is rain consisting of water droplets that are unusually
acidic because of atmospheric pollution - most notably the excessive amounts of sulfur and nitrogen rel
eased by cars and industrial processes.
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.
There is also a strong relationship between lower pH values and the loss of populations of fish in lakes. Below 4.5 no fish survives, whereas 6 or higher will promote a healthy population.
Carbon dioxide Carbon dioxide in the air can dissolve in rain water to form carbonic acid, H2CO3. Carbonic acid is a weak acid, which partially ionises to form hydrogen ions. The hydrogen ions from carbonic acid give natural rain water a slightly acid pH value of 5.6. Sulfur dioxide Fossil fuels naturally contain sulfur compounds. These produce sulfur dioxide, a gas with a sharp, choking smell, when the fuel is burned. When sulfur dioxide dissolves in water droplets in clouds, it makes the rain more acidic than normal.
By: Pascal Lu