JOHN Van der Sande, professor ofmaterial science at the MIT and histeam are using a new technique tocompile information on all types ofsoot. This knowledge will be used to detect the exact sources of pollution.The library of sootprints will be basedon the molecular structure of theparticles emitted from wood-burningstoves, diesel trucks, factories and powerplants.
The airn of the project is to helppolicymakers formulate even moreeffective environmental regulations andmake it easier to catch polluters. "Iwant to be able to tell you the details ofthe specific engine manufacturer, Lisinga particular lubricant and burning a certain fuel," says Van der Sande aboutsootprinting. Sootprints even look likefingerprints with white circles strewnwith distinctive patterns of short blacklines. A year's research has achieved15 soot signatures from a single dieselengine for Van der Sande and his colleague Adel Sarofim, a professor ofchemical engineering at the MIT.
Soot, which is also called particulatematter, has been termed "a deadlythreat" by the American LungAssociation. People who work longhours in close association with soot areprone to cancer and have to contendwith innumerable respiratory tract disorders. Till date, Studies on soot havefocussed on its chemical structure andtrace metal content. Now, Van derSande and his group has received a US$ 100,000 federal grant for analysing thephysical structure of soot particles. Sootfrom one source differs from another asthe spacing of certain carbon atoms inthem varies.
MIT researchers have begun theirdocumentation of sootprints with theparticulates derived from diesel fumes.Particulate matter derived from diesel ishard to differentiate and tracing it backto its source is not an easy job. Cleardistinctions cannot be drawn with thestandard techniques available today.Van der Sande and Sarofim are using aUS $2 million high-resolution transmission electron microscope. The electron microscope uses a beam of electrons tostudy a sample while a regular microscope employs light rays. The imageprochIced by the electron microscope isdigitised and then run through a computer programme. This allows the genciation of a sootprint based on the spacing of carbon atoms. Alongside the production of a soot print, trace elementsare also simultaneously analysed. Thestudy of these elements serves to establish further distinctions between onesoot sample and another.
The biggest obstacle to the researchproject comes in the form of the infiniteH umber of sources of soot to be tracedin the case of air Pollution. In LosAngeles alone, there are 70 major typesof emissions, contends Glen R Cass,professor of environmental engineeringat the California Institute of Technologyin Pasadena, US. Thus, such a sootlibrary can be compiled only by ancxhaustive study. But once the missionis complete, the emission of smokewould certainly be a crime.