To validate pollution data, subject-matter experts in Airpl (an organizationthat maintains a network of air pollution monitoring stations in westernFrance) daily perform visual examinations of the data and check theirconsistency. In this paper, we describe these visual examinations andpropose a formalization for this problem. The examinations consistin comparisons of so-called shorth intervals so we build a statisticaltest that compares such intervals in a nonparametric regression model.This allows to detect atypical data. A practical applicationof the test is given.
