Dispersion modelling work at Kings College London David Carslaw Environmental Research Group Kings College London

London Air Quality Network-LAQN

Insight from measurements –Secondary pollutants from UK/Europe –Natural particle episodes e.g. Saharan dust in March 2000 –Very localised conditions e.g. congested traffic and the specific configuration of buildings

Particle episode, February 2003

Model development Data from LAQN has been used in the development of practical models for London –NO 2 and PM 10 regression and receptor models (Carslaw et al., 2001; Fuller et al., 2002) –Techniques used in tandem with ADMS to predict concentrations London-wide Carslaw, D.C., Beevers, S.D., Fuller, G., An Empirical Approach for the Prediction of Annual Mean Nitrogen Dioxide Concentrations in London. Atmospheric Environment, Vol. 35, Fuller, G.W., Carslaw, D.C., Lodge, H.W., An Empirical Approach for the Prediction of Daily Mean PM 10 Concentrations. Atmospheric Environment, Vol. 36,

Met pre-processors Some account has been taken of urban meteorology based on parameterisations in the literature –Addition of anthropogenic heat flux –Approach is too simplistic –Need for more appropriate met data for urban modelling (heat fluxes, energy balances)

Application of dispersion models in London Projections of future base case concentrations of NO 2 and PM 10 Analysis of the efficacy of different potential policies in London e.g. a low emission zone and the use of new vehicle technologies

Congestion charging (CCS) ERG will be working with Transport for London to monitor the CCS scheme (AQ measurement, emissions, prediction) It will provide an unprecedented level of traffic activity information –Continuous traffic counters –Manual counts – specific vehicle types –Automatic number plate recognition (ANPR)

Congestion charging Many interesting research questions: CCS is a large natural experiment i.e. the effect of a perturbation How atmospheric composition responds to a specific policy in a large urban area Potential effects of displacing emissions to hours of the day where dispersion is less efficient How secondary pollutants respond to emissions changes over a comparatively small area Re-suspended particulate matter from vehicle-induced turbulence

Research priorities Urban meteorology –Significantly more information is required Connecting the different scales –No one model works at all scales Developments in dispersion modelling needs to be matched with developments in emissions inventories –Emission factors, spatial and temporal scales, species considered –A wider context: urban morphology, heat release etc. –Data management e.g. expertise with GIS