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VW emission scandal

Posted on 25 September 2015

Atmospheric Chemistry researchers from the Department of Chemistry have been providing expert commentary on the recent VW emission scandal

NO2 Emissions

Atmospheric Chemistry researchers from the department of Chemistry at the University of York have been providing expert commentary on the recent VW emission scandal to a variety of UK and international media organisations. Much of the original research that demonstrated the mismatch between predicted and measured levels of nitrogen oxides (NO & NO2) in the UK, has been carried out at the University of York in the Wolfson Atmospheric Chemistry Laboratories (WACL). WACL is the only dedicated atmospheric chemistry building in the UK, housing world leading researchers from both the chemistry department and National Centre for Atmospheric Science (NCAS).

Nitrogen oxides (NOx) emitted from diesel cars are of great importance to public health and are known to cause lung irritation in the short term, with longer exposures at sustained high levels promoting cardiovascular diseases (Atkinson et al., 2013). Recent studies by experts from WACL, have highlighted the mismatch between real-world NOx and expected concentrations based on industry estimates. A recent study by Lee et al., (2015) showed almost twice as much NOx being released in London compared to that predicted by the UK’s National Atmospheric Emission’s Inventory (NAEI), The study used a novel measurement method that ‘looked down’ on central London from the BT Tower.

Discrepancies between the predicted and observed NOx from vehicles operating under under ‘real world’ conditions was reported in Carslaw and Rhys-Tyler, (2013). This work found NO2 emitted from individual diesel vehicles was much higher than reported by car manufacturer testing. View a more in-depth discussion on this subject by David Carslaw into both health effects and scale of NO2 emitted on the UK’s road.

Whilst the media focus of attention recently has been on NOx, diesel vehicles also emit other classes of pollutants. In a separate study published two weeks ago, Dunmore et al., (2015) showed for the first time that unburnt diesel fuel was present at levels up to 70 times higher than predicted in London air. Unburnt diesel fuel in air is important since it leads to the promotion of secondary pollutants such as Ozone (O3) and particulate matter.

Notes to editors:

ATKINSON, R. W., CAREY, I. M., KENT, A. J., VAN STAA, T. P., ANDERSON, H. R. & COOK, D. G. 2013. Long-Term Exposure to Outdoor Air Pollution and Incidence of Cardiovascular Diseases. Epidemiology, 24, 44-53. doi: 10.1097/EDE.0b013e318276ccb8

CARSLAW, D. C. & RHYS-TYLER, G. 2013. New insights from comprehensive on-road measurements of NOx, NO2 and NH3 from vehicle emission remote sensing in London, UK. Atmospheric Environment, 81, 339-347. doi: 10.1016/j.atmosenv.2013.09.026

DUNMORE, R. E., HOPKINS, J. R., LIDSTER, R. T., LEE, J. D., EVANS, M. J., RICKARD, A. R., LEWIS, A. C. & HAMILTON, J. F. 2015. Diesel-related hydrocarbons can dominate gas phase reactive carbon in megacities. Atmos. Chem. Phys., 15, 9983-9996. doi: 10.5194/acp-15-9983-2015

LEE, J. D., HELFTER, C., PURVIS, R. M., BEEVERS, S. D., CARSLAW, D. C., LEWIS, A. C., MOLLER, S. J., TREMPER, A., VAUGHAN, A. & NEMITZ, E. G. 2015. Measurement of NOx Fluxes from a Tall Tower in Central London, UK and Comparison with Emissions Inventories. Environmental Science & Technology, 49, 1025-1034. doi: 10.1021/es5049072