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Research Article | | Peer-Reviewed

Calibration of LR-115 Type II SSNTDs and Indoor Radon-222 Assessment in Man, Côte d'Ivoire

Gnionnihindjoue Romaric Nonka*,  Aka Antonin Koua,  N’guessan Guy Leopold Oka
Published in American Journal of Physics and Applications (Volume 14, Issue 1)
Received: 26 November 2025     Accepted: 14 January 2026     Published: 27 January 2026
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Abstract

This study focused on the calibration of LR-115 type II solid-state nuclear track detectors (SSNTDs) and the assessment of indoor radon-222 concentrations in dwellings in Man, Côte d’Ivoire. Detector calibration was performed in a certified radon chamber by exposing the LR-115 to a radon concentration of 2.29 kBq·m⁻3 for 64.33 h. After chemical etching and microscopic analysis, a calibration factor of 198.35 ± 21.43 tr/cm2/kBq·m-3·h was obtained. Twenty-six detectors were then deployed in dwellings for three months. Radon concentrations ranged from 52.13 to 219.4 Bq/m3, with an average of 119.69 ± 13.36 Bq/m3 (120 Bq.m-3). Most measured values were below internationally recommended reference levels; however, several sites (M1, M6, M9, M14 and M18) exceeded 150 Bq·m-3. Apart from geological factors, elevated concentrations were mainly associated with poor ventilation and low foundation height. Excess cancer risk (ECR), estimated using EPA and UNSCEAR coefficients, showed significant spatial variability. According to the EPA model, ECR values ranged from 32 to 98 for site M19 and from 134 to 410 for site M14, while UNSCEAR-based estimates ranged from 41 to 111 at M19 and from 174 to 469 at M14. Corresponding annual effective doses varied between 2.09 and 8.81 mSv·y-1. These findings highlight the spatial variability of indoor radon concentrations linked to local geology and building characteristics, and provide essential baseline data for radon mapping and risk mitigation strategies in Côte d’Ivoire. The results support targeted ventilation improvements and foundation design considerations within existing housing stock without altering measured.

Published in American Journal of Physics and Applications (Volume 14, Issue 1)
DOI 10.11648/j.ajpa.20261401.11
Page(s) 1-11
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2026. Published by Science Publishing Group
Previous article
Keywords

