Future impact of traffic emissions on atmospheric ozone and OH based on two scenarios

The future impact of traffic emissions on atmo- spheric ozone and OH has been investigated separately for the three sectors AIRcraft, maritime SHIPping and ROAD traffic. To reduce uncertainties we present results from an en- semble of six different atmospheric chemistry models, each simulating the atmospheric chemical composition in a possi- ble high emission scenario (A1B), and with emissions from each transport sector reduced by 5 % to estimate sensitivities. Our results are compared with optimistic future emission sce- narios (B1 and B1 ACARE), presented in a companion paper, and with the recent past (year 2000). Present-day activity in- dicates that anthropogenic emissions so far evolve closer to A1B than the B1 scenario. As a response to expected changes in emissions, AIR and