Estimating PM~(-2).5 Transport Fraction Using Acreageweighted County Land Cover Characteristics - Example of Concept

摘要

Much note has been made in recent years of the apparent overestimate of fugitive dust emissions that is contained in the EPA's National Emissions Inventory.Efforts to reconcile model estimates of dust concentrations with ambient estimates of the crustal component of PM-10 and PM_(2.5).have been unsuccessful.Modelers have resorted to arbitrarily scaling back emissions by a factor of four and even this has not been enough to satisfy the model - ambient reconciliation in all cases.A workshop at Desert Research Institute in 2000 began to explore the reasons for this apparent disparity.Following this,an expert panel was convened to further discuss the issue,several papers have been presented or circulated and several field studies have been completed.This paper presents the notion of a transport fraction,which is what remains airborne and potentially transportable from the vicinity of the source.It illustrates the concept,showing that the transport fraction will vary substantially from county to county and state to state due to variations in vegetative cover and urbanization.