Radon-222, WHO, SSNTD LR-115, Effective Dose, Man City, Lung Cancer

1. Introduction
Radon is a naturally occurring radioactive gas, colourless and odourless, produced by the decay of uranium and thorium contained in the Earth’s crust. It represents the leading source of ionising radiation exposure for the general population
[1, 2]
. Since 1987, the International Agency for Research on Cancer (IARC) classified radon as a human lung carcinogen, following several epidemiological studies conducted among uranium and coal miners
[3]
. Its health impact depends mainly on the geological characteristics of the soil and on the presence of its most significant isotope, radon-222.
In Côte d’Ivoire, several studies reported noteworthy concentrations in specific localities
[4, 5]
. The city of Man (Côte d’Ivoire), underlain by a basement composed of slightly uraniferous granites and gneisses
[6]
, is therefore considered as an area with a high radon exhalation potential. The aim of the present study was to assess radon concentrations in this city using Solid State Nuclear Track Detectors (SSNTDs), and to estimate the resulting effective dose. Prior calibration of the SSNTDs was a crucial step, as it enables the conversion of track-density measurements into radon volumetric activities
[4]
.
These data will contribute to the establishment of an essential baseline for the development of a national radon map for Côte d’Ivoire.
2. Materials and Methods
2.1. Determination of the Calibration Factor
The calibration of solid-state nuclear track detectors (SSNTDs) represents a fundamental step in establishing the quantitative correlation between the number of recorded interactions and the effective radon activity, particularly with respect to its volumetric concentration
[7]
. This process enables the conversion of observed track densities into precise activity values, thereby ensuring the accuracy, reliability, and reproducibility of the measurements.
The calibration procedure consisted of two stages: LR-115 SSNTDs were first irradiated at the Radiation Dosimetry Laboratory of the Nuclear Research Center of Algiers (CRNA), then chemically etched at Felix Houphouet-Boigny University in Côte d’Ivoire. This dual approach, combining controlled irradiation with chemical development, provides a robust calibration of the detectors, allowing the acquisition of quantitative data of high relevance for assessing radon volumetric activity in diverse environments.
The experimental calibration setup developed at the Nuclear Research Center of Algiers (Algeria) consists of a standard radon source (Figure 1), a hermetically sealed cylindrical stainless-steel vessel with a volume of 101.1 liters, an electronic pump, and an active AlphaGUARD detector. The AlphaGUARD detector, coupled to a radium source enclosed within the sealed vessel, enables reliable, continuous, and precise measurement of radon concentration through alpha-particle detection, facilitated by controlled air sampling and electronic data processing. The standard source (SRM 4973), certified by NIST, contains Ra-226 with an activity of 449 ± 6 Bq and a radon-222 emanation fraction of 0.88 ± 0.01 at 21°C. Five non-strippable LR-115 film of 3 cm × 2 cm size were exposed inside the calibration chamber to an average radon concentration of 2.29 kBq/m3 for 64.33 hours.
The detectors were then etched in 2.5 N NaOH solution for 120 minutes at a constant temperature of 60°C
[4].
At the end of this period, each detector was removed and rinsed with tap water for 2 minutes, followed by a 2 minutes’ rinse with distilled water. The detectors were then air-dried. Two control detectors, which had not been exposed, underwent the same steps in order to evaluate the background.
The counting of alpha tracks recorded by LR-115 detectors were carried out using an optical microscope.
Figure 1. Experimental Setup. Experimental Setup.
The calibration factor is calculated using the following formula
[4-8]
by comparing the track density observed on the detector with the known radon concentration in the chamber.
k=ρ-ρ0C.t(1)
where
k is the calibration factor (tr/cm2/kBq/m3h);
ρ is the trace density read (tr/cm2);
ρ₀ is the background (tr/cm2);
C is the radon concentration (kBq.m-3);
and t is the exposure duration of the SSNTDs (Solid State Nuclear Track Detectors) (h).
2.2. Presentation of the City of Man
Man is a city located in the western part of Côte d’Ivoire, approximately 600 km from Abidjan, and serves as the capital of the Tonkpi region. According to the December 2021 census, the city of Man has a population of 241,969 inhabitants, comprising 127,234 men and 114,735 women
[9].
Most dwellings in the surveyed areas were bricks houses with partial ventilation. These houses were constructed using cement and sand bricks as building materials. In the majority of cases, roofs were made of corrugated iron sheets, while some are built of brick, positioned at a height of approximately 2.5 to 4 meters above ground level. Each house consists of rooms with adjoining walls, and some older dwellings were built of clay. The city lies on Archean formations characterized by intense metamorphism. These formations contain granitoids and uraniferous gneisses of low grade
[6]
, yet sufficient to generate radon, particularly in fracture zones.
2.3. Location of Measurement Sites and Setup Preparation
The measurement points were selected in the most densely populated parts of the city. Their positioning was determined using a Global Positioning System (GPS). The experimental device was prepared in the Nuclear Physics and Radioprotection laboratory at Felix Houphouet-Boigny University. It consisted of a non-strippable LR-115 II pre-cut films of 3 cm × 2 cm size inserted into a hermetically sealed cup equipped with a selective membrane. The sealed cup was specifically designed to allow radon gas to diffuse through the selective membrane while effectively retaining solid progeny. These detectors were purchased with ALGADE, in France.
Figure 2. Photo of the Detector in its closed cup mode, in "off" and "on" states. Photo of the Detector in its closed cup mode, in "off" and "on" states.
In total, 26 dwellings in the city were examined for the study between February 12, 2021, and May 14, 2021, corresponding to an exposure period of three months. In parallel, two (02) unexposed detectors were used to evaluate the background. Each device was affixed to a wall at approximately 1.5 meters above the ground using an adhesive strip, with care taken to avoid openings (doors, windows) as well as sources of heat. The installation was carried out with recording of the date and time. At the end of the exposure period, the detectors were removed and the retrieval date and time was documented.
3. Results
3.1. Results of the Calibration Factor
The trace densities measured, along with the associated calibration factors, obtained from the five exposed films, are presented in the Table 1 below. The arithmetic mean is 198.35 ± 21.43 tr/cm2/kBq.m-3.h. This value was used for evaluation radon concentration measure in the dwelling.
Table 1. Average tracks densities read by the microscope and Average Calibration Factors.

Track density (tr/cm2)

Calibration factor (tr/cm2/kBq.m-3.h)

29,100.00 ± 492.00

197.53 ± 21.00

30,391.66 ± 503.25

206.30 ± 22.26

28,033.00 ± 483.00

190.29 ± 21.00

29,225.00 ± 493.49

198.38 ± 21.39

29,350.24 ± 494.55

199.23 ± 21.49

kmoyen

198.35 ± 21.43
Our value is consistent with that determined by AGBA in the same laboratory
[4]
in 2015.
3.2. Measurement of Radon Concentration
The radon concentration, expressed as volumetric activity, was determined according to the following equation:
C=ρ-ρ0k.t(2)
Where C represents the radon concentration (kBq.m-3),
k represents the calibration factor (tr/cm2/kBq/m3h),
t is the exposure duration (h),
and ρ0 corresponds to the background.
The radon measurements in the various studied sites reveal concentrations ranging from 52.13 ± 6.31 Bq/m3 to 219.4 ± 24.59 Bq/m3. Site M14 exhibited the highest concentration, while M19 recorded the lowest concentration. The average radon concentration in the dwellings was 119.69 ± 13.36 Bq/m3.
These results take into account factors such as the exposure period, foundation height, condition of the dwellings, and duration of exposure.
Table 2. Radon concentrations and corresponding effective doses received in the homes of the Man sites.

