Joint air pollution sampling program in twin cities on the U.S.-Mexico border.

Ciudad Juárez (Chihuahua) and El Paso (Texas), two cities on the U.S.-Mexico border, form a single environmental system in which the same natural resources, especially air and water, are shared. It also constitutes a single metropolitan area which is characterized by high rates of pipulation growth, economic development, and urban expansion, all these factors mitigating against air quality. Early in 1972 the health authorities in El Paso and Ciudad Juárez initiated a joint air pollution sampling program with assistance from the Pan American Health Organization. The nearby city of Las Cruces (New Mexico) was later included in the program as well. Activities are carried out in accordance with a document entitled "Bases of Cooperation." The guiding criteria of the program are: functional simplicity, operational economy, and complementarity with other sampling programs conducted by the participating services. An Air Pollution Control Subcommittee is responsible for execution coordination of the program. Three studies are currently underway to determine levels of dust pollution in the air. A fourth study is aimed at measuring sulfur dioxide levels through the use of sulfation plates. The results collected reveal concentrations of particulates in the ambient air levels higher than the U.S. Federal primary standards. The program should be expanded to include the study of other pollutants and a joint inventory of emissions. In this way criteria on air quality may be established and joint plans of action and strategies drawn up for the control of air pollution in this important area.