Efficient methods are developed for modeling emissions - air quality relati
onships that govern ozone and NO2 concentrations over very long periods of
time. A baseline model evaluation study is conducted to assess the accuracy
and speed with which the relationship between pollutant emissions and the
frequency distribution of O-3 concentrations throughout the year can be com
puted along with annual average NO2 values using a deterministic photochemi
cal airshed model driven by automated objective analysis of measured meteor
ological parameters. Methods developed are illustrated by application to th
e air quality situation that exists in Southern California. Model performan
ce statistics for O-3 are similar to the results obtained in previous short
-term episodic model evaluation studies that were based on hand-crafted met
eorological inputs that are supplemented by expensive field measurement cam
paigns. Model predictions at one of the highest NO2 concentration sites in
the US indicate that measured violation of the US annual average NO2 air qu
ality standard at that site occurs because other species such as HNO3 and P
AN are measured as if they were NO2 by the chemiluminescent NOx monitors in
current use. (C) 1998 Elsevier Science Ltd. All rights reserved.