Foundation height (cm)

Ventilation condition

Radon Concentration (Bq/m3)

Dose Effective (mSv/y)

M1

40

N.V

171.51 ± 18.92

6.89 ± 0.76

M2

40

N.V

93.23 ± 10.46

3.74 ± 0.42

M3

20

N.V

73.12 ± 8.11

2.94 ± 0.33

M4

80

V

129.34 ± 12.15

5.19 ± 0.49

M5

30

V

146.47 ± 16.06

5.88 ± 0.65

M6

30

N.V

189.34 ± 20.78

7.60 ± 0.83

M7

20

V

101.77 ± 11.25

4.09 ± 0.45

M8

30

N.V

161.97 ± 17.89

6.51 ± 0.72

M9

35

N.V

168.83 ± 18.63

6.78 ± 0.75

M10

50

V

102.18 ± 11.74

4.10 ± 0.47

M11

20

V

96.11 ± 10.68

3.86 ± 0.43

M12

40

V

131.81 ± 14.83

5.29 ± 0.60

M13

40

N.V

92.58 ± 10.36

3.72 ± 0.42

M14

20

N.V

219.4 ± 24.59

8.81 ± 0.99

M15

30

N.V

69.24 ± 8.37

2.78 ± 0.34

M16

10

N.V

121.8 ± 13.43

4.89 ± 0.54

M17

10

V

91.5 ± 10.58

3.68 ± 0.42

M18

50

N.V

194.99 ± 21.95

7.83 ± 0.88

M19

80

V

52.13 ± 6.31

2.09 ± 0.25

M20

40

N.V

73.47 ± 8.12

2.95 ± 0.33

M21

50

N.V

68.03 ± 7.67

2.73 ± 0.31

M22

60

N.V

147.72 ± 16.26

5.93 ± 0.65

M23

30

V

85.56 ± 9.52

3.44 ± 0.38

M24

40

N.V

181.64 ± 19.92

7.30 ± 0.80

M25

60

V

58.39 ± 6.56

2.35 ± 0.26

M26

50

N.2V

87.98 ± 9.93

3.53 ± 0.40

Average

119.69 ± 13.36

4.81 ± 0.54
Figure 3. Radon concentration in the city of Man. Radon concentration in the city of Man.
Figure 4. Distribution of radon concentration (Bq/m3) in dwellings of city of Man.
Figure 5. Frequency of radon concentration in homes at Man sites.
Figure 6. Effective dose (mSv/y) according to measurement sites. Effective dose (mSv/y) according to measurement sites.
The theoretical calculation of the excess risk of lung cancer (ECR) is determined by the following formula:
ECR = 0,4 x 0,8 x RiskFactor x WLM(3)
In this formula, 0.4 represents the equilibrium factor and 0.8 the occupancy factor.
In practice, the excess risk of lung cancer per million people per year, as a function of radon concentration in residential settings, is obtained using Figure 7. This calculation is based on risk estimates derived from studies of miners, which have been extrapolated to the general population
[10].
According to ICRP 65, the radiological risk is 8×10-5per mJ·h·m-3, i.e., about 7×10-5per mSv for home (domestic) exposure. ICRP 65 also recommends, for calculations, assuming an annual residence time of 7,000 hours at home and 2,000 hours in the workplace
[11].
The results of our measurements are presented in Table 3.
Figure 7. Determination of the excess lung cancer risk (ECR) as a function of radon concentration
[12].
Determination of the excess lung cancer risk (ECR) as a function of radon concentration
[12].
Table 3. Values of ECR and radiological risk at the measurement sites in the city of Man. Values of ECR and radiological risk at the measurement sites in the city of Man. Values of ECR and radiological risk at the measurement sites in the city of Man.

Sites

Radon Concentration (Bq/m3)

