Sootprinitng is the eco-sleuth's new weapon for identifying the source of air pollution by setting up a databank on various types of soots to help Policymakers frame stricter norms for emissions, especially for the manufacture of cars, automobile lubricants and gasoline
JOHN Van der Sande, professor of
material science at the MIT and his
team are using a new technique to
compile information on all types of
soot. This knowledge will be used to
detect the exact sources of pollution.
The library of sootprints will be based
on the molecular structure of the
particles emitted from wood-burning
stoves, diesel trucks, factories and power
plants.
The airn of the project is to help
policymakers formulate even more
effective environmental regulations and
make it easier to catch polluters. "I
want to be able to tell you the details of
the specific engine manufacturer, Lising
a particular lubricant and burning a certain fuel," says Van der Sande about
sootprinting. Sootprints even look like
fingerprints with white circles strewn
with distinctive patterns of short black
lines. A year's research has achieved
15 soot signatures from a single diesel
engine for Van der Sande and his colleague Adel Sarofim, a professor of
chemical engineering at the MIT.
Soot, which is also called particulate
matter, has been termed "a deadly
threat" by the American Lung
Association. People who work long
hours in close association with soot are
prone to cancer and have to contend
with innumerable respiratory tract disorders. Till date, Studies on soot have
focussed on its chemical structure and
trace metal content. Now, Van der
Sande and his group has received a US
$ 100,000 federal grant for analysing the
physical structure of soot particles. Soot
from one source differs from another as
the spacing of certain carbon atoms in
them varies.
MIT researchers have begun their
documentation of sootprints with the
particulates derived from diesel fumes.
Particulate matter derived from diesel is
hard to differentiate and tracing it back
to its source is not an easy job. Clear
distinctions cannot be drawn with the
standard techniques available today.
Van der Sande and Sarofim are using a
US $2 million high-resolution transmission electron microscope. The electron microscope uses a beam of electrons to
study a sample while a regular microscope employs light rays. The image
prochIced by the electron microscope is
digitised 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 elements
are also simultaneously analysed. The
study of these elements serves to establish further distinctions between one
soot sample and another.
The biggest obstacle to the research
project comes in the form of the infinite
H umber of sources of soot to be traced
in the case of air Pollution. In Los
Angeles alone, there are 70 major types
of emissions, contends Glen R Cass,
professor of environmental engineering
at the California Institute of Technology
in Pasadena, US. Thus, such a soot
library can be compiled only by an
cxhaustive study. But once the mission
is complete, the emission of smoke
would certainly be a crime.
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