Pollution Flashcards
What is smoke?
Smoke is made up of particles produced from the incomplete combustion of carbon-based materials.
What are the main causes of smoke?
Combustion of coal, diesel cars, crop waste, wood fuel.
Why does particle size matter?
PM1/ Smaller particles will stay in the atmosphere for longer and are more easily inhaled.
What are the toxic chemicals mostly found in smoke?
Fluorides, aluminium, lead, acids and organic compounds.
What are some effects of smoke pollution on humans?
Respiratory disease like asthma, bronchitis and lung cancer.
Chemicals in the smoke may also be carcinogenetic.
What are some effects of smoke pollution on living organisms?
Reduced photosynthesis.
There may be some substances in the smoke that are toxic to plants e.g., heavy metals and acids.
What are some effects of smoke pollution on non-living objects?
Smoke solvents can cause damage to buildings due to the chemicals and acids they contain, smoke can also make buildings appear dirty which is expensive to clean.
What is smog?
Smoke + Fog = Smog
How is fog formed?
When moist air cools until it reaches a dew point and water vapour condenses as airborne droplets of water.
How is smog formed?
The incomplete combustion of fossil fuels releases coarse particles which become suspended in the air.
The ash from forest fires or the burning of wood fuels.
What is the London smog of 1952?
London was positioned in a valley and in December 1952, anticyclonic weather conditions provided clear skies and low wind velocities. This allowed a temperature inversion to form and atmospheric pollutant levels rose as it couldn’t escape. Within a week 12,000 people had died and another 8,000 followed during the month.
How do temperature inversions form?
When warm pollutant gases are released at ground level they are less dense and more buoyant, so they rise and disperse.
As they rise they cool down, but the surrounding air is already cooler so they will continue to rise and disperse.
Basically warm air forming a blanket over cold air, pollutants released will be trapped in the cold air and their concentrations rise.
What is photochemical smog?
Produced in a temperature inversion in warm conditions under UV light in which reactions between primary pollutants, NOx and hydrocarbons, and secondary pollutants, Ozone, produce high concentrations of PANs.
No fog present
What are PANs/ Peroxyacetyl nitrates
A secondary pollutant in photochemical smog’s caused by the reaction of tropospheric ozone, nitrogen oxides and unburnt hydrocarbons .
What are the general methods of controlling air pollution?
Legalisation, Energy conservation and fuel substitution.
Legalisation Examples
Clean air act 1956, the restricted use of fossil fuels that produce smoke in large urban areas of the UK.
The Montreal Protocol, an international agreement to phase out the use of ozone-depleting substances.
How can energy conservation methods be used to reduce atmospheric pollutants?
-Use energy efficient appliances
-Improving insulation
-Reusing industrial energy
-Using public transport
What are some sources of pollution?
-Toxic Leachate
-Chlorofluorocarbons,(Aerosol, fridges)
-Mining, (dust and noise)
-Sewage into water sources
How does density affect the level of harm?
Dense materials don’t get carried very far and stay close to the source at high concentrations.
How does persistence affect the level of harm?
More persistent materials will stay in the environment for longer periods of time and cause more harm, e.g. CFCs, DDT.
How does toxicity affect the level of harm?
-The more toxic a material is the greater the damage.
-Most toxins damage proteins by enzyme inhibition.
How does specificity affect the level of harm?
The more specific a pollutant is the less harm it will cause.
-Pyrethroid insecticide is specific to pests like fleas however it is toxic to fish.
How does reactivity affect the level of harm?
Reactivity can affect the severity of the pollution caused. High reactivity will cause more damage.
-CFCs have a low reactivity, however they breakdown into chlorine and damage the ozone.
How does solubility affect the level of harm?
High solubility means they will be easily dispersed in water, so pollutants can travel further, e.g. nitrates.
-Lipids are insoluble in water.
What is bioaccumulation?
The process by which the amount of a substance within an organism increases. The body cannot excrete these substances so they stay forever.
What is biomagnification?
Where the concentration of a substance increases as it goes through the food chain, e.g. heavy metals.
-Fish-Seals-Polar bears
What is synergism?
Where the effects of two or more pollutants react to cause a greater effect than their individual effect.
-Ozone damages the leaf cuticles which enables sulfur dioxide to cause more damage to newly exposed cells.
What are the gonadic effects of mutagenic action?
A mutation in an egg or sperm cell which may cause a birth abnormality in the offspring produced.
What the somatic effects of mutagenic action?
A mutation in a body cell can make it behave abnormally, as the damaged DNA cannot control normal cell function, e.g. cancer where uncontrolled cell division produces a tumour.
What is carcinogenic action?
Mutagens that cause cancer.
-Asbestos
-DDT
-Cadmium
What is teratogenic action?
Causes birth abnormalities by preventing normal gene expressions, they inhibit the function of proteins and enzymes.
-THESE ARE NOT INHERITED BY FUTURE GENERATIONS.
What is adsorption?
When some pollutants can become attached to the surface of some materials such as soil particles, clay particles
-Adsorption may immobilise the pollutant and stop it causing problems.
What is mobility?
The ability of a pollutant to move in the environment depends on their other properties. Pollutants that are more mobile are likely to travel greater distances and affect larger areas.
-CFCs
-SO2, acid rain
What is the diffuse source of pollution?
This is where the pollution cannot be traced back to a single source, e.g. cars or pesticides in gardens.
What is the fixed point source of pollution?
This is where the source of pollution can be identified and can be tracked back to a single point.
What is Critical Pathway Analysis/CPA?