Radiological risk

ECR

EPA

UNSCEAR

M1

171.51 ± 18.92

(5.32 ± 0.53)10-4

105 - 328

137 - 374

M2

93.23 ± 10.46

(2.62 ± 0.29)10-4

57 - 182

74 - 207

M3

73.12 ± 8.11

(2.06 ±0.23)10-4

45 - 137

58 - 156

M4

129.34 ± 12.15

(3.64 ± 0.34)10-4

80 - 245

104 - 280

M5

146.47 ± 16.06

(4.12 ±0.45)10-4

89 - 274

116 - 313

M6

189.34 ± 20.78

(5.32 ±0.53)10-4

116 - 354

150 - 405

M7

101.77 ± 11.25

(2.86 ± 0.31)10-4

62 - 190

81 - 217

M8

161.97 ± 17.89

(4.55 ± 0.50)10-4

99 - 303

128 - 346

M9

168.83 ± 18.63

(4.75 ±0.52)10-4

103 - 316

134 - 361

M10

102.18 ± 11.74

(2.87 ±0.33)10-4

62 - 191

81 - 218

M11

96.11 ± 10.68

(2.70 ±0.30)10-4

59 - 180

76 - 205

M12

131.81 ± 14.83

(3.71 ± 0.41)10-4

81 - 247

105 - 282

M13

92.58 ± 10.36

(2.60 ± 0.29)10-4

57 - 173

73 - 198

M14

219.4 ± 24.59

(6.17 ± 0.69)10-4

134 - 410

174 - 469

M15

69.24 ± 8.37

(1.95 ± 0.35)10-4

42 - 130

55 - 148

M16

121.8 ± 13.43

(3.42 ± 0.38)10-4

74 - 228

97 - 260

M17

91.5 ± 10.58

(2.57 ±0.30)10-4

56 - 171

73 - 196

M18

194.99 ± 21.95

(5.48 ± 0.61)10-4

119 - 365

155 - 417

M19

52.13 ± 6.31

(1.47 ± 0.18)10-4

32 - 98

41 - 111

M20

73.47 ± 8.12

(2.07 ± 0.23)10-4

45 - 137

58 - 157

M21

68.03 ± 7.67

(1.91 ± 0.22)10-4

42 - 127

54 - 145

M22

147.72 ± 16.26

(4.15 ± 0.46)10-4

90 - 276

117 - 316

M23

85.56 ± 9.52

(2.41 ± 0.27)10-4

52 - 160

68 - 183

M24

181.64 ± 19.92

(5.11 ± 0.56)10-4

111 - 340

144 - 388

M25

58.39 ± 6.56

(1.64 ± 0.18)10-4

36 - 109

46 - 125

M26

87.98 ± 9.93

(2.47 ± 0.28)10-4

54 - 165

70 - 188

Average

73-224

95-256
3.3. Evaluation of Effective Dose and Radiological Health Risk
The dose coefficients recommended by the ICRP have evolved with advances in dosimetry and epidemiological research. In 1993, the ICRP recommended 1.4 mSv/mJ·h·m-3 for workers and 1.1 mSv/mJ·h·m-3 for the public. However, Publication No. 115 in 2000 doubled the estimate for the risk of lung cancer, while Publication No. 137 in 2017 raised the dose coefficient to 3 mSv/mJ·h·m-3 for both workers and the public, with a coefficient of 6 mSv/mJ·h·m-3 for specific situations. The Potential Alpha Energy (PAE) and the equilibrium factor (F) are essential parameters for assessing the biological risks of radon and its progeny. The Effective Dose (nSv) can be calculated using the following formula:
PAE=5,56C×F.
D=0,86x3xPAExt
D = 0,86x3x5,56xCxFxt(4)
Where:
D is the effective dose (nSv)
PAE is the radon exposure level (nJ/m3)
t is the time an adult spends on average in the building or workplace during exposure (h)
0.86 m3/h is the standard inhalation rate for an adult
F is the radon equilibrium factor in buildings (0.4)
The radiological risk according to the ICRP 65 is 8 × 10-5 per mJhm-3, or approximately 7 × 10-5 per mSv at home.
4. Discussions
The results obtained in the Table 2 show significant variations in radon concentrations from one site to another. The radon concentration level for dwellings varies from (52.13 ± 6.31) Bq/m3 to (219.4 ± 24.59) with an average of (119.62 ± 13.27) Bq/m3 (about 120 Bq/m3). The variation in the values of indoor radon concentrations may be due to the local geology, different ventilation conditions and the use of such building materials.
These values are crucial for assessing radiological risk in each area, as radon is a radioactive gas known for its harmful effects on health, particularly as a major risk factor for lung cancer. Figure 5 represents the frequency distribution of the radon concentration levels among the 26 dwellings of the study area. The radon concentration activity values fall in the ranges 0 -100, 101 -150; 151 - 200 and 201 – 300 Bq/m3 in 46.15 %, 26.92 %, 23.08 % and 3.85 % of the houses.
The effective dose, which quantifies the impact of radon in terms of radiation on health, also varies depending on the observed concentrations. For example, M14 shows the highest effective dose of (8.81 ± 0.99) mSv, correlated with its maximum radon concentration of (219.4 ± 24.59) Bq/m3. Conversely, M19 displays the lowest effective dose at (2.09 ± 0.25) mSv/y, corresponding to its lower concentration of (52.13 ± 6.31) Bq/m3. These results clearly illustrate the linear relationship between radon concentration and radiation exposure, highlighting the importance of continuous monitoring to reduce health risks for exposed populations. The annual inhalation dose due to radon was found to vary from 2.09 to 8.81 mSv/y with an average of 4,81 mSv/y. These differences clearly reveal that areas with high radon concentrations, such as M14, present a significantly higher risk of excess lung cancer.
The measured values in different cities, such as Bingerville and Treichville, show notable similarities in terms of construction materials, as well as similar lifestyles within their populations. The highest radon concentrations are observed in poorly ventilated homes, particularly in rooms located on the ground floor or those with doors and windows that remain frequently closed. As for the measured radon levels, they generally remain below the limits recommended by internationally recognized institutions, such as Canada, WHO, ICRP, EPA, and the EU, except for the city of Boundiali, where the concentration reaches 333 Bq/m3. However, it should be noted that the concentration measured in San-Pedro exceeds the limit set by the EPA, and that of Boundiali exceeds the thresholds of all the aforementioned organizations, which warrants special attention for this city
[4]
.
The cities of Boundiali and Aboisso present geological factors that promote radon emission, such as the nature of the bedrock and proximity to faults. Dimbokro, on the other hand, is situated in a basin and is subdivided into two geological domains: volcano-sedimentary and granitogneissic.
Table 4. Comparison of Radon Concentration Limit Values.

