Question

a) what are the technologies or policies that are currently used to combat acid rain

           b) what are the new technologies or policies that could be used to further reduce the problem

            c) what is the current threat of acid rain on the forests of the Eastern United S  tates based on the information that you found in your search for policies

                and technologies

Answer 1

a) To combat with acid rains following processes are used :

1) Using of renewable sources of energy such as solar, wind and water energy and not to use non renewable fuels.

2) Limestone are used in th water bodies such as lake and in soil to neutralise the effect of acid rain. Acid rains makes the water bodies and soil acidic due to presence of nitric acid. Limestone reacts with nitric acid and produce water, carbon dioxide and salt ( Calcium nitrate). Thus the acidic nature is being converted into neutral. Thus soil and water body is deploid of acidic nature and becomes neutral.

3) Reduction of emission of nitogen oxide from engine of vehicle by using exhaust gas recirculation (EGR) and selective catalytic reduction (SCR). 54% 0f nitrogen oxide are being emmited by engine which causes nitric acid and thus acid rain. EGR is used with very high temperature which reduce amount of oxygen intake from air to engine by recycling some of exhausted gas to cylinder which decreases combustion temperature of engine. SCR acts as reduction of emission of nitrogen oxide by making it in exhaust line of engine to react with ammonia or urea to produce water and nitrogen.

b) The new technologies used to further reduce the aid rain is made by acid rain programe which is used by power plant to reduce emission of causative agent of acid rain such as SO₂ and nitrogen oxide. In power plants scrubbers are used to reduce the emission of these gases which are technically called flue gas desulphurization). Two typs of scrubbers are used to reduce the emission are wet and dry scrubbers which achieve the same goal of cleaning up emmisions befor it enters into the air.

1) Wet scrubbers cleans emissions by rinsing them down with liquid pollution removal reagent.

2) Dry scrubbers remove SO₂ emission without using liquid. Limestone slurry is added to emission as this slurry dries out, limestone particles are suspended in mixture. SO₂ then react with limestone instead of air.

Another advanced technology used by power plants are fluidised bed combustion and reagent injection to reduce the SO₂ emission.

c) Quantity of sulphur exported by surface water (primarily as SO₂^-4 is essentially equivalent to input from atmospheric deposition. This suggested that there should be control in emission of sulphur which will decrease in sulphur deposition thus result in equivalent decrease in amount of SO₂^-4 that enters surface water.