United States
Environmental
Protection
Agency
Office of
Research and
Development
Washington DC 20460
Air and Energy
Engineering
Research Laboratory
Research Triangle Park NC 27711
Office of
Environmental Engineering and
Technology Demonstration
Washington DC 20460
EPA/600/F-94/035
September 1994
v>EPA Radon Mitigation Research
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Improved Technology for Environmental Protection.
\
Radon mitigation technology developed by EPA's Air
and Energy Engineering Research Laboratory (AEERL)
has been the basis for the installation of radon mitigation
systems in over 300,000 U.S. homes.1 This has resulted
in over 100 lives saved per year. If the technology is
applied to mitigate radon levels in all U.S. homes with
radon levels above the EPA guideline of 4 pCi/L, an
estimated 2200 lives would be saved annually.2
This brochure summarizes the impact that AEERL's
research has had on radon mitigation in the U.S. It also
includes background information on radon and AEERL's
future research plans.
Background
Radon is the second leading cause of lung cancer
deaths in the U.S.3 In order to reduce the public health
risk from radon exposure, EPA's Air and Energy Engi-
neering Research Laboratory (AEERL) is conducting
research to develop and demonstrate cost-effective
radon mitigation technologies. These improved tech-
nologies for environmental protection in homes, schools,
and other large buildings are communicated to radon
mitigators, builders, school facility personnel, architects,
engineers, homeowners, and federal, state, and local
governments through technical guidance manuals,
training courses, reports, and symposia.
The Radon Problem
Radon is a colorless and odorless radioactive gas that
results from the decay of naturally occurring radium
found in many soils and rocks. Because radon is a gas,
it can move through the soil and enter homes and other
buildings through openings in foundations. Radon can
also enter buildings through radon-contaminated
groundwater. Once radon enters a building, concentra-
tions can build up to dangerous levels.
Radon is the largest source of exposure to ionizing
radiation in the U.S. (Figure 1). EPA estimates approxi-
mately 13,600 lung cancer deaths per year from indoor
radon exposure.2 These estimates are based on exten-
sive epidemiological evidence from about 20 different
studies of lung cancer in occupational^ exposed
uranium miners. In addition, independent evaluations by
the International Agency for Research on Cancer, the
International Commission on Radiological Protection,
and the National Council on Radiation Protection and
Measurement have reached comparable conclusions on
the significance of the indoor radon problem.
Radon 55.0%
Cosmic 8.0%
Terrestrial 8.0%
Internal 11.0%
Consumer
Products 3.0%
Nuclear
Medicine 4.0%
Medical X-Rays 11.0%
Figure 1 Radon - a Naturally Occurring Radioactive Gas - is the
Largest Source of Exposure from Ionizing Radiation
in the U.S.
A 1990 EPA Science Advisory Board Report on "Reduc-
ing Risk: Setting Priorities and Strategies for Environ-
mental Protection"4 ranked radon as one of the most
significant environmental health risks facing the Nation.
EPA's Radon Action Program
EPA's Office of Radiation and Indoor Air (ORIA) is
responsible for implementing the Radon Action Pro-
gram, a non-regulatory approach to reduce the public's
risk to indoor radon. The program has four components
(Figure 2):
1)
2)
Problem Assessment - EPA's ORIA has under-
taken radon surveys at both the national and state
levels to determine the magnitude and distribution
of the radon problem (see map in Figure 3).
Mitigation and Prevention - EPA's AEERL conducts
research to develop and demonstrate cost-effective
radon mitigation and prevention technologies.
Problem
Assessment
(ORIA)
Mitigation &
Prevention
(AEERL & ORIA)
Capability
Development
(ORIA)
Public
Information
(AEERL & ORIA)
Figure 2 Components of EPA's Radon Action Program
Printed on Recycled Paper
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Improved Technology for Environmental Protection
Zone 1 counties have a predicted average indoor
screening level of more than 4 pCi/L.
Zone 2 counties have a predicted average indoor
screening level of between 2 and 4 pCi/L.
Zone 3 counties have a predicted average indoor
screening level of less than 2 pCi/L.
Figure 3 EPA Map of Radon Zones
EPA's ORIA conducts mitigation demonstration
projects and has developed radon-resistant
model construction standards for homes.
3) Capability Development - EPA's ORIA is transfer-
ring new technologies to state and local govern-
ments and the private sector.
4) Public Information - Both ORIA andAEERL com-
municate radon information and guidance to the
public through brochures, technical guidance
manuals, input to EPA training courses, reports,
and symposia.
Radon Mitigation Research
AEERL research focuses on radon mitigation and radon
prevention for homes, schools, and other large build-
ings. AEERL has researched, developed, and demon-
strated several radon reduction techniques, including:
soil depressurization, sealing, building ventilation,
building pressurization, and water systems.
Soil Depressurization-Suction pipes are installed
beneath the building foundation, and a fan is used to
pull the radon-containing soil gas away from the building
before it can enter. Soil depressurization is the most
effective technique both for reducing radon levels in
existing buildings and for preventing elevated radon
levels in new construction (Figure 4).
