Air pollutants and global effects
|Local authorities, health and environment|
Air pollutants and global effects
While most pollution can be said to be of "local" - or national - origin, requiring local solutions, air pollution can also be a transboundary problem requiring agreement by governments world-wide or regionally on measures to deal with it. Three issues, all of which have implications for the health and well-being of people in every country, have resulted in such cooperation. These are described briefly below and in more detail in WHO pamphletClimate Change
Also described as global warming or the greenhouse effect, most scientists now agree that the climate is warming up - the expert Inter-Governmental Panel on Climate Change (IPCC) has predicted a possible rise in the average global temperature of 1 degree Celsius by 2025 and 3 degrees Celsius before the end of the 21st century.
As well as nitrogen and oxygen, the atmosphere also contains small amounts of water vapour, carbon dioxide, methane, nitrous oxide and ozone; these are sometimes referred to as "greenhouse gases" as they keep the earth's surface about 30 degrees C warmer than it would otherwise be.
In the last few hundred years the rising human population and industrialisation have increased the levels of these gases in the atmosphere. Water vapour is an important greenhouse gas, but its concentration is determined by the weather so is beyond our control. Carbon dioxide is increasing due to the burning of coal, gas and oil (fossil fuels) and the destruction of forests. Methane (CH4) is generated through modern agricultural practices ranging from rice growing to livestock farming, as well as emissions from coal mining, natural gas production and distribution, refuse and sewage disposal.
There are still uncertainties about the effects on the climate of increasing concentrations of greenhouse gases and indeed the extent and rate at which the climate is changing.
Despite these uncertainties governments worldwide have agreed that precautions need to be taken now. Table 8 shows both the huge differences in the amount of CO2 emitted in different countries of the European Union as well as the different trends regarding CO2 emissions. Climate change is likely to affect human health through the shifts in the distribution of diseases, such as malaria and respiratory disorders (IPPC, 1995).
Local authorities can also help to reduce emissions of greenhouse gases by, for example:
- reducing fossil fuel emissions of carbon dioxide through energy conservation and energy efficiency programmes;
- stopping the destruction of forests; planting trees to reabsorb carbon dioxide from the atmosphere;
- encouraging the use of timber from sustainable managed sources for building, rather than energy intensive materials such as steel, bricks and cement;
- encouraging the reduction in use, and where possible elimination, of products containing CFCs - (see B2 below);
- reducing transport emissions.
|CO2 emissions in the EU|
|United Kingdom||578.8||556.2||- 3.9||9.6|
Concern over depletion of the stratospheric ozone layer - which helps to filter out some of the sun's harmful rays - was first raised in the 1970s. Exposure to these rays (ultraviolet radiation) increases the risk of skin cancer and eye cataracts, can depress the human immune system, and harm aquatic systems and crops. Scientists now reckon that over the last ten years or so average global ozone concentrations have decreased by 3%.
Current efforts to reduce production and use of chemicals affecting the ozone layer will however not have an immediate effect in restoring the ozone layer; in fact damage is expected to go on getting worse until 2000; it should then begin to improve so long as individual countries adhere to the timetables in the Montreal Protocol and EU Regulations.
Many manufacturers now use alternatives to
CFCs and wherever possible local authorities should consider
using products that do not contain ozone depleting chemicals.
Consumers should also be encouraged to switch to CFC-free
products. As refrigerators which do not contain CFCs become
available, local authorities should encourage consumers to
dispose of their old unit safely, perhaps by having it removed by
the manufacturer or retailer as CFCs can be recycled.
|Source : EMEP/MSC-W Report 1/96|
In the late 1960s and early 1970s, Scandinavian rivers and lakes and their aquatic life began to show signs of being adversely affected by pollution, and in the late 1970s trees in Central European forests showed signs of being similarly affected. Investigations suggested the causes to be acidification of the ground and the water from atmospheric depositions of sulphur dioxide and nitrogen oxides - from mainly industrial sources - carried in the air over long distances.
The Convention on the Long Range Transport of Air Pollution was adopted in 1979. The Convention covers Europe and North America and calls on countries to "endeavour to limit and, as far as possible, gradually reduce and prevent air pollution, including long range transboundary air pollution". The protocols under the Convention aim to reduce emissions of pollutants which can result in acid deposition and ground level ozone formation.
Since most acid pollution comes from burning fossil fuels, local authorities can help to reduce national emissions by reducing the overall demand for energy, by encouraging energy conservation and by improving the efficiency of electricity generation.