Climate Change and Pollution:Common Air Pollutants and Carbon Cycle

Done by: Lee Heansuh Marilyne Tan Khine Victoria Melissa Peh Chua Hui Qing

Carbon Monoxide (CO)- a colourless, odourless, toxic and lethal gas- produced from the incomplete burning of

fuels, such as coal, oil, and natural gas- many internally-combusting engines produce

this gas- In U.S., around 170 people die annually, just

from CO produced by non-automotive consumer products, such as cars in the garage left running.

- undetectable to the human senses, people do not realise the exposure, resulting in carbon monoxide poisoning, which may result to death

- new cars are equipped with catalytic converters at their exhaust line, chemically reacting with oxygen to produce carbon dioxide.

Methane (CH4)- the second-most common greenhouse gas

from various human activities- e.g. natural gas leakage and livestock's

digestion, landfills decomposition- natural processes in soil and chemical

reactions in the atmosphere help remove CH4 from the atmosphere

- can be captured by changing manure management strategies at livestock operations or animal feeding practices and emission controls that capture landfill CH4

Nitrogen Oxides (NOx)- a group of gases made up of different

levels of oxygen and nitrogen- two of the most common nitrogen oxides are

nitrogen dioxide and nitric oxide- formed when certain fuels (oil, gas and

coal) are combusted and from explosives manufacturers

- forms acid rain, deteriorate global warming and destroys the growth of plants

- can prevent emission by replacing older gas powered appliances (gas stove/heater), not smoking cigarettes, not burning gases at high temperatures and not using aerosol cans.

Ozone (O3)- formed when solar radiation strikes

oxygen molecules, processing photolysis by splitting apart, then the freed atom joins to form ozone

- usually formed at higher level, as the greater the solar radiation, the more prevalent it gets

- ground level ozone can cause respiratory problems and interrupts photosynthesis, causes susceptibility to diseases and pests

- to reduce ground level ozone emission, we can use public transport and bicycles as commuting methods, and conserve electricity and set temperatures higher

Sulphur Dioxide (SO2)- produced from fossil fuel combustion at

power plants and various industrial activities

- causes respiratory illnesses and worsening of cardiovascular disease

- main cause of acid rain, which can corrode man-made metallic structures and biotic organisms, especially amphibians and plants

- can be minimised in three ways – decreasing the sulphur content, removing sulphur from exhaust gas and altering fuel to alternatives, such as natural gas

Unburnt Hydrocarbons (UHCs)- hydrocarbons are part of fuels such as

petrol, diesel and gaseous fuels- mainly produced from the vehicles’ engines- when petrol drip evaporates into the

atmosphere without getting burnt, it is UHC

- toxic and cancerous, they react with oxygen, nitrogen oxides and water vapour to form ozone at ground level (in the presence of sunlight radiation)

- ozone then worsens global warming as it stays at a lower level than where it should suppose to be

Carbon Cycle

Our Sun’s infrared radiations get into the Earth, but nutrients do not enter the biosphere from an external source. The same pool of nutrients will then circulate and recycle for as long as the earth exists, just like water. The nutrients involve both macronutrients and micronutrients. Macronutrients include carbon, hydrogen, oxygen, nitrogen and phosphorus.  In the Carbon Cycle, the carbon from the atmosphere enters the living part of the ecosystem by photosynthesis. Dense forest vegetation takes in the carbon dioxide, and fix it in organic compounds such as glucose, starch, cellulous and other carbohydrates.

Carbon dioxide is then returned to the atmosphere by respiration in plants. As plants are at the bottom of the food chain, when it is consumed by primary consumers, carbon will be passed to them and this would continue till it reaches the tertiary consumers. Respiration takes place in the cells of the consumers and carbon is again released back to atmosphere as carbon dioxide.

When the consumers die, their organic matters enter the soil through process of decay and broken down by decomposers. Thus, respiration in the decomposers also returns carbon back to the atmosphere. After a long time, carbon will be converted to fossil fuels and combustion of them would produce carbon dioxide, and other carbon compounds which eventually return back to the atmosphere.