Sealing-Sealing cracks and other openings in the
foundation can help prevent radon from entering a
building. While sealing alone is often not sufficient to
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Improved Technology for Environmental Protection
Outside
Fan
Draws
Radon
Away
Soil Depressurization in a Basement
or Slab-on -Grade Building
Seal
Floor/Wall
Crack f_
X?
!HC
i
•
Pipes
Benea
I
jseal Pipe
Penetrations
Penetrate
th Slab
Jp
Sump
• Suction
•1
—
b
$
in a Crawl Space Building
Fan
Exhausts
Crawl
Space
Polyethylene
Screened Y Air Barrier
Vent Ll \
Figure 4 Radon Mitigation Soil Depresurization Techniques
mitigate the radon problem, it is typically included as a
component of most radon control techniques.
Building Ventilation-Opening windows, doors, and
vents on lower levels or supplying conditioned outdoor
air to the building will help to lower radon levels by
dilution and by reducing negative pressures in the
building.
Building Pressurization-Building pressurization uses a
separate fan (such as a heat recovery ventilator) or an
existing building ventilation system to create positive
pressure which prevents the entry of radon-containing
soil gas.
Water Systems-Radon can be removed from water by
aeration before it enters the building.
AEERL has conducted radon mitigation and prevention
research in 19 states. This research has directly re-
sulted in radon diagnosis and/or radon mitigation in 190
houses, 49 schools, and 7 large commercial buildings.
The research also has far reaching effects, leading to
the development of radon mitigation techniques that can
be used to reduce levels in the estimated 6 million
homes with radon levels above the EPA guideline of 4
pCi/L.2
Additional outputs from AEERL's radon research pro-
gram are:
Development of technology to cost-effectively
prevent elevated radon levels in new construction
of large buildings,
Providing expertise and technical support to
develop model building standards for new
construction,
Reducing highly elevated levels in radon "hot
spots" in eastern Pennsylvania, New Jersey, and
Tennessee, and
Development of nationally recognized expertise in
radon mitigation cost analysis.
Program Impact
According to a 1993 study by the Conference of Radia-
tion Control Program Directors, over 300,000 homes
have already been mitigated for radon. The technologies
used to mitigate these homes have largely been devel-
oped and disseminated by AEERL.
Radon reduction technologies developed by AEERL are
used extensively by the radon mitigation industry (Figure
5). In fact, 900 radon mitigators are currently listed as
Technical
Manuals
EPA Reports
Training
Courses
Symposia
Engineers
Federal,
State, & Local
Governments
i nuincuwriciD I
Figure 5 AEERL's Research Results Are Widely Used
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Improved Technology for Environmental Protection
part of EPA's Radon Contractor Proficiency Program.
These technologies developed and demonstrated by
AEERL are also used extensively by school facility
personnel, architects, engineers, homeowners, and
federal, state, and local governments responsible for
implementing radon programs. The results of AEERL's
radon mitigation research are communicated through
technical guidance manuals, technical support for
national radon training courses, reports, and symposia .
The technologies developed and demonstrated by
AEERL's research program have had a major impact on
reducing radon exposure for the population most at risk
from radon: those exposed to highly elevated radon
levels, above 4 pCi/L.
These technologies have consistently reduced radon
levels to below 4 pCi/L in most cases and to below 2
pCi/L in many cases. Installation of AEERL's demon-
strated technology in all of the estimated 6 million U.S.
homes with radon levels above 4 pCi/L would avoid
approximately 2200 radon-induced lung cancer deaths
annually.2
Costs for installing radon mitigation systems are rela-
tively low. This is critical since homeowners bear the
burden of the mitigation costs. Typical radon reductions
and installation and operating costs for these various
techniques are shown in Table 1. These estimates are
for existing homes. Costs for schools and other large
Table 1s Radon Reductions & Costs for Common Mitigation
Techniques
Radon
Mitigation
Technique
Soil
Depressunzation
Natural
Ventilation
Heat Recovery
Ventilation
House
(Basement)
Pressunzation
Sealing of
Radon Entry
Routes
Water Systems
Typical
Radon
Reduction
%
80-99
Variable
25-75
50-99
0- 50
95-99
Typical Range
of Contractor
Installation
Costs in Houses
S800 - 2500
S200 - 500
(If additional vents
installed)
S1 200 -2500
S500-1500
S1 00 -2000
S3000 - 4500
Typical Annual
Operating Cost
Range in
Houses
S75-175
S1 00 - 700
S50 - 500
(continuous)
S150-500
None
S40 - 90
buildings would typically be higher and vary widely.
Installation during home construction would normally be
less. EPA recommends that passive systems (i.e.,
without a fan) be installed in areas of high radon poten-
tial as designated by EPA's map of radon zones (Figure
3). These systems cost $350-$500. Current AEERL
research is investigating innovative techniques for radon
mitigation in order to lower the installation and operating
costs.
Future Plans
Reducing indoor radon levels to 4 pCi/L still does not
solve the entire health risk from indoor radon exposure.
This is because a significant percentage (78%) of lung
cancer deaths6 are attributed to radon levels above
ambient (about 0.4 pCi/L). (See Figure 6.)
