Nitrogen Oxides - Emissions and Pollution 1991

Statistical Base


In order to provide a differentiated evaluation of the causes of nitrogen oxide pollution and contribute toward their elimination, the Berlin Department of Urban Development and Environmental Protection maintains an emission data base for the principal polluter groups.

The data for the establishing the emission data base industry have been taken from the principal individual polluters (power – and heating plants as well as all industrial plants requiring licenses) using their emissions declaration, according to the instructions the Federal Pollution Control Law must be submitted by to the pollution control authorities by the management every two years.

The emission data base domestic heating is laid out statistically for the multitude of small heating systems in the urban area. For all residential buildings, the heat requirements and the shares by heating type, e.g. coal ovens, oil-fired central heating, gas-floor heat, electric- and long-distance heat are determined based on the amount of built-up space. With the help of specific factors assigned to each heating type the emission of each individual housing block is determined. Heating requirements met with electric heat and long distance energy are not taken into account if the heating is produced in plants requiring a license.

The emission data base traffic is based on traffic survey on the part of the traffic administration as well as on statements as to the motor vehicle inventory and the average road performance of the motor vehicles. The emission is calculated with the help of factors, which are determined for different vehicle classes. Thereby passenger cars and delivery vehicles with four-stroke engines with and without exhaust fume cleaning are distinguished from those with two tact – or diesel motors as well as heavy transport vehicle and buses.

All estimates and calculations are compared with the energy balance, in which the entire consumption of fuels in Berlin is compiled.

Calculated Pollution

The pollution calculations were undertaken with the help of a computer-supported of meteorological dispersion model for large individual polluters. The polluter groups domestic heating and traffic (c.f. Fath et al. 1991) were calculated separately.

For the dispersion calculations the domestic heating and traffic emissions were distributed on a grid of 500 by 500 m. Fixed emission levels are attributed to them, while the large individual polluters have been entered with the respective chimney location and the smoke stack height in the calculations. The calculations assume that the pollutant particles contained in the trails of smoke are transported with the wind and expand vertically for the central transport direction vertically and horizontally in the form of a normal distribution. This pollution can only so far disperse until a temperature inversion prevents further dispersion. The calculations take into account wind direction, wind speed, turbulent dispersion capacity in the atmosphere and the inversion altitude. In addition, it is assumed that the heating requirements and thus also the pollutant emission greatly increase in the winter with decreasing temperature.

Since the model calculations assume an unlimited expansion of the pollutants and the domestic heating- and traffic emissions are assigned to the all-inclusive 500 × 500 m grid, the calculation at the nearest measuring points represent results, which are ordered in greater distance from pollutant sources, particularly streets. The pollutant concentration is calculated for about 100 surface points distributed throughout the entire urban area.

Link to: Vergrößern
Fig. 3: 98 % Values of NO2 -Pollution in Typical Traffic Corridors of the Berlin Inner City (background- and additional motor vehicle-induced pollution). The street names indicated represent selected traffic corridor segments
Image: IVU 1993

In connection with the application of the EC Guideline for nitrogen dioxide and the draft of 23 BImSchV, increased measurement of the pollutant load in traffic corridors and at traffic concentrations has been begun to be determine using dispersion calculations. Figure 3 shows the calculated concentrations in 17 traffic corridors of the Berlin inner city. These were determined with the help of a specific dispersion model developed on behalf of the Federal Environment Agency. The first results of these inquiries show equally high (and/or partly higher) values at the street monitoring points. These are presented in the Maps 03.03.8 to 03.03.10. As a result of an extensive study for the assessment of air pollutant pollutions for Berlin’s main streets, intensive investigations have to be carried out because under application of the draft presented by the federal government 23 BImSchV in approx. 6% the street sections, the allowable concentrations have been exceeded. Pollutions in these areas exceed the 98 %-concentrations, calculated at 160 µg/m³, planned to take effect 1 July 1995 (cf. Blümel 1994 and IVU 1993).

Measured Pollution

In 1991, pollution measurements for nitrogen monoxide, nitrogen dioxide and the sum of nitrogen oxides were taken at 26 stations in Berlin.

Automatic measuring instruments are used, which are continuously in service and transmit their data in three minute sequence by telephone lines to the central computer of the Berlin Air Quality Monitoring Network. In the measuring instruments, ozone is added in high concentration to the measured air. With the help of photo sensors the light quantity is measured. This appears as chemical luminescence, if nitrogen monoxide reacts with ozone. The nitrogen dioxide concentration is registered with this process, in that one conducts half of the measured gas through a catalyst, by which the nitrogen dioxide is transformed into nitrogen monoxide (cf. SenStadtUm 1992b).

To obtain information as to the distribution of the pollution in the urban area, 18 stations are ordered in that 4 × 4 km grid in the populous inner-city residential areas as well as in the more suburban transition area. Three stations lie in the Grunewald and in the northern and southern outskirts. According to the instructions for the measurement and evaluation of the pollutant load, these stations have been arranged in more than 20 m distance from pollutant sources.

Three stations (No. 14 in Charlottenburg, No. 74 in Friedrichshain and No. 120 in Neukölln) lie in main traffic arteries in the area of sidewalks. With them representative data are collected about the near street air pollution caused above all by motor vehicle traffic. Two stations are found in approx. 200 m and/or 300 m height above the ground on radio towers in the south and north of the city. The latter serve the registration of nationally-induced air pollution.