Includes bibliographical references (p. 45-48).Biomass burning is the burning of living and dead vegetation which includes grasslands, forests, and agricultural lands (Levin, 1998). It is a global phenomenon and serves a multitude of purposes such as clearing of forests and brushland for agricultural use; control of weeds; production of charcoal; and energy production for cooking and heating (Crutzen and Andreae, 1990). The Baylor Institute for Air Science (BIAS) equipped an aircraft to measure trace gases and aerosols during two science flights in the south Texas region. One science flight was flown to collect "background" continental and marine layer air data and the other to collect data in biomass-burning smoke plumes from Mexico and Central American countries. Measurements were taken in the geographic region along the US-Mexico Border and adjacent area over the western Gulf of Mexico. Results of this study indicate that individual smoke plumes may occur episodically over the Texas border region to Mexico under prevailing southeasterly wind directions. The origin of these plumes may be diverse ranging from individual local fire emissions to medium range transport of biomass burning.by Sergio L. Alvarez.I.M.E.S.