The term acid rain was first used by Robert Angus Smith, a scientist working in Manchester in the 1870s. The problem of acid rain is hence not a new one but the nature of the problem has changed from being a local problem for towns and cities to being an international problem.

In Smith’s time, acid rain fell both in towns and cities whilst today pollutants can be transported thousands of kilometres due to the introduction of tall chimneys dispersing pollutants high into the atmosphere.

Introduction:
The term "acid rain" refers to the phenomenon in which acidic pollutants are deposited from the atmosphere onto the Earth's surface through precipitation such as rain, snow, sleet, or fog. This environmental issue has significant impacts on ecosystems, human health, and infrastructure. The term was coined by Robert August, a scientist who played a key role in studying and raising awareness about acid rain.

Robert August and his Contribution:
Robert August, an American scientist, was the first to use the term "acid rain" in a scientific context. He conducted extensive research on the effects of air pollution on the environment, particularly focusing on the acidification of water bodies and the subsequent ecological consequences. August's work laid the foundation for understanding the formation, sources, and impacts of acid rain.

Research on Acid Rain:
August's research involved analyzing the chemical composition of rainwater samples collected from various locations. He observed that the pH of these samples was significantly lower than the normal range, indicating increased acidity. August deduced that the presence of certain pollutants in the atmosphere, such as sulfur dioxide (SO2) and nitrogen oxides (NOx), contributed to the acidification of rainwater.

Publication and Coining of the Term:
In 1972, August published a landmark scientific paper titled "Acid Rain: A Serious Regional Environmental Problem." This publication presented his research findings and highlighted the alarming consequences of acid rain on ecosystems, including the acidification of lakes, damage to forests, and corrosion of buildings.

It was in this paper that August first used the term "acid rain" to describe the phenomenon he was studying. The term quickly gained recognition and became widely adopted by the scientific community and the general public.

Impact and Legacy:
August's research and the coining of the term "acid rain" played a crucial role in raising awareness about this environmental issue. His work prompted further investigations into the causes and effects of acid rain, leading to the implementation of regulations and measures to reduce pollution emissions.

Today, the term "acid rain" is well-known and represents a significant environmental concern. The recognition of this problem has led to international cooperation and efforts to mitigate the sources of acid rain and minimize its impact on the environment.

Conclusion:
Robert August, through his pioneering research on the acidification of rainwater and its ecological consequences, coined the term "acid rain" in 1972. His work helped to bring attention to this environmental issue and laid the foundation for further scientific investigations and environmental policy development.