clear Document title Documents Gaps in the monitoring of Ozone Depleting Substances: Options, approaches and potential locations - Jucks and Coetzee en 11ORM -Tina Birmpili en Closing the gaps in top-down regional emissions quantification: Needs and action plan - Ray F. Weiss en Observing system simulation experiment: Assess potential sites for new high frequency (agage-type) stations using 3D model simulations - Ronald Prinn and Jianxiong Sheng en clear