It is used to predict the movement of potential pollutants in the environment to assess the severity and location of pollution events.
-Is it mainly used to monitor the dispersal of radioactive waste.
What is Critical Group Monitoring/CGM?
A method to assess the risk of public exposure to pollutants. It labels people as the ‘critical group’ if their risk is high.
How do air and water currents affect pollution?
The direction and velocity of the currents will affect how far a pollutant is dispersed and how much it is diluted.
What happens to pollutants in higher temperatures?
Degradable pollutants will breakdown more rapidly, this will increase deoxygenation.
How mobile is lead dust?
It has high density so not very mobile, it will settle near the source
How does the oxygen level affect pollutants?
More oxygen means more aerobic decomposition of sewage.
More oxidation of sulfide ores producing SO2.
How does pH affect pollutants?
Heavy metals, like lead become more mobile in acidic conditions so will be dispersed more.
What do NOx and hydrocarbons form when they react together?
PANs
Where are temp inversions most likely to form?
Valleys: cold dense air collects here
Low wind velocity: wind currents are not blowing the warm layer away.
What does adsorption do to pollutants?
Pollutants, like aluminium and lead can adsorb onto clay particles and become immobilised this stops them causing problems.
What can the emissions location affect? Give examples
Affects the severity of pollution.
Marine discharges where the pollutant will be diluted and dispersed.
Pollutants released onto permeable rock above aquifers.
How can the time of emissions being released be controlled?
Releasing emissions when the tide is going out will mean they will be carried out and dispersed.
Releasing emissions when the tide is coming in means the pollutants will be bought in and not dispersed.
When released in a temp inversion they wont disperse.
What is the polluter pays principle?
Where the organisation/person is held responsible to prevent pollution.
What is the precautionary principle?
Where it is assumed the emission will cause pollution unless research confirms it wont.
How can smoke pollution be controlled?
Legalisation
Use natural gas/electricity
Diesel particulate filters in diesel cars
How does an electrostatic precipitator work?
Used in coal fired power stations.
A chamber with electrically charged wires, the particles in smoke are attracted to the wires they accumulate and fall as ‘fly ash’.
How do cyclone separators work?
Like a vacuum cleaner.
Effluent gases forced to spin in a cylindrical chamber, this throws the suspended particles to the outer surface where they fall.
Clean gases are produced.
How do scrubbers work?
Uses water sprays to wash out suspended solids and dissolves soluble gaseous pollutants.
How do bag filters work?
Smoke particles from effluent gases get trapped on a fabric filter.
What do turbo chargers do in diesel engines?
They allow more oxygen to pass into the engine so combustion is more efficient, less smoke is produced.
What kind of pollutant is NOx and how is it formed?
A primary pollutants, it forms when nitrogen and oxygen react together in high temps and pressure in exhausts or power stations
Where do hydrocarbons come from?
Unburnt fuel in engine exhaust gases
Oil spills
What is the affect of NOx on humans?
Colds, flu, bronchitis
Makes asthma worse
What is the affect of PANs on humans?
Eye irritation
Asthma
Emphysema
Increased heart attacks
What is the affect of O3 on humans?
Asthma
Bronchitis
Heart disease
How can NOx be controlled?
Platinum or palladium catalytic convertors in engines.
The NOx is reformed into nitrogen and oxygen.
How can unburnt hydrocarbons be controlled?
Catalytic convertors oxidise hydrocarbons to CO2 and H20
Vapours at filling stations collected and returned to fuel tank
Why is it good for primary pollutants to be controlled?
If theyre controlled no secondary pollutants will be produced.
What gases are involved in acid rain?
SO2
NOx
Where does SO2 come from?
Combustion of coal containing sulphur or smelting sulphide ores.
What is the effect of acid rain on non-living things?
Corrosion of metal
Damage to limestone buildings as the acids dissolve it
What are the direct effects of acid rain on living organisms?
Denatures proteins in cell membranes
Inhibits enzyme action
Damage to root hairs, stomata, fish eggs and gills.
Invertebrates with calcium exoskeletons die as the acid dissolves calcium.
What are the indirect effects of acid rain on living organsisms?
Heavy metals becoming more soluble in acidic conditions.
Acidic solutions from acid rain percolating through the soil and leaching metals ions, important plant nutrients are lost.
Lead becoming mobilised, can be leached into water bodies.
What is natural gas desulfurisation?
Removing hydrogen sulfide by dissolving in an amine solution, this prevents SO2 being produced when burnt.
What is dry-flue gas desulfurisation?
Flue gases passed through crushed calcium carbonate.
Solid calcium sulfur is produced, SO2 is not produced when burnt.
What is wet-flue gas desulfurisation?
Flue gases bubbled through a sodium sulfite solution, stops SO2 being produced when burnt.
What is coal desulfurisation?
Iron pyrites removed by washing and streaming, when burnt no SO2 is produced.
How is NOx controlled?
Catalytic convertors
Urea sprays
Low temp combustion, less NOx is produced
How can tropospheric ozone be controlled?
Reducing NOx which contributes to it forming.
What are the effects of carbon monoxide on humans?
It binds to the iron in haemoglobin in red blood cells so prevents oxygen being carried around the body.
Possible brain damage
How is carbon monoxide produced?
The incomplete combustion of hydrocarbons.
How can CO be controlled?
Catalytic convertors
What factors affect degradation?
Higher temps means faster
High dissolved oxygen conc means faster
High lvls of sunlight/UV can cause photochemical degradation.
Where does hot effluent water come from?
Steam turbine power stations