Meteorology applied to urban air pollution problems: COST 715

The requirements of the framework Directive on air quality assessment and management introduce real practical problems for the meteorological community. Some of the meteorological variables needed in urban air pollution assessments are not routinely measured and in normal circumstances the number of meteorological stations in urban areas is limited to a few sites, often just at airports. The European wide project COST 715 on 'Meteorology applied to urban air pollution problems' has been set LIP to review these problems. This paper describes the limitations of current methods. It recognizes that the urban boundary layer is a non-equilibrium situation where standard theories applied to rural areas may not be valid. It shows that predictions of concentrations for assessments should always state the uncertainty associated with them. This uncertainty can be large because of the complexity of urban pollution situations, particularly the description of the local urban meteorology. An example is given of how, with some additional local meteorological measurements, the uncertainty can be reduced. The paper concludes by listing some of the key areas where further work is required. Information about the COST 715 project is available from the website at http://www.dmu.dk/atmosphericenvironment/cost715.htm.