Volcanic ash from Iceland and re-routed flights has brought to the fore the science of air-flow patterns, according to Virginia Tech engineer Shane Ross. Similarly, the flow of oil particles in the Gulf of Mexico is also high on the environmental agenda at the moment. Although the flow of particles is apparently random, Ross's work suggests that it can be characterized more effectively. Working with colleagues in Belgium he has developed a way of modeling such systems that exploits Lagrangian coherent structures. The model was based on Antarctic ozone hole data, but is equally applicable to a wide range of geophysical phenomena, including atmospheric and oceanic transport of pollution.