Acid Rain Charles Fletcher, Martyna S. Sowa, Svetlana Zusina, ACID RAIN AND ITS EFFECT ON THE ENVIRONMENT
What is acid rain and what is the scale of the problem?
How do we know if the rain is acid?
What causes acid rain (chemical reactions)?
Where do the acid rain precursors come from?
How does acid rain affect the environment?
What can we do to protect our planet form acid rain?
Acid rain, or acid deposition, is a mixture of sulphuric and nitric acids.
gases and particles
The valid risk assessment
The net acid deposition flux
the total acid deposition flux
deposition flux of base cations.
The acidity status of precipitation is a result of a balance between
acidifying compounds (oxides of sulfur and nitrogen) and alkaline compounds (ammonia and alkaline material in windblown soil dust).
The acidity of precipitation is measured by the concentration of hydrogen ion.
(pH value -below 5.6 is acidic).
Causes and chemistry
a) Acid reactions with sulphur
S + O 2 -> SO 2
2SO 2 + O 2 ->2SO 3 2-
SO 3 2- + H 2 O -> H 2 SO 4
b) Acid reactions with nitrogen
N 2 +O 2 ->2NO
2NO +O 2 ->2NO 2
4NO 2 +O 2 + 2H 2 O ->4 HNO 3
PRECURSORS AND SOURCES
The main precursors of acid rain are emissions of sulphur dioxide (SO 2 ) and nitrogen oxides (NO x )
Fuel combustion in power plants (SO 2 )
Exhaust pipes in automobiles (NO x )
Terrestial, tidal, and nutrient-rich oceanic areas
Outgassings from anaerobic wetlands
Breakdown of amino acids in organic wastes
TRANSPORT OF ACID RAIN PRECURSORS
Acid rain in a certain area can be caused by pollutants from emissions that are hundreds, even thousands of kilometers away especially through wet deposition.
Water and marine life
Extinction of fish in lakes
Plants, forests, crops
leaf necrosis, tissue damage, death of the whole tree
Improper growth of plants and trees
POLICIES AND TAKING ACTION
Strategies for mitigating acid rain
Liming bodies of acidified water
This process of neutralizing acidity in endangered lakes and streams is through the addition of lime (calcium carbonate and calcium hydroxide). Chemicals such as caustic soda, sodium carbonate, slacked lime and limestone help raise pH of acidified water.
Treatment needs to be repeated every 3-6 years
Remote lakes are inaccessible
Large pieces of lime dissolve slowly
Doesn’t solve the problem for soil acidification
Reducing SO 2 and NO x emissions
Changing from high to low sulfur coal
Moving to non-fossil fuels such as nuclear power
Using Solar, Wind or Hydro resources
IMPROVING IN-PROCESS TECHNOLOGY
REDUCTION OF COMBUSTION TEMPERATURE (NO X )
CHANGING THE FUEL USED:
1979 - Geneva Convention on Long-Range Transboundary Air Pollution took place with the idea to limit sulfur and nitrogen emissions was successfully achieved
1995-1997 Title IV of the Clean Air Act was established to reduce the adverse effects of acid deposition through reductions in annual emissions of sulfur dioxide of ten million tons from 1980 emission levels.
Many policies and programs were established in the past couple of decades once governments started to become concerned with the harmful effects of air pollution.
Results and Conclusions
Acid rain remains an acute problem in many parts of the world and is threatened by the rapid industrial development of the developing countries
The future strategies should concentrate on both the decrease of acidifying compounds and the increase of alkaline elements
Everyone should stayed informed and educated on the matter of acid rain and lead an energy efficient lifestyle