There are 2 main types of primary pollutants:

• Oxides of nitrogen (NO and NO ) and carbon monoxide (CO) formed when fossil fuels are burnt under high temperatures.

• Unburnt hydrocarbons, mainly alkanes (VOCs) which are released from cars’ exhausts or from the evaporation of fuels inn petrochemical plants or petrol stations.

The formation of secondary pollutants involves free radicals. The main secondary pollutants are:

• Partially oxidised hydrocarbons

Primary and Secondary pollutants produced by motor vehicles

Fuels contain compounds of nitrogen (NOx) these are oxidised when the fuel is burnt and make fuel NOx or thermal NOx when burnt under very high temperatures:

Each OH radical can form an ozone molecule so overall 1 ozone molecule can undergo the previous reactions and make 2 ozone molecules.

In natural conditions this reaches a steady state so that the rate of production of ozone is equal to the rate of destruction of ozone. However this is disrupted when hydrocarbons are added. The hydrocarbons are broken down into new products in 3 steps:

Even though the oxygen produced reacts to form ozone (equation 1) the nitrogen oxide reacts with it and turns it back into nitrogen dioxide and oxygen:

The peroxy radical reacts with nitrogen oxide. This reaction converts NO back to NO and therefore reduces the concentration of NO so that less ozone is broken down because this reaction does not involve breaking down of ozone unlike reaction 3 which now has less NO to react.

Some topics in this essay:
CO Photochemical, Donald Miller, OH RCH, , NOx Longannet, Primary Secondary, Pilling Coal, Freemantle Sulphur, Environmental Option, Equations Chemical, secondary pollutants, primary pollutants, rch +, photochemical smog, + 2, carbon monoxide, ²¯ aq, aq +, nitrogen dioxide, ozone molecule, power” donald miller, coal power” donald, primary pollutants undergo, clean coal power”, “longannet clean coal,