pollution

• What are the factors affecting the formation of temperature inversions?

  Valleys (colder denser air accumulates), low wind velocity (prevents dispersal of pollutants), cloudless skies (infrared radiation can be radiated from the ground cooling it down) and mist/fog (water vapour reflects sunlight and slows ground heating)
• What is the purpose of CPA?

  To predict the movement of pollutants in the environment, assessing the severity and location of the pollution. If the pollution is predicted to be highly dispersed or carried to a less sensitive location, little to no action has to be done to prevent it, and vice versa. CPA is mainly used to track the dispersal of radioactive waste discharges.
• What are the two principles of pollution control?

  1. the polluter pays principal: if the costs of preventing the damage are less than the cost of the damage, then there is a financial incentive to prevent it. The incentive to comply is greater if financial penalties are high.
  2. the precautionary principle: assumes that a waste will cause pollution if released until research confirms that it's unlikely to do so. Being unaware of a problem not yet understood isn't an excuse and doesn't reduce responsibility.
• What are the four control methods of pollution?

  1. production prevention e.g. desulfurisation of fossil fuels before combustion
  2. prevention of release e.g. electrostatic precipitators for smoke control and catalytic converters
  3. post-release remediation e.g. oil spill clean up, phytoremediation of land polluted with heavy metals
  4. alternative processes e.g. use of electric vehicles, use of pyrethoid pesticides, use of renewable energy
• What are the three different smoke categories?

  PM10 - when particulates are less than 10 microns in diameter

  PM5 - When particulates are less than 5 microns in diameter

  PM1 - when particulates are less than 1 micron in diameter

  Smaller particles remain in the atmosphere for longer so are less likely to be inhaled.
• What respiratory disease can smoke pollution cause in humans?

  Respiratory disease
• How does smoke pollution affect cilia in the bronchioles?

  It kills cilia, making it hard to clear particles
• What is the impact of smoke pollution on photosynthesis in living organisms?

  It reduces photosynthesis by blocking sunlight
• How can smoke particles damage non-living objects?

  They may damage buildings due to acidic content
• What effect does smoke pollution have on climate temperatures?

  It causes temperatures to cool
• Why does smoke pollution lead to cooler temperatures on Earth?

  It increases planetary albedo, reflecting light
• How long can smoke particles remain suspended in the atmosphere?

  For long periods of time
• What is the effect of smoke in the stratosphere on the ozone layer?

  It can deplete the ozone layer
• What happened in the London smog of 1952?

  there was a 5 day period where anticyclonic weather conditions caused clear skies and calm winds, forming a temperature inversion where atmospheric pollution increased. This caused 12,000 deaths.
• What are the smoke pollution control measures?

  Legislation, such as the 1956 clean air act restricting fuels that produced smoke in urban areas

  Domestic sources, increasing the use of non-smoke producing fuel

  Transport sources, using diesel particulate filters (dpf) in the exhaust pipe of diesel engines to trap 80% of smoke particles.
• What are electrostatic precipitators?

  a method of industrial control that passes effluent gas through a chamber containing electrically charged wires or plates, attracting the smoke particles. When the particles accumulate, they fall to the floor as fly ash which can be removed.
• what are cyclone separators?

  a method of industrial control that draws effluent gases into a chamber where they are forced to rotate until the particles are thrown to the outside surfaces of the chamber where they fall and collect. This cleans the gas, which is discharged from a pipe out of the chamber
• What are scrubbers, bag filters and coal treatment

  scrubbers - uses a fine water spray to wash out suspended solid particles and dissolve soluble gaseous pollutants

  Bag filters - remove smoke particles from effluent gases by trapping them on a fabric filter

  Coal treatment - heating coal allows tar that produces smoke to be drained off, leaving smokeless coal.
• What are the reactions that form photochemical smog?

  NO2 from combustion processes is split by photolysis into NO and O. O can react with O2 to form O3 - tropospheric ozone. NO, O3 and unburnt hydrocarbons from unburnt fuel in gases can react to form PANS (peroxy acetyl nitrates) that are photochemical smogs.
• How can unburnt hydrocarbons be controlled?

  Catalytic converters oxidise hydrocarbons to form carbon dioxide and water. The vapours at filling stations can be condensed and returned to the main fuel tank, or passed through an activated carbon filter where hydrocarbons adsorb onto the carbon particles
• What are the 5 gases that can create acid rain, and where are their sources?

