Flashcards
Atmospheric pollution
Cards in this deck (9)
- 1BackgroundPollutants in air behave differently than in water or on the ground. Interactions with UV can cause chemical reactions, producing secondary pollutants.
- 2Smoke and smoke smogs backgroundSmoke made from particulates produced by incomplete combustion. Categorised by the size of particles:
-PM10: less than 10 microns in diameter
-PM5: less than 5 microns in diameter
-PM1: less than 1 micron in diameter
Small particles easily inhaled. Smoke can act synergistically with other pollutants. - 3Effects of smoke pollution-Humans: respiratory diseases, increase risk of infections and can be carcinogenic
-Other living organisms: reduced photosynthesis as smoke blocks light
-Non-living objects: can damage buildings due to acids and solvents
-Climate: reduce temperatures as high albedo reflects light
-Smoke particles are small and can remain suspended for long periods
-Smoke in stratosphere can deplete ozone - 4Smoke smogsSmoke+fog=smog. Fog forms when moist air is cooled until dew point. Temperature inversions make fog more likely. Smoke more easily inhaled. Smog-high albedo, temp inversion can last for long.
London Smog 1952: valley, temp inversion formed, 12,00 deaths - 5Smoke pollution control measures-Legislation: Clear Air Act 1956
-Domestic sources: increased use of fuels that don't produce smoke,e.g.natural gas
-Transport sources: diesel particulate filters
-Industrial sources: electrostatic precipitators, cyclone separators, scrubber, coal treatment, bag filters
-More efficient combustion technology: turbochargers, more oxygen supplied - 6Photochemical smog backgroundUse of word smog misleading as don't involve smoke or fog but do involve urban pollution and temperature inversions.
- 7Pollutants involved in photochemical smogs-Variety of reactions between primary and secondary pollutants in presence of sunlight, including UV
-Sources of primary pollutants: NOx released in exhaust gases, NO2 only toxic at high concentrations but in presence of sunlight and other pollutants more toxic secondary pollutants can be produced, e.g. PANs. Unburnt hydrocarbons from variety of sources including unburnt fuel in exhausts. - 8Photochemical pollutant effects-NOx increase respiratory infections
-PANs more toxic at lower concentrations, cause breathing difficulties
-Tropospheric ozone contributes to production of PANs but is also toxic itself; heart disease.
-Some cities more prone due to topography and climate; los Angeles, Paris. - 9Control of photochemical smogsMOx and hydrocarbons controlled using catalysts, e.g in catalytic converters.
NOx reduced to re-form oxygen and nitrogen. Unburnt hydrocarbons controlled: catalytic converters oxidise it to carbon dioxide and water, vapours at filling stations collected, condensed and returned to main fuel tank, vapours passed through activated carbon filter.
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- A level Environmental Studies Flashcards on Atmospheric pollution, created by Mollie Munday on 14/02/2019.
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- Mollie Munday
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