In order to reduce computing time we have assumed that the sensitivity of road traffic
emission to the ozone concentration is representing the sensitivity of all other emissions. There are deviations to this assumption.
However, these have to be small, since the overall sensitivity is given by the derivative to the NOx emission e ozone curve (Figs. 1b and 2), which is obviously close to that from road traffic. The tagging method includes no residuum, since all partial slopes, independent from their order, have no y-intercept.