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CLEAN AIR RESEARCH
PROGRAM
RESEARCH CHARACTERIZES PARTICULATE MATTER (PM) AND
IMPROVES MONITORING AND POLLUTION CONTROL
Issue:
Under the Clean Air Act, states
are required to operate and
maintain air monitoring networks
to determine if they are meeting
the federal standards for high-
priority air pollutants, known as
criteria pollutants. One of these
pollutants, paniculate matter
(PM), offers unique challenges to
monitoring and regulation
because it is the only criteria
pollutant that is not defined by its
chemical composition.
Unlike an ozone molecule, which
is the same wherever it is
measured across the country,
PM's characteristics vary greatly.
Airborne PM comes in many
different sizes, ranging from the
size of the smallest viruses to
larger than the diameter of a
human hair. It also comes in a
variety of chemical "flavors,"
meaning chemical properties vary
from one particle to the next.
PM's qualities are also defined by
the source of the pollutant such as
an automobile or industry, and by
the changes of seasons,
geographic location, or even local
meteorological conditions. As a
result, particle pollution is
different depending on where you
live.
Research to better characterize
PM is needed by the U.S.
Environmental Protection Agency
and others to more accurately
identify and define the many
different types of PM across the
country and to advance the
technology to measure, monitor,
and control the pollutant.
Scientific Objective:
Scientists in the Clean Air
Research Program in EPA's
Office of Research and
Development (ORD) are working
to understanding the chemical
composition, size, and
concentration of PM at different
locations across the country.
They are also studying the origin
of the source of PM which will
assist state governments with
regulating the pollutant and
developing more targeted control
measures.
While some pollutants can be
studied in a laboratory,
researchers studying the many
characteristics of PM must
conduct research in outdoor
settings across the country to
assess the many unique and
differing factors that contribute to
the creation of particle pollution.
Key questions being addressed
include:
• What air pollutants need to be
routinely monitored and
controlled to protect public
health?
• What methods are needed to
ensure sufficient measurement
accuracy and precision of air
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Office of Research and Development
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CLEAN AIR RESEARCH PROGRAM
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monitors for each regulated
pollutant?
• What testing requirements and
measurement criteria are
needed to ensure methods used
to obtain data from monitors
are accurate?
Research is under way to:
• Develop and evaluate methods
that characterize coarse PM,
i.e., particles ranging in size
from 2.5-10 micrometers (|im)
in diameter.
• Develop and evaluate methods
for fine PM2.5 and coarse PMio-
2.5 to enable PM measurement
with high-time resolution of
periods of one hour or less.
• Develop, evaluate, and apply
advanced air monitoring
methods to identify air
pollution sources contributing
to non-attainment of the air
quality standards in certain
areas of the country.
Application and Impact:
The Clean Air Research Program
is uncovering the secrets of PM
by defining the many different
properties and qualities of the
pollutant. Research has led to
improved understanding of the
characteristics of PM at different
locations across the country and
is providing critical regulatory
support to implement the national
air quality standards for PM.
Health researchers can use the
discoveries about the
characteristics of PM to study in
more detail how the pollutant
causes adverse heart and lung
effects. In this way, the Clean Air
Research Program is providing a
source-to-health outcome
approach to protecting the public
from air pollutants.
Accompli shments:
• ORD science supported the
adoption of testing
specifications and acceptance
criteria for PM2.5 and PMio-2.5
monitors.
• ORD developed a method for
use by EPA's regulatory
programs to measure coarse
PM.
• Since 2003, ORD science has
supported the designation of 19
monitor types that can be used
by states to determine if their
air is in compliance with
federal standards.
ORD science led to the
designation of new test
methods and equivalent
methods for PM2.5 and PMio-2.5
monitoring instruments.
REFERENCES
Vanderpool, R.; Hanley, T.; Dimmick, F.;
Solomon, P.; McElroy, F.; Murdoch, R.; Natarajan,
S., Multi-Site Evaluations of Candidate
Methodologies for Determining Coarse Particulate
Matter (PMio-is) Concentrations: August 2005
Updated Report Regarding Second-Generation and
New PMio-2.5 Samplers.
http://www.epa.gOV/ttn/amtic/files/ambient/pm25/c
asac/att2casac.pdf
CONTACT
Robert Vanderpool, National Exposure Research
Laboratory, EPA's Office of Research and
Development, 919-541-7877,
Vanderpool.robert(g!epa. gov.
JANUARY 2009
U.S. Environmental Protection Agency
Office of Research and Development
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