6.4 Acid Deposition Flashcards
Acid Deposition
process by which acidic particles, gases, and precipitation are deposited on Earth’s surface, including both wet deposition (rain, snow) and dry deposition (dust, aerosols).
Formation of acid rain (reactions)
Acid rain forms when sulfur dioxide (SO2) and nitrogen oxides (NOx) are released into the atmosphere, react with water vapor, oxygen, and other chemicals, forming sulfuric acid (H2SO4) and nitric acid (HNO3).
pH of acid rain
typically ranges from 4.0 to 5.0, which is more acidic than natural rainwater (pH around 5.6).
Wet vs Dry Acid Deposition
Dry Deposition: Refers to acidic gases and particles that settle out of the atmosphere
Wet Deposition: Involves acids being removed from the atmosphere by precipitation (rain, snow).
Natural sources of SO2
volcanic eruptions, sea spray, and decomposition of organic matter.
Anthropogenic sources of SO2
burning fossil fuels (coal, oil) and industrial processes,
Effect of acid rain on vegetation
can damage leaves, reduce photosynthesis, and leach essential nutrients from the soil, harming plant growth.
Acid rain weakens plants, making them more susceptible to disease, pests, and harsh weather.
Why is rain naturally acidic?
it absorbs carbon dioxide (CO2) from the atmosphere as it falls. When CO2 dissolves in rainwater, it forms carbonic acid (H2CO3), a weak acid.
Effect of acid rain on (freshwater) aquatic ecosystems
Lowers the pH of water bodies, leading to harmful effects. Sensitive species may die, reducing biodiversity and disrupting ecosystems.
Different from ocean acidification (which is to do with the oceans absorbing CO2)
Effect of acid rain on soil
Leaches essential nutrients like calcium and magnesium from the soil, depleting its fertility.
Acid rain can also mobilize toxic metals like aluminum, further harming plant and soil health.
Effect of acid rain on humans
contamination of drinking water, reduction of air quality, and damage to crops.
can also lead to respiratory problems
Effect of acid rain on buildings
accelerates the deterioration of buildings and monuments, especially those made of limestone, marble.
Acid rain reacts with calcium carbonate in these materials, leading to erosion and structural damage.
Downwind vs upwind
Downwind refers to the direction wind is blowing in
Upwind refers to the direction the wind is coming from
Prevailing wind
the dominant or most common wind patterns observed in a particular area over a long period
Wind is named the direction it is blowing from, not the direction it is heading towards.
Reaction of acid rain with marble/limestone
forms calcium sulfate, which is soluble and washes away, leading to surface erosion.
Chemical Reaction: CaCO3 + H2SO4 → CaSO4 + H2O + CO2
Connection between aluminium ions and acid rain
Acid rain can mobilize aluminum ions from soil minerals, which are toxic to plants and aquatic life.
Industrial Scrubber
a device (installed in chimneys and smoke stacks) used to remove pollutants, such as SO2, from exhaust gases before they are released into the atmosphere.
Liming (application of lime)
Liming involves adding lime (calcium carbonate) to acidic soils or water bodies to neutralize acidity and restore pH balance.
Cap and trade
An environmental policy that sets a limit (cap) on total SO2 emissions and allows companies to buy and sell emission permits (trade) to meet their individual caps.
Countries still affected by acid rain
China, India, and some Eastern European nations still face significant acid rain issues due to high levels of industrial pollution.
High vs low sulfur coal
High sulfur coal contains more sulfur, leading to greater SO2 emissions when burned, whereas low sulfur coal produces fewer emissions.
Positive effect of acid rain on peat bogs
The increased acidity can slow down the decomposition of organic material in peat bogs, helping to preserve the bog and its carbon storage capabilities.
