The term acid rain was coined by the British chemist Robert Angus Smith (1817–1884), who in 1872 published Air and Rain: The Beginnings of a Chemical Climatology. Since then acid rain has become an increasingly used term for rain, snow, sleet, or other precipitation that has been polluted by acids such as sulfuric and nitric acids. When gasoline, coal, or oil are burned, their waste products of sulfur dioxide and nitrogen dioxide combine in complex chemical reactions with water vapor in clouds to form acids. The United States alone discharges 40 million metric tons of sulfur and nitrogen oxides into the atmosphere. This, combined with natural emissions of sulfur and nitrogen compounds, has resulted in severe ecological damage. Hundreds of lakes in North America (especially in northeastern Canada and the United States) and in Scandinavia are so acidic that they cannot support fish life. Crops, forests, and building materials such as marble, limestone, sandstone, and bronze have been affected as well, but the extent is not as well documented as it is with fish life. However, in Europe, where many trees are stunted or have been killed, a new word—Waldsterben (“forest death”)—has been coined to describe this phenomenon.