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2nd International Conference on the Sources, Effects and Risks of Ionizing Radiation (SERIR2) &
14th Biennial Conference of the South Pacific Environmental Radioactivity Association
35
Mapping of Indoor Radon Concentration in Houses Located
in South Sulawesi Province
Wahyudi, Kusdiana and Dadong Iskandar
Center for Technology of Radiation Safety and Metrology,National Nuclear Energy Agency of Indonesia
Jl. Lebak Bulus Raya No. 49 Jakarta Selatan, 12440 Indonesia, E-mail : wah_yudi@batan.go.id
Abstract. Mapping indoor radon concentrations in South Sulawesi Province by using a passive method had been
conducted. In this research, the area under study was divided into several sections (grid). Each grid represents a 40km x
40km area that there will be installed passive radon monitoring at 6-10 population dependent response. Of 144 indoor
passive radon monitor that had been installed for 3-4 months there were 140 pieces (97.22%) were taken back and
further analyzed for radon in the lab for processing, read the track and then the radon concentrations were calculated.
Furthermore, data concentration of radon in the home and GPS location as an input in the manufacture of radon
concentration map using MapInfo Software v.10.5. The results of the analysis of the concentration of radon in houses in
South Sulawesi were in the range of 3.43
0.24 Bq/m3and 69.38
4.91 Bq/m3. These results were lower than those of the
reference level radon set by UNSCEAR (300 Bq/m3). This data is useful in the development plans and regional
development, as well as the basis for health policy analysis due to radon in Indonesia. Furthermore, these data will be
userd for the contribution of Indonesia in the international world through UNSCEAR, IAEA and WHO.
Keywords : concentration, radon indoor, South Sulawesi
Introduction
Radiation and radioactivity in the environment
are described in the map of the natural radioactivity
including dose rate of gamma radiation exposure in
the environment and the concentration of 226Ra,
232Th and 40K on the ground surface, excluding
radon and thoron. Based on the UNSCEAR (United
Nations Scientific Committee on the Effects of
Atomic Radiation) report radiation exposure to
radon in houses is the largest contributor to the
natural radiation exposure that reaches 50%
(UNSCEAR 2010). Exposure to natural radiation is
the largest contributor (up to 85 %) of the total
radiation exposure received by the world's
population (Anonymous 2004). In an effort to
elaborate natural radiation sources in Indonesia to be
characterized its natural sources of radiation it is
necessary to measure the concentration of indoor
radon (222Rn) thoron (220 Rn). Radon and thoron are
natural radioactive substances in the form of gas that
can cause significant radiological problems. Radon
is a short-lived radionuclide that emits alpha particle
and can be attached to small particles in the air and
can be inhaled and can expose lung tissue so that it
can raise the risk of lung cancer. Another isotope of
radon is radon-220 (thoron) that has the same
properties but with a smaller degree of radiation
exposure in the lung. Figure 1 shows the scheme of
radon gas that filled spaces within a building.
Lung cancer due to radon exposure is caused
by inhalation of short-lived radon particulate such as
218Po, 214Pb, 214Bi or 214Po. Inhaled radon decay
products in the room has a particle with diameter of
about 50-200 nm. While the percentage of radio-
activity of 218Po as super fine particles with
nanometer diameter varies between a few percent up
to 50% (Lippmann 2008). In a study that analyzed
data of 400 cases of lung cancer and 400 cases as a
control in New Jersey, it was concluded that the
environmental consequences of radon exposure was
associated with the occurrence of lung cancer
(Lippmann, 2008). Meanwhile, the US National
Research Council (NRC) reported that 10-14% of
deaths or around 10000-14000 people/year was due to
cancer cases that came from exposure to radon in the
environment. Lung cancer due to radon exposure is
caused by inhalation of short-lived radon particulate
such as 218Po, 214Pb, 214Bi or 214Po. Inhaled radon decay
products in the room has a particle with diameter of
about 50-200 nm. While the percentage of radioactivity
of 218Po as super fine particles with nanometer diameter
varies between a few percent up to 50% (Lippmann
2008). In a study that analyzed data of 400 cases of
lung cancer and 400 cases as a control in New Jersey, it
was concluded that the environmental consequences of
radon exposure was associated with the occurrence of
lung cancer (Lippmann 2008). Meanwhile, the US
National Research Council (NRC) reported that 10-
14% of deaths or around 10000-14000 people/year was
due to cancer cases that came from exposure to radon
in the environment.
