Core activitiesReview user requirements for the observations related to the three atmospheric composition application areas: atmospheric monitoring, forecasting, and urban applications in support of the WMO Rolling Review of Requirements (RRR);Review and harmonize user requirements for the atmospheric composition variables in the other WMO application areas;Regularly update the user requirements in the OSCAR database;Assess current observational capabilities in light of user requirements;Summarize recommendations on integrated network design in Statements of Guidance for each application area ...