Paris Transport and Travel 2007 Report - (Page 50)

Threshold overshoot results Number of notification and alert days in Ile-de-France per year, all pollutants considered 30 25 Number of days 20 15 10 5 0 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 15 24 Notification and alert procedure: In order to obtain coherent records, AIRPARIF carried out a retrospective calculation and a simulation of the notification and alert procedure trigger events in Ile-deFrance (according to the procedure defined by the Order dated 12 July 2005). 8 6 8 5 3 9 7 5 In 2007, the notification threshold was exceeded on 5 days, or in other words, 4 days fewer than in 2006. Number of notification and alert days in Ile-de-France per pollutant and per year 20 18 16 Number of days 14 12 10 8 6 4 2 0 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 4 4 5 1 5 2 8 6 4 1 2 1 1 7 8 13 19 OZONE (03) NITROGEN DIOXIDE (NO2) 3 2 Of the 5 trigger occasions in 2007, 3 were due to ozone in the summer, and 2 to nitrogen dioxide in the winter. The first ozone threshold trigger was recorded exceptionally early in the season, on 15 April, and then again on 25 May and 4 August. No notification level was reached in the months of June and July. In the winter, the nitrogen dioxide (NO2) notification threshold was reached twice, on 22 and 23 December. These days also saw very high particle counts, very little wind and a significant temperature inversion with the formation of a hot air cap leading to a rise in the concentrations of these two pollutants. Since 2001, the threshold overshoot days have been mostly due to ozone in summer and, with the exception of 2003, the number of days the NO2 notification threshold has been triggered has been between 0 and 2. Conversely, from 1998 to 2000, more trigger events were due to NO2 than ozone. As in previous years, the alert threshold was reached for none of the pollutants regulated by the interprefectoral Order. 50

Table of Contents for the Digital Edition of Paris Transport and Travel 2007 Report

Cover
Contents
Journeys in the Paris region
Public transport
Travel by bicycle
Pedestrians on the move
Journeys made by people with reduced mobility
Traffic
Travel by motorcycle
Parking
Journeys by taxi
Journeys made by tourists
The carriage of goods
Travel safety
Planning public space
Atmospheric pollution
Economic backdrop
Key figures for 2007
The Observatoire des déplacements (Paris transport  monitoring center)

Paris Transport and Travel 2007 Report

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