ICSE Class 9 Answered
Acid rain: Gases like sulphur dioxide and nitrogen dioxide when react with rainwater forms sulphuric acid and nitric acid respectively. These acids come down along with the rain. This is called acid rain.
Acid rain has several harmful effects.
It is harmful as follows:
a) Acid rain damages soil, plants, and buildings, especially those made of marble.
b) Even in very low concentrations, SO 2 causes irritation in the respiratory tract. It causes throat and eye irritation and can also affect the larynx to cause breathlessness.
c) It is extremely harmful to plants. Plants exposed to sulphur dioxide for a long time lose colour from their leaves. This condition is known as chlorosis. This happens because the formation of chlorophyll is affected by the presence of sulphur dioxide.
Steps to control the pollution by SO2 as follows:
SO2 emitted into the atmosphere from industries. It is the main contributors to acid deposition Additionally, individuals and society as a whole can participate in various efforts to help reduce acid deposition:
ii)Clean up smokestacks and exhaust pipes
iii) Use alternative energy sources
iv) Restore a damaged environment
v) Look to the future
vi) Take action as individuals
vii) Reduce industrial SO2 emission
2. Sulphur Removal During CombustionA number of technologies to prevent the production and release of SO2 during combustion have been developed over the past decade, but very few have achieved wide commercial application to date. The most developed are the Fluidised Bed Combustion (FBC) process and the integrated Gasification Combined Cycle (IGCC) system.
3. Removal of Sulphur after Combustion: Emissions of SO2 generated during the combustion of fossil fuels can be reduced by treating the flue gases before they are emitted into the atmosphere via the stack; this is termed Flue Gas Desulphurisation (FGD). Flue gas desulphurisation systems can be classified as either Regenerable or Non-regenerable.