Using routing apps to model real-time road traffic emissions

General awareness of air quality has grown significantly in recent years, with 'Low Emission' and 'Clean Air' zones proposed for many cities across the UK. However, cities are a complex landscape and air pollutant concentrations can vary greatly from street to street. Therefore, a synthesis of techniques to quantify air pollution is required to account for variations in traffic, meteorology and urban geometry. While the transport sector accounts for much of the outdoor air pollution in UK cities, a limiting factor of current techniques is that traffic is approximated at coarse temporal and spatial resolutions. For example, the UK Department for Transport provides manual hourly counts of traffic volume for point locations, but these tend to only be for major roadways and the data is typically collected on one day of the year. In this study, we present a novel technique that helps to 'fill in' the gaps in our traffic data by harnessing the power of real-time queries to online mapping services, such as Google Maps, to obtain vehicle speed information. This data set can then be used to determine more accurate emission factors for oxides of nitrogen at the resolution of a single street. Initial results are promising, shown here by the application of this technique to the Birmingham (UK) road network.