Simulating secondary organic aerosol from missing diesel-related intermediate-volatility organic compound emissions during the Clean Air for London (ClearfLo) campaign
Riinu Ots1,2,Dominique E. Young3,a,Massimo Vieno2,Lu Xu4,Rachel E. Dunmore5,James D. Allan3,6,Hugh Coe3,Leah R. Williams7,Scott C. Herndon7,Nga L. Ng4,8,Jacqueline F. Hamilton5,Robert Bergström9,10,Chiara Di Marco2,Eiko Nemitz2,Ian A. Mackenzie11,Jeroen J. P. Kuenen12,David C. Green13,Stefan Reis2,14,and Mathew R. Heal1Riinu Ots et al. Riinu Ots1,2,Dominique E. Young3,a,Massimo Vieno2,Lu Xu4,Rachel E. Dunmore5,James D. Allan3,6,Hugh Coe3,Leah R. Williams7,Scott C. Herndon7,Nga L. Ng4,8,Jacqueline F. Hamilton5,Robert Bergström9,10,Chiara Di Marco2,Eiko Nemitz2,Ian A. Mackenzie11,Jeroen J. P. Kuenen12,David C. Green13,Stefan Reis2,14,and Mathew R. Heal1
1School of Chemistry, University of Edinburgh, Edinburgh, UK
2Natural Environment Research Council, Centre for Ecology & Hydrology, Penicuik, UK
3School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, UK
4School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
5Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, UK
6National Centre for Atmospheric Science, University of Manchester, Manchester, UK
7Aerodyne Research, Inc., Billerica, MA, USA
8School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
9Swedish Meteorological and Hydrological Institute, Norrköping, Sweden
10Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
11School of GeoSciences, University of Edinburgh, Edinburgh, UK
12TNO, Department of Climate, Air and Sustainability, Utrecht, the Netherlands
13MRC PHE Centre for Environment and Health, King's College London, London, UK
14University of Exeter Medical School, Knowledge Spa, Truro, UK
anow at: Department of Environmental Toxicology, University of California, Davis, CA, USA
1School of Chemistry, University of Edinburgh, Edinburgh, UK
2Natural Environment Research Council, Centre for Ecology & Hydrology, Penicuik, UK
3School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester, UK
4School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
5Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, UK
6National Centre for Atmospheric Science, University of Manchester, Manchester, UK
7Aerodyne Research, Inc., Billerica, MA, USA
8School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
9Swedish Meteorological and Hydrological Institute, Norrköping, Sweden
10Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
11School of GeoSciences, University of Edinburgh, Edinburgh, UK
12TNO, Department of Climate, Air and Sustainability, Utrecht, the Netherlands
13MRC PHE Centre for Environment and Health, King's College London, London, UK
14University of Exeter Medical School, Knowledge Spa, Truro, UK
anow at: Department of Environmental Toxicology, University of California, Davis, CA, USA
Correspondence: Mathew R. Heal (m.heal@ed.ac.uk) and Riinu Ots (r.ots@ed.ac.uk)
Received: 12 Nov 2015 – Discussion started: 18 Jan 2016 – Revised: 26 Apr 2016 – Accepted: 11 May 2016 – Published: 27 May 2016
Abstract. We present high-resolution (5 km × 5 km) atmospheric chemical transport model (ACTM) simulations of the impact of newly estimated traffic-related emissions on secondary organic aerosol (SOA) formation over the UK for 2012. Our simulations include additional diesel-related intermediate-volatility organic compound (IVOC) emissions derived directly from comprehensive field measurements at an urban background site in London during the 2012 Clean Air for London (ClearfLo) campaign. Our IVOC emissions are added proportionally to VOC emissions, as opposed to proportionally to primary organic aerosol (POA) as has been done by previous ACTM studies seeking to simulate the effects of these missing emissions. Modelled concentrations are evaluated against hourly and daily measurements of organic aerosol (OA) components derived from aerosol mass spectrometer (AMS) measurements also made during the ClearfLo campaign at three sites in the London area. According to the model simulations, diesel-related IVOCs can explain on average ∼ 30 % of the annual SOA in and around London. Furthermore, the 90th percentile of modelled daily SOA concentrations for the whole year is 3.8 µg m−3, constituting a notable addition to total particulate matter. More measurements of these precursors (currently not included in official emissions inventories) is recommended. During the period of concurrent measurements, SOA concentrations at the Detling rural background location east of London were greater than at the central London location. The model shows that this was caused by an intense pollution plume with a strong gradient of imported SOA passing over the rural location. This demonstrates the value of modelling for supporting the interpretation of measurements taken at different sites or for short durations.
This study investigates the contribution of diesel vehicle emissions to organic aerosol formation and particulate matter concentrations in London. Comparisons of simulated pollutant concentrations with observations show good agreement and give confidence in the skill of the model applied. The contribution of diesel vehicle emissions, which are currently not included in official emissions inventories, is demonstrated to be substantial, indicating that more research on this topic is required.
This study investigates the contribution of diesel vehicle emissions to organic aerosol...
