Development air quality and air pollution control
The air-quality limit for particulates introduced by the EU is very ambitious. Whereas the annual average value of no more than 40 micrograms per cubic meter of air is usually complied with, the daily average values of 50 micrograms per cubic meter of air are exceeded more often than the 35 occurrences permitted. The year 2014 also demonstrated that breaching the limit mainly depends on meteorological parameters. In the winter the limit is exceeded by a large margin, in the summer as good as never. Road traffic cannot therefore be the cause of these winter exceedances.
By a quite overwhelming margin, the particulates measured in urban areas come from the surrounding area, and to some extent from abroad. It is referred to as “regional background.” About 20 percent of fine dust comes from urban pollution, including house fires. The German Environmental Agency has calculated that wood burning alone causes average PM10 values to increase by between 4–5 micrograms per cubic meter. The latter therefore exceed the contribution from road traffic. Approximately one quarter of particulate volume is generated at the “hotspots”; typically these are measuring stations close to main thoroughfares. Although road traffic is concentrated in these locations, traffic emissions from engines are low. At a hotspot in Stuttgart, the latter account for only 4 percent of the total volume, for example, in Frankfurter Allee in Berlin for 7.2 percent. This proportion will fall yet further as a result of the increasing prevalence of Euro 6.
Since 1995 particulate pollution in Germany has fallen by 40 percent. That is essentially attributable to the success road traffic has had in its reduction. In the next few years, engine particle emissions from German road traffic will be reduced yet further. There will be a reduction not just in particulate mass but in the number of particles. All particles will thus be filtered out, not just the large ones.That means that a Euro 6 diesel vehicle in real operation will achieve, de facto, zero emissions. Particle emissions from a spark ignition engine are already at this level. The conclusion of a study carried out on behalf of the German Environmental Agency is that total German road traffic engine emissions in 2020 would no longer even equal the level of emissions as a result of the smoking of cigarettes in Germany. Summer barbecue emissions are then significantly higher than all passenger vehicle engine emissions together.
The environmental zones introduced in Germany enjoy only limited success if road vehicle traffic alone is regulated. An analysis conducted on behalf of the German Federal Department of the Environment identified an ever-diminishing effectiveness of the environmental zone if the latter was based solely on cars, commercial vehicles and buses. Owing to the major successes of the automotive industry, the German Federal Government has discovered that emissions from construction machinery “account for as much as half engine combustion-related road traffic emissions in urban areas.” It is therefore clear that anyone wishing to reduce total particulate emissions needs to keep their eye on all emission sources and not just focus solely on traffic.