Application of mobile aerosol and trace gas measurements for the investigation of megacity air pollution emissions: the Paris metropolitan area

摘要

For the investigation of megacity emission development and the impact outside thesource region, mobile aerosol and trace gas measurements were carried out inthe Paris metropolitan area between 1 July and 31 July 2009 (summerconditions) and 15 January and 15 February 2010 (winter conditions) in theframework of the European Union FP7 MEGAPOLI project. Two mobilelaboratories, MoLa and MOSQUITA, were deployed, and here an overview of thesemeasurements and an investigation of the applicability of such measurementsfor the analysis of megacity emissions are presented. Both laboratoriesmeasured physical and chemical properties of fine and ultrafine aerosolparticles as well as gas phase constituents of relevance for urban pollutionscenarios. The applied measurement strategies include cross-sectionmeasurements for the investigation of plume structure and quasi-Lagrangianmeasurements axially along the flow of the city's pollution plume to studyplume aging processes. Results of intercomparison measurements between thetwo mobile laboratories represent the adopted data quality assuranceprocedures. Most of the compared measurement devices show sufficientagreement for combined data analysis. For the removal of data contaminated bylocal pollution emissions a video tape analysis method was applied. Analysistools like positive matrix factorization and peak integration by key analysisapplied to high-resolution time-of-flight aerosol mass spectrometer data areused for in-depth data analysis of the organic particulate matter. Severalexamples, including a combination of MoLa and MOSQUITA measurements on a cross section through the Paris emission plume, are provided to demonstratehow such mobile measurements can be used to investigate the emissions of amegacity. A critical discussion of advantages and limitations of mobilemeasurements for the investigation of megacity emissions completes this work.