Spatial variations in nitrogen dioxide concentrations in urban Ljubljana, Slovenia

Katja Vintar Mally,Matej Ogrin

doi:10.1515/mgr-2015-0015

Abstract

Abstract Ambient nitrogen dioxide (NO2) concentrations are regularly measured at only two monitoring stations in the city centre of Ljubljana, and such scanty data are inadequate for drawing conclusions about spatial patterns of pollution within the city, or to decide on effective measures to further improve air quality. In order to determine the spatial distribution of NO2 concentrations in different types of urban space in Ljubljana, two measuring campaigns throughout the city were carried out, during the summer of 2013 and during the winter of 2014. The main source of NO2 in Ljubljana is road transport. Accordingly, three types of urban space have been identified (urban background, open space along roads, and street canyon), and their NO2 pollution level was measured using Palmes diffusive samplers at a total of 108 measuring spots. This article analyses the results of both measuring campaigns and compares the pollution levels of different types of urban space.

Highlights

Air pollution from road transport in urban areas is a serious problem, both in central cities as well as elsewhere in urban regions, as the traffic volume and congestion on roads are increasing
Nitrogen oxide emissions contribute to acid rain and the eutrophication of water and soil (EU-28 – Air pollution fact sheet 2014, 2014, p. 3), and are a significant component of photochemical smog, which affects the formation of ozone
Measurements of nitrogen dioxide using diffusive samplers were carried out in the city of Ljubljana over three weeks in the summer of 2013. In this account we provide the results of measurements of nitrogen dioxide for 35 measuring points in the urban background (Fig. 7), 27 measuring points in open space along roads (Fig. 8) and 18 measuring points in street canyons (Fig. 9)

Summary

Introduction

Air pollution from road transport in urban areas is a serious problem, both in central cities as well as elsewhere in urban regions, as the traffic volume and congestion on roads are increasing. In Slovenia air quality is further diminished by poor ventilation in low-lying areas, especially in the cities in the interior of the country Ljubljana is among these poorlyventilated cities, where there are no steady strong winds, which reduces the self-cleaning capacity of the air. In 2012, road transport contributed 53% of nitrogen oxide emissions Judging from official data from the national air quality monitoring network, the urban population in Slovenia in the 2010–2012 period was not exposed to excessive concentrations of nitrogen dioxide It is necessary to set up a dense network of measuring points, and to repeat these measurements many times, in order to gain an accurate picture of spatial pollution patterns and of the change in concentrations in urban space

Theoretical background and methods

Results and discussion

Conclusions