Air Pollution

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Temps de lecture : 4 minutes  

Mexico, sous un nuage de pollution - Mexique © Yann Arthus-Bertrand
Although air quality has improved over the last thirty years – largely in industrialised countries – atmospheric pollution continues to kill almost 2.4 million in the world. In Western towns, cars are the main cause. In poor countries, it is the pollution of interior air – attributed to dilapidated means of cooking. Rich countries are not spared, however, due to the increasing use of chemical products in homes.

2.4 Million Deaths Per Year

According to the WHO, atmospheric pollution is the cause of 2.4 million human deaths in the world. (1) In France, the 11 million tonnes of pollutants emitted into the atmosphere each year are responsible for 30 000 premature deaths. (2) (3) On average, these pollutants represent one year less life expectancy per person, causing heart failure as well as respiratory and reproductive disorders. They also increase the risk of allergic respiratory dieseases (like asthma, which has doubled over the last 20 years). [Debate]

Two Worlds

In industrialised countries, emissions from the main pollutants have greatly diminished as a result of both deindustrialisation and stricter regulations. (4) Since the 1980s, sulphur dioxide (SO2) discharge has decreased by 85%. Since the 1990s, lead emissions have fallen by over 96%, thanks to the introduction of lead-free petrol.

In developing countries, the situation appears to be evolving in the opposite direction. China has thus become the number one polluting country in the world, largely because of its cause coal-fuelled electricity plants.

Interior Pollution: 1.6 Million Deaths Per Year

Air pollution is often associated with heavy clouds above cities. But nowadays it is air pollution inside buildings that is responsible for the majority of deaths. This kills some 1.6 million people each year in the world – that is 5 times more than exterior pollution. (5) It is only recently that we have become aware of this fact.

The main cause of this pollution is in cooking food. Indeed, in developing countries, the combustibles (wood or leaves, coal, cow dung…), used for cooking in homes without chimneys, release particles: carbon monoxide, nitrogen, sulphur dioxide etc. (6) These increase the risk of respiratory and lung infections, eye illnesses, lung cancer and numerous other sicknesses. (7)

In the European Union, interior air pollution has grown in the last few years as a result of the increasing use of synthetic materials and chemical products for domestic purposes. Volatile Organic Compounds (VOCs), that may be highly toxic, can be found in polishes, glues, pesticides, agglomerated wood fiber boards and cleaning products. The confined air of underground transport services is not spared either: a report published by France’s Régie Autonome des Transports Parisiens (RATP) – the Paris transport services – in June 2007 revealed that the presence of fine particles was over ten times more concentrated than European norms (8) [Debate].

Cars, the Bane of Cities

In industrialised countries – as well as in the large developing country cities – industrial emissions have been overtaken by those generated by increased vehicle traffic: nitrogen monoxide (NO), nitrogen dioxide (NO2), carbon monoxide (CO) and fine particles – the dust created by diesel motors in particular. In France, the Afsset (French agency for health safety for the environment and work) estimates that between 6 450 and 9 500 people died prematurely in 2002 because of pollution related to these particles; that is more deaths than from road accidents. (11) As for the ozone (O3), produced in large towns when it is very hot, in particular from nitrogen oxide emissions let off by vehicles, its levels are increasing in the Northern hemisphere. (12) (13)

Since 1993, the European Union has adopted a number of measures, called Euro I, Euro II etc., imposing the gradual phasing out of polluting emissions by vehicles. For example, passing from the norm Euro III in 2000 to the norm Euro IV in 2005 meant manufacturers proposed vehicles releasing only half as much nitrogen oxide (NOx). The Euro V norm should make car exhaust filters obligatory and impose a 20% reduction of NOx on new cars. The Euro VI norm, planned for 2013-2015, should further increase these reductions.

Nevertheless, the reduction of car emissions is compensated by an increase in the number of vehicles. Moreover, as regulations evolve rapidly, the age of vehicles has become an important factor: in France, for example, in 2001, vehicles that were over ten years old were responsible for 60 % of the pollution whilst they represented only 20 % of the circulation!

Acid Rain

Acid rain began to gain the public’s attention in the 1970s. This is precipitation polluted primarily by sulphur dioxide and nitrogen oxides. These gases are produced by industry and transport; they circulate by wind and threaten natural zones even at a far distance. Their great acidity, that may be as high as that of vinegar, threatens the ground and has been held responsible for the dwindling of Eastern European and Canadian woodland. They are also associated with the acidification of Northern European lakes, endangering the biodiversity inhabiting there.

There once more, it took a major crisis to gain a reaction: The Convention on Long- range Transboundary Air Pollution was signed in 1979 and extended several times. In the USA, a sulphur gas emission market was set up; it was introduced before the one created for greenhouse gases more recently. Yet if the problems related to acid rain are subsiding in the West, they are now more serious in the West, and especially in China. (10)

Each year from April through October, a gigantic pollution cloud 3 kilometers thick covers the South of Asia, Pakistan, China and India. It is so dense that it reduces the quantity of solar energy to reach the ground by 10% and modifies precipitation, damaging agricultural productivity. It is also harmful to human health and contributes to global warming.

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