Predictors of Ambient NO2 in North Seattle Tim Gould, Courtney O’Neill, Darren Wilton University of Washington Purpose: The objective of this project is to determine the most effective predictors of NO2 concentrations based on typically available geographic parameters and field measurements at 25 sites throughout north Seattle. The ambient samples were collected over a 2 week period using passive Ogawa samplers as a pilot test of a community NO2 saturation study for the UW MESA Air Pollution Study during March of 2005. North Seattle NO2 Concentrations Summary: This project analyzed the correlation between NO2 concentrations and a number of spatial parameters including traffic volumes, street and arterial lengths, topography, population and development density, as well as income. The analysis was performed using ArcGIS and the Statistical Toolbox in MatLab. The street networks and arterials were the most effective predictors of NO2 with the 1000 ft buffers of both returning the highest correlations.