Understanding Acid Rain and Its Causes
Launch library · evergreen read
Acid rain forms when sulphur dioxide and nitrogen oxides, released mainly from burning fossil fuels, react with water vapour, oxygen and other chemicals in the atmosphere to form dilute sulphuric and nitric acids. These can then fall to earth as rain, snow, fog or even as dry particles.
Its effects build up gradually rather than appearing overnight. Repeated exposure can lower the pH of lakes and streams, stress or kill sensitive aquatic life, strip nutrients from forest soil, and slowly corrode stone and metal on buildings and monuments, particularly older limestone and marble structures.
Because the pollutants that cause acid rain can travel long distances before reacting, the damage often appears far from the original emission source. This cross border character is part of why acid rain became one of the clearer early examples of pollution needing coordinated, multi region responses. A single country reducing its own emissions cannot fully solve a problem that arrives, in part, on the wind from somewhere else entirely.