scope:

This standard should be used for performing and checking dispersion calculations in the context of an air pollution forecast of vehicle-generated emissions. It should also facilitate the examination of expert reports by governmental agencies.

Depending on the particular task's level of detail, the standard's scope extends from examination of the relevant air pollution effects of single road sections to that of complex road networks in agglomerations.

In the preparation and examination of studies and expert reports, the standard serves as a supporting aid. Use of the standard makes an important contribution to compliance with the data quality objectives in EU Directive 2008/50/EC. It does not, however, replace the expertise needed for carrying out or examining an air pollution forecast. A simple reference in an expert report to this standard is not sufficient to demonstrate that the methods and assumptions relied upon in the report lead to plausible results in the air pollution forecast.

Air pollution forecasts distinguish between the traffic- generated additional pollution in the road section or network being investigated and the total pollution, consisting of the sum of the initial pollution and the additional pollution (for inert gases, without chemical conversion). This standard discusses first and foremost the additional pollution arising from vehicular traffic and computed by means of an air pollution forecast, but details are provided for determining the total pollution.

The choice of models appropriate to the specific task at hand is an integral part of the investigation method described here. The approach pursued by RLuS 2012 [1] is not addressed here directly. The checklist included in this standard, however, can be used where sensible for implementing RLuS 2012.

This standard does not include the method for computing vehicle emissions (see standard VDI 3782 Part 7), nor methods for validating the models used (see e.g. standard VDI 3783 Part 9 or Part 10).

In principle, this standard can also be used to determine ambient air pollution due to off-road vehicles and to construction vehicles on surfaced and unsurfaced roads. The emission factors for the description of these situations may need to be looked up in standard VDI 3790 Part 3. In the event of licensing procedures, the air pollution forecast can be carried out pursuant to the Technical Instructions on Air Quality Control (TA Luft) in accordance with standard VDI 3783 Part 13.

For certain tasks, it may be necessary to consider the deposition of pollutants. For example, for flora and fauna habitats (FFH) the "critical loads" of nitrogen inputs have to be determined for nitrogen-sensitive biotopes. A distinction is made between dry and wet deposition. In most cases, the annual mean of wet deposition of traffic-generated pollutants is significantly lower than dry deposition. Parameterisation of the deposition is covered in standard VDI 3782 Part 5.