The primary goal of the study is to extend the air quality project in Doña Ana County and west Texas to northwestern Chihuahua. The study objectives are to: - Obtain a quality database of precipitation in northwestern Chihuahua for use in model evaluation, and to help develop conceptual models of wind- blown dust -Obtain episodic PM10, PM2.5, pollen, and meteoroligcal measurements during high particulate matter events -Determine past and present locations of air quality and climate monitoring stations in northwestern Chihuahua summarized in a database -Enhance and evaluate the air quality emission inventory in northwestern Chihuahua with a focus on PM10 and PM2.5