Further study

Natural phenomena such as volcanic activity and decomposition of plants release sulfur dioxide (SO2) in the atmosphere. This will lead to increased acidity of rain water but not enough to cause ecological damage because the effect of the acid is neutralized on contact with alkaline substances present in water and soil.
The industrialization and the advent of cars begin to break this balance.
Sulphur dioxide (SO2), resulting from burning coal in power plants and nitrogen oxides (NO2) released in large quantities by motor vehicles also enter the atmosphere.
In contact with oxygen and water vapor in these gases become sulfuric acid (H2SO4) and nitric acid (HNO3) returning to the surface as rain, snow or microscopic particles of dust acidic.
This causes acid rain and corrosion in metal buildings, and also cause serious damage to nature.

The term acid rain was coined by a chemist, Robert Angus Smith, in describing the pollution in Manchester, England, for over a century. However, globally, the perception of acid rain only occurred from the 1950s, when many ecosystems (lakes and forests, mainly) were already seriously compromised.
This hindsight due to the fact that natural environments have a long response time to attacks such as acidification.