Proposed interventions to reduce noxious air pollution at Birmingham New Street station

Birmingham New Street railway station in the UK has recently undergone a substantial redevelopment at a cost of more than £600 million. However, the unique underground tunnel geography of the platforms has remained virtually unchanged, which means that diesel exhaust gases are effectively trapped causing a daily build-up of air pollution in the station. A new ventilation system has been installed consisting of 98 bi-directional fans that are meant to disperse any air pollution out of the station. Unfortunately, the fans were triggered by carbon dioxide levels that do not significantly correlate with more serious air pollutants such as nitrogen oxides. In August 2018, new workplace exposure limits (WELs) were introduced for nitrogen monoxide (NO) and nitrogen dioxide (NO2). However, during a recent measurement campaign, one of the new WELs would have been exceeded on most days. Network Rail has undertaken to introduce a number of interventions, including the installation of new nitrogen monoxide/dioxide sensors to drive the ventilation system together with new sonic wind sensors, encouraging train operating companies to switch off idling diesel engines and encouraging more electric/hybrid trains.