Air pollution - State and impacts (Luxembourg)

The state and impacts of air pollutants, along with drivers and pressures, can be examined in two ways: firstly with regard to air quality and secondly with regard to quantities emitted.

Air quality

Luxembourg has established three air quality monitoring zones: the Canton of Luxembourg (30 % of the population), which includes the capital city and its immediate surroundings; the Canton of Esch-sur-Alzette (30 % of the population), which is highly industrialised; and a zone consisting of the remaining 10 cantons, which are largely rural (40 % of the population).

Concentrations of sulphur dioxide (SO₂) have remained well below the limits for the protection of both human health and ecosystems [Figure 1]. Concentrations of carbon monoxide (CO) also comply with the limits for the protection of human health [Figure 2], as do those of benzene and lead (mostly found in suspended dust particles).

In the case of nitrogen dioxide (NO₂), a limit value of 40 μg/m³ (annual average) has been set for 2010, however the city of Luxembourg has been breaching this limit. Moreover, the city has exceeded the hourly average of 200 μg/m³ on a number of occasions since 2000, although never beyond the 18 exceedances allowed per year. The main cause is automobile traffic and, due to the ever-increasing volume of traffic to and through the city, the introduction of catalytic converters and the renewal of the automobile fleet have not had the desired impact [Figure 3]. In rural areas, the limit of 30 μg/m³ (annual average) for the protection of ecosystems has been respected [Figure 4].

Levels of fine particulate matter (PM₁₀) do not seem to pose a major problem to human health. Over the last 10 years, the limit of 40 μg/m3 (annual average) has never been exceeded. The annual averages in the cities of Luxembourg and Esch-sur-Alzette have dropped from 30 μg/m³ in the 1990s to 25 μg/m³ in recent years. Exceedances of the 50 μg/m3 daily average in these two monitoring zones have also declined since the 1990s, and are now below the 35 exceedances allowed per year [Figure 5].

Over the past decade, in urban and rural areas alike, there have been between 10 and 30 occasions every summer when ground-level ozone concentrations have exceeded the summer pre-alert threshold of 160 μg/m³ (human health threshold measured hourly), and up to 10 exceedances of the reporting threshold (180 μg/m³). However, the alert threshold (one-hour average concentrations above 240 μg/m3 over a period of at least three consecutive hours) has not been exceeded [Figure 6].

Figure 1 - SO2 emission measurements: 1995-2009

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Figure 2 - CO emission measurements: 1989-2009

Source: Ministry of Sustainable Development and Infrastructure - Environment Agency: Annual Activity Report, p. 178-179.
Note: The 3 stations are Luxembourg city centre (LC), Luxembourg-Bonnevoie (LB) and Esch/Alzette (ES).

Source: Ministry of Sustainable Development and Infrastructure - Environment Agency: Annual Activity Report, p. 161.

Source: Ministry of Sustainable Development and Infrastructure - Environment Agency: Annual Activity Report, p. 173-175.

Source: Ministry of Sustainable Development and Infrastructure - Environment Agency: Annual Activity Report, p. 175-177.

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Air pollutant emissions

Since falling sharply (–80 %) during the 1990s as a result of the shift from blast furnaces to electrical arc furnaces in the steel industry – see climate change mitigation common environmental theme – SOx emissions in Luxembourg have continued to decline (–12 %) during the first decade of the 21^st century. The rising market share of low-sulphur fuels, encouraged by tax incentives, has played an important role here.

NOx emissions also fell during the 1990s (–25 %), reflecting efforts to curb industrial combustion and, to a lesser extent, mobile sources. NOx emissions from these two sources have continued on a downward trajectory since 2000. Nevertheless, Luxembourg is likely to fall short of the 52 % reduction objective for the period 1990-2010 set by the Gothenburg Protocol, which is equivalent to the ceiling in the NEC Directive (2001/81/EC). In order to comply with the ceiling one important factor is the reduction of emissions from the glass industry, whose operating permit is to be reviewed to enforce the introduction of the appropriate technology to reduce NOx emissions.

NMVOC emissions fell significantly in the 1990s and have declined further since 2000, reflecting continued progress with mobile sources. Luxembourg’s NMVOC emissions are likely to meet the NEC Directive target for 2010. There are many kinds of NMVOC, and many different emission sources. The expected improvements will mainly come from a reduction in the use of organic solvents in paints and varnishes (Directive 2004/42/EC) or from vapour recovery at service stations (Directive 1994/63/EC). As of 2008, all installations using organic solvents must respect limits on emissions (Directive 1999/13/EC) [Figure 7].

The Luxembourg steelmaking industry is represented by three electric-arc steel mills, located close to one another in an urban setting (Esch-Schifflange, Esch-Belval and Differdange). If the conventional impact zone is taken as a three-kilometre radius, 55 000 people, or 12 % of the national population, are affected. Emissions of dioxins and furans (PCDD/F) from the steel mills are regularly checked by licensed agencies. In order to supervise operating conditions more closely, the Environment Administration has also been taking supplementary measurements. Over the course of the last 5 years, PCDD/F emissions have been below the 0.1 ng/m³ limit, although there was one exceedance in 2009 (Differdange). The PCDD/F accumulation in leafy vegetable crops is measured by a network of monitoring points in the immediate vicinity of the steel mills. These measurements indicate that the preventive health threshold is still being exceeded on occasion, particularly at Schifflange. In a study of PCDD/F concentrations in soils, a significant percentage of soil samples were not meeting the standards for an unrestricted farming use (30 % in 1993/94 and 25 % in 2006).

Figure 7 - Air pollutant emissions according to the NEC Directive: 1990-2010

Source: Ministry of Sustainable Development and Infrastructure - Environment Agency. For background data, click here.
Note: new calculation method from 2007 onwards: break in time series.