Air Pollution Safe Limits

Pollutant...........................Safe Exposure (8 h/day, 5 days/wk)

Asbestos..............................0.2 fiber/cm3 ** 
Benzene...............................0.3  mg/m3** 
Bromine...............................0.66 mg/m3
Cadmium...............................0.002 mg/m3
Carbon Dioxide........................9,000 mg/m3
Carbon Disulfide......................31 mg/m3
Carbon Monoxide.......................29 mg/m3
Carbon Tetrachloride..................31 mg/m3***
Chlorine..............................1.5 mg/m3
Chloroform............................49 mg/m3*
Cresol................................22 mg/m3
Ethyl Alcohol (ethanol)...............1,880 mg/m3
Fluorine..............................1.6 mg/m3
Formaldehyde..........................0.37 mg/m3*
Gasoline..............................890 mg/m3
Hydrogen Cyanide......................11  mg/m3
Iodine................................1 mg/m3
Iron Oxide (fume).....................5 mg/m3
Isopropyl Alcohol.....................980 mg/m3
Lead (dust & fume)....................0.2 mg/m3
Manganese.............................0.2 mg/m3
Mercury...............................0.01 mg/m3
Methyl Alcohol (Methanol).............260 mg/m3
Nitric Oxide..........................30 mg/m3
Nitrogen Dioxide......................5.6 mg/m3
Propane...............................simple asphyxiant
Selenium..............................0.2 mg/m3
Sulfur Dioxide........................5.2 mg/m3
Sulfuric Acid.........................1 mg/m3
Tellurium.............................0.1 mg/m3
Tetraethyl lead.......................0.1 mg/m3
Toluene...............................188 mg/m3
Turpentine............................560 mg/m3
Vinyl Chloride........................13 mg/m3**
Zinc Oxide (fume).....................5 mg/m3

* Suspected Human Carcinogen (1993)
** Confirmed Human Carginogen (1993)
*** Animal Carcinogen (1993)


source: American Industrial Hygiene Association: 1993

What Is Air Pollution?

Introduction:

Air pollution in its great magnitude has existed in the 20th century from the coal burning industries of the early century to the fossil burning technology in the new century.  The problems of air pollution are a major problem for highly developed nations whose large industrial bases and highly developed infrastructures generate much of the air pollution.

         Every year, billions of tonnes of pollutants are released into the atmosphere; the sources include power plants burning fossil fuels to the effects of sunlight on certain natural materials.  But the air pollutants released from natural materials pose very little health threat, only the natural radioactive gas radon poses any threat to health.  So much of the air pollutants being released into the atmosphere are all results of man’s activities.

Problems?

Health Risks:

In the United Kingdom, traffic is the major cause of air pollution in British cities.  Eighty six percent of families own either one or two vehicles.  Because of the high-density population of cities and towns, the number of people exposed to air pollutants is great.  This had led to the increased number of people getting chronic diseases over these past years since the car ownership in the UK has nearly trebled.  These include asthma and respiratory complaints ranging through the population demographic from children to elderly people who are most at risk.  Certainly those who are suffering from asthma will notice the effects more greatly if living in the inner city areas or industrial areas or even near by major roads.  Asthma is already the fourth biggest killer, after heart diseases and cancers in the UK and currently, it affects more than three point four million people. 

         In the past, severe pollution in London during 1952 added with low winds and high-pressure air had taken more than four thousand lives and another seven hundred in 1962, in what was called the ‘Dark Years’ because of the dense dark polluted air.

Environmental Risks:

Air pollution is also causing devastation for the environment; many of these causes are by man made gases like sulphur dioxide that results from electric plants burning fossil fuels.  In the UK, industries and utilities that use tall smokestacks by means of removing air pollutants only boost them higher into the atmosphere, thereby only reducing the concentration at their site. 

         These pollutants are often transported over the North Sea and produce adverse effects in western Scandinavia, where sulphur dioxide and nitrogen oxide from UK and central Europe are generating acid rain, especially in Norway and Sweden.  The pH level, or relative acidity of many of Scandinavian fresh water lakes has been altered dramatically by acid rain causing the destruction of entire fish populations.

         In the UK, acid rain formed by subsequent sulphur dioxide atmospheric emissions has lead to acidic erosion in limestone in North Western Scotland and marble in Northern England.

 

 

Solutions?

In 1998, the London Metropolitan Police launched the ‘Emissions Controlled Reduction’ scheme where by traffic police would monitor the amount of pollutants being released into the air by vehicle exhausts.  The plan was for traffic police to stop vehicles randomly on roads leading into the city of London, the officer would then measure the amounts of air pollutants being released using a CO2 measuring reader fixed in the owner's vehicle's exhaust.  If the exhaust exceeded the legal amount (based on micrograms of pollutants) the driver would be fined at around twenty-five pounds.  The scheme proved unpopular with drivers, especially with those driving to work and did little to help improve the city air quality.

         In Edinburgh, the main causes of bad air quality were from the vast number of vehicles going through the city centre from west to east.  In 1990, the Edinburgh council developed the city by-pass at a cost of nearly seventy five million pounds.  The by-pass was ringed around the outskirts of the city where its main aim was to limit the number of vehicles going through the city centre and divert vehicles to use the by-pass in order to reach their destination without going through the city centre.  This released much of the congestion within the city but did little very little in solving the city’s overall air quality.

         To further decrease the number of vehicles on the roads, the government promoted public transport.  Over two hundred million pounds was devoted in developing the country's public transport network.  Much of which included the development of more bus lanes in the city of London, which increased the pace of bus services.  Introduction of gas and electric powered buses took place in Birmingham in order to decrease air pollutants emissions around the centre of the city.

         Because children and the elderly are at most risk to chronic diseases, such as asthma, major diversion roads were build in order to divert the vehicles away from residential areas, schools and elderly institutions.  In some councils, trees were planted along the sides of the road in order to decrease the amount of carbon monoxide emissions. 

            Other ways of improving the air quality included the restriction on the amounts of air pollutants being released into the atmosphere by industries; tough regulations were placed whereby if the air quality dropped below a certain level around the industries area, a heavy penalty would be wavered against them.

©  Copyright 2000, Andrew Wan.

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