Implications to society

Acid Rain Formation

Fossil fuel combustion produces several important pollutants:  carbon monoxide, nitrogen oxides, sulfur oxides, and hydrocarbons.  Nitrogen oxides and sulfur oxides are important constituents of acid rain. These gases then combine with water vapor in clouds, forming sulfuric and nitric acids, which later become part of rain and snow. The accumulation of acids results in the lakes and rivers becoming too acidic for plants and animals to survive. Acid rain adversely affects crops and buildings.[1]

Carbon monoxide and its effect on haemoglobin

Carbon monoxide is a gas formed as a by-product during the incomplete combustion of all fossil fuels. Carbon monoxide is colourless, odourless and tasteless. Since there is no indication of its presence, it is very dangerous. It is formed in car engines and can also be produced by faulty gas cookers, water heaters and fires.

The main oxygen-carrying substance in red blood cells is the protein haemoglobin. Each haemoglobin molecule contains four iron-containing units called haem groups. Each haem can pick up one molecule of oxygen (O2) so each haemoglobin molecule can carry up to four oxygen molecules, forming oxyhaemoglobin.

Oxyhaemoglobin travels around the body and releases oxygen to cells that do not have much oxygen. This process can be represented by the following equation, where Hb represents haemoglobin and Hb(O2)4 represents oxyhaemoglobin:

Hb(aq) + 4O2(g) Hb(O2)4(aq)

Carbon monoxide is toxic because it interferes with this process. It binds about 200 times stronger to haemoglobin than oxygen. Even if there is far more oxygen present than carbon monoxide, the carbon monoxide binds to the haemoglobin, resulting in fewer places for oxygen to bind to haemoglobin when carbon monoxide is present.  It modifies the other three oxygen binding sites on the haemoglobin molecule so that they are unable to release oxygen when they reach the body cells. This means that the haemoglobin stops acting as the body’s oxygen delivery system, and carbon monoxide poisoning may result in many people. [2]

Fun Fact 4: Natural gas has no smell so a chemical called mercaptan is added so that it can easily be detected.[3]

Greenhouse Effect

When fossil fuels are burned, gases (such as unwanted by-products known as carbon emissions) enter the atmosphere. Carbon dioxide (CO2), in particular, is given off when fossil fuels are burned.

The build-up of greenhouse gases in the atmosphere acts like a greenhouse around the planet, trapping heat inside the Earth’s atmosphere. This is the greenhouse effect, and the resulting increase in global temperatures is called global warming. Greenhouse effect leads to the following adverse effects:

  • The Earth becomes warmer on average.
  • Overall, there will be more evaporation and precipitation.
  • Oceans will be warmed, partially melting glaciers and other ice, leading to rising sea levels. Ocean water also expands when it warms, contributing further to rising sea levels.
  • Higher temperatures and shifting climate patterns may change the areas where crops grow best, affecting the makeup of natural plant communities. [4][5]

References:

1. http://www.ucsusa.org/clean_energy/our-energy-choices/coal-and-other-fossil-fuels/the-hidden-cost-of-fossil.html#.VQ6Z8YuZbdk

2.http://www.rsc.org/Education/Teachers/Resources/Inspirational/resources/2.7.1.pdf

3. http://www.softschools.com/facts/energy/fossil_fuel_facts/407/

4.http://www.bbc.co.uk/schools/gcsebitesize/geography/climate_change/greenhouse_effect_rev1.shtml

5.http://climate.nasa.gov/causes/

Header Image:
http://news.sciencemag.org/sites/default/files/styles/thumb_article_l/public/si-climatefossilfuel.jpg?itok=m7-LfKlX

AY2014/15 Sem 2