Agencies/Countries

Radon concentration limits in the dwellings (Bq /m3)

Canada

200

WHO

From 100 to 300, with an average value of 200

ICPR 103

300

EPA (USA)

150

Europ Union (EU)

200

Our results

120

Average value mesured in Yopougon

[5
]

93

Average value mesured in Abobo

[
13]

113

Average value mesured in Boundiali

[4
]

333

Average value mesured in Aboisso

[4
]

144

Average value mesured in Dimbokro

[4
]

87

Average value mesured in San-Pedro

[
14]

169

Average value mesured in Treichville

[
15]

139
The histogram (Figure 8) of radon concentrations measured in selected Ivorian towns shows a right-skewed distribution. Most of the monitored locations display values ranging from 87 to 170 Bq/m3, whereas Boundiali stands out with a markedly higher concentration (333 Bq/m3). This extreme value inflates the mean and widens the overall dispersion, an effect consistent with the local geological substrate, characterised by bands of schists, migmatites, and plutonic rocks
[4]
.
Figure 8. Histogram of radon concentrations in selected cities in Côte d’Ivoire. Histogram of radon concentrations in selected cities in Côte d’Ivoire.
Table5. Characteristics of the studies included.
 [16].

Author

Year

Country

Measurement period (days)

No. of dwellings

Average radon concentration (Bq/m3)

Mosupya and al

2019

South Africa

90

5

105

90

7

41

Kgabi and al

2009

South Africa

21

1

1115.92

25

1

1704.22

Ndjana and al

2019

Cameroon

90

26

134

90

20

131

Opoku-Ntim and al

2019

Ghana

180

40

101.35

Our results

2025

Côte d’Ivoire

90

26

120
Indoor radon concentrations measured in dwellings located near gold mine tailings in several African countries are comparable to those recorded in the city of Man (Côte d’Ivoire). However, the values reported in the locality of Botshabelo (South Africa) are markedly higher
[16]
.
The excess cancer risks (ECR) calculated using the EPA and UNSCEAR coefficients highlight significant differences between the sites studied. For the EPA model, values range from 32 to 98 at M19 and from 134 to 410 at M14. According to UNSCEAR, they vary from 41 to 111 at M19 and from 174 to 469 at M14. These results confirm that higher radon concentrations are associated with increased radiological risk, in line with the findings reported in numerous studies on radon in residential environments. The use of EPA and UNSCEAR models therefore provides a reliable basis for guiding public policies on radon management and public health protection.
Finally, it should be noted that while the average radon concentration remains generally below reference levels, the risk estimated using the EPA model exceeds the recommended limit, which warrants particular attention.
The results stress the need for increased vigilance and preventive actions to reduce radon exposure, particularly in high-risk areas such as M14. Dwellings with inadequate ventilation exhibit markedly higher radon concentrations.
5. Conclusion
The results of the present study provide a database on indoor radon level in the city of Man. In this study, we determined the calibration factor of LR-115 type Solid-State Nuclear Track Detectors (SSNTDs), a necessary preliminary step for obtaining a reliable estimate of indoor radon activity concentration. The method is based on the recording, by the SSNTDs, of tracks produced by alpha particles emitted during radon decay. Measurements conducted in the city of Man indicate an average concentration of 120 Bq/m3. Although this value remains generally below internationally recommended reference levels, enhanced vigilance is required for certain dwellings where concentrations reach or exceed 150 Bq/m3, particularly at sites M1, M6, M8, M9, M14, and M18. The effective dose values range from 2.09 to 8.81 mSv/y, with an average of 4.81 mSv/y. This study highlights the need for continuous monitoring of radon concentrations in certain households in the city of Man, due to the occasionally elevated levels observed. The recommended measures include improving ventilation, strengthening building airtightness, and using materials with low radon permeability. The use of active detectors is also considered relevant to ensure regular and reliable monitoring of concentration variations. Finally, raising awareness among local authorities and providing training for building professionals are essential levers to enhance the effectiveness of radon-risk reduction measures.
Abbreviations

