Shell Engineering and Associates, Inc., specializes in ambient air quality monitoring services. As opposed to dispersion modeling’s reliance on mathematical predictions, ambient air monitoring actually measures for level of air quality at a specific location over a given time period. The results of ambient air quality monitoring can be used to establish actual pollutant levels, confirm predictions from dispersion models, and provide air quality trends over a long time period. Monitoring data can also be used to refine dispersion modeling outputs and, establish air quality maintenance areas.