X-ray Microscopy of Particulate Matter in Automotive Filters

Airborne particulate matter (PM) presents a hazard to human health and the environment and advanced filtration technologies have been developed to reduce the harm of PM, driven by tightening regulation and economic drivers such as fuel efficiency and the cost of catalyst metals. This project uses x-ray tomography and electron microscopy to image particulate matter and to observe the capture of aerosolized PM within particulate filters. The project addresses why exhaust filters can have variable effectiveness according to sizes and composition of PM, why particulate filters age over time, and how filters may be better designed and manufactured in the future. Furthermore, it develops a unique flow system able to observe In situ filtration in a variety of filters including HEPA and respiratory protective equipment ('face masks').

The approach is to combine synchrotron x-ray radiation (Diamond Light Source) with an new purpose built in situ aerosol flow system developed by the student. Sophisticated 3D image analysis is then used on the tomographic datasets applying high performance computation for image processing and machine learning algorithms for image segmentation and measurement. The characteristics of the filter geometry and construction are assessed in relation to the observed build up of particulate matter in the filter during operation.

This addresses EPSRC research areas in Catalysis, Combustion engineering, Manufacturing technologies, Particulate technology and Image and vision computing.