulphuric dioxide and nitrous oxide into the atmosphere.