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Berlin Environmental Atlas

03.03 Nitrogen Oxides - Emissions and Pollution (Edition 1997)

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Measured Pollution

Sum of Nitrogen Oxide - Yearly Average 1995

For comparison, the yearly average sum of nitrogen oxide is also depicted with the dispersion calculation of the nitrogen dioxide concentration in Map 03.03.8. This is because of the problem presented by the transformation of nitrogen oxide to nitrogen dioxide in the atmosphere. In this map, the concentration differences for near street and off-street are more noticeable than for nitrogen dioxide (c.f. Map 03.03.9), because nitrogen monoxide, primarily from motor vehicle exhaust, is also taken into account. Its concentration declines very quickly with the distance from the streets through the double effect of dispersion and transformation.

The highest levels were all measured at street monitoring stations. That means the city expressway near the interchange Spandauer Damm in Charlottenburg, the Schildhorn Strasse in Steglitz, the Karl-Marx-Strasse in Neukölln recorded more than 200 µg/m³. 166 µg/m³ has been recorded in the Frankfurter Allee.

Nitrogen Dioxide - Yearly Average 1995

Generally it can be said that the level of measured pollution depends on the distance of the measurement stations from the main traffic arteries. The Map 03.03.9 shows values of 28 to 34 µg/m³. at the inner-city measuring points positioned at more than 20 m distance from streets. That is 35 to 45 % of the pollution IW1 specified in TA-Luft. In comparison to 1991 (c.f. SenStadtUm 1994b) this means a load reduction of about 15 %. The minimum level of 28 µg/m³ in Wedding was measured at a distance of more than 200 m from the main traffic arteries. The highest level of 34 µg/m³ were recorded near the Red City Hall (Rote Rathaus) at the monitoring station Mitte. This monitoring station is located 25 m from the heavily traveled Gruner Strasse and thereby in the wider impact area of the main traffic arteries.

An yearly average of 32 µg/m³ can be assigned to the area center. At the city's edge, levels between 15 and 18 µg/m³ have been measured, only about half that found in the city center. The forest station Grunewald, with 19 µg/m³, shows only minimal impact from the AVUS which is located 700 m away.

The street measuring stations in Charlottenburg, Steglitz, Neukölln and Charlottenburg exhibit considerably higher values than the grid stations, each with an yearly average of 53 to 56 µg/m³. Only the station at the intersection of Frankfurter Allee and Warschauer Strasse, with 46 µg/m³ exhibits a somewhat lower level. The Charlottenburg station lies directly on the city expressway, exit ramp Spandauer Damm, in open terrain. The air samples are drawn about 5 m above the level of the southbound lane at the height of the nearest sidewalk. The city expressway has a traffic volume of approx. 150,000 motor vehicles per day in the vicinity of the measuring point. The other stations lie in traffic corridors with traffic volume between 35,000 and 60,000 vehicles per day. The air samples were taken at 3.5 m between the roadway and the sidewalk.

As an yearly average, all stations reach practically the same yearly average level for nitrogen dioxide despite large differences in the volume of traffic and nitrogen oxide emissions. In the case of total nitrogen oxide (Map 03.03.8), the differences are greater yet do not correspond to variances in traffic volume. This can be explained by the fact that the stations on the city expressway are subject to free air flows while the other stations lie in traffic corridors of varying breadth. The wind speed is thereby lower and therefore the pollutant dilution is considerably reduced. Since nitrogen dioxide is formed primarily in the atmosphere, the nearness to the polluter is a fairly insignificant emission factor.

This also explains the relatively slight nitrogen dioxide concentration at the street measuring station intersection Frankfurter Allee / Warschauer Strasse. Of course, these streets have a traffic volume of 70,000 respectively 22,000 motor vehicles per day. The samples were drawn from a height of 4 m above a green strip in 25 resp. 15 m distance from the streets. In addition, the adjacent house facades are far removed from the traffic lanes, so that the intersection is always well ventilated. Analogous to the Environmental Atlas 1994, no excesses of IW1 for TA-Luft were ascertained at the street monitoring points in 1995.

The EC Guideline limit of 50 µg/m³ for the 50 % nitrogen dioxide concentration is observed only at points in Berlin not directly affected by motor vehicle traffic. At the street monitoring points, it is exceeded. It can therefore be concluded that the limits are exceeded in many of the city's main traffic arteries- particularly in traffic corridors.

Measured Nitrogen Dioxide Pollution - 98 % Value 1995

The Map (03.03.10) of measured pollution I2 shows a similar picture to that of the map of I1 -levels of nitrogen dioxide (Map 03.03.9). With a maximum of 124 µg/m³, no pollution values in excess of the IW2 of the TA-Luft at 200 µg/m³ and the same upper EC nitrogen dioxide limit were ascertained. Also the EC Guideline limit of 135 µg/m³ is complied with. Since this 98 % value is heavily influenced by weather, the compliance for 1995 cannot be assumed as based upon a general tendency toward values below the compliance norm.

The nitrogen dioxide concentration in the outskirts lies at about 60 % of the inner city values or somewhat higher than the yearly average. This is due to the fact that the high concentrations which determine the I2-value occur predominantly under weather conditions in which low-lying inversions occur. Here the pollutants cannot expand vertically and therefore are carried in relatively high concentration to the outskirts.

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