Evaluation of Regional Measures in order to Improve the Air Quality in the North-West European Hot Spot Region

Abstract

The effects of four regional emission scenarios on the concentrations of PM₁₀, PM_2.5, NO₂ and EC (elementary carbon) in the North-West European (NWE) Hot Spot region have been studied. The emission estimates were provided by TNO, regional calculations were carried out for the years 2009 and 2020 using the BelEUROS model (Deutsch et al. 2009) on a 15 × 15 km² grid. The effect of a highway speed limit reduction to 90 km/h on all highways in the NWE region (Belgium, France, Germany, Luxemburg, the Netherlands and the UK) showed up to 4.4% lower concentrations of EC and up to 3.5% reduction of NO₂ concentrations (mean over Belgium). The introduction of low emission zones (LEZ) in all cities in the NWE region with more than 50.000 inhabitants and more than 700 inhabitants/km² resulted in a reduction of 1.8% of the EC-concentrations (mean over Belgium). However, in the areas that actually make part of a LEZ the EC concentration is reduced by 19% and hence this scenario could be more effective in terms of population exposure. In the healthy diet scenario, 75% less meat production in Europe was assumed, leading basically to lower ammonia emissions (reduction of approximately 30%). This scenario results in significant reductions (4.2% as a mean over Belgium) in particulate matter (PM_2.5) concentrations due to a reduction of secondary aerosol formation. EC-concentrations are not affected by this scenario. Finally, a pellet stoves scenario was calculated in which 20% of the non-wood energy consumption (gas, oil) in the residential combustion sector had been converted to pellet stoves. This scenario resulted in considerable increases in emissions and in an increase of EC-concentrations by up to 21% as a mean value over Belgium. PM_2.5-concentrations increase by up to 4%. Results for all scenarios are available for the whole NWE region.

Question and Answer

Questioner: Heinke Schluenzen

Question: Is the small impact of the low emission zones maybe a result of the difficulty to determine sufficient amounts of corresponding urban areas and, in addition, averaged out due to the 15 × 15 km² grid applied?

Answer: It is true that the resolution of 15 × 15 km² is not sufficient to determine the effect of the LEZs within the LEZs themselves. Therefore, much higher resolution is to be used. However, the goal here was to check if a more widespread use of LEZ would decrease the concentrations significantly outside of the LEZs. It is shown that this decrease is very small.