Dispersão de poluentes

Air pollution is a major problem that has been recognised throughout the world for hundreds of years. In the Middle Ages, the burning of coal in cities released increasing amounts of smoke and sulphur dioxide to the atmosphere. In the late 18th century, the Industrial Revolution, beginning in the UK, led to escalation in pollutant emissions based around the use of coal by both homes and industry. Pollutant emissions continued to grow through the 19th and early 20th centuries, and the dramatic smog episodes known as pea-soupers became common place in many of Britain’s inner cities, leading to poor air quality. After the infamous London Smog of 1952, pollution from industries and homes was dramatically reduced in an attempt to protect health.
In more recent times pollution from motor vehicles has become the most recognised air quality issue. Present pollution monitoring is revealing that if we do not think and act cautiously then vehicle pollution could harm the environment in which we live and reduce the quality of life for future generations. The number of cars, both in Britain and in most countries around the world, is now steadily increasing, and a speed up in technological development is required to try and combat the pollution problem. People need to be encouraged to use public transport or share cars whenever possible so only the minimum amount of pollution is created.
Poor air quality has negative effects on the environment in which we live. Air pollution from transport includes emissions of carbon monoxide, particulates, nitrogen oxides and hydrocarbons. Ozone is a secondary pollutant produced when many of these primary chemicals react in sunlight in the atmosphere. Such primary and secondary pollutants can impact on wildlife and vegetation, and human health.
The UK National Air Quality Strategy was published in 1997, with commitments to achieve new air quality objectives throughout the UK by 2005. The strategy aims to address areas of poor and declining