AEERL's long term research targets developing tech-
nologies to reduce indoor radon levels to ambient levels
(0.4 pCi/L) at a low cost. These new, low cost technolo-
gies are crucial to motivating more home and large
building owners to mitigate (an estimated 16 million
homes in the U.S. have radon levels above 2 pCi/L),
thus further reducing lung cancer risks in the U.S. If
successful, EPA's ongoing research to reduce indoor
radon to below 2 pCi/L could result in the prevention of
up to 3,100 radon-induced lung cancer deaths annually.2
AEERL's research objectives are supported by the
Indoor Radon Abatement Act7 which states, "The
national long-term goal of the United States with respect
to radon is that the air within buildings should be as free
of radon as the ambient air outside of buildings."
OS
CD
O
c
n)
O
O)
100
80
60
40
20
5 0
AEERL Research Target
(to 0.4 pCi/L, National
Ambient Average)
CD
EC
0.4 4 5 10 15 20 25
Radon Concentration to Which Levels Are Reduced (pCi/L)
Note: The fan electricity and heating/cooling loss cost ranges are based on
assumptions for climate, house size, and fuel costs.
Figure 6 Reducing Radon Levels to Ambient (0.4 pCi/L) Will
Avoid Approximately 78% of the Radon-Induced Lung
Cancer Deaths
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Environmental Protection
Ongoing and planned research includes:
Continued development and demonstration of
innovative, low-cost radon mitigation techniques for
buildings with radon levels in the 1 to 4 pd/L range.
Development of radon diagnostic and mitigation
protocols for large buildings to reduce costs and provide
technologies that are unique to large buildings.
Technical support of building standards and codes
for radon-resistant new construction. The emphasis of
this research is on low cost passive systems in homes
that are easy for builders to install.
Development of American Society of Testing and
Materials (ASTM) guidance for construction of radon
resistant schools and other large buildings based on an
AEERL technical guidance manual.
AEERL Radon Publications
AEERL's technical guidance represents state-of-the-art
technology in radon mitigation and radon prevention.
ERA'S Center for Environmental Research Information
(CERI) has published and distributed over 150,000
copies of AEERL's eight technical guidance manuals on
radon mitigation and prevention. AEERL has also
prepared 42 technical reports and three editions of a
homeowner's guide to radon reduction, distributed over
25,000 copies of four radon mitigation research newslet-
ters, and sponsored four international symposia on
radon and radon reduction techniques. This information
is used by the radon mitigation industry, builders, school
facility personnel, architects, engineers, homeowners,
and federal, state, and local governments throughout
the U.S. and internationally.
Key publications from EPA/AEERL's Radon Mitigation
Branch include:
> Radon Reduction Techniques for Existing Detached
Houses, Technical Guidance (Third Edition) for Active
Soil Depressurization Systems (EPA/625/R-93/011,
October 1993)
> Radon Mitigation Research Updates (EPA/600/N-93/
013, August 1993; EPA/600/N-92/009, June 1992; EPA/
600/9-91/038, November 1991; EPA/600/9-91/005,
March 1991; EPA/600/9-90/048, December 1990)
> Radon Prevention in the Design and Construction of
Schools and Other Large Buildings (EPA/625/R-92/016,
January 1993)
> Radon Resistant Construction Techniques for New
Residential Construction-Technical Guidance (EPA/625/
2-91-032, February 1991)
> Radon Reduction Techniques in Schools-Interim
Technical Guidance (EPA/520/1-89/020, NTIS PB 90-
160086, 1989)
> Application of Radon Reduction Methods (Revised)
(EPA/625/5-88-024, NTIS PB 89-205975, 1989)
Publications with NTIS numbers are available (prepaid)
from the National Technical Information Service at: 5285
Port Royal Rd., Springfield, VA 22161; 703-487-4650 or
800-553-6847.
For more information contact:
U.S. Environmental Protection Agency
Tim Dyess
Radon Mitigation Branch (MD-54)
Air & Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 27711
phone: 919-541-0688; fax: 919-541-2157
References
1 Conference of Radiation Control Program Directors
Inc., Radon Bulletin, Vol. 3, No. 3, Spring 1993.
2 Marcinowski, F. and Napolitano, S., Reducing the
Risks From Radon, Journal of the Air & Waste Manage-
ment Association, Vol. 43, pp. 955-962, July 1993.
3 U.S. EPA, A Citizen's Guide to Radon (Second Edi-
tion), EPA-402-K92-001, May 1992.
4 U.S. EPA, Reducing Risk: Setting Priorities and
Strategies for Environmental Protection, SAB-EC-90-
021, September 1990.
5 U.S. EPA, Consumers Guide to Randon Reduction,
EPA-402-K92-003, August 1992.
6 Puskin, J. and Nelson, C., "EPA's Perspective on Risks
From Residential Radon Exposure," Journal of the Air
and Waste Management Association, Vol. 39,
pp. 915-920, July 1989.
7 U.S. EPA, Indoor Radon Abatement Act, October 28,
1988. Title III of the Toxic Substances Control Act 15
U.S.C. 2661-2671 .
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Floor
Chicago, IL 60604-3590
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