Luxembourg's Environment Administration has carried out, for the third time, the air quality measurement campaign "Besser Loft fir méi Liewensqualitéit" for 2020, in collaboration with municipalities, as part of the Klimapakt.
A total of 23 municipalities took part in this campaign and measured the concentration of nitrogen dioxide at 63 locations. Between January and December 2020, no exceeding of the limit value of 40 µg / m3 was observed; on the contrary, a drop in values throughout the Grand Duchy was observed. One of the reasons for this is the general societal slowdown caused by the COVID-19 pandemic.
Results
Compared to the measurement campaigns of previous years, there is a particularly pronounced drop in 2020. This drop is primarily linked to the COVID-19 pandemic which has led to a considerable decrease in road traffic.
Given the sharp decrease in road traffic during the containment of March and April 2020, the concentrations measured dropped drastically during this period. At this time of year, concentrations are generally much higher. Subsequently, the resumption of activities gave rise to an increase in concentrations which, however, remained below the levels observed in previous years.
A peak in NO2 concentrations was observed during the period from 2 to 18 September 2020. This period was marked by a large area of high pressure. The exceptionally warm air transport to our regions for the period even led to a new temperature record for the month of September. In this dry weather, the dispersion of air pollutants was considerably disadvantaged.
In general, somewhat higher concentrations of nitrogen dioxide are observed during the winter months due to the additional contribution of emissions from heating installations. In addition, weather conditions in winter favour periods of temperature inversion that prevent the evacuation of air pollutants. In summer, better mixing of the air, as well as photochemical degradation reactions by ozone, lead to a decrease in concentrations.
Method
The Environment Administration added nine additional locations on the territory of Luxembourg city, Esch-sur-Alzette, Remich and the municipality of Beckerich. The municipalities of Ell, Waldbillig and Ettelbruck took part in the campaign for the first time in 2020. Samples are collected every two weeks using simple equipment, that of passive diffusion tubes, in order to determine the concentration of nitrogen dioxide NO2 at specific locations.
Passive sampling consists of exposing the adsorbent tubes to the open air for a period of time set at about 3 metres in height. By simply diffusing the pollutant present in the air, it will be trapped by the sampler. The samples are then analysed in the laboratory by spectrophotometry.
The full report is available on www.emwelt.lu. Data by station can be viewed on the geoportal, “environment” section.
