4.4. Summer smog episodes 1995

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4.4 Summer smog episodes in 1995

A first analysis of the episodes during summer 1995 has been presented by the EC (EC, 1995). From the data now available it is clear that exceedances of the threshold value set for information to the public were occasionally observed in January - April in the Southern Member States (Greece, Italy, Portugal and Spain). During the first week of May smog was observed in nearly the whole EU: in the period 5-7 May only Finland, Greece and Portugal have not reported an exceedance of the 180 µg/m3 level.

June started as a "low ozone" month although in Greece and Italy on nearly every day one or more stations reported an exceedance. Starting in the last week of June, exceedances were frequently observed in the EU with the exception of the Nordic Countries. The period with frequent violation of the threshold value across Europe ended in the last week of August. During the last four months of 1995, exceedances were less numerous and again confined to the Southern part of Europe.

Table 7 gives a graphical representation of the percentage of stations in every Member State that reported exceedances of the threshold value for population information (180 µg/m3 for hourly values) during the 1995 summer season. Note that in this period no exceedances were observed in Finland. In July-August some short periods of several days can be recognized during which exceedances are only observed in a few Member States (e.g. 15-19 July). On the other hand there are also periods during which smog is wide spread over Europe, e.g. 1 August. As an example the maximum hourly ozone concentrations in excess of 180 µg/m3 as measured on 1 August are geographically presented in Map 13.

Table 7. Qualitative overview of exceedances of the 180 µg/m3 population information threshold value (1h) during the period 6 July - 28 August 1995. The number of asterisks refers to the percentage of stations in a country which reports an exceedance: *: at least one station but less than 25%; **, between 25 and 50%, ***: between 50 and 75%; ****: more than 75%.. The number of reporting stations is indicated above the Country Code.

    110 20 342 6 86 11 110 32 10 6 54 5 37 8 6
m d AT BE DE DK ES FI FR GB GR IE IT LU NL PT SE
7 6     *       *   ***     *      
7 7 *   **   *   *   ***   * *** *    
7 8 * *** *   *   *       * *** **    
7 9 * *** *       * *     * *** *    
7 10   *** **       * *     * *** **    
7 11 * ** *       *       * * *    
7 12 *   *       *   ***   *   *    
7 13 * * *       *       *   *    
7 14 *   *           *   *        
7 15                 ***            
7 16                 ****            
7 17                 **   *        
7 18                     *        
7 19     *       *       *        
7 20   * *   *   *       * *      
7 21 * *** **   *   *       ** *** ***    
7 22 *   *       *       **        
7 23   *     *           *     *  
7 24   * *   *   *       *   * *  
7 25   *** *   *   * *   * * * *    
7 21 * *** **   *   *       ** *** ***    
7 22 *   *       *       **        
7 23   *     *           *     *  
7 24   * *   *   *       *   * *  
7 25   *** *   *   * *   * * * *    
7 26 * * *       * *     ** * ***    
7 27 *   *   *   *       **        
7 28                     *        
7 29   * *       *   *   *   *    
7 30   *         * *     *   *    
7 31 * * *       * * ** * *   *    
m d AT BE DE DK ES FI FR GB GR IE IT LU NL PT SE
8 1 * *** *       * ** **** * * * * *  
8 2   *** *       * * ** * *        
8 3   * *       * *     *     *  
8 4     *       *   *   * *   *  
8 5   ** *       *   ***   * ** * *  
8 6   *** *       *       * **** * *  
8 7 *   *           **   *     *  
8 8                 **            
8 9         *       ***         *  
8 10   * *       * *     *   *    
8 11 * ** *       * **     * * **    
8 12 * *** *       * * *   * ** ****    
8 13     * ** *           *   *   *
8 14                     *        
8 15                 *            
8 16             *                
8 17             * *              
8 18   * *   *   * * **       *    
8 19   ** *       * *         * *  
8 20     *       * * * *       *  
8 21     *       * * **            
8 22 * ** *   *   * * **     * *    
8 23     *   *           *        
8 24             *                
8 25             *   **   *        
8 26                     *        
8 27             *       *        
8 28                 **            

 

Map 13. Example of an ozone smog episode: hourly ozone concentrations in excess of 180 µg/m3 as measured on 1 August 1995.

   
 
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