&EPA
www.epa.gov/airscience
science in ACTION
CLEAN AIR RESEARCH
PROGRAM
RESEARCH IDENTIFYING SOURCES OF AIR POLLUTANTS
TO IMPROVE CONTROL STRATEGIES
Issue:
Humans are exposed to a number
of air pollution sources. Major
sources include motor vehicle
exhaust, both large and small
industries, power plants,
agricultural and forest fires, and
domestic activities (e.g., lawn
mowing).
Numerous health studies have
demonstrated an association
between air pollution sources and
adverse health and environmental
effects. Therefore, it is important
to know all we can about the
sources we are exposed to and the
characteristics and concentration
of those sources.
For example, if we know which
specific sources contribute to air
pollution in a given area, and
where people are most likely to
be exposed, strategies such as
changing fuels or installing air
pollution control equipment can
be used to reduce the impact of
those sources.
Source-related research informs
the air pollution control strategies
of EPA, state, and local
governments for specific sources
or categories of sources.
Science Objective:
Scientists and engineers in EPA's
Clean Air Research Program in
the Office of Research and
Development (ORD) are
identifying and quantifying more
clearly the various sources of air
pollution to improve EPA's
understanding of the links
between sources and health
effects.
The focus of this "source-
apportionment" research is on
several sources of air pollutants:
fine particulate matter (PM2.5),
coarse PM, regulated gaseous
pollutants, volatile organic
compounds, and mercury.
Research is being conducted
across the country and in EPA
laboratories to evaluate source
emissions, determine where they
travel, and learn how people and
ecosystems are exposed.
Efforts are underway to advance
the sampling and analytical
methods to measure specific
pollutants in air. The routine
measurements collected in areas
that are not meeting air quality
regulations are typically not
sufficient to identify local source
contributions.
Work is also underway to
improve modeling tools that can
be used to identify and quantify
the local, urban, and regional
sources. The modeling tools are
publically available and are used
by EPA, state and local
governments, as well as academic
continued on back
U.S. Environmental Protection Agency
Office of Research and Development
-------
&EPA
www.epa.gov/airscience
science in ACTION
CLEAN AIR RESEARCH PROGRAM
continued f-omjront
and international environmental
researchers. These models are:
• EPAPMFS.Omodel:
http://www.epa.gov/heasd/prod
ucts/pmf/pmf. htm.
• EPA Unmix 6.0 model:
http://www.epa.gov/heasd/prod
ucts/unmix/unmix. htm.
Application and Impact:
The science developed by the
Clean Air Research Program
provides information and tools to
EPA, states, and local agencies
for developing effective air
pollution regulations.
Recent advances in the
understanding of source
contributions to air pollution
include:
• Studies in Tampa, Fla., showed
a reduction in mercury impact
when a major power plant
changed its fuel from coal to
natural gas. In addition,
Steubenville, Ohio research
demonstrated the large impact
of regional domestic coal
combustion on the deposition
of mercury in rain water.
• A study in Baltimore, Md.,
found that 30 percent of
particulate matter (PM) from
motor vehicles infiltrated inside
a retirement home. The indoor
level reflected the PM pollution
from local coal fire power
plants (sulfate). Another study
in Research Triangle Park,
N.C., found around 50 percent
of PM from motor vehicle
exhaust was present inside
homes and that cooking was a
major contributor to PM
personal exposure.
• World Trade Center research
results showed differences in
air pollution sources during the
different stages of the recovery
effort after 9/11.
• In St. Louis, studies at a major
steel facility helped quantify
the impact of various industrial
sources on local areas.
This research underlines the
importance of tracking specific
sources in exposure assessments
and using the results to improve
control strategies.
REFERENCES
"Chemical Characterization of Ambient Particulate
Matter near the World Trade Center: Source
Apportionment using Organic and Inorganic
Source Markers," Atmos. Environ., in press.
Olson, David A.; Norris, Gary A.; Seila, Robert L.;
Landis, Matthew S.; and Vette, Alan F. (2007)
"Chemical Characterization of Volatile Organic
Compounds near the World Trade Center: Ambient
Concentrations and Source Apportionment,"
Atmos. Environ., 41(27) 5673-5683.
Keeler, G.J.; Landis, M.S.; Norris, G.A.;
Christiansen, E. M.; Dvonch, J.T. (2006) Sources
of Mercury Wet Deposition in Eastern Ohio, USA,
Environ. Sci. Technol., 40(19) 5874-5881.
Zhao, W.; Hopke, P.K.; Norris, G.; Williams, R.;
Paatero, P. (2006) Source apportionment and
analysis on ambient and personal exposure samples
with a combined receptor model and an adaptive
blank estimation strategy. Atmos. Environ. 40
(20)3788-3801.
Hopke, P.K.; Ramadan, Z.; Paatero, P.; Norris,
G.A.; Landis, M.S.; Williams, R.W.; Lewis, C.W.
(2003) Receptor modeling of ambient and personal
exposure samples: 1998 Baltimore Epidemiology-
Exposure Study Atmos. Environ. 37: 3289 - 3302.
CONTACT
Gary Norris, Ph.D., EPA's Office of Resaearch
and Development, National Exposure Research
Laboratory, 919-541-1519, norris.gary@epa.gov.
MARCH 2009
U.S. Environmental Protection Agency
Office of Research and Development
------- |