Acid rain is precipitation that has been turned acidic to a pH value of 4 or lower due to air pollution. Acids can be very harmful to living beings and the environment around us. However, in the case of acid rain, the acid is very dilute. The acids present in acid rain are sulphur dioxides and different oxides of nitrogen (SO2, NOx) (gsu.edu). Acid rain occurs because of the pollution that is caused when fossil fuels are burnt (national geographic). This causes the acids to be released into the atmosphere, only to be fused with the rain (epa.gov). These acids get dissolved extremely easily and can travel long distances with the wind (epa.gov). Fossil fuels like coal are used in most factories across the world. Furthermore, motor vehicles release huge amounts of sulphur dioxide and different oxides of nitrogen too. Acid rain is a major environmental issue because the earth soaks up the acid rain which has permanent issues in the ecological system. Buildings can also suffer minor damage due to acid rain. The urbanisation of the world is causing more and more fossil fuels to be burnt which is causing more SO2 and NOx to be released into the atmosphere, thereby increasing the acidity of rain. With the growing technology, science has to find an efficient way to neutralise acid rain as not only does it destroy the environment, it might soon pose a serious threat to humanity.
Most coal-fired power stations use desulphurisation apparatus that removes sulphur off the plant. The most common way sulphur dioxide is eliminated is through 'wet scrubbing'. Wet scrubbing is performed by various apparatus know as 'wet scrubbers'. These objects remove pollutants from gas streams. Wet scrubbing is mostly done with limewater and/or limestone, however other alkali are also used. Wet scrubbers remove sulphur dioxides by mixing the flue gas with alkali and water to neutralise the flue gas (howstuffworks).