  1. Sulfur dioxide: combustion or oxidisation of materials containing sulfur, including coal or sulfide ores
  2. oxides of nitrogen: sourced from high temperature combustion in power stations or petrol/diesel internal combustion engines
  3. ozone: formed from reaction of O2 and O in the troposphere
  4. Hydrogen chloride: combustion of coal, waste incineration containing chlorine e.g. PVC plastic waste
  5. sulfur trioxide: oxidisation of sulfur dioxide by ozone
• What are the direct effects of acid rain on living organisms

  can denature proteins in cell membranes and inhibit enzyme action. Living cells exposed to the environment are likely to be damaged, e.g. cells inside stomata, root hair cells, fish gills etc. Invertebrates with exoskeletons will die if their skeleton is dissolved by acid rain. Sulfur dioxide can cause or exacerbate respiratory issues
• What are the indirect effects of acid rain on living organisms?

  Metal ions become more soluble at low pHs, causing them to be leached from the soil. Important nutrients such as magnesium and potassium are lost first. Toxic ions lost from the surface of clay particles can inhibit enzyme action in plant root cells and soil biota. If metal ions are consumed by humans, neurological issues may be caused.
• What is natural gas desulfurisation?


  the removal of sulfur from the fuel before it is burned, for example in ships.
• How is natural gas desulfurised?

  hydrogen sulfide is removed through dissolving it in an amine solution or reacting it with iron particles, preventing the production of sulfur dioxide.
• How is crude oil desulfurised?

  Distillation using molybdenum catalysts (hydrodesulfurisation) removed sulfur compounds
• How is coal desulfurised?

  solid iron pyrites in coal can be removed through streaming and washing. This is done by crushing the coal and putting it in a flowing stream of water, fast enough to take the coal away but leave the iron pyrites behind.
• how is dry flue gas desulfurised?

  passing the flue gasses through a bed of crushed calcium carbonate, causing the sulfur to react with the calcium carbonate leading to solid calcium sulfur. The remaining calcium sulfate can be used as gypsum building plaster
• how is wet flue gas desulfurised

  by bubbling the flue gas through sodium sulfite solution, leaving behind sodium hydrogen sulfite. This can be heated to break down as sodium sulfite and water (reusable) and solid sulfur dioxide which can be converted to solid sulfur or sulfuric acid, important for industry.
• How does low temperature combustion control oxides of nitrogen?

  Having a larger surface area for combustion maintains rapid combustion without needing higher temperatures (fluidised bed combustion)
• How do catalytic converters control oxides of nitrogen?

  a platinum or paladium catalyst is kept in a chamber in a car's exhaust pipe, chemically reducing NOx into nitrogen and oxygen gases
• What is the equation for NOx being reacted with urea spray?

  2CO(NH2)2 + 4NO + O2 -> 4N2 + 2CO2 + 4H2O
• What are the effects of carbon monoxide

  Binds to the haemoglobin in the blood preventing it from carrying oxygen. This may cause brain damage and eventual death. Low concentrations may increase health problems caused by chronic heart disease
• What are the 3 factors affecting dilution of pollutants in the water?

  effluent quantity

  Volume of water

  residence time of the water
• what are the effects of thermal pollution

  as the temperature of the water increases, its ability to dissolve oxygen decreases, leading to a lower concentration. Water with abnormally high temperatures may kill aquatic species through denaturing enzymes and proteins. Any species left will be thermophilic (heat-loving).
• How do cooling towers work

  they spray hot water from the base, and as it rises, it mixes with incoming air which absorbs the heat and rises upwards into the atmosphere.
• what are the causes of oil pollution?

  -waste lubricating oil which may have been used in an engine or as industrial machine oil that is washed into drains or mixed with other effluents

  -accidental releases such as from shipping accidents, oil rig accidents, pipeline leaks, storage tank leaks

  -oil exploration: drilling pipes need lubrication to reduce friction, often done with clay suspended in water. Oil based clay may leach into surrounding water
• what are the effects of oil pollution

  -some crude oil components (benzene) are toxic, effecting planktonic organisms

  -oil can cover marine life causing asphyxiation, especially in algae or molluscs.

  -birds covered in oil may drown

  -birds covered in oil may lose insulating properties, so may die of hypothermia.

  -oil on the surface may reduce the dissolved oxygen content, reducing the survival rate of aerobic organisms

  -oil can mask odours causing difficulty for marine predators
• How can oil releases be prevented?

  recycling waste lubrication oil through removing contaminants and chemical reforming or distillation can make the oil viable. Non-recyclable waste oil can be burnt and used as fuel
• how do better shipping routes reduce the risk of oil spills?

  oil tankers can be kept a greater distance from the shore as much as possible. If an engine failure occurs, this gives the tanker more time to deal with the issue before it is washed to shore by currents