In cooperative information systems, the quality of data exchanged and provided by different data sources is extremely important. A lack of attention to data quality can imply data of low quality to spread all over the cooperative system. At the same time, improvement can be based on comparing data, correcting them and thus disseminating high quality data. In this paper, we present an architecture for managing data quality in cooperative information systems, by focusing on two specific modules, the Data Quality Broker and the Quality Notification Service. The Data Quality Broker allows for querying and improving data quality values. The Quality Notification Service is specifically targeted to the dissemination of changes on data quality values.