Synergetic or Non-Linear Effects in PM₁₀ and PM_2.5 Scenario Calculations for 2015 in Belgium

Abstract

We applied the extended version of the EUROS model to evaluate the impact of emission reductions on PM₁₀ and PM_2.5 concentrations in Flanders and Belgium for 2015. Individual sector contributions were assessed and the current and future changes in aerosol concentrations and compositions over Belgium and Europe were investigated. Contributions from anthropogenic sources in Flanders were found to be responsible for 34.3% of the annual averaged PM₁₀ concentrations in Flanders in 2003. In 2015 this contribution is estimated to be 35.0%. For PM_2.5 these contributions are 29.1% in 2003 and 27.8% in 2015 respectively. Results show that non-linear effects can not be neglected. Because of the non-linear processes that take place when secondary aerosols are formed, a small reduction in a gaseous compound (e.g. SO₂) does not necessarily lead to the same amount of reduction of the secondary compound (e.g. sulphate). Another “non-linear” aspect is the formation of aerosols by contributions from two compounds that are delivered by two individual sectors. The synergetic effect of these “non-linear” contributions was found to be an additional 2.1% for PM₁₀ and 3.7% for PM_2.5, representing an increase of 6–13%, which is not negligible and might become relevant in abatement policies.