On the effective indices for emissions from road transport

Abstract

The emissions from the road traffic are in a way different from the ship and airplane emissions: (i) the road network can be pretty dense in some cells of the large scale model grid; (ii) the emissions are continuous with time; (iii) the road traffic sources are close to earth’s surface. That is why the concept of deriving effective emission indices from the interaction of an instantaneous plume with the ambient air is perhaps not so convenient in the case of road transport emissions. On the other hand, the vertical turbulent transport is a very important process near earth’s surface, which means that it is relatively easy to parameterize the vertical structure of the pollution fields and so relegate the considerations to a two-dimensional problem within a layer where the emissions heterogeneity can be important for the nonlinear chemical reactions.