Power stations/ cars burn fossil fuels and releases sulphur dioxide (SO2) + Nitrogen Oxide (NOX) in the atmosphere.Gases react in the upper atmosphere water vapour in clouds to acid.Falls as H2SO4 (Acid Rain)Main Sources of SO2 NOXSource AmountPower station 61% 46%Refineries/Industry 28%Domestic (Houses) 5% 23%Commercial & Public 4% 3%Transport 2% 28%The causes of acid rain is down to emission of pollutants from ~ combustion of fossil fuels ~ industrial processes~ Transport sectorEspecially SO2 & NoxSome countries have suffered more than others. Some of them are net importers and others are net exporters.The effects of acid rain are~ Direct impact on vegetation as a result of exposure to acid solution~ Percolation of acid rain through soil increases teaching of nutrients, so soil becomes less fertile.
Also mobilises cadmium, aluminium and mercury. These move through the soil and may become concentrated in toxic quantities.~ Lakes, rivers, streams may become polluted with cadmium, mercury and aluminium, killing aquatic life.~ Water in watercourses becomes more acid. May go beyond “range of tolerance” of most organisms. This leads to a rapid decline in species diversity.~Acidic water may get into drinking supplies including corrosion of pipes.~ Human health may be at risk by contaminated water supplies e.
g. diahorrea and vomiting.~ Acid rain increase damage to statues i.e. stonework caused by chemical weathering e.
g. Salisbury Cathedral, St Paul’s Cathedral and Trafalgar Square.A third of all German trees have been damaged by acid rain. The Germans call this “Waldsterben”.
4000 lakes are devoid of fish in Sweden. There has been a drastic decline of otters in UK. This is due to lack of fishWhat can be done?Normal rain is already slightly acidic in the region of about 5.6ph.
Nowadays extremes of ph in our rainfall have measured 3ph or ph 4. The environment economic, social and political implications are serious. What can be done?The first action was taken by environmental pressure groups in the late 70’s and early 80’s with their “stop acid rain!” campaign. By this time net importers of acid rain already identified signs of ecological disaster.
These countries began to mobilise and here are some significant dates:1984: Scandinavian countries signed an informal agreement to reduce SO2, emmitions by 30%. These countries called themselves the “30% club”.1985: Helsinki protocol was signed. Most Euro countries agreed to a 30% reduction of SO2 emmitions, by 1993 from a 1980 base. Britain didn’t sign it.
1979: The first internation agreement was signed in Geneva called “convention on long range trans boundary air pollution in Europe”. It didn’t set any targets for reducing emmitions.1988: the first EC directives were coming in.
These said countries had to reduce SO2 + NOX in membered states. Still using 1980 as a base year. By 93 it had to be reduced to 23%1995 it had to be reduced to 42%2000 it had to be reduced to 57%NOX 1993 it had to be reduced to 10%1998 it had to be reduced to 30%1992: The Rio summit encouraged governments to make plans for sustainable developments including reducing the problem of acid rain.At last there are a number of conventions and plans to reduce levels of acid rain around the world.There are two ways to solve this they are either avoiding the illness or treat the symptoms.Avoiding the illness~ Change energy sources~Fit pollution control equipment e.g.
filters i.e. flue gas desulphurisation (Flue gas)(All new power stations now have this equipment~Increase efficiency/ conservation methodsTreating the symptoms~ Treat lakes with powdered limestone but costly and only short term~ Shells placed in water causes to produce calcium carbonate over timeNB. To achieve EC directive levels Britain’s bill for fitting flue gas desulphurisation equipment is about ï¿½2billion (that could be a reason why the government was slow to accept that acid rain was a problem. They need a lot of limestone to FGD operation this limestone is mined in National park.