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[Ed Edney]
The overall purpose of the research we're conducting
is to develop models for assessing PM control
strategies and take the information that we
generate by conducting laboratory experiments
and field studies to put together a model
which we then can give to the people in the
Office of Air and Radiation to develop and evaluate
control strategies for reducing the adverse health effects
due to exposure to ambient PM 2.5.
Particulate matter is a mixture of microscopic solids
and liquid droplets. PM 2.5 are fine particles
that measure 2.5 microns or smaller in diameter,
such as those commonly found in smoke and haze.
Fine particles can lodge deep in the lungs and even in the
bloodstream, causing respiratory and cardiovascular problems.
We need to look for all the major sources of secondary PM,
that is, a whole range of biogenic and manmade gases,
develop fingerprints for all of them, and then go out in the
field and see which one of them we see occurring in the field.
And the results we've conducted to date suggest that we've
been fairly successful, because ultimately our
goal is not to hand the EPA regulators a fingerprint.
We want to hand them a model, which is a product,
which they can use to determine if they reduce the emissions
of these gases by a certain amount, what is that going
to do for the particulate matter concentrations?
And that's our objective.
Our field study involves taking a filter pack out into the
field and drawing air across them over a day or two
and then collecting the sample on the filter,
which is something we do when we collect our laboratory samples.
Then we take these filters back into the laboratory and we
analyze them for the compounds that make up our fingerprint.
In the smog chamber, we're first taking a variety of gases
and we're irradiating them under conditions typical of the
atmosphere and seeing, one, are we obtaining particles?
The reason why the particulate matter is so complicated is,
even when you're dealing with a single gas,
it can undergo not just one type of reaction,
but a variety of reactions, all leading to different
compounds, and all of them, in principle,
may form particulate matter. So, the particular matter
you get from a single gas can contain hundreds to
thousands of compounds, so this is a very difficult
analytical challenge for us to address.
People have asked me about what part of my research
I find the most exciting, and the simple fact is
I find all of them very exciting.
We're looking at systems that other people and most other
scientists have not looked at.
We're looking at the system that's been given to us
in the atmosphere.
It is highly complex, and it's not an isolated
system, so our challenge is to make sense out of this mess.
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