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.