In many of today’s moderncities, the main environmental health
hazard to the population is exposure toair
pollution. The three main airpollutants are:Suspended Particles : made up of soot, smoke, dust and liquid droplets.Associated health hazard : particles and soot exposure over a long period of time is related to a wide range of chronic respiratory illness such as asthma and chronic obstructive pulmonary diseases as well as worsening heart conditions and other conditions.
Sulfur Dioxide – produce by the combustion of fossil fuels, on the whole, motor vehicles and small and varied sources (such as boilers and stoves) contributing the most.Associated health hazard: causes acid rain and can be extremely detrimental to the health of the young and elderly. Nitrogen Dioxide – caused by fuel combustion, aerobic decomposition and nitrogenous fertilizers.Associated health hazard:causes acid rain and can damage lung tissue by forming into acid in thepresence of waterAssociated with theconsiderable but temporary spikes of
air pollution related deaths is Winter
smog whichis made up of mainly of dust, soot and sulfur dioxide. A good example of asevere case of Winter smog which was related to a large number of deaths of theLondon Smog of December 1952 which was thought to be responsible for up to 4000deaths. Summer smog is also very common in
cities and is caused byground level ozone occuring due to actions of the sun mixed with particles andvolatile organic compounds. Summer smog causes extreme breathing difficultiesfor asthmatics as well as having an adverse affect on plant life, oftenseverely reducing numbers. Furthermore, According to the World Bank 1992, atleast half a million premature deaths are caused by air pollution worldwide andthe significant number of these occur in major cities around the world.Diagramshowing global air pollution (smog density) on a winter’s day.Every city is faced with adifferent a unique air pollution problem of its own. Some cities, such asBeijing and Athens have, in general, considerably higher air pollution levelscompared to cities such as Montreal or Dublin. However, this it is interestingto see that although some cities general air pollution levels can be quite low,levels of particular individual pollutants such as particle matter or nitrogenoxides can be high and therefore still cause severe health problems to thepopulation. It is clear therefore, thatmaking a comparison between different cities and their levels of air pollutionand the health hazard they pose can be extremely hard to measure. Below is atable which shows air pollution data about many major cities around the worldtaken in 1995. As well as the population of each city been shown, the levels ofair pollution are displayed in three separate headings e.g. levels of suspendedparticles, sulfur dioxide and nitrogen dioxide (the three main contributors ofair pollution in cities).The most polluted citiesinclude Beijing and Mexico City which high levels of all three pollutants. Aswell as this, Athens, Moscow and Bombay have high levels of suspendedparticles, Cairo and Moscow have high levels of sulfur dioxide and Amsterdam,Athens, Copenhagen, London, Los Angeles, Milan, New York and Tokyo have highlevels of nitrogen dioxide.The reasons for suchvarying pollutant levels from city to city is due to a number of reasons bethey natural or man made. Natural factors include:Geography in which city is located e.g. valley, coast etc.Weather e.g. sunlight levelsTemperatureNitrogen cycle e.g. aerobic decompositionMan made factors include:Combustion of fossil fuels e.g. vehicles, factories etc.Fertiliser overuse
More abstracts about the Air Pollution Problems Facing Cities