The project Effect of Megacities on the Transport and Transformation of Pollutants on the Regional and Global Scales, EMeRGe, was created to experimentally investigate the transport and transformation of air plumes coming from major population centres, MPCs. It comprises a set of unique airborne measurement campaigns carried out in two parts of the world having MPCs of very different characteristics and emissions. The two measurement campaigns using the HALO research aircraft (http://www.halo-spp.de/) were conducted in Europe in summer 2017 and in East Asia during the intermonsoon period in March-April 2018. The initial scientific team of EMeRGe, comprising scientists from four German universities and four research centres in 2016 (http://www.iup.uni-bremen.de/emerge/home/home.html), was extended within the EMeRGe international membership, incorporating more than 50 research partners from 16 different countries. The combined and synergetic set of information obtained from airborne and ground-based data, satellite products, and their comparison with models enables the patterns of atmospheric composition and meteorological parameters observed during the campaigns to be constrained and thereby our understanding of the emissions, their transport, and physico-chemical transformation of the outflow from MPC emissions to be tested and assessed.

The EMeRGe special issue aims to publish the scientific results achieved by the project EMeRGe. This comprises contributions of the partners of the national and international EMeRGe scientific community. It solicits all relevant submissions addressing the EMeRGe science objectives.