Paris air is as dirty as in 19th century

21st November 2003, Comments 0 comments

PARIS, Nov 21 (AFP) - The notion that cities in western Europe have cleaned up their acts after the unbridled air pollution of the Industrial Revolution has been dented by an unusual study that has delved into Paris's atmospheric past.

PARIS, Nov 21 (AFP) - The notion that cities in western Europe have cleaned up their acts after the unbridled air pollution of the Industrial Revolution has been dented by an unusual study that has delved into Paris's atmospheric past.

Using data taken by a long-forgotten scientist who set up an experiment on top of the Eiffel Tower in the 1890s, it found that the air in Paris today is just as dirty as it was 110 years ago, at a time when the city was expanding at breakneck speed and was recklessly burning coal, the dirtiest of fossil fuels.

The obscure scientist was Benjamin Chauveau, who carried out tests atop of the just-completed tower to assess the conductivity of atmospheric electricity.

The potential atmospheric electrical field varies according to altitude, time of day and the season.

The phenomenon is so well known that values for these can be calculated, allowing researchers to determine the remaining variable: particle pollution - such as dust from industrial sources or ash and soot from the burning of carbon fuels.

The atmospheric electrical potential falls just as concentrations of these substances rise.

Poring over Chauveau's carefully recorded data, British meteorologist Giles Harrison of the University of Reading and Karen Aplin of the Rutherford Appleton Laboratory relaised they could work backwards, to get a good idea about how bad pollution was in Paris during the Naughty Nineties.

Writing in December's issue of a specialist journal, Atmospheric Environment, they figure that the concentration of surface smoke pollution in mornings in the French capital in the 1890s was between 30 and 90 microgrammes per cubic metre of air.

"The 19th century potential gradient measurements in both polluted and clean Parisian air present a unique resource for European air pollution and atmospheric composition studies," they note.

Coal burning has long been banned in Paris to help clean up the air in a city that sits in a basin and is notoriously vulnerable to atmospheric inversions.

But the figures show that the particulates spewed up by coal have been replaced by those from burning petrol and diesel.

The website of Airparif, the agency that monitors airquality in Paris, says that the daily average level of fine particulates in 2001 was 70 microgrammes per cubic metre of air.

The goal is to bring this down to 50 in 2005 by encouraging cleaner vehicles and greater use of public transport.

Harrison and Aplin have previously used the same technique, sifting through atmospheric potential data from an observatory in Kew Gardens, to get a picture of air pollution in London in the 1860s.

There, they found, the British capital truly lived up to its former nickname of "The Smoke" - particulate levels were as high as a choking 170 microgrammes per cubic metre of air.

© AFP

Subject: French news



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