Local debate issues in this area
The
wide range of emission sources means that action to combat air
pollution must be at a local, national and international level.
A number of measures are in place, or planned, as a result of
National and International law. These are expected to have significant
effect on pollution levels.
Local Authorities are now required to review and assess air quality
in their area and they have been given a wide range of powers
to execute air quality management plans and achieve improvements
in air quality.
| What causes air pollution |
Air pollution is made up of a mixture of gases and particles that have been released into the atmosphere by man-made processes. Such emissions are typically from the combustion of fossil fuels such as coal, oil, petrol or diesel. The sources, health effects and chemical behaviour of each separate pollutant are different, makng the task of understanding and controling air pollution as a whole very complex.
There are seven main pollutants
of concern - carbon monoxide (CO), nitrogen dioxide (NO2), ground
level ozone (O3), particulate matter (PM10 and PM2.5, sulphur
dioxide (SO2), hydrocarbons and lead.
They are produced or emitted into the athmosphere by road transport,
badly ventilated domestic fuel appliances (gas, oil or solid
fuel), power stations and other industrial combustion processes,
domestic heating, combustion of fossil fuels, construction dust
or soot and petrol filling stations.
The manufacture and use of fridges, aerosols, foam and packaging
results in the release of pollutants, although emission levels
have been reduced by 80% over the past ten years.
Waste buried in landfill sites in the UK releases nearly two
million tonnes of methane every year.
Read
more about those pollutants: A Guide to Air Pollution, by the
London Air Quality Network (LAQN)
| What are the effects |
Acid Rain
Whilst this acid rain does not affect plants and animals directly, it has been linked to the killing of fish, birds and trees and can cause damage to buildings. Because it is airborne and can be carried for great distances on the wind, acid rain can affect plants, animals and buildings thousands of miles from the original pollution source.
Burning of fossil fuels is the
biggest single source of acid rain. However, reducing emissions
through energy efficiency measures, new technologies and cleaner
fuels can all help to reduce acidification.
The Greenhouse effect
Whilst some insulation from heat loss is essential for creating a stable environment, an overall increase in air temperature could have dramatic effects. Global average surface temperatures have increased by between 0.3° and 0.6°c since the late nineteenth century and could rise by about a further 2°c by 2100.
In certain areas the effects of global warming may be positive, increasing crop yields for example, but other areas may experience dramatic and unpredictable changes in weather. Low-lying ground could be flooded as sea levels rise due to oceans expanding as they warm up and polar ice-caps melt and swell their waters (global sea levels have now risen between 10 and 25cm).
UK sources released around 550 million tonnes of carbon dioxide in 1994. Energy efficiency, cleaner technology and increasing forest cover (which absorbs carbon dioxide) are all ways in which the greenhouse effect can be reversed. Alternative energy sources like wind, solar, hydro, wave, tidal and nuclear power do not release greenhouse gases, although there remain environmental concerns associated with all of these sources.
Ozone
At ground level Ozone can be toxic to plants and animals, but high in the atmosphere a layer of ozone protects the earth's surface from the harmful effects of ultra violet light. Whilst a little ultra violet light is good for us, too much of it can damage our eyes and cause skin cancer.
Halocarbons (like CFCs), when released into the air, drift slowly up through the atmosphere and start to destroy ozone, increasing the amount of ultra violet light reaching earth. There are a number of international agreements designed to limit the production and consumption of ozone depleting substances. Production and consumption in the EC has decreased by more than 80% in the past ten years, but halocarbons are long-lived chemicals and will continue to destroy ozone for many years. Assuming compliance with the international agreements, the ozone layer should have recovered by the middle of the next century.
Human Health
Many atmospheric pollutants have
been linked to human health problems. Sulphur dioxide can increase
asthma symptoms, lead from cars and industry can damage our
brains (although, largely due to the introduction of unleaded
petrol, lead levels in Scotland's air in 1993 was only 24% of
the 1981 level), particles can affect breathing, carbon monoxide
reduces our blood's ability to carry oxygen and ground level
ozone irritates eyes, throat and lungs.
A
Guide to Air Pollution, by the London Air Quality Network (LAQN)
Read
more in the Manchester University Web site: Air Pollution has
also effects on the built environment and the Wildlife
These are cross boundary pollutants that can be generated in one country and felt in others; these require international actions and collaboration to control their formation and effects. Transboundary air pollutants can survive for periods of days or even years and can be transported 100s or thousands of miles before they affect the air we breath, soils, rivers, lakes and/or our food. Transboundary air polutants cause a number of different problems: e.g formation of particles, ground level ozone which are hazardous to health, the formation of acid rain which can damage buildings and sensitive ecosystems and some that are toxic to human health and the environment.
Read more: National Atmospheric Emissions Inventory
| What you could do |
It is clear from consideration of the sources of pollution that decisions that we take about the way we use energy and other products have direct impact on air pollution. Since energy costs money reducing pollution can save you money. There is considerable opportunity for all of us to take simple measures to reduce air pollution. Click here for some tips.
More on "Doing Our Bit": Manchester University Web site
This week's pollution graph in Hammersmith & Fulham