6.4 Acid Deposition Flashcards
pollution components of acid deposition
sulfur dioxide and oxides of nitrogen
dry deposition
Dry deposition occurs when acidic particles and gases settle directly onto surfaces without the involvement of precipitation. This can include:
- Ash particles from industrial processes
- Acidic dust
- Gaseous forms of sulfur dioxide and nitrogen oxides
wet deposition
Wet deposition involves the incorporation of acidic compounds into water droplets in the atmosphere, which then fall as precipitation. This can manifest as:
- Acid rain
- Acid snow
- Acid fog or mist
direct effects of acid deposition: acidified lakes characteristics
- an impoverished species structure
- visibility several times greater than normal
- white moss spreading on bottom of lake
- increased levels of dissolved metals like lead
indirect toxic effects of acid deposition
- increased solubility of certain metals
- high levels of aluminum ions = toxic effect on fish
indirect nutrient effects of acid deposition
ability to flush trace metals from soil and pipes:
- wells in Sweden have a drastically increased level of aluminum levels
- more mercury accumulated in fish = health problems for humans when eaten
- falling numbers of fungi, bacteria, earthworms (earthworms do not tolerate low pH soils -> acidification = less mixing)
geographic scope of impacts T
- Transboundary Nature: Pollutants can be carried by wind currents over long distances, often crossing national borders. This means that the source of emissions and the area experiencing impacts may be in different countries.
geographic scope of impacts D
Downwind Effects: Areas downwind of major industrial regions are particularly vulnerable to acid deposition, even if they have little industrial activity of their own.
pollution management strategies 1
Altering Human Activity
- less private cars -> more use of public transport or park -and- ride schemes (EVALUATION: can be expensive and inconvinient)
- switch to low-sulfer oil
- reducing fossil fuel use (EVALUATION: difficult to do in a fossil-fuel-reliant society -> governments need to use legislation and funding to implement infrastructure for renewable resources eg. solar panels, wind turbines,etc.)
pollution management strategies 2
Regulating and Monitoring Pollutant Release
- burning coal in the presence of crushed limestone to reduce acidification process
- removing sulfur before combustion
- wet scrubbing - uses alkaine scrubbers such as limestone to absorb sulfur dioxide
Evaluation:
- possible to do on large scale (PRO)
- costly (CON)
- needs proper technology / infrastrucutre, which is often difficult to acquire (CON)
pollution management strategies 3
Clean-up and Restoration Measures
While prevention is key, some efforts focus on mitigating existing damage.
- Liming: Adding lime to acidified lakes can help neutralize acidity and restore aquatic ecosystems, though this is often a temporary solution.
- Reforestation: Planting trees in areas affected by acid deposition can help restore ecosystem function and potentially increase the buffering capacity of soils.
acid deposition and international cooperation real life example
The acid rain program in North America, involving cooperation between the United States and Canada, is a notable example of successful international efforts to address acid deposition.
direct effects of acid deposition: affect on trees
- sulfur dioxide interferes with process of photosynthesis
- acidic soil: damages root systems, decreases tree growth, increases development of abnormal cells, premature loss of needles
- nitrogen acts like fertiliser -> trees grow very fast, but root systems dont develop as well, trees are easily blown over
Distribution of acid deposition: geographical aspects high damage from acid rain
granite
- naturally acidic
- low buffering capacity
Scandanavia, Scotland, northern Canada
Distribution of acid deposition: geographical aspects with low damage from acid rain
lime-rich soils / rocks
- better able to absorb and neutralise
Distribution of acid deposition: volcanoes
important sources of sulfur dioxide and nitrogen dioxide
Distribution of acid deposition: conifer plantations
litter is acidic, not easily broken down and adicifies soil
evaluation of acidification, pollution management strategy 3
pros:
- allows fish to remain in lakes
- enables aquatic ecosystems to function
cons:
- expensive
- has to be done repeatedly
- short-term solution
are lower or higher values of ph more acidic?
lower ph values are more acidic than higher ones
