Monitoring atmospheric composition & climate
MACC-III for Policy Use

The MACC-III Policy Portal provides an overview of the information available from the MACC-III services that can be of interest for policy users.

Information, products and tools on this webpage are intended to identify the contribution of different sources to exceedances of air quality limit values and to help in the design of policy responses to prevent severe air pollution episodes. 

European Air Quality and Pollution Episodes

MACC-III produces annual assessment reports with validated information on the state and evolution of background concentrations of air pollutants in Europe. The reports are based on best available information from the MACC-III model ensemble combined with observations through data assimilation techniques. They include a number of regulatory indicators for policy use and detailed information on the origin of specific pollution episodes.

European Air Quality Forecasts

MACC-II produces regional air quality forecasts every day, accompanied with quarterly verification reports. In addtion, model performance is monitored on a daily basis for the past 7 days and for the past 3 months.

Source allocation

The source allocation products from MACC-III are intended to support authorities to identify the origin of exceedances of air quality limit values. MACC-III products may be used for the assessment of the long-range transboundary component of an air pollution episode, in regard to anthropogenic emissions. Two different products are available:

The Regional SR product allows focus on selected agglomerations in Europe. For example, when the Air Quality forecasting system of MACC-III predicts a high-ozone episode for an agglomeration, the tool can be used to quantify indigenous (from local sources) and transported contributions (from sources outside the agglomeration) to this episode. Until now this service is provided only for a small selection of urbanized regions. However, the tool will soon provide such calculations on a regular basis for a larger selection of European agglomerations.

Country SR product calculations identify the main contributors to forecasted air pollution episodes for countries, pre-defined territories, or for user-defined regions (bounded by longitude and latitude values), in a quantitative manner. As this calculation is computationally expensive, the service is provided only on request.

Green Scenarios

Daily air quality forecasts from MACC-III are currently used as boundary conditions for the operational air quality forecasting services at several European cities. The MACC-III green scenario products are intended to help policy users in the design of policy responses to prevent severe air pollution episodes. The green scenarios provide daily regular information on the expected effect that short term measures on either traffic and residential emissions may have on the forecasted pollution episodes.

In addtion, long-term scenarios (2015-2030) applicable at the European scale have been evaluated, and the potential effect of various emisison reduction measures on two air pollution episodes in the past have been calculated.

Alert services

Currently, an aerosol alert service for Europe is available and updated daily at AeroCom/MET Norway. The alerts are computed from the IFS aerosol fields provided by MACC-III. Only areas exceeding critical levels for PM (>50 micrograms per cubic meter) are marked with colors. Different colors reflect by how much the PM levels exceed the monthly-mean MACC-III reanalysis climatology.

User Cases

  • MACC-II contribution to EEA reports
  • Contribution from MACC-II to FAIRMODE
  • Belgium Plume case
  • MACC- II support Norwegian Clean Air 


During the period of MACC-II and MACC-III, two workshops are organized to promote the use of policy-relevant MACC products and to obtain valuable feedback from users.