A new report out this month aims to shed light on real-world NOx/NO/NO2 emission rates using novel roadside remote sensing devices.

The report, commissioned by the City of London and the London Borough of Ealing with funding from Defra is the result of collaborative work between King's and Newcastle University. The study used a roadside instrument that measures components of exhaust emissions by infrared and ultraviolet spectrometry. It is the first time such measurements have been undertaken in the UK.

Whilst it is possible to analyse trends in NOx and NO2 emission rates using aggregated data from monitoring sites across the LAQN, this roadside sensing technique has the advantage of being able to quantify the variation in NOx and NO2 emissions across the urban road vehicle fleet by vehicle type (e.g. car, LGV, HGV, bus, taxi), fuel type, Euro standard, engine size and vehicle age.

Of particular importance to the project was the quantification of NOx and NO2 emission ratios by vehicle category. Research in recent years has indicated that the proportion of NO2 in total NOx produced by the latest generation of road vehicle diesel engines has increased. However, these findings have been generally based on measurements from a relatively small number of vehicles (perhaps a few hundred at most), and carried out either in the laboratory, or measured from instrumented vehicles operating on-road. Secondly, previous studies using remote sensing devices have only considered NO, not NO2. This project aims to overcome some of these limitations by measuring NO2 and NO in road vehicle exhaust directly.

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Item date 12/06/2013