2.22 Air Quality Models Sensitivity to On-Road Traffic Speed Representation: Effects on Air Quality of 80 km h~(-1) Speed Limit in the Barcelona Metropolitan Area

摘要

This work explores the changes in urban air quality caused by the introduction of a maximum speed limit to 80 km h~(-1) on motorways in the Barcelona Metropolitan Area. The tool used is the WRF-ARW/HERMES/CMAQ modelling system. Simulations take into account the entire year 2008 versus the traffic conditions for the year 2007. This speed limitation has been implemented in the HERMES emissions model, which considers hourly variable speeds and hourly traffic intensity in the affected area, taken from measurement campaigns for the aforementioned years; it also permits to take into account the traffic congestion effect. Overall, for the whole metropolitan area, the emissions are reduced up to 4%; however the local effects of this reduction achieve an important impact for specific points of the domain under study, reaching 11%. In this sense, the speed limitation effects assessed represent improvements in air quality levels (5-7%) of primary pollutants over the area affected. Hence, limiting the circulation speed to 80 km h~(-1) has been proved as a feasible traffic management strategy for air quality improvement in urban areas.