Emission inventories of ozone precursors are routinely used as input to com
prehensive photochemical air quality models. Photochemical model performanc
e and the development of effective control strategies rely on the accuracy
and representativeness of an underlying emission inventory. This paper desc
ribes the tasks undertaken to compile and evaluate an ozone precursor emiss
ion inventory for the El Paso/Ciudad Juarez/Southern Dona Ana region. Point
, area and mobile source emission data were obtained from local government
agencies and were spatially and temporally allocated to a gridded domain us
ing region-specific demographic and land-cover information. The inventory w
as then processed using the US Environmental Protection Agency (EPA) recomm
ended Emissions Preprocessor System 2.0 (UAM-EPS 2.0) which generates emiss
ions files compatible with the Urban Airshed Model (UAM). A top-down evalua
tion of the emission inventory was performed to examine how well the invent
ory represented ambient pollutant compositions. The top-down evaluation met
hodology employed in this study compares emission inventory ratios of non-m
ethane hydrocarbon (NMHC)/nitrogen oxide (NOx) and carbon monoxide (CO)/NOx
ratios to corresponding ambient ratios. Detailed NMHC species comparisons
were made in order to investigate the relative composition of individual hy
drocarbon species in the emission inventory and in the ambient data. The em
ission inventory compiled during this effort has since been used to model o
zone in the Paso del Norte airshed (Emery et at., CANx modeling of ozone an
d carbon monoxide in the Paso del Norte airshed. In: Proc of Ninety-Third A
nnual Meeting of Air & Waste Management Association, 18-22 June 2000, Air &
Waste Management Association, Pittsburgh, PA, 2000). (C) 2001 Elsevier Sci
ence B.V. All rights reserved.