Air quality/ air pollution

• Atmospheric pollutants:


  Particulates in urban areas are greater than rural

  • Higher carbon monoxide
  • Higher sulphur dioxide
• Where do atmospheric pollutants come from?

  • Vehicle exhausts
  • Burning - wood, coal, rubbish etc
  • Construction, mining and quarrying
  • Plants generate coarse particulates e.g. pollen, mould spores
• Carbon monoxide from vehicles

  Road vehicles engines perform combustion but when insuffienct oxygen supply, carbon monoxide forms > highest concentration of carbon monoxide on busy roads (90%)

  • Also a switch to coal
• Sulphur dioxide:

  • Produced from coal power stations and oil refineries > cause haze and acid rain, coughing, chest problems
  • The increased haze affects lichens photosynthesis and chlorophyll
• Poor urban air quality impacts:

  • Respiratory problems e.g. asthma
  • Increases haze - sulphur dioxide
  • Increase carbon dioxide > enhance greenhouse effect and global warming
  • Increaed particulates in the atmopshere attack building facades - weathering
  • Photochemcal oxidants cause eye irritations and headaches
• Photochemical smog: Ozone and PAN (Peroxyacetyl Nitrate) 


  Photochermical smog is a mixture of pollutants that are formed when nitrogen oxides and volatile organic compounds (VOC) react to ultraviolet light from the sun > creates a brown haze above cities

  • Road transport produced 50% of nitrogen oxides
  • Causes asthma and lung inflammation and accerlerated weathering
  • More common in warm, sunnier ctieis as these areas suffer from temperature inversion fog (layer of warm air trapped below dense cooler air) > keeps pollutants at surface level
• Particulate matter (PM's)

  • Produced from power stations, vehicle exhausts, dust and ash and pollen
  • Damage lungs and airways
• Ella-Adoo Kissi Debrah:

  • The first person in the world to have air pollution listed on her death sentence
  • High levels of PM's 2.5's and nitrogren dioxide and pollution from wood burning stoves > developed asthma > admitted to hospital 27 times > died from asthma attack

  
• Trapping air pollution: Temperature inversions and development of photochemical smog:

  1. Extended periods of high pressure (anticyclonic conditions) in winter - calm and clear
  2. Solar radiation reaches ground and warms it up
  3. Night > lack of cloud cover means ground loses heat rapidly and air in contact with ground becomes colder
  4. Cooler air sinks in lower areas e.g. valleys, basins > condensation > fog forms
  5. Warm air rises > acts as lid > trap colder air and fog closer to ground
• Trapping air pollution: Temperature inversions and development of photochemical smog


  6. Air pollution also trapped > layer close to ground becomes more polluted

  7. Fog and pollution mix > smog > trapped