There are three gases which could cause acid rain, which are Sulphur Dioxide (sulphuric acid), NOx (oxides of nitrogen which produce nitric acid) and also perhaps Carbon Dioxide (weak carbonic acid), produces these acids because these gases dissolve in rain water/ precipitation and this forms a weak version of the acid, as the gases dissolve it lowers the pH of the rainwater.
I think that there has been a increase in the production of acid rain, due to the fact that the country as a whole has become much more industrialised, and because industry needs energy, they start to burn fossil fuels which contain a mixture of carbon and sulphur/nitrogen impurities, meaning when they are burnt they can release all of these acidic rain causing gases.
Lakes
Aquatic settings are the most clearly impacted by acid deposition though because acidic precipitation falls directly into them. Both dry and wet deposition also runs off of forests, fields, and roads and flows into lakes, rivers, and streams.
As this acidic liquid flows into larger bodies of water, it is diluted but over time, acids can accrue and lower the overall pH of the body. Acid deposition also causes clay soils to release aluminum and magnesium further lowering the pH in some areas. If the pH of a lake drops below 4.8, its plants and animals risk death and it is estimated that around 50,000 lakes in the United States and Canada have a pH below normal (about 5.3 for water). Several hundred of these have a pH too low to support any aquatic life.
Forests
Aside from aquatic bodies, acid deposition can significantly impact forests. As acid rain falls on trees, it can make them lose their leaves, damage their bark, and stunt their growth. By damaging these parts of the tree, it makes them vulnerable to disease, extreme weather, and insects. Acid falling on a forest’s soil is also harmful because it disrupts soil nutrients, kills microorganisms in the soil, and can sometimes cause a calcium deficiency.