Air Pollution

Topic: Air Pollution - City Comparisons

Background Information - In many of today's modern cities, the main environmental health hazard to the population is exposure to air pollution. These air pollution problems are facing cities. The three main air pollutants 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 the presence of water

Associated with the considerable but temporary spikes of air pollution related deaths is Winter smog which is made up of mainly of dust, soot and sulfur dioxide. A good example of a severe case of Winter smog which was related to a large number of deaths of the London Smog of December 1952 which was thought to be responsible for up to 4000 deaths.

Summer smog is also very common in cities and is caused by ground level ozone occurring due to actions of the sun mixed with particles and volatile organic compounds. Summer smog causes extreme breathing difficulties for asthmatics as well as having an adverse affect on plant life, often severely reducing numbers. Furthermore, According to the World Bank 1992, at least half a million premature deaths are caused by air pollution worldwide and the significant number of these occur in major cities around the world.

Problem: The air pollution problem are facing many cities.

Hypothesis: Every city is faced with a different a unique air pollution problem of its own.

Procedure: It is clear therefore, that making a comparison between different cities and their levels of air pollution and the health hazard they pose can be extremely hard to measure. Below is a table which shows air pollution data about many major cities around the world taken in 1995. As well as the population of each city been shown, the levels of air pollution are displayed in three separate headings e.g. levels of suspended particles, sulfur dioxide and nitrogen dioxide (the three main contributors of air pollution in cities).some cities general air pollution levels can be quite low, levels of particular individual pollutants such as particle matter or nitrogen oxides can be high