Ambient Air Monitoring
Due to complaints about decreased air quality levels from border communities in Southern California, the US EPA made funds available to develop, install, operate, and maintain a network of monitors in the border region of California and Mexico. This network was designed to monitor pollution impacts on Southern California due to emissions from Mexico. A total of 13 monitoring stations have been established that measure and sample for all of the criteria pollutants (CO, O3, NO2, SO2, PM10 and Pb), as well as two additional sites devoted solely to TSP (Total Suspended Particles) and PM10 sampling. Meteorology data collected includes wind speed, wind direction, and ambient temperature. Data collected on this program is being used to develop attainment strategies on both sides of the border. Not only does this project assist with understanding pollutant transport over the border, it provides a quantitative measure of its severity. Tracer ES&T was selected for this program by the California Air Resources Board, the key regulatory agency for implementing the monitoring effort.

Model Validation
In order to provide data for model validation purposes, the scientists of Tracer ES&T were called upon by the US Marine Corp to simulate a plume release in the middle of downtown Los Angeles. In the summer of 2001, Tracer ES&T performed a series of tracer releases in order to collect data that was compared against modeled information. An impact zone of one kilometer was chosen, in which fifty receptor sites were established in the urban street canyons and atop buildings. The time dependent concentrations were plotted to demonstrate dispersal patterns for each of the 30 minute trials. This method effectively allowed for a comprehensive look at how a release of a toxic plume would function if released in the middle of a complex urban environment, and has useful applications for refining models and the planning strategies of emergency responder personnel.

Tracer Sciences
Tracer ES&T embarked upon an innovative venture primarily co-funded by the U.S. Department of Energy and Western States Petroleum Association to explore alternative methods of measuring pollution impacts. The Remotely Piloted Airship for Atmospheric Tracer Sampling (RPATS) was designed and built by Tracer ES&T personnel in order to obtain detailed plume measurements in the lower atmosphere. The RPATS was used to measure plume characteristics over oil production operations in the San Joaquin Valley and was equipped with a miniaturized, real-time electron capture detector (ECD). Plume data was then telemetered to the ground station and processed to formulate a detailed mapping of plume structure. By having a more thorough understanding of plume behavior close to a specific source, models can be further refined to provide more accurate assessments of regional impacts. This information has been used to allow for more practical planning and subsequent rule making by regulatory agencies with regards to industrial emissions.