Future PM Research Articles

An empirical approach for the prediction of daily mean PM 10 concentrations

An empirical model has been devised to predict concentrations of PM 10 at background and roadside locations in London. Factors to calculate primary PM 10 and PM 2.5 concentrations are derived from annual mean NO X , PM 2.5 and PM 10 measurements across London and south east England. These factors are used to calculate daily means for the primary and non-primary PM 10 fractions for the London area. The model accurately predicts daily mean PM 10 and EU Directive Limit values across a range of sites from kerbside to rural. Predictions of future PM 10 can be made using the expected reductions in secondary PM 10 and site specific annual mean NO X predicted from emission inventories and dispersion modelling. The model suggests that the EU Directive Limit values will be exceeded close to many of London's busiest roads, and perhaps at central background sites should there be a repeat of 1996 meteorological conditions during 2005. A repeat of 1997 meteorology conditions during 2005 would lead to the EU Limit Value being exceeded alongside the busiest central London roads only. The model is applicable for London and south east England but the methodology could be applied elsewhere at a city or regional level. The model relies on the currently observed ratio between NO X and PM 10. This ratio has remained constant over the last 4 years but might change in the future. The NO X :PM 10 ratio derived from measurements and used in this model, implies that emission inventories might over estimate primary PM 10 by more than 50%.

Receptor modelling of PM 10 concentrations at a United Kingdom national network monitoring site in central London

A receptor model for predicting future PM 10 concentrations has been developed within the framework of the UK Airborne Particles Expert Group and applied during the recently completed review of the UK National Air Quality Strategy. The model uses a combination of measured PM 10, oxides of nitrogen and particulate sulphate concentrations to provide daily estimates of the contributions to total particle concentrations from primary combustion, secondary and other (generally coarse) particle sources. Projections of past and future concentrations of PM 10 are estimated by applying appropriate reductions to the current concentrations of the three components based on an understanding of the likely impact of current policies on future levels. Projections have been derived from 1996, 1997 and 1998 monitoring data and compared with UK national air quality objectives and European Union limit values. One of the key uncertainties within the receptor modelling method is the assignment of the residual PM 10, remaining after the assignment of primary combustion and secondary particle contributions, to the ‘other’ particle fraction. An examination of the difference between measured PM 10 and PM 2.5 concentrations confirms our assignment of the bulk of this residual to coarse particles. Projections based on 1996 monitoring data are the highest and those based on 1998 monitoring data are the lowest. Whilst there is considerable difference between these projections they are consistent with measured concentrations for previous years. All three projections suggest that with current agreed policies the EU annual mean limit value will be achieved. The 24-h mean limit value is projected to be achievable when projections are derived from 1997 and 1998 data, but not from 1996 data. All three projections suggest that with current agreed policies the central London site will not achieve the provisional 1997 UK National Air Quality Strategy objective.

New management and future PM parts manufacture : H.A. Tews. (Technology Management and Associates, USA.)

New management and future PM parts manufacture : H.A. Tews. (Technology Management and Associates, USA.)