Acid Rain D. Crowley, 2008

Friday, November 23, 2018 Acid Rain To know how acid rain is formed

Rock Weathering Complete the rock weathering worksheet

Rock Weathering

Rain Normal rainwater has a pH of around 5.6 – this means it is naturally slightly acidic This natural acidity is due to CO2 which dissolves in rainwater, forming carbonic acid Rainwater with a lower pH than normal is called… acid rain! We can test the pH using Universal Indicator (remember, green is pH 7 (normal); red for pH 1 (acid); and purple for pH 14 (alkali)

Acid Rain Acid rain has a higher than normal acid level (a low pH) Acid rain may contain weak solutions of carbonic, sulphuric, and nitric acids Where it falls over a prolonged period it can cause damage to the environment…

Naturally These chemicals can occur naturally, for example sulphur is released at active volcanic sites However, the vast majority of these chemicals are pollutants, produced from cars and power stations When these dissolve in rainwater they produce strong acids (sulphuric acid and nitric acid) forming acid rain

Acid Rain

Effects Of Acid Rain Trees lose some of the protection in their leaves, leaving them more at risk from frost and diseases Tree roots may also become stunted, so they can't take up as many nutrients Soils lose some of their nutrients

Effects Of Acid Rain Increasing acid levels may cause problems for aquatic animals and plants (e.g. fish may have trouble breathing) Acid rain may dissolve the stonework and mortar of buildings causing structural problems

Pollution Acid rain pollution may also cause acid rain many miles away from the source Pollution controls were introduced in the US in the 1980s, after Canada claimed that its forests were being harmed by US pollution Highland areas (where the rainfall is higher) are particularly susceptible to acid rain – high levels of acid rain in Scandinavia are believed to be caused by pollution originating in other countries…

Pollution In many European countries up to one half of the total area of forests have been damaged by acid rain - in particular, in Germany's Black Forest more than 50% of the forest has been severely damaged by acid rain Many trees have dried out and died already, while many others have discolored leaves Even tree planting has failed to halt this destruction, since the soil is already acidic

Unfair Scandinavian countries such as Sweden and Norway do not contribute much to atmospheric pollution However they are suffering extensive damage from atmospheric pollutants carried there from other countries

Reducing Acid Rain Sulphur dioxide is formed when coal containing sulphur is burned in power stations – this can be removed within the power station before being released into the atmosphere Nitrogen oxides are formed when petrol burns in vehicle engines – this can be converted into harmless gases using a catalytic converter

“Acid rain does not affect global warming” Explain why the following statement is not entirely true… “Acid rain does not affect global warming” Think about what happens when the acid dissolves rocks (what is released etc…) and how destroying plants may increase the rate of global warming… Acid rain can dissolve rocks which release carbon dioxide (a greenhouse gas) Acid rain also increase soli acidity, inhibiting plant growth (which usually absorb CO2)