Figure 1. Scheme of radon emanation in a house where
CR-39 passive indoor radon monitor was
installed in typical Indonesian home.
2nd International Conference on the Sources, Effects and Risks of Ionizing Radiation (SERIR2) &
14th Biennial Conference of the South Pacific Environmental Radioactivity Association
36
Figure 2. Graph of the relationship between the Relative
Risk (RR) with a concentration of radon to 8 cases
of lung cancer (Lippmann 2008).
Radon and thoron are the highest trigger of lung
cancer in the United States based on the report of the
WHO (Anonymous, 2004). Radiological impact on the
society and the environment can be either external or
internal radiation exposure. Potential radiation hazard
can be taken into the body through multiple pathways:
Gamma radiation will give a risk of external
radiation exposure.
Particles/dust are suspended and carried into the
body through the respiratory tract (inhalation), and
have the potential hazards to provide an internal
radiation exposure risk.
Radon Gas (222Rn) and thoron (220Rn) with their
decay are carried into the body through the
respiratory tract (inhalation) and potentially provide
an internal radiation exposure risk.
Due to the potential hazards of exposure from radon, it
is necessary to do the mapping of radon concentration
levels in the South Sulawesi Province that is a part of
the mapping of radon concentration levels in Indonesia.
Research on the indoor radon concentration was done
according to UNSCEAR stating that more than 90% of
the doses were derived from the natural doses radiation
exposure (UNSCEAR 2010). This is the first study in
Indonesia so that the radon concentration data will
give the contribution to the international world through
UNSCEAR, IAEA and WHO. For local government,
this data can be used as a consideration in the regional
development planning.
Figure 3. Map of South Sulawesi with a grid
of 40 km x 40 km
Materials and Methods
Equipment and materials used were GPS
(Global Positioning System), CR-39 detectors which
has been mounted, aluminum ladder, rope, nail and
hammer. Meanwhile, as the supporting materials
were a leaflet and a digital map of the South
Sulawesi with several sections or grids in which 40
km x 40 km per grid.
In this research, the area was divided into
several sections or grids. Each grid represented a
40km x 40km area that was installed a passive radon
monitor at 6-10 population dependent response.
Tracking a passive radon monitors will be installed
based on the grid. The passive radon monitor has
been hung under the roof or ceiling in the room for
3-4 months. Then the detectors were taken and
etched using 6.25 N of NaOH at the temperature of
702 °C in the Memmert oven for 7 hours. These
CR-39 detectors were washed with distilled water in
a Branson ultrasonic vibrator machine for 5 minutes
and then dried in the electric desiccator. After that
the CR-39 detector was placed in a glass object and
then was read the number of alpha particles tracts
using a Nikon microscope with a magnification of
400 times and it was done as many as 25 times
reading the viewpoint.
Figure 4. Foto of track radon read by using a microscope.
The value of the indoor radon concentration
(CRn) depends on the exposure time (T, days) and the
number of track readings (NBand NT) as well as the
calibration factor. Calibration factor depends on the
magnification of observation with the microscope,
and the number of readout standpoints. To make it
easier in calculating the indoor radon concentration
can be used the following equation (Sutarman et al.
2005; Bunawas & Warsona 2001).
TFk
NN
CTB
n
R
Bq/m3
with :
T
N
and
B
N
is the total number of sample and
background tracks (tracks / 5.0625mm2)
Fk is radon calibration factors (0.00241)
Tis exposure times (day)
2nd International Conference on the Sources, Effects and Risks of Ionizing Radiation (SERIR2) &
14th Biennial Conference of the South Pacific Environmental Radioactivity Association
37
Figure 5. The etching process detectors CR-39 by using 6.25 N NaOH at 702 °C in oven for 7 hours.
Based on both radon concentration and GPS data,
maps of radon concentrations was made by using
MapInfo software. To easily see the differences in the
level of radon concentration in the house, the colored
degradation on a digital map was made. The darker
indicates the higher level of the indoor radon
concentration.
Results and Discussion
The passive radon monitoring in the South
Sulawesi was installed in 24 groups of attached detector
mounting locations with 144 pieces in which 140
(97.22%) pieces were taken back and 4 pieces were not
taken or failed. Monitors that could not be taken back
(failed) were due to the house occupants were not in
place at the time of collecting or other reasons such as
breakage detectors due to fall and lost.
