&EPA
www.epa.gov/airscience
science in ACTION
CLEAN AIR RESEARCH
PROGRAM
RESEARCH EXPLORES LINKS BETWEEN AIR POLLUTANTS AND ASTHMA
Issue:
It is estimated that over 20
million Americans suffer from
asthma. This includes almost two
million emergency department
visits, 5,000 deaths, and a
financial cost of $14 billion each
year.
Asthma has been identified as a
serious and growing health
problem by the U.S. Department
of Health and Human Services.
Air pollution, both outdoor and
indoor, is a significant risk factor
for the exacerbation of asthma. In
addition, because asthmatics may
have difficulty clearing pollutants
from their airways, they may be
at an increased risk of non-
respiratory effects of air
pollutants such adverse effects on
cardiac health.
Though it has been firmly
established that air pollution can
initiate asthma attacks, its role in
causing asthma in the first place
is still unclear. At greatest risk
may be individuals who are
exposed to pollutants in the
womb or at a young age. The
elderly who have asthma on top
of already age-related loss of
function may also be at greater
risk. The Office of Research and
Development (ORD) in the U.S.
Environmental Protection Agency
has a research program dedicated
to resolving these uncertainties
about asthma.
Scientific Objective:
ORD conducts asthma research in
its Clean Air Research and
Human Health Research
Programs. Research is conducted
in several main areas:
• Induction and exacerbation of
asthma
• Susceptibility factors
contributing to asthma
• Risk assessment issues related
to induction, exacerbation, and
susceptibility
ORD addresses key issues to
understand the role of pollutants
on asthma, including:
• Determining the critical time
window of exposure that
predisposes one to asthma
• Understanding the key
biological pathways by which
air pollutants cause asthma
• Identifying the factors that
make asthmatics more
vulnerable to the effects of air
pollutants
A major epidemiological research
project sponsored by ORD is the
Detroit Children's Health study,
which is providing data on the
association between exposure of
air pollutants, particularly
particulate matter (PM), and
adverse health outcomes. The
study is examining whether long-
term, early-life exposures to
mobile-source emissions,
particularly diesel exhaust
particles, play a key role in the
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Office of Research and Development
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CLEAN AIR RESEARCH PROGRAM
continued from front
induction of allergic asthma in
school children.
Asthma research is also focused
on:
• Exploring the association
between exposure to mobile
sources in the womb or early in
life and its role in induction of
asthma in children and in the
elderly
• Exploring the mechanisms by
which air pollutants impact
respiratory and cardiac health
in asthmatics
• Understanding the effects of
outdoor air pollution on
moderate and severe asthma
subjects
• Understanding the acute effects
of exposure to different sizes of
particulate matter (PM) on
cardiopulmonary function,
biomarkers of inflammation,
and other factors in mild to
moderate asthmatics
• Identifying biomarkers unique
to elderly asthmatics, which
differs from younger asthmatics
following air pollutant
exposure
Application and Impact:
Asthma research at ORD is
leading to the development of
new scientific methods, models,
and data that is helping to assess
the risks of asthma from exposure
to air pollutants.
The research has contributed to
the development by EPA of
regulatory standards for two high-
priority air pollutants—ozone and
particulate matter. Studies have
also supported health assessments
for diesel emissions.
Among other contributions,
research showed that residual oil
fly ash from oil combustion in
power plants causes immune
system changes that make mice
more sensitive to dust mite
allergens. Residual oil fly ash
often contains nickel as well as
vanadium and iron. Each metal
could cause the mice to develop a
stronger allergy to dust mites.
This may help explain why some
geographic regions have higher
rates of asthma.
REFERENCES
ORD's Asthma Research Strategy:
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm7de
id=54825
ORD's Asthma Research Highlights:
http://www.epa. gov/ord/articles/2005/Asthma_04_
28_05.pdf
Gong, H. Jr., Linn, W.S., Clark, K.W., Anderson,
K.R., Sioutas, C., Alexis, N.E., Cascio, W.E.,
Devlin, R.B. Exposures of Healthy and Asthmatic
Volunteers to Concentrated Ambient Ultrafine
Particles in Los Angeles. Inhal. Toxicol. 2008 Apr;
20(6):533-45.
Yeatts, K., Svendsen, E., Creason, J., Alexis, N.,
Herbst, M., Scott, J., Kupper, L., Williams, R.,
Neas, L., Cascio, W., Devlin, R.B., and Peden,
D.B. Coarse Particulate Matter (PM2.5-10)
Affects Heart Rate Variability, Blood Lipids, and
Circulating Eosinophils in Adults with Asthma.
Environ. Health Perspect. 2007 May; 115(5):709-
14.
CONTACT
David Diaz-Sanchez, National Health and
Environmental Effects Research Laboratory,
EPA's Office of Research and Development, 919-
966-0676, diaz-sanchez. david(g!epa. gov.
JANUARY 2009
U.S. Environmental Protection Agency
Office of Research and Development
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