What are the impacts of acid rain?
Acid rain lowers the pH of lakes and rivers, killing some fish and preventing some fish eggs from hatching. It causes defoliation of plants and trees, and changes soil chemistry by leaching essential minerals away from plants that need them.
There are two major sources of acid rain:
- Nitrogen oxides, which are produced in cars by oxidation of nitrogen gas from the air, react with water to form nitric acid in clouds and rain.
- Sulfur oxides, which are produced by combustion of high-sulfur coal in power plants, react with water to form sulfuric acid in clouds and rain.
Government regulations, combined with cap-and-trade programs, have greatly reduced the use of high-sulfur coal in power plants. The use of catalytic converters on cars has also greatly reduced nitrogen oxide emissions by converting them back to nitrogen and oxygen before being emitted from the exhaust pipe.
These measures have greatly reduced the acid rain problem in the US, but much more needs to be done to reduce harmful emissions in the US, China, Brazil and many other countries before we can consider the problem to be solved.