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Air quality of major French cities

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Sunday, 11 May 2008

The 112 number of environmental data published yesterday by the french Institute of Environment (IFEN) despite a mixed development, air quality of French cities over 100,000 inhabitants has improved between 2000 and 2005. To conduct its study, IFEN was based on measurements made each day by the associations to monitor the air quality (AASQA) and has constructed an index that figure changes for all agglomerations more than 100,000 inhabitants for the four best observed pollutants: ozone, sulphur dioxide and nitrogen and fine particles.   Stable between 2000 and 2002, air quality has deteriorated significantly in 2003 with a 5% increase concentrations of pollutants, then improved in 2004 and 2005, with a lower level of pollution by 10% in the years 2000-2002. This general trend is the result of a downward trend in primary emissions  Ozone is likely to be decisive in the future development of air quality in France  and the effects of weather, explains the french Institute of the Environment in a statement.   The analysis conducted by the IFEN confirms an index of ozone and PM10 very high in August 2003, corresponding to the episode of heat wave. The ozone index rose 180 for a 100 level corresponding to the average for the year 2000 while for PM10, it amounted to 130. However, the 2003 heat wave does not explain alone the poor performance of the year. If the month of August 2003 was the same level of pollution that other month since August 2000, 2003 results would have been the worst period for ozone and for particulate matter, wishes to emphasize the IFEN.   The best results of the years 2004 and 2005, they are mainly explained by favorable weather conditions in air quality in the city (encouraging the dispersion of pollutants) as conditions less conjecturally. It is too early to say that less cyclical conditions are added, as a decline in emissions in the city, or less favorable conditions for the emergence of pollutants by photochemical or chemical transformation, says the Institute on . The results also show that improving air quality varies depending on the size of the metropolitan area and according to the pollutants. Thus, between 2000 and 2005, medium-sized cities (between 250,000 and 1,000,000 inhabitants) decreased by 17% of the index of air pollution against 12% for cities of more than one million people and 9% for smaller cities (between 100,000 and 250,000 inhabitants). It should be noted that sulfur dioxide has contributed largely to the decline in the overall index, the index of this pollutant have decreased by 33% in 5 years including through the tougher regulations on emissions from large facilities combustion and transport in place since 1990. However, while the index of nitrogen dioxide is down 10% since 2000 and that the fine particles decreased by 7%, the index of ozone only found in 2005 its 2000 level, reductions in 2004-2005 offsetting increases in 2001-2003. In addition, global warming might enhance the frequency of conditions favorable to the creation of ozone since it is not emitted directly, but is the result of reactions between volatile organic compounds (VOCs) and nitrogen oxides in the effect of solar radiation. This gas will probably decisive in the future development of air quality in France, concludes the IFEN.

Last Updated ( Thursday, 03 July 2008 )

 

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