1. Max-Planck-Institut für Chemie; Mainz Germany
2. South African Weather Service; Stellenbosch South Africa
3. GKSS Forschungszentrum Geesthacht GmbH; Geesthacht Germany
4. IVL Swedish Environmental Research Institute; Gothenburg Sweden
5. Atmospheric Environment Service; Downsview Canada
6. Norwegian Institute for Air Research; Kjeller Norway