Where: Meeting Room No.8, Weijin Road Campus

Lecturer: Professor Alastair C Lewis, Wolfson Atmospheric Chemistry Laboratories, University of York, York, United Kingdom

About the Lecture: Air pollution has been an environmental problem for many hundreds of years and the first laws to control air pollution were introduced more than 700 years ago in the UK. Despite continued investment in emission reduction technologies many areas in Europe continue to suffer from air pollution that is above both European and WHO guidelines. This presentation will review the progress that has been made in reducing certain pollutants and the new challenges that have arisen associated with expansion of the diesel vehicle fleet. Observations of the emissions of NO2 from a variety of experiment methods including tall tower fluxes, aircraft eddy covariance and tailpipe remote sensing have been used to identify the scale of NOx emissions in London. Total London emissions of NOx are typically two times higher than are currently reported in the national emissions inventory. Testing of more than 100,000 different vehicles shows however that individual emissions from EUROIV and EUROV vehicles can be as much as 6 times higher than estimates based on rolling-road tests. Understanding the exact geographic distribution of different vehicle types in London is however central to creating effective control policies. A secondary consequence of increases in the European diesel vehicle fleet has been an increase in the total emissions of volatile organic compounds (VOCs). Using novel multidimensional chromatography methods we demonstrate that the distribution of VOCs has shifted from smaller hydrocarbon compounds to longer chain hydrocarbons >C9. The impacts of this change in speciation of VOCs will be discussed both in terms of urban atmospheric reactivity and the formation of secondary organic aerosols. A potential policy consequence of this shift to diesel (with enhanced higher carbon number VOCs emitted) is that some European countries may find it challenging to meet their 2020 commitments for limiting emissions under the Gothenburg protocol.

Organizer: Institute of Surface-Earth System Science