Modelling the impact of road traffic on ground level ozone concentration using a quantile regression approach

► This paper describes the effect of road traffic on ground-level ozone. ► On average ozone levels are lower in urban areas by about 26%. ► Urban decrement varies at different quantiles of the ozone concentration. ► Buses flow shows the strongest effect on ozone concentration. ► The effect of several traffic scenarios on urban decrement has been investigated.