Analysis of ozone monitoring data

The concentration data obtained by monitoring pollutants do not follow a symmetric or even regular, for example log-normal, distribution so that statistical methods which are insensitive to the type of distribution are required. Such a robust statistical method has been applied for the analysis of data obtained by monitoring ozone in different environments. Since ozone is formed at ground level through photochemical reactions, its volume fractions follow a typical diurnal behaviour with a maximum at about noon and a minimum during the night. A convenient way of representing ozone monitoring data is described. The distribution is represented by percentiles, and for each hour of a day averaged over the whole period. Five most characteric percentiles are represented by so-called boxes and whiskers.