Atmospheric pollution
- Created by: student111319
- Created on: 03-04-23 08:29
atmospheric pollution
problem: 1 billion people exposed to outdoor air pollution, 90% of air pollution in LEDCs comes from oil motor vehicles which are poorly maintained
primary pollutants: emitted direclty from polluting prcocesses, source be natural/anthroprogenic. greatest emitter fossil fuel combustion creates primary polllutants: carbon monoxide, carbon dioxide, unburned hydrocarbons, nitrogen oxides, sulphur oxides, particulate matter
secondary pollutants: formed when primary pollutants undergo reactiosn with other chemicals present in the atmosphere, sometimes this is a photochemica reaction in the presence of sungligh e.g. tropospheric ozone, particles produced from gaseous primary pollutants, peroxyacetyl nitrate
atmospheric pollution behvaiour:
- behave differently compared to on ground/in water
- transboundry, large areas of dispersal
- interact easily with electromagnetic radiations e.g, UV from the suns visible light = photochemical reactions = secondary pollutans
- interact with infra read energy radiated from earth
smoke
sources: inomplete combustion of carbon based materials produce smoke, combustion of wood fuel = small suspended solid particles in the atmosphere = measured by size range of particles
particle size important: smaller particles remain in atmosphere for longer likely be inhaled
PM10: <10 microns in diameter
PM5: <5 microns in diameter
PM1: <1 micron in diameter
smoke is made of particles of varying size. smaller they are the more damaging they are to humans
smoke smogs (smoke + fog = smog)
- fog formation occurs when cooled moist air reaches dew point - smoke that is part of smog easily inhaled
- water vapour condenses as a water layer of airbore droplets - smoke has very high albedo as it reflects light to temp inversion can last for long period of time = increase in pollutant levels
- temperature inversions more likley to cause fog formation - does not reach the ground to be absorbed/converted into heat
thermal inversion: normal warm air from city wll rise, allowing pollutant to escape, on warm days a hot layer can trap cooler air from the city, trapping the pollutants, precipitation can clear air pollutants, wind will disperse it
effects + imapacts of smoke:
- climate: reduce temps due to increased albedo reflectivity, prolonged presence in atmopshere, presence in stratosphere deplete ozone
- living organisms: various impacts on humans, synergisms causing secondary pollutants, reduce photosynthesis, contain toxic substances
- non living organisms: acid rain, damage to hard substrate surfaces, corrosion, rust
photochemical smog
cities e.g. los angeles prone to photochemical smogs as of traffic pollution, topography + sunny climates + temp inversion are common
photochemical smog formation: sunlight reacts with (nitrogen dioxide) NO2 whihc then interacts with other molecules in air to form smog
formation of photochemical smog:
- haze caused by high levels of atmospheric pollutant primarily ozone + nitrogen oxides, interacting with strong sunlight
- on warm sunny days with lots of photochemical smog be formed over cities
- fossil fuel combustion
- forest buring
- frequency + severity of smog depend…
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