• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Production of Photochemical Smog.

Extracts from this document...

Introduction

Atmospheric Pollution Caused by Coal-Fired Power Stations and Motor Vehicle Engines Production of Photochemical Smog Photochemical smog comprises of 'primary' and 'secondary' pollutants, which are extremely oxidising. Primary pollutants are pollutants created as by-products of chemical processes such as combustion in car engines and industrial factories, and released directly into the atmosphere. These pollutants produced from motor vehicles include nitrous oxides, (NOx) carbon monoxide, (CO) and volatile organic compounds (VOCs) such as hydrocarbons. Secondary pollutants are formed when primary pollutants undergo further reactions. Secondary pollutants from motor vehicles include ozone, nitrogen dioxide (NO2), Hydrogen Peroxide (H202), Peroxylacetyl nitrate (PAN), incompletely oxidised VOCs and Nitric Acid (HNO3). Ozone is formed when the sun shines on a mixture of primary pollutants. (This indicates the origin of the name 'photochemical' smog.) Hydrocarbons are expelled from car exhausts as unburnt fuel, and can be released by evaporation from petrol and diesel fuel. Formation of Primary Pollutants Primary pollutants are often formed by oxidation under high heat during combustion in coal-fired power stations and in car engines. ...read more.

Middle

Other pollutants are produced in the following processes: (Ref 1) NO2 can also react with radicals produced from VOCs in a series of reactions to form toxic products such as PAN. NO2 + R* ? PAN (Ref 5) "The World Health Organisation advise that people's lungs and breathing system can be damaged if the ozone concentration rises above 50 parts per billion (ppb)." (Ref 4) "On 3rd May 1995, this concentration reached 71 ppb over 8 hours in Yorkshire, UK." Many health experts believe this concentration of ozone to be carcinogenic, and periods of smog lasting for 5 days, such as in 1991, can have long lasting negative effects on health. Although its composition varies greatly due to the nature of the primary and secondary pollutants, local geography, time of day, and weather conditions, a photochemical smog can still have devastating effects for those who breathe in the air. Healthy humans can suffer breathing difficulties and soreness in the eyes and nose; if vulnerable people such as the elderly, small children or people with respiratory problems such as asthmatics breathe in smoggy air, the effects can be much more dangerous. ...read more.

Conclusion

Flue gases also contain NOx, (mainly thermal NOx.) Many power stations including Logannet use 'low NOx burners,' which burn at a lower temperature, decreasing the production of NOx. Also, finely-ground coal can be controlled to give lower temperature burning, which gives significantly lower NOx emissions. Using 'gas reburn' techniques, NOx formed are chemically turned into nitrogen with the addition of natural gas into the boilers, above the flame. NOx react to form nitrogen, carbon dioxide and water. The Logannet management chose to implement these procedures to improve efficiency in the power station, to cut waste products, e.g. Wasted Sox can now be turned into useful building products and reduce pollutant release. Research Into Photochemical Smog Scientists have set up monitoring stations in over 20 locations nationwide, to monitor the concentration of ozone and NOx in the troposphere. Chemists measure the rate of formation of photochemical smog, and make predictions about pollution in the future. Using computer modelling, chemists can simulate the behaviour of pollutants. Huge smog chambers (volume 1500m3 to minimise any surface effects) contain primary pollutants which are mixed and exposed to sunlight to measure the formation and concentration of photochemical smog. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Environmental Management section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Environmental Management essays

  1. TOPIC: OZONE - DEVIL IN DISGUISE?1.0 INTRODUCTION Ozone (O3) is an allotropic ...

    4.0 OZONE DEPLETION 4.1 Ozone depletion processes During the early 1980s, scientists discovered that the ozone level in the Antarctic has been decreasing steadily every spring. Ozone holes, areas with very little ozone, appeared there while research shown that ozone depletion also happened in North and South America, Europe, Asia, Australia and Africa.

  2. The Ozone a Hole in the TheoryThe protective ozone layer around our world undergoes ...

    An environmental scientist knowingly sending 20-40 million people to their deaths yearly! Banning CFCs would not only kill 20-40 million a year it will also lower the health of the remaining living people, by causing world-wide hunger, and food-borne diseases(Howard)!

  1. Photochemical smog.

    Ozone is formed when sunlight and primary pollutants react and therefore is a secondary pollutant. Ozone molecules are formed in the troposphere from the reaction: O2 + O O3 The oxygen radical needed for the formation of ozone is produced when nitrogen dioxide ( a primary pollutant)

  2. Ozone (O3) is an allotropic form of oxygen with three atoms in each molecule. ...

    and strychnine poisoning, canker sores, and whooping cough 1904 Uses of ozone expanded to counter tuberculosis, asthma, tinnitus, bronchitis, hay fever, pneumonia, gout and syphilis 1912 Ozone used for treatment of gangrene, poison gas effects and wounds during World War I 1915 Treatment of colon and cervical cancer by Dr.

  1. Emerging Chemical Contaminants: The Case of Perfluorochemicals

    While PFOS and PFOA can certainly enter local aquatic systems hydrologically, it does not explain how they can appear in remote ecosystems with no direct source of contaminant. The presence of PFOS and PFOA in a wide variety of Arctic biota, far from anthropogenic sources, demonstrates the capacity of the PFCs to undergo long-range transport.

  2. Sociocultural Factors Affecting BP Petrol Filling Stations in the UK

    Economically, the external environment in which BP operates in can be affected by both micro and macro influences. Some of these issues are discussed on a local, national and global scale and affect petrol stations and the price at which petrol is sold.

  1. Photochemical smog.

    This is another primary pollutant. * Describe and explain the most favourable conditions for forming photochemical smog, and how high concentrations of tropospheric ozone are produced. The reactions leading to the formation of photochemical smog are initiated by sunlight and involve hydrocarbons and nitrogen oxides emitted from vehicles and power stations.

  2. Photochemical smog.

    Where there is plentiful sunlight then a number of reactions will take place; NO2(g) hv NO(g) + O� (g) The oxygen radical formed will react with an oxygen molecule to form tropospheric (the lowest region of the atmosphere between the earth's surface and the tropopause, characterized by decreasing temperature with increasing altitude)

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work