| Air quality in urban |
|
|
|
| Sunday, 27 April 2008 | |
|
Definitions
This indicator aims to monitor trends in the medium and long-term background pollution in urban and peri-urban areas. It is calculated from the monthly average hourly concentrations of pollutants 5 reported on measuring stations in operation in major cities. It is defined as the arithmetic mean of the monthly averages calculated on each city.The pollutants are sulphur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), fine particulates less than 10 microns in diameter (PM10). Carbon monoxide (CO) Concentrations peak, located in winter, are also down for 6 years. The suspended particulates (PM10) The concentrations in air particles with a diameter less than 10 micrometers (PM10) tend to decrease in urban areas Burgundy over the last five years, for which there is a significant number of analyzers.Fine particles are relatively constant over the years, except in the winter months where values are higher. From time to time, the network can record episodes of particulate pollution resulting from weather on a large scale.It is noteworthy that knowledge of the composition of the particles is just as important as the extent of their concentration in the atmosphere. The nitrogen dioxide (NO2) Concentrations of nitrogen dioxide recorded on the Burgundian towns tend to stabilize since 1996. At the national level, concentrations of nitrogen dioxide have declined slightly over the last seven years in most cities. Nitrogen dioxide is mainly emitted by motor vehicles. Technological developments (including vehicles catalyzed) tend to significantly reduce emissions unit vehicles, as the renewal of the park. But this development is offset by other factors: the overall increase in traffic, the number of short journeys made cold cities, namely the use of air conditioning, which leads to over-consumption of the vehicle and an increase in emissions pollutants, including nitrogen oxides. The increase in the proportion of diesel vehicles, which emit more nitrogen oxides than gasoline vehicles, was also accompanied by an increase in emissions of the pollutant.   The air pollution problems do not arise in the same way today as they were 30 years ago. Until the 1970's, industry was the main source of air pollution. This is our day of traffic. The pollution have changed. The acidic pollution emitted by industrial and household heaters have declined. The photochemical pollution, mainly cars, have increased in contrast with the increase in transport. This pollution are more difficult to control the emission sources are many and diffuse. They are also moving. The first pollutants have been measured carbon monoxide and lead, and they are now more representative of pollution from automobiles. The changes in the park and fuels (dieselisation, unleaded petrol in particular) have led to the onset or increase of certain pollutants: nitrogen oxides, ozone, hydrocarbons, aldehydes… Some of them still not measured, an impact on public health equally important. At the local level, urban pollution have adverse consequences for health. The health risks they represent did not summarize the short-term consequences of pollution peaks. Epidemiological studies also highlight long-term effects of chronic exposure to moderate levels of pollutants. The air pollution related to transport comes from car journeys made in the city or regionally (for more than half the emissions of nitrogen oxides and nearly two-thirds of particulate emissions). The organization of urban and regional travel falls under the jurisdiction of local authorities. Their policies on urban planning, transport and land use planning are an important arm for the control of air pollution. Their intervention can focus on the development of public transport, the organization of parking and sharing the streets between pedestrian traffic, bicycle and automobile. The equipment encouraging car use have long been privileged. Through the plans for urban travel, mandatory for agglomerations of more than 100 000 inhabitants, the recent law on air and rational use of energy encourages cities to rethink the organization of transport to reduce traffic automotive and rebalance the proportion allocated to different modes of transport. The development of habitat peri-urban, largely responsible for the increase in traffic in the city, leading to reflect on the forms of urbanization and improving the provision of public transport in the areas concerned. |
|
| Last Updated ( Thursday, 03 July 2008 ) |
| < Prev | Next > |
|---|