ARSN

Radiation Protection, Nuclear Safety and Security

IARC

International Agency for Research on Cancer

ICRP

International Commission on Radiological Protection

IREN

Institute for New Energies Research

LASMES

Laboratory for Matter, Environmental and Solar Energy Sciences

LR-115

Lexan Resin 115

M

Man (city)

Max

Maximum

Min

Minimum

mSv

Millisevert

NaOH

Sodium Hydroxide

NIS

National Institute of Statistics

NV

Not Ventilated

PAE

Potential Alpha Energy

Rn-222

Radon-222

SSNTD

Solid-State Nuclear Track Detectors

UFHB

University Felix Houphouet Boigny

UNA

University Nangui Abrogoua

V

Ventilated

WHO

World Health Organization
Acknowledgments
We would like to express our heartfelt gratitude to our colleagues at LASMES of the Felix Houphouet-Boigny University for their invaluable support and continuous collaboration, which have been key to the success of this article, especially to the head of the nuclear physics research team.
Author Contributions
Gnionnihindjoue Romaric Nonka: Conceptualization, Data curation, Formal Analysis, Funding acquisition, Methodology, Supervision, Validation, Visualization, Writing – original draft, Writing – rewiew & editing
Aka Antonin Koua: Conceptualization, Methodology, Supervision, Validation, Visualization, Writing – rewiew & editing
N’guessan Guy Leopold Oka: Conceptualization, Methodology, Supervision, Visualization, Validation, Writing – rewiew & editing
Conflicts of Interest
The authors declare no conflicts of interest.
References
[1] WHO (World Health Organization), (2009). "Radon and health”.

https://www.who.int/news-room/fact-sheets/detail/radon-and-health

[2] IRSN, Radon: Properties, Sources, and Hazards, 2022.
[3] International Agency for Research on Cancer (IARC), Monographs on the evaluation of carcinogenic Risks to Humans, Vol 43, Man-made Mineral Fibres and radon (1988).

https://publications.iarc.who.int/61

[4] D. S. I Agba, Measurements of radon volumetric activity using LR 115 solid-state nuclear track detectors in the cities of Boundiali, Aboisso, and Dimbokro. Doctoral thesis in Physics, Felix Houphouet-Boigny University of Cocody, (Côte d’Ivoire) (2017).
[5] G. R. Nonka, T. P.A. Dali, A. A. Koua, B. D.L. H. Gogon, G. A. Monnehan, K. Djagouri, Dosimetric impact of indoor radon gas on the population from the commune of Yopougon, Abidjan, Côte d’Ivoire. Journal of Radiation Research and Applied Sciences 10 (2017) 295-300.
[6] Yapo Assi Martial, Geophysical and Geotechnical Characterization of Potential Granite Rock Quarry Sites in the Ivorian Birimian: A 3D Modeling Attempt, Felix Houphouet-Boigny University, 2024. Français.NNT: 2024ICME2782.
[7] Turtiainen, T., Laine, J.-P., Rantanen, S., & Oinas, T. Nonlinear Calibration and Temperature Sensitivity of Makrofol Solid-State Nuclear Track Detectors for Radon Measurement. Atmosphere, 15(10), 1179 (2024).

https://doi.org/10.3390/atmos15101179

[8] Rutherford, E. (1908). "The existence of an element with radioactive properties." Nature, 81(2105), 140-141.
[9] National Institute of Statistics (NIS), RGPH 2021, Global results.

