The Environmental Fluid Mechanics group studies a range of environmental fluid flows in air and water, occurring both at the Geophysical and the Urban scales. We are particularly interested in fluid flows relating to the Sustainable Urban environment. Our research activities combine basic numerical and experimental modelling of urban airflow and pollution dispersion at street scale with aim to better understand human exposure to pollution; with applications of fluid dynamics to Green technologies such as Solar ponds, low-energy desalination methods and use of vegetation to improve indoor and outdoor air quality in the urban environment. We have a large collaborative base with researchers at UCL and overseas, as well as with the cleantech industry in the UK. The EFM group has recently expanded its research capabilities and employs a range of computational simulation, sensing and experimental techniques to understand natural flows in the Urban environment: Experimental Fluid Modelling techniques with a range of state of the art facilities in the Fluids Laboratory including a Laser system with 2-component fibre-optic LDV, _Simultaneous_ measurements with PLIF and PIV in a low turbulence flume and in the wind tunnel. A suite of ultrasonic anemometers and a range of pollution detectors to allow high resolution measurements in urban streets CFD simulations with ANSYS/CFX running on UCL's High-Performance Computing network