These guidelines are intended to provide useful advice to National Meteorological and Hydrological Services (NMSs) on methods of incorporating air quality forecasts and biometeorological information into the suite of products and services offered to the public.The guidelines were developed by the Public Weather Services (PWS) Expert Team on Product Development and Service Assessment at the request of the Commission on Basic Systems (CBS). It is acknowledged that several NMSs already provide this type of information and some others are on the verge of developing an air quality programme. However, all NMSs should find this document useful, especially those in developing countries that would be seeking to develop or improve their national public weather services delivery while, at the same time, attempting to come to terms with some aspects of the widening array of environmental issues.