scope:

Several statutory provisions (e.g. 2008/50/EC; BImSchG (German Federal Immission Control Act); 39. BImSchV (39^th German Federal Immission Control Ordinance); TA Luft) require a calculation of the NO₂ concentration that arises under the effect of local NO and NO₂ emissions at distances ranging from a few metres to a few kilometres. For such tasks, this standard describes a reaction system with which the NO₂ concentration can be calculated. This reaction system was reduced from the more complex RACM (Regional Atmospheric Chemistry Model) system [1], with the objective of providing a method for calculating NO₂ concentrations that is as simple as possible but sufficiently accurate. Chemistry modules for calculating NO₂ concentrations as part of numerical transport models, should at least be compatible with the presented reaction mechanism.

The described system of chemical transformations is so designed, that it can be used for determining NO₂ pollution resulting from exhaust gas plumes of combustion plants (including large-scale ones, see VDI 3783 Part 13) just as it can be used for calculating the NO₂ concentration caused by vehicular traffic in street canyons and on motorways (VDI 3783 Part 14).

It is suitable, therefore, for evaluating procedures for reducing nitrogen oxide pollution with the aim of complying with statutory provisions.

An example of an application in the road sector, e.g. street canyons and motorways, is shown in Annex B of this standard. The application to exhaust gas plumes from industrial plants will be covered in a later part of this series.