www.plan.gouv.ci/assets/fichier/RGPH2021-RESULTATS-GLOBAUX-VF.pdf

[10] Smith, D., Jones, A., & Roberts, M. (2003). Estimates of lung cancer risk in miners and their extrapolation to the general population. Environmental Health Perspectives, 111(12), 1483-1490.
[11] ICRP, 1993. Protection against radon-222 at home and at work. ICRP Pubtication 65. Ann ICRP 23(2).
[12] A. A. Matiullah, S. Rehmahn, and M. L. Mirza, Indoor radon levels and lung cancer risk estimates in seven cities of the Bahawalpure Division, Pakistan Radiation Protection Dosimetry, 107 (2003), P269-276.
[13] K. J. F. N’Guessan et al; Indoor Radon Measurement and Excess Lung Cancer Rick. Evaluation in the District of Abidjan: The Case of the Commune of Abobo (Côte d’Ivoire); Int. j. Pure Appl.Sci.Technol., pp. 46-56(2016).
[14] KINI Alla (2017), Seasonal Variation Study of Indoor Radon Concentration in Dwellings in the City of San Pedro Master’s Program in Physics at Félix Houphouet Boigny University, Abidjan, specialization: Nuclear Science and Technology.
[15] Kouakou Kouassi Jeremie (2022), Assessment of Radon Concentration in Residential Buildings of Treichville Municipality, Master’s Program in Physics at Félix Houphouet Boigny University, Abidjan, specialization: Nuclear Science and Technology.
[16] Phoka C. Rathebe, Lerato Khosi & Mota Kholopo (2025) Indoor Concentration of Radon in Residential Houses Proximal to Gold Mine Tailings – A Review of Sub-Saharan Africa Studies, Environmental Forensics, 26:3, 368-379,

https://doi.org/10.1080/15275922.2024.2431325

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    Nonka, G. R., Koua, A. A., Oka, N. G. L. (2026). Calibration of LR-115 Type II SSNTDs and Indoor Radon-222 Assessment in Man, Côte d'Ivoire. American Journal of Physics and Applications, 14(1), 1-11. https://doi.org/10.11648/j.ajpa.20261401.11

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    ACS Style

    Nonka, G. R.; Koua, A. A.; Oka, N. G. L. Calibration of LR-115 Type II SSNTDs and Indoor Radon-222 Assessment in Man, Côte d'Ivoire. Am. J. Phys. Appl. 2026, 14(1), 1-11. doi: 10.11648/j.ajpa.20261401.11

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    AMA Style

    Nonka GR, Koua AA, Oka NGL. Calibration of LR-115 Type II SSNTDs and Indoor Radon-222 Assessment in Man, Côte d'Ivoire. Am J Phys Appl. 2026;14(1):1-11. doi: 10.11648/j.ajpa.20261401.11

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  • @article{10.11648/j.ajpa.20261401.11,
  author = {Gnionnihindjoue Romaric Nonka and Aka Antonin Koua and N’guessan Guy Leopold Oka},
  title = {Calibration of LR-115 Type II SSNTDs and Indoor Radon-222 Assessment in Man, Côte d'Ivoire},
  journal = {American Journal of Physics and Applications},
  volume = {14},
  number = {1},
  pages = {1-11},
  doi = {10.11648/j.ajpa.20261401.11},
  url = {https://doi.org/10.11648/j.ajpa.20261401.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajpa.20261401.11},
  abstract = {This study focused on the calibration of LR-115 type II solid-state nuclear track detectors (SSNTDs) and the assessment of indoor radon-222 concentrations in dwellings in Man, Côte d’Ivoire. Detector calibration was performed in a certified radon chamber by exposing the LR-115 to a radon concentration of 2.29 kBq·m⁻3 for 64.33 h. After chemical etching and microscopic analysis, a calibration factor of 198.35 ± 21.43 tr/cm2/kBq·m-3·h was obtained. Twenty-six detectors were then deployed in dwellings for three months. Radon concentrations ranged from 52.13 to 219.4 Bq/m3, with an average of 119.69 ± 13.36 Bq/m3 (120 Bq.m-3). Most measured values were below internationally recommended reference levels; however, several sites (M1, M6, M9, M14 and M18) exceeded 150 Bq·m-3. Apart from geological factors, elevated concentrations were mainly associated with poor ventilation and low foundation height. Excess cancer risk (ECR), estimated using EPA and UNSCEAR coefficients, showed significant spatial variability. According to the EPA model, ECR values ranged from 32 to 98 for site M19 and from 134 to 410 for site M14, while UNSCEAR-based estimates ranged from 41 to 111 at M19 and from 174 to 469 at M14. Corresponding annual effective doses varied between 2.09 and 8.81 mSv·y-1. These findings highlight the spatial variability of indoor radon concentrations linked to local geology and building characteristics, and provide essential baseline data for radon mapping and risk mitigation strategies in Côte d’Ivoire. The results support targeted ventilation improvements and foundation design considerations within existing housing stock without altering measured.},
 year = {2026}
}

