lecture 9

• Environmental impacts of fossil fuels


  • Extraction phase
  • Transportation phase
  • Processing phase
  • Burning phase
• Coal stripmining


  • Landscape alteration and mine tailings
  • Coal washing (water use and pollution)
  • Coal waste (toxic ash)
  • Air pollution & climate change
• Oil drilling


  • Landscape alteration and mine tailings
• Oil tanker


  • Oil spills
• Oil refinery


  • Air pollution – toxic gasses, VOC's (benzene, xylene etc)
  • Greenhouse gasses – Climate change
  • Wastewater – production water, cleaning effluents
  • Oil/petroleum spills
  • Explosions
• Exhaust gasses from traffic

  • Air pollution
• Flue gasses from powerplant

  • Air pollution
• Coal washing


  • Water use and pollution
• Coal trains


  • Air pollution
• Coal industry has a huge environmental footprint
• Acid Mine Drainage


  1. Run-off released at certain types of mines can cause local increases in the acidity (pH <5) of soils, streams, and rivers – kill aquatic organisms and plants

  2. Associated primarily with the mining of coal deposits rich in the mineral Pyrite (FeS2)

  3. When underground sources of pyrite-rich coal are mined, the coal becomes exposed to water and the atmosphere

  4. The pyrite reacts with oxygen and water, and acid is formed
• Underground coal fires in abandoned coal mines

  Can burn for 10s-100s years and contribute significantly to CO2 emissions globally
• Methane


  • Released under anaerobic conditions and is combustible
• Unconventional gas extraction (hydraulic 'fracking')

  • Pollution by "extraction chemicals" into groundwater
  • Wastewater – large amounts of water is used in the process
  • Release of methane to surrounding geology – leak into ground water
  • Injection of large amounts of water and sand with very high pressure (or use of explosives) in shale rock – to decrease the porosity of the rock -> release the gas
  • Chemical additives (e.g. diesel, benzene) to lubricate extraction process
• Oil shipping


  • Hot-spots for oil-spills
• Worst oil spills in history

  • Deep-Water Horizon in Gulf of Mexico 2010 (>200 million gallons)
  • Exxon-Valdez oil tanker in Alaska 1989 (11 million gallons)
  • First Gulf war oil spill in Irak, Arabian Gulf 1991 (60-250 million gallons)
• Decrease in the number of oil spills due to improved oil tankers – must be "double-hulled" and have separate ballast water tanks
• Refineries


  • Pollution: Air pollution – toxic gasses, VOC's (benzene, xylene etc), Greenhouse gasses – Climate change, Wastewater – production water, cleaning effluents, Oil/petroleum spills
  • Explosions: Chemicals (petrochemicals), Gasses (methane, hydrogen)
• Environmental consequences of burning coal and oil


  • Air pollutants
  • Climate change
  • Acid rain
  • Public Health Impacts
  • Thermal pollution
• Why coal is worse to burn than oil and gas
• Primary air pollutants


  CO, SO2, VOC's, NOx, PM10 & PM2.5
• Secondary air pollutants


  Formed from reactions between primary pollutants and other substances in the atmosphere
• Air Quality Index (AQI)


  Scale/index used to show how polluted the air is, along with the risks associated with each rating
• UAE National Ambient Air Quality Standards correspond to 100 points in the AQI table, which is the level EAD has set to protect public health
• Particulate Matter (PM)


  • Suspended particulate matter from both natural or anthropogenic sources
  • Consists of: Aerosols particles <10m (e.g. soot, fine fly-ash), Particulates >10m (e.g. dust, fly-ash)
  • Diameters smaller than <10m is most dangerous for health - not filtered by hair or mucus in nose/throat; can reach deep into lungs and can be carrying adsorbed chemicals
  • Consequences: Asthma, coughing, emphysema, cardiovascular disease
• Pollution Control in Industry – PM removal


  • Cyclone separator, Electrostatic precipitators, Filter separator
• SO2 emissions in the atmosphere


  • Causes acid rain
  • Impacts on ecosystems and buildings
• Pollution Control in Industry - SO2 removal


  • Flue-gas desulfurization (scrubbing) to remove SO2 from flue gasses
• Carbon Monoxide (CO)


  • Main anthropogenic source is from incomplete combustion of gasoline/diesel in automobile engines
  • Interferes with the oxygen-carrying capacity of blood
• Nitrogen Oxides (NOX)


  • Practically all anthropogenic NOx enter the atmosphere from the combustion of fossil fuels
  • NO2 can cause irritation of the eyes, inflammation of lung tissue, and emphysema
  • NOx gives the red/brownish color of photochemical smog
• Volatile Organic Compounds (VOC's)


  • A great variety of VOC's, including hydrocarbon's, enter the atmosphere from both natural and anthropogenic sources
  • Petroleum industry is the main anthropogenic source
  • React with other substances in the atmosphere to form secondary air pollutants associated with photochemical smog
• Photochemical smog


  • Develops as a yellow-brown haze in hot sunny weather in many big cities where automobile traffic is congested
  • Involves the HC's and NOx emitted in automobile exhaust reacting with sunlight
• Pollution Control Traffic – CO, NOx and VOC's


  • Catalytic converters reduce emissions of CO, NOx and VOC's from vehicles
• Clean air act (US) - regulating the 5 primary pollutants (SO2, CO, NOx, VOC, PM) and lead
• China not part of the Clean air act, and are now biggest emitter of SO2 – increased emissions by 27% between 2000-2006
• Clean air act does not regulate CO2 emissions – a greenhouse gas
• Satellite monitoring of air pollution can detect dust, sulphates, organic black carbon, and sea salts
• Pollutants that are toxic by-products of fossil fuel combustion are removable in principle by engineering the fuel, the combustion process, or the treatment of combustion products. Carbon dioxide, in contrast, is an essential product of fossil fuel combustion.
• Air pollution is the most serious traditional impact of fossil fuel combustion. Air pollutants include particulate matter (PM), sulfur compounds, carbon monoxide, nitrogen oxides, mercury and other heavy metals, and even radiation.
• Technologies exist to reduce air pollution significantly, but they're expensive and they consume energy. Air pollution from fossil fuels continues to have a major impact on human health.