Regional and urban scale modelling of particulate matter: Can PM10 be managed at a local level?

In March 1997, the British government launched the United Kingdom National AirQuality Strategy. The Strategy sought to reduce levels of PM10 in the UK so that theobjective of 50µg/m3, measured as a daily maximum of running 24-hour means, wasexceeded on no more than four days per year. Within three years this objective hadbeen relaxed to allow for thirty five exceedences per year, albeit of a slightly lowerlevel (because of changes in measurement technique), due to concerns that longrangetransport of secondary particles would prevent local authorities from achievingthis objective through local air quality management techniques.The study presented in this thesis seeks to contribute to the current body of workexamining this issue. Two models, one at a regional/European scale, the other at anurban scale, have been used to estimate contributions to atmospheric PM10 levelsfrom various sources. The results of the models, both independently and combined,have been used alongside relevant monitoring data to assess effect that localmanagement techniques might have upon levels of PM10 in both urban and rurallocations.The results suggest that, in many locations where the original air quality objectivemay not have been achieved, local emissions of primary combustion related sourcesmay not have contributed more than 10-15% of total observed PM10 levels. Thisraises questions regarding exactly what the nature of the remaining portion of PM10 iscomprised of, as current modelling techniques are unable to estimate this accurately:either due to an inability to represent the physics and chemistry, or due to lack ofinformation about the sources. However, in the absence of a full understanding ofeither the composition or health effects of PM10, what factors should be consideredin deciding whether or not local management strategies should be applied to thepollutant