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  • TY  - JOUR
T1  - Calibration of LR-115 Type II SSNTDs and Indoor Radon-222 Assessment in Man, Côte d'Ivoire
AU  - Gnionnihindjoue Romaric Nonka
AU  - Aka Antonin Koua
AU  - N’guessan Guy Leopold Oka
Y1  - 2026/01/27
PY  - 2026
N1  - https://doi.org/10.11648/j.ajpa.20261401.11
DO  - 10.11648/j.ajpa.20261401.11
T2  - American Journal of Physics and Applications
JF  - American Journal of Physics and Applications
JO  - American Journal of Physics and Applications
SP  - 1
EP  - 11
PB  - Science Publishing Group
SN  - 2330-4308
UR  - https://doi.org/10.11648/j.ajpa.20261401.11
AB  - This study focused on the calibration of LR-115 type II solid-state nuclear track detectors (SSNTDs) and the assessment of indoor radon-222 concentrations in dwellings in Man, Côte d’Ivoire. Detector calibration was performed in a certified radon chamber by exposing the LR-115 to a radon concentration of 2.29 kBq·m⁻3 for 64.33 h. After chemical etching and microscopic analysis, a calibration factor of 198.35 ± 21.43 tr/cm2/kBq·m-3·h was obtained. Twenty-six detectors were then deployed in dwellings for three months. Radon concentrations ranged from 52.13 to 219.4 Bq/m3, with an average of 119.69 ± 13.36 Bq/m3 (120 Bq.m-3). Most measured values were below internationally recommended reference levels; however, several sites (M1, M6, M9, M14 and M18) exceeded 150 Bq·m-3. Apart from geological factors, elevated concentrations were mainly associated with poor ventilation and low foundation height. Excess cancer risk (ECR), estimated using EPA and UNSCEAR coefficients, showed significant spatial variability. According to the EPA model, ECR values ranged from 32 to 98 for site M19 and from 134 to 410 for site M14, while UNSCEAR-based estimates ranged from 41 to 111 at M19 and from 174 to 469 at M14. Corresponding annual effective doses varied between 2.09 and 8.81 mSv·y-1. These findings highlight the spatial variability of indoor radon concentrations linked to local geology and building characteristics, and provide essential baseline data for radon mapping and risk mitigation strategies in Côte d’Ivoire. The results support targeted ventilation improvements and foundation design considerations within existing housing stock without altering measured.
VL  - 14
IS  - 1
ER  -

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Author Information

  • Gnionnihindjoue Romaric Nonka

    Laboratory for Matter, Environmental and Solar Energy Sciences (LASMES), Felix Houphouet Boigny University (UFHB), Abidjan, Côte d'Ivoire

    Biography: Gnionnihindjoue Romaric Nonka is a Nuclear Physicist and Expert in the implementation of Nuclear Safety measures, responsible for Nuclear Protection, Safety, and Security at the Authority for Radiological Protection, Safety, and Security (ARSN). Currently, I am pursuing a PhD at the Laboratory for Matter, Environmental, and Solar Energy Sciences (LASMES) at Felix Houphouet-Boigny University (UFHB) in Abidjan, Côte d’Ivoire.

    Research Fields: Study of radon concentrations in the air of dwellings, Radioecology, Optimization of nuclear security measures for Major Public Events.

    Contact Email

    http://orcid.org/0000-0002-4629-7220

  • Aka Antonin Koua

    Laboratory for Matter, Environmental and Solar Energy Sciences (LASMES), Felix Houphouet Boigny University (UFHB), Abidjan, Côte d'Ivoire;Radiation Protection, Nuclear Safety and Security Authority (ARSN), Abidjan, Côte d'Ivoire

    Biography: Aka Antonin Koua is a Full Professor specializing in nuclear physics and radiation protection at the Felix Houphouet Boigny university of Cocody in abidjan, côte d'ivoire. He is the director of radiation protection at the radiation protection authority for nuclear safety and security in côte d'ivoire. He has published several scientific articles in several journals in the field of nuclear physics.

    Research Fields: Evaluation of the Radiological quality of some foods consumed and NOMRs management in Côte d’Ivoire, Study of optimization of doses.

    Contact Email

    http://orcid.org/0009-0002-3791-8352

  • N’guessan Guy Leopold Oka

    Research Institute for New Energies (IREN), Nangui Abrogoua University (UNA), Abidjan, Côte d'Ivoire;Radiation Protection, Nuclear Safety and Security Authority (ARSN), Abidjan, Côte d'Ivoire

    Biography: N’guessan Guy Leopold Oka is a nuclear physicist and a Qualified Expert in Radiation Protection. He is currently the Deputy Director of Nuclear Safety and Security of the Radiation Protection, Nuclear Safety and Security Authority (ARSN, Regulatory Body for Nuclear Safety and Security of Côte d'Ivoire) and Sworn Inspector of ARSN. He is also a Research Associate at the Laboratory of Nuclear Energy and Radiation Protection of the Institute for Research on New Energies of the University of Nangui-Abrogoua. He was Head of Radiation Protection Services at the Sub-Directorate of Protection against Ionizing Radiation (SDPRI) of the National Public Health Laboratory (LNSP) from 2002 to 2008 and then Manager of the "Radiation Protection and Environment Consulting"

    Research Fields: Evaluation of the Radiological quality of some foods and drinking waters consumed in Côte d’Ivoire, Study of optimization of doses, Optimization of nuclear security measures for Major Public Events.

    Contact Email

    http://orcid.org/0009-0003-9087-9820

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