Research

Air quality and climate

Introduction
Atmospheric emissions due to human activities have an impact on both climate and air quality. Emissions may have an impact on the radiation budget of the atmospere, by acting directly as a greenhouse gas (ozone), by reflecting or absorbing radiation (particulate matter) or by an effect on cloud formation and properties. In return, climate change will have an impact on air quality. Higher temperatures will enhance chemical reactions, which will lead to higher ozone concentrations, wind has an impact on transport and ventilation and precipitation is an important removal process. The complex interplay between climate and air quality implies that the effect of emission reductions may be beneficial for climate but adverse for air quality and vice versa, and that local effects may be different from global effects.
Coupling of LOTOS-EUROS to a regional climate model
One of the key tools to investigate the impact of a changing climate on air quality and vice versa is through integrative modelling of climate and air quality. Such integrative modelling can be attained by a coupling of climate models with chemistry transport models.

To use LOTOS-EUROS for climate change studies, it was coupled to the regional climate model RACMO2. A one-way coupled model system, in which the meteorology from RACMO2 was used to drive LOTOS-EUROS, was used to produce two transient climate scenario runs covering 1970-2060. Meteorological boundary conditions stemmed from the global models ECHAM5 and Miroc-Hires, using the A1B scenario, as well as from ERA-Interim. This was done under the Dutch programme Knowledge for Climate Research Programme co-financed by the Ministry of Housing, Spatial Planning and the Environment (VROM). These runs showed that due to changes in meteorology, ozone concentrations would increase, but for PM10 the response was weak and the two different global models led to different results.

The next step was to introduce air quality information obtained with LOTOS-EUROS as an input for climate scenario runs with RACMO2, to investigate the feedback aspects of aerosol concentrations on climate. A version including the direct aerosol effect was developed as an NMDC project, and the two-way coupled version have been tested as part of the AQMEII/ COST Action ES1004 model intercomparison exercise.

Emission scenarios
Apart from the impact of climate change, the impact of emissions scenarios must be investigated for a complete assessment of future air quality. In the 7th Framework Programme, project EnerGEO several energy transition scenarions have been investigated, e.g. the impact of biomass plantations on ozone concentrations. It is also possible to calculate optical properties of the aerosols in LOTOS-EUROS and use these in a radiative tranfer code, either directly or as part of the RACMO model. In this way the feedback of emission scenarios to incoming solar radiation and secondary effects have been assessed.