NUI Galway PhD student in the School of Physics, Ann McDonagh, has just returned from participating in a US Department of Homeland Security study on the spread of airborne contaminants released in subway systems. The study measured the flow of gas and particles through tunnels and cars in the Massachusetts Bay Transportation Authority (MBTA) system. Ann's PhD work is supervised by Dr Miriam Byrne, Lecturer with the School of Physics at NUI Galway, and funded by the Radiological Institute of Ireland. Her work aims to develop a better understanding of how contaminant particles, especially those of a radioactive nature, might become redistributed in the environment, if a person or population group were contaminated during an accidental or terrorist-motivated release. Ann developed a relationship with scientists at the Lawrence Berkeley National Laboratory (LBNL) through a visit funded under the NUI Galway/University of California Travel Scheme earlier this year. She has also been asked to participate as a LBNL guest scientist in two scientific missions, in Washington and Boston. This latest study ran from 5-11 December, and involved the release of common, harmless tracer gases used for indoor and outdoor air testing; an inert particle tracer tagged with a biologically inert, non-toxic organic dye used in medical imaging applications; and a common chemical often used as a brightening agent in laundry detergents and paper manufacturing. Particle and gas concentrations were sampled in more than 20 stations and in subway cars, but normal MBTA operations were not disrupted by the activities of the researchers. Regarding the study, Dr Miriam Byrne says: "It is a great achievement for Ann to be selected as a member of the international team for this high profile scientific mission. The results obtained will complement her PhD research, and advance our general understanding of toxic air pollution transport. As well as having applications in the control of accidental and terrorist releases, our knowledge of the spread mechanisms of airborne infectious diseases will also be enhanced". Joining LBNL scientists in the MBTA study were scientists from Argonne National Laboratory, ICx Technologies of Arlington, Virginia, the Defence Science and Technology Laboratory of the United Kingdom, and the Chemistry Centre of Australia. -ends-