Long path ambient air quality monitoring

Abstract

Fixed long path monitoring is an old art with respect to stack emissions and airport visibility, but has yet to be developed for ambient air pollutants. Despite this, the characteristics required for monitoring instruments can be described and the relative merits of various path geometries identified. One of the most attractive geometries would use a single instrument consisting of an energy source and detector in the center of the area to be monitored with reflectors at the intersections of radial cardinal wind direction vectors from, and concentric circles around, the instrument site.