Intercomparison of measures

List of participating institutions

List of reports

• The long-term and European-wide formulated emission reduction scenarios "Trend 2005" and especially its more ambitious variation, "Reduction 2005", are by far the most effective measures to reduce high ozone concentrations during the summer months. If fully implemented (by the year 2005), it can be expected that peak ozone concentrations will decrease by as much as 40%. The warning threshold ozone value of 180 µg/m³ would still be exceeded; however, the number of exceedances would be clearly lower than at present.

• Temporary and locally restrictive measures, such as a speed limit, a ban on non-cat motor vehicles, or the burning of reformulated fuels, are not very effective in decreasing high ozone levels, because the attainable emission reduction is small. For each single measure, the decrease of peak ozone concentrations would be at most 5%.

• Only the combination of several such locally restrictive measures can lead to a distinct reduction of the precursor emissions (50% or more) and therefore also to a distinct reduction of peak ozone concentrations. However, even if all possible local measures would be implemented, the resulting decrease of peak ozone concentrations would be at most 20%.

• The expansion of an emission control domain increases the efficiency of ozone reduction measures. A speed limit or a traffic ban for non-cat cars put into force in several states or even in all of Germany would be much more effective than local implementation of the same measure.

Summary

Temporary, locally restrictive measures are not very effective, if the emissions reduction potential is below 50% .

Control measures which are permanent and implemented on a large control domain (national or even international) are even with lower overall percentage emissions reduction more effective in reducing high ozone concentrations than temporary and locally restrictive measures.