Dangerous acid rain from cars

A new form of acid rain caused by car smoke is threatening tropical forests around the world.

Internal combustion engines of cars emit NO ₂ gas. When flying into the atmosphere, this gas can create acid rain. Photo: Corbis.

Telegraph said that in the 1980s, smoke from coal-fired thermal power plants caused sulfuric acid rain (H ₂ SO ₄ ). Many forests were devastated when this type of acid rain fell. After that, many governments forced thermal power plants to put SO ₂ gas filters on the chimneys to prevent the formation of acid rain.

The presence of filtering equipment caused a sharp decrease in sulfuric acid rain, but another type of smoke is becoming a worrying factor. It is car smoke. The internal combustion engines of cars emit nitrogen dioxide gas (NO ₂ ).

A report in American Scientific Scientific warns that NO ₂ in car smoke and chemical fertilizers are accumulating in the atmosphere and creating nitric acid rain (HNO ₃ ). This kind of rain can kill trees and fish. When falling to the ground, acid rain can help many harmful minerals dissolve into water sources.

William Schlesinger, president of the Cary Ecology Research Institute in the United States, confirmed that nitric acid rain can have serious consequences like sulfuric acid rain.

'Both are strong acids and cause numerous serious environmental problems,' he said.

The US Environmental Protection Agency said chemical fertilizers are the most sources of NO ₂ emissions. Automobile smoke and smoke from thermal power plants are ranked second and third.

Professor Schlesinger fears the amount of nitrogen emitted by cars will increase in the future as more cars are put into use. The length of distance that people travel by car also increases over time.