A11T-04
Direct Measurements of the Local Ozone Production Rate in the Pollution Outflow from a Megacity

Monday, 14 December 2015: 08:55
3004 (Moscone West)
Leigh Crilley1, Louisa J Kramer2, Robert Woodward-Massey3, Danny R Cryer3, Lisa K Whalley3,4, Dwayne E Heard3, Claire Reeves4, Grant Forster4,5, David Oram4,6, Brian Bandy4, Chris Reed7, James D Lee7,8 and William Bloss9, (1)University of Birmingham, School of Geography, Earth and Environmental Sciences, Birmingham, B15, United Kingdom, (2)University of Birmingham, School of Geography, Earth and Environmental Sciences, Birmingham, United Kingdom, (3)University of Leeds, School of Chemistry, Leeds, United Kingdom, (4)National Centre for Atmospheric Science, Leeds, United Kingdom, (5)School for Environmental Sciences, University of East Anglia, Norwich, United Kingdom, (6)University of East Anglia, Norwich, United Kingdom, (7)Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, United Kingdom, (8)National Centre for Atmospheric Science, University of York, York, United Kingdom, (9)University of Birmingham, Birmingham, United Kingdom
Abstract:
Tropospheric ozone (O3) is major secondary air pollutant that is formed in the atmosphere through the complex oxidation of volatile organic carbon compounds (VOCs) in the presence of nitrogen oxides (NOx) and sunlight. In order to effectively implement control measures to reduce O3 levels, it is necessary to understand the chemical processes that in part govern O3 concentration, and to disaggregate local chemical O3 production from transport. To address this issue, a major field campaign was organised at the Weybourne Atmospheric Observatory (WAO), a coastal site in the UK that is regularly within the pollution outflow from London and Western Europe. As part of this campaign, a novel approach to directly measure in situ the rate of local O3 production was employed along with a range of instrumentation to measure concentrations of different radical species as well as with detailed VOC and NOx speciation. We will present preliminary findings from a major O3 pollution event (~120 ppb) that occurred during the campaign as a case study for investigating the contributing factors influencing O3 formation at a NOx limited site. Direct measurements of local chemical O3 production rates are compared with those inferred from a range of indirect approaches.