A method for spatial interpretation and visualisation of measured air quality data is presented that may serve as a tool for ambient air quality characterisation using the least possible number of factors. This method enables comparison of different areas in relative terms and has practical consequences in decision making and public information. The 1996 data for the Czech Republic was used as a database. According to my results, not a single universal indicator can fully describe the ambient air quality albeit the three factors identified as "ambient air pollution", "ground-level ozone" and "wet atmospheric deposition" which are recommended. These selected factors represent three different aspects of ambient air quality and its impact on receptors. For the above factors black and white charts are presented classifying the Czech Republic territory into five categories as to relative ambient air quality. The air quality picture differs for the respective factors considerably.