Atmospheric Pollution

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Open Book-Coursework

Introduction

    This open book report is about atmospheric pollution, and I will be mostly focusing on photochemical smog. Photochemical smog is a thick haze in the troposphere and is very dangerous. It is caused by reactions in the atmosphere between sunlight and pollutants from motor vehicles and industries.

Formation of Photochemical smog

    Primary and secondary pollutants with the help of sunlight form photochemical smog. A primary pollutant is an air pollutant emitted directly from a source (motor vehicles or industries). Examples of primary pollutants include NOx gases, SOx gases, COx gases and also hydrocarbons. Secondary pollutants are formed when primary pollutants, undergo further reactions and are not emitted directly into the atmosphere. An example of a secondary pollutant is ozone.

The Formation of primary pollutants

    Primary pollutants are formed in the combustion of fuel in a coal-fired station. The output pollutants produced by coal fired stations are, sulphur oxides, nitrogen oxides and carbon dioxide. Sulphur is found in coal. When coal burns the sulphur compounds are oxidised so convert into sulphur oxide gases. Nitrogen oxide emissions can be produces in two ways. Firstly, most fuels contain compounds of nitrogen as it is formed by proteins. When nitrogen combusts, the nitrogen compounded are oxidised giving us NOx gases.  The other way is that at high temperatures of combustion atmospheric nitrogen and oxygen combine to produce thermal NOx gases.  Carbon dioxide is formed by the carbon in the coal reacting with the oxygen, making carbon dioxide when combusted.

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Conditions for Photochemical Smog

    In order to make photochemical smog, certain conditions are needed. Photochemical smog happens, in generally summer events n the UK.  There needs to be high pressure and anticyclone conditions. Still air it needed with little mixing with high altitude air, therefore the pollutants are trapped near to the ground. A lot of ozone and bright sunshine is needed. This is because; sunlight and ozone is needed to react with the primary pollutants to form photochemical smog.

How High Concentrations of Troposphere Ozone is Produced

    Troposphere ozone is the ozone, in ...

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There some spelling and punctuation errors throughout this essay. These can usually be avoided if you take the time to throughly proof read your work. However the candidate does uses scientific terms accurately which demonstrates a good understanding of the topic.

The candidate has written a good introduction to this topic, they clearly state what they plan to discuss and have included a brief explanation of their chosen topic. In addition to this the candidate shows good scientific understanding throughout the essay. However I feel that they could have improved their work by linking together other related topics such as the uses of CFC’s and how these effect the atmosphere. This would show a breadth of knowledge and can make the essay more interesting to read. That said, the candidate has unfortunately not written a conclusion. It is essential that you conclude your work, as it allows you to draw the your essay to a close. A good conclusion summarises key points from your essay and includes a personal reaction to the topic.

The candidate has given a very detailed response and it is clear that they understand what they are discussing. They have also included information on current scientific research which is not only interesting to read but shows dedication and that the candidate is interested in their subject.