The colder the climate, the higher the respirable dust values
The year 2007 can be justifiably called the "year of low respirable dust levels”. Only 38 municipalities recorded more than the admissible exceedances of the daily values. The lower number of exceedances is first and foremost due to the warm winter and spring season…
The meteorologic measuring results of the past year emphasize the strong influence of the weather and/or the seasons on the respirable dust values once again. Exceedances of the average daily value occur in the winter season and simultaneously in large areas only. This effect is due to high-pressure or inversion weather conditions. In addition, the air is loaded with secondary particles and wood combustion, especially in winter times. In particular emissions from small combustion plants, i.e. from radiators, occasionally exceed the overall respirable dust emission from diesel vehicles significantly.
The Federal Environment agency explained that the operation of private wood combustion plants in municipal residential quarters increases the number of days with exceedances for respirable dust significantly. Wood combustion plants alone increase the median PM10 values by 4 to 5 µg/m and therefore exceed the contribution of the road traffic.
The Federal Environment agency furthermore calculated in an impressive example that the overall engine emissions from the road traffic in Germany will even fall below the emission value generated by cigarettes in about 10 years.
Long-distance traffic impacts regional respirable dust values
The Federal Government recently discovered with the help of model calculations that without the long-distance traffic as an emission source, the respirable dust concentration PM10 in the middle and southern regions of Germany would fall below an annual average of 10 µg/m and below 15 µg/m in the western and eastern peripheral regions. The long-distance traffic’s contribution may be even higher in some cities. In Berlin, e.g. half of the respirable dust load is generated by external sources.
Numerous cities and municipalities have prepared action plans in order to reduce the respirable dust load with local measures. The decision of the Federal Administrative Court from September 2007 has increased the pressure in the municipalities. This decision stated correspondingly: "If applicable respirable dust limits are exceeded, reasonable measures must be taken to reduce the load, even if no action plan has been prepared.” This has led to the implementation of environment zones in numerous municipalities.