Berlin Environmental Atlas

03.11 Traffic-Related Air Pollution - NO2 and PM10 (Edition 2008)

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Nitrogen oxides are acidifiers. They are harmful to human health, cause damage to plants, buildings, and monuments, and contribute significantly to the excessive formation of ground level ozone and various noxious oxidants during summer heat waves.

Nitrogen oxides, especially nitrogen dioxide, lead to irritation of the mucus membranes of the respiratory passages in people and animals, and can increase the risk of infection (see Kühling 1986). Cell mutations have also been observed (BMUNR 1987). Various epidemiological studies have shown a correlation between the deterioration of the functions of the lungs, respiratory tract symptoms, and increased nitrogen dioxide levels (see Nowak et al. 1994).

Diesel soot is a major component of particulate matter (PM10) in motor vehicle exhaust. It is a carrier for polycyclic aromatic hydrocarbons (PAH), a carcinogen, but also on its own, it is a possible cause of lung and bladder cancer (see Kalker 1993). Moreover, such ultra-fine particulate as diesel soot, smaller than 0.1 µm, is suspected to increase the risk of cardiovascular disease.

Legal Stipulations and Limit Values

An evaluation of air pollution from motor vehicle traffic has only become concretely possible for immission control authorities since 1985, since the European Community, in the Directive of the Council of 7 March 1985 on Air Quality Standards for Nitrogen Dioxide (Directive 85/203/EWG), specified limits and goals for this pollutant. In addition, it stipulated that measurements be taken of concentrations of nitrogen dioxide on "canyon streets" and major intersections.
In 1996, due to a multiplicity of new findings regarding this and other air pollutants, "Directive 96/62/EG On Ambient Air Quality Assessment and Management (the so-called "Framework Directive ") was drafted and brought into force.
In this Directive, the Commission is called upon to submit, within a specified time period, so-called "subsidiary directives" stipulating limits and details for the measurement and assessment of a specified list of components.

Since then, four subsidiary directives have come into force:

  • on July 19, 1999, Directive 99/30/EG, with limits for sulphur dioxide, particulate matter (PM10), nitrogen dioxide and lead;
  • on December 13, 2000, Directive 2000/69/EG, with limits for benzene and carbon monoxide;
  • on February 9, 2002, Directive 2002/3/EG, for comparing ozone at ground level to the data and level of excess over the limits; and
  • on December 15, 2004, Directive 2004/107/EC, with limits for arsenic, cadmium, mercury, nickel and PAH.

Germany had two years to enact the first two subsidiary directives into national law, a deadline it missed substantially, as the Seventh Amendment to the Federal Immissions Protection Law (BImSchG), which addressed the first subsidiary directive, was not enacted until September 2002. The new Ozone Directive has now also been enacted into German law with the new 33rd Ordinance of the BImSchG.

The core elements of the Air Quality Directives are the immission limit values, which are "to be attained within a given period and not to be exceeded once attained". The pollution concentrations, and the time in which the limits must be met, are stipulated in the subsidiary directives, and in the 22nd Ordinance to the BImSchG (22nd BlmSchV).

Table 2 shows the stipulated limits for the two air pollutants which pose the greatest potential problem for Berlin: PM10 and nitrogen dioxide.

Tab. 2: EU wide immission limit values and deadlines for PM10 and nitrogen dioxide stipulated in the 22nd BlmSchV

[Table is also available as Excel-File (MS-Excel is required).]

In the new EU Directive 2008/50, new limit and reference values have been established for very fine particulate PM2.5 (i.e., with a particle diameter of less than 2.5 µm), and the compliance deadline for the NO2 and PM10 limit values is extended by up to 5 years, under certain circumstances.

Under Paragraph 1 of the 22nd BlmSchV, Berlin is a metropolitan area in which the air quality must be evaluated annually and, if necessary, measures must be taken to comply with the limits. The entire city was designated as a planning area for the possible establishment of a plan to preserve air quality. Exceeding of the limits occurs throughout the city, especially on primary roads. It therefore makes no sense to limit the planning area to parts of the city, or to divide the city into distinct planning areas.

Problems in Applying Directive 99/30/EC and the 22nd BImSchV, Using the Example of PM10 Pollution in the City

In the proximity of high pollution immission, such as on canyon streets, high concentrations of immission occur. Unlike in most industrial areas, there are many people on traffic filled streets, be they residents, customers or workers, who face increased exposure to pollution. In order to meet the EU Directives for emissions at the locations of the highest concentrations, quantification of harmful pollutants must be as accurate as possible. For this purpose, such measurements have in Berlin been supplemented by model calculations for all high-traffic streets in which limits could potentially be exceeded.
However, even on a high-traffic canyon street, the proportion of pollution stemming from other sources in the city or transported in from outside , is an important factor. Therefore, for the planning of measures to improve air quality in Berlin, a system of models was used, which can calculate the effect of pollution from the surrounding area as well as the effect of all emitters within the city, even on high-traffic canyon streets. The model uses the levels:

  • "canyon streets"
  • city wide background pollution, and
  • regional background pollution.

The simplified diagram shown in Figure 1, which shows the spatial distribution of PM10 concentrations in Berlin and the surrounding area, was developed from these investigations of the source of particulate matter pollution in Berlin.

Fig. 1: Diagram showing the concentration of particulate (PM10) pollution in Berlin and the surrounding area (SenStadt 2005b)

There is a broadly distributed background level (green area of chart) which, according to measurements taken at several rural stations in Brandenburg in 2002, amounts to almost 20 µg/cu.m. The component, known as the "regional background pollution", is distributed relatively evenly outside of the city, as the results of the large-scale model show. Added to that is the proportion of PM10 pollution caused by local Berlin-based sources. It includes:

  • that portion obtained by the combination of all of the emissions form all Berlin sources: power plants, industry, residential heating (blue area). Together with the regional background, this equals the particulate concentrations measured in the residential areas of the city remote from traffic and industry;
  • an additional portion caused by local emitters in the immediate area of the source, such as motor vehicle traffic on Frankfurter Allee (red peaks).

In sum for Berlin, barely half the PM10 pollution measured at stations near traffic in the inner city comes from the regional background and the other locally caused particulate pollution. That portion is equally divided between the amounts produced by local traffic and the pollution sources in the remainder of the city. Only this last share can be influenced by local measures in Berlin.

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