Acid deposition occurs when acidic substances from the atmosphere are deposited on the Earth’s surface. These deposits include both wet deposition, where acidic compounds become incorporated into precipitation such as rain or snow, and dry deposition, where particles and gasses settle on surfaces without precipitation. Human activities, industrial processes and the combustion of fossil fuels are the primary sources of emissions of the gasses sulfur dioxide (SO2) and nitrogen oxides (NOx) which then form the acid substances deposited on the Earth’s surface. Acid deposition can cause acid rain, snow, or dust, which adversely impacts aquatic environments, air quality, soil quality, and vegetation.
Origin of the term and application
When scientists began to research the consequences of increased emissions of sulfur dioxide and nitrogen oxides, the term “acid deposition” was coined. As scientists identified the environmental impacts of these acidic pollutants in the later part of the 20th century, the term gained increasing significance in discussions around air pollution. For those involved in ecology and climate change, acid deposition became a focal point in developing international policies to regulate emissions and mitigate its effects.
