Monitoring of NO₂ air pollution in the port of Livorno and spatialization of data

Abstract

In this work, an estimate of the spatial distribution of NO₂ is presented starting from data measured with passive samplers in 10 locations in the municipality of Livorno in Tuscany (Italy). The data from the passive samplers were integrated with measurement campaigns carried out within the port of Livorno and with data from the fixed stations. The Municipality of Livorno is subject to pressures deriving from the emissions of the port, the heavy industry and the demographic activity (traffic and heating) of a municipality with middle/high population density (270 inhabitants/km²) for Tuscany Region. Despite the many and varied pressures, the only exceedances of the air quality limit values ​​in the last decade concerned the annual average of nitrogen oxides in the urban traffic station. However, the port makes an important contribution in terms of emissions to nitrogen oxides, therefore the main objective of this work is to represent the NO₂ levels in the urban area of ​​Livorno, highlighting the various contributions. To do this, Ordinary Kriging was carried out on the measured values ​​after removing the local trend through the use of a beta index, a method reported in the literature for Belgian network and also applied in Italy for spatial representativeness. In this work we also tried to best represent the contribution of traffic as in our data set there is a urban traffic station, with the highest NO₂ levels in Tuscany, lower only than those in the regional capital Firenze. With a very simplified method, that can be improved in future works, it was possible to estimate the effects of the port on the city in comparison with the other sources, treating the background levels separately and stratifying the levels of road traffic based on the flows of the main roads.