Functional zoning for air quality

This paper presents a land classification in zones featured by different criticality levels of atmospheric pollution, considering pollutant time series as functional data: we call this proposal “Functional Zoning”. We aim to meet a request of European laws that impose to dis- tinguish zones needing further actions from those needing only maintenance according to air quality status. To carry out zoning for Piemonte (northern Italy), we consider the hourly concentration fields of the main pollutants produced by a deterministic air quality model, and we preprocess them by assimilating observations gathered by monitoring networks. In order to consider administrative units which policy makers refer to, we present three different alternatives to upscale data to municipality scale. Then, to aggregate by pollutant, we evaluate two strategies to summarize time series: air quality index assessment, and use of the Multivariate Functional Principal Component Analysis (MFPCA), respectively. Therefore, we partition municipalities clustering air quality time series and MPFCA scores, and finally we illustrate a comparison study of the different strategies’ results.