Based on data from the number of tracks in CR-39
detector at 25 times reading, it can be determined the value
of the indoor radon concentration. Map of the radon
concentration was made using MapInfo, based on the
indoor radon concentration that were integrated with the
measurement location using GPS coordinates. The indoor
radon concentration in the South Sulawesi is in the ranged
from (3.43±0.24) Bq/m3to (69.38±4.91) Bq/m3with a mean
of (32.69±16.22) Bq/m3. These results are almost the same
as the measurement results performed at the BATAN
Complex in Pasar Jumat, Pasar Minggu and Serpong that
are in the ranged from 5.5 Bq/m3to 55.5 Bq/m3(Affandi et
al. 1996).
The research were done in the another location have
the results that the indoor radon concentration in Rio de
Janeiro City-Brazil were in the range from 5 Bq/m3to 200
Bq/m3(Al-Saleh 2007) and in Riyadh City-Saudi Arabia in
the ranged from 2 Bq/m3to 69 Bg/m3with the average 18.4
Bq/m3(Magalhães et al. 2003). Based on the indoor radon
concentration in Rio and Riyadh City that the concentra-
tions were not much different in the value of the indoor
radon concentration in the South Sulawesi.
Figure 7. Map of the mounting location of passive
radon monitors in South Sulawesi.
Figure 8. Map of the concentration of radon in
South Sulawesi region.
The value of the indoor radon concentration
depends on the geological conditions of measurement
area, type of house, ventilation systems as well as
building materials. For many houses made of brick the
radon concentrations are relatively higher than that made
of boards or the simple house that has a good ventilation
system. In the simple houses the radon concentrations
2nd International Conference on the Sources, Effects and Risks of Ionizing Radiation (SERIR2) &
14th Biennial Conference of the South Pacific Environmental Radioactivity Association
38
are still lower even if the doors and the windows of
these simple houses are closed. This is because in the
simple houses the air exchange can still run well or
good air exchange.
These measurement data resulted from the survey
are then integrated with the GPS to obtain the map of
the radon concentration in the South Sulawesi region
that was part of the map of the radon concentration
through Indonesia archipelago. The result is presented
in Figure 8.
In general the indoor radon concentration data in
the South Sulawesi can be seen in Figure 8 where the
values of about 50 Bq/m3except for Makassar which
has relatively higher radon concentrations. This may be
caused by the fact that the house in Makassar is
permanent type and often relatively closed. The highest
indoor radon measurement data obtained in the South
Sulawesi with the highest population was (69.38 ±
4.91) Bq/m3. This concentration is below the reference
level of radon of 300 Bq/m3as stated by the
International Commission on Radiation Protection
(ICRP) and the International Atomic Energy Agency
(IAEA) (Anony-mous, 2004), so that the results of
these measurements are still below the va lues
recommended by UNSCEAR (UNSCEAR 2010).
Conclusion
From indoor radon concentration measurement
results in the South Sulawesi t hat is in the range from
(3.43±0.24) Bq/m3to (69.38±4.91) Bq/m3with a mean
value of 32.69 Bq/m3, it can be concluded that this data
is still below from the value recommended by
UNSCEAR and ICRP. Data obtained will be used as
an input in making a map of radon concentration in the
South Sulawesi, which is part of the map of radon
concentration in all houses in Indonesia.
Suggestion
The radon research needs to be done because
according to UNSCEAR that more than 90%
acceptance doses of the world's populatio n coming
from exposure to natural radiation. The main cause of
the magnitude of this contribution is the amount of
exposure to radon gas which reaches more than 50%.
Acknowledgements
We thank to the residents living in the selected
houses who helped during the installed and the
collection of the dosimeters and to the Head of the
Centre for Technology of Radiation Safety and
Metrology, the National Nuclear Energy Agency for
Indonesian who has sponsored this research project in
2015.
References
Affandi, M., Iskandar, D. & Bunawas, 1996. Radon in
houses in BATAN Complex. In Proceedings of
Scientific Presentations Radiation and Environ-
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Al-Saleh, F.S., 2007. Measurements of indoor gamma
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Riyadh City, Saudi Arabia. Applied Radiation and
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Anonymous, 2004. Radiation, People and the Environ-
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Bunawas & Warsona, A., 2001. Distribution of radon
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Lippmann, M., 2008. Environmental Toxicants: Human
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