Acid Rain

• Fossil fuels contain many impurities like sulfur-contains impurities - when these burn, they produce sulfur dioxide (SO2) - thus gas reacts with water in atmosphere forming surfeit acid causing acid rain.
• • Acid rain has a pH between 2 and 4 (strong acid) - compared to ’clean’ rain which is a weak acid with pH of 5.5.
• Effect of acid rain:

  • Decrease in pH of natural water sources like lakes and rivers - damage to aquatic animals and plants (kill fish).
  • Increasing acidity of soil - damage to land based plant life like forests and other vegetation.
• Effect of acid rain:

  • Can cause damage to building and statues (especially those made of carbonate rocks like limestone).
  • Increases rate of corrosion of metal structures like bridges and metal statues / sculptures.
• Can reduce acid rain same way as global warming by using renewable sources of energy (solar, wind, geothermal, biofuels, hydrogen fuel, etc.).
• • Acidity in soil and lakes can be neutralised by adding a weak alkali, preventing damage to plant and animal life.
• • Industrially, can reduce effect of acid rain (remove SO2) by sulfur scrubbing - exhaust gases containing SO2 are sprayed with calcium hydroxide (slaked lime) and both react forming calcium sulfate which is removed as solid waste and can be used for other purposes like making plaster boards - neutralises waste gases before leaving chimneys.