The aim of this paper is to investigate possible advances obtained by the
implementation of the framework of Fr\'echet mean and the generalized sense of
mean that it offers, in the field of statistical process monitoring and
control. In particular, the case of non-linear profiles which are described by
data in functional form is considered and a framework combining the notion of
Fr\'echet mean and deformation models is developed. The proposed monitoring
approach is implemented to the intra-day air pollution monitoring task in the
city of Athens where the capabilities and advantages of the method are
illustrated.Comment: 31 pages, 11 figure