4.2.4.3 Relevant Results for Planning

The studies revealed that NO₂ is the most critical air pollutant in relation to the threshold values and that the 98-percentile values (the "peak load") of the concentrations are higher relative to the threshold values than the yearly average values. The results for the 98-percentile value of NO₂ were therefore especially relevant for the planning of the project. Figure 4/21 shows the 98-percentile values for NO₂ in the initial state, while Figure 4/22 shows them for the final state. The threshold value for NO₂ – 0.2 mg/m³ according to EC-Guidelines (1985) – was substantially exceeded in the initial state in the area of the tunnel portals and the B10. In the final state as originally planned, further increases in concentrations were found in the area of the tunnel portals, so that the threshold values were considerably exceeded e.g. also in the area of the swimming complex.

The studies showed, as did previously-taken measurements, that maximum pollution levels were already exceeded prior to the implementation of any construction measures, and that the implementation of the planned measures would not improve but rather worsen the emissions situation in sensitive areas (swimming pools, residences).

With the help of the planned construction measures and the exhaust shafts it was possible on one hand to restrict areas where threshold values were exceeded and on the other hand to significantly improve the emissions situation in comparison with the initial state of the area.

	Fig. 4/21: Initial state. NO2-percentile values. Hatched areas: surfaces on which the NO2 limit value of 0.2 mg/m3 is exceeded. Isometric lines are for 0.16 mg/m3 (dashed lines), 0.2 mg/m3 (solid lines with hatched areas), and 0.24 mg/m3 (dotted lines), Source: LOHMEYER (1989)
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	Fig. 4/22: Final state without exhaust structure. NO2 98-percentile values. Hatched areas: surfaces on which the NO2 limit value of 0.2 mg/m3 is exceeded. Isometric lines are for 0.16 mg/m3 (dashed lines), 0.2 mg/m3 (solid lines with hatched areas), and 0.24 mg/m3 (dotted lines), Source: LOHMEYER (1989)
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	Fig. 4/23: Final state with exhaust structure. NO2 98-percentile values. Tunnel stretches emit 20% of the overall exhaust air through the tunnel portals. Hatched areas: surfaces on which the NO2 limit value of 0.2 mg/m3 is exceeded. Isometric lines are for 0.16 mg/m3 (dashed lines) and 0.2 mg/m3 (solid lines with hatched areas), LOHMEYER (1989)
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