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Radiation Measurements 46 (2011) 1803e1806

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Radiation Measurements

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Assessment of seasonal indoor radon concentration in dwellings of WesternHaryana

Rohit Mehra a,*, Komal Badhan a, Sandeep Kansal b, R.G. Sonkawade c

aDepartment of Physics, Dr. B.R.Ambedkar National Institute of Technology, Jalandhar 144011, IndiabDepartment of Physics, Giani Zail Singh Institute of Engineering and Technology, Bathinda, IndiacBabasaheb Bhimrao Ambedkar University, Lucknow

a r t i c l e i n f o

Article history:Received 9 November 2010Received in revised form17 June 2011Accepted 20 June 2011

Keywords:Indoor radonLR-115 plastic track detectorEtchingOptical microscope

* Corresponding author. Tel.: þ91 988853459.E-mail address: rohit_mimit@rediffmail.com (R. M

1350-4487/$ e see front matter � 2011 Elsevier Ltd.doi:10.1016/j.radmeas.2011.06.059

a b s t r a c t

Naturally occurring radon 222Rn in indoor air is a significant cause of lung cancer and the houses are animportant exposure location due to the large proportion of time spent at home. The indoor radonmeasurements have been carried out in some of the dwellings belonging to different villages of Fatehbadand Hisar districts of Western Haryana. LR-115 Type II plastic track detectors in bare mode were used forthe measurement of indoor radon concentration for over a period of one year. The calculated annualaverage indoor radon concentration values vary from 126.3 Bq m�3 to 172.1 Bq m�3 with an averagevalue of 145.21 Bq m�3, which is less than the recommended action level (200e300 Bq m�3). The valuesof annual effective dose vary from 2.16 mSv to 2.94 mSv which is less than the lower limit of the rec-ommended action level (3e10 mSv). The measured values of lifetime fatality risk vary from 1.67 to 2.27with an average value of 1.92. The winter to summer ratio calculated for the studied dwellings rangesfrom 0.86 to 2.15 with an average of 1.46. The results indicate that the indoor radon concentration ishigher in winter season than in the summer season. An attempt has also been made to find a correlationbetween the ventilation conditions and the measured values of indoor radon concentration. In most ofthe cases the radon values are less in well ventilated houses than partially/poorly ventilated houses. Themeasured indoor radon concentration values for the studied area are on the higher side than the worldaverage of 40 Bq m�3.

� 2011 Elsevier Ltd. All rights reserved.

1. Introduction

Radon is one of the most extensively investigated humancarcinogens. Radon and its progeny in the air contribute to humanexposure from natural radiation sources (UNSCEAR, 2000). Radonhas been the subject of much controversy in regard to its potentialfor radiological impact on homes and buildings. The alpha emittedby this gas and other radiation emitted by its daughters increase theabsorbed dose in respiratory and digestion systems. Since we spendsomuch of our time indoors, indoor air is the predominant source forexposure to pollutants. More than half of the body’s intake airbornematerial during a lifetime is air inhaled in the home. Thus mostillness related to environmental exposures stem from indoor airexposure (Sharma and Virk, 2001). In general, residential radon isregulated by an action level of radon concentration between 200 and

ehra).

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300 Bq m�3 based on ICRP recommendations (ICRP, 2009). In recentyears, an increase in lung cancer risk has been observed even withexposure levels below 200 Bq m�3. Therefore, the importance of theaccurate evaluation of radon concentration and exposure has beenrecognised again. In the past decades, systematic radon surveys indwellings were carried out all the world, but Westran Haryanadistrict of India has not been studied for environmental radon so far.Therefore, the present survey has been carried out first time in thestudy area, in order to assess the health risks due to radon and itsprogeny. The houses are chosen in such a manner that the dwellingsconstructed with different types of building materials and indifferent localities of the towns/villages are covered.

2. Experimental procedure

Now days, numerous methods are used for measuring radon andits progeny in dwellings. For the present study we have employedSolid State Nuclear Track Detector (SSNTD) passive technique, whichis most reliable technique for the integrated and long term moni-toring of radon (Singh et al., 2001; Ramola et al., 1998; Mehra et al.,

Table

1Th

eav

erag

eindoo

rradon

leve

lsreco

rded

invilla

gesof

thestudyarea

.

Sr.N

oSa

mple

location

(Villag

e)

No.

ofdwellin

gsstudied

Rad

onco

ncentration

(Bqm

�3)in

winter

(DeceFe

b)

Rad

onco

ncentration

(Bqm

�3)in

spring

(MareMay

)

Rad

onco

ncentration

(Bqm

�3)in

summer

(Junee

Aug)

Rad

onco

ncentration

(Bqm

�3)in

Autumn

(Sep

eNov

)

Ave

rage

Annual

Rad

onco

ncentration

(Bqm

�3)

LifeTime

Fatality

Risk�

10�4

Ave

rage

Annual

Dose

(mSv

)

Max

.Min.

Ave

rage

value�

S.D.

Max

.Min.

Ave

rage

value�

S.D.

Max

.Min.

Ave

rage

value�

S.D.

Max

.Min.

Ave

rage

value�

S.D.

1Ratiya

521

116

518

5.6�

9.82

194

143

173.2�

19.66

9879

88.6

�8.20

171

111

143�

9.44

147.6

1.95

2.52

2Bah

man

wala

518

711

214

6.8�

27.74

187

153

170.2�

15.74

113

7899

�13

.86

152

107

129.4�

19.73

136.35

1.8

2.33

3Fa

tehab

ad5

178

117

146.6�

25.68

155

101

132.2�

20.09

154

100

132.8�

20.03

148

7611

2.2�

28.05

130.95

1.73

2.24

4Jakh

al5

201

143

176.6�

24.55

201

157

173.8�

16.45

199

143

174.8�

20.70

127

9011

0.4�

16.10

158.9

2.1

2.71

5To

han

a5

212

167

189�

17.93

169

141

157.6�

11.50

170

151

163�

8.22

142

116

127.2�

12.76

159.2

2.1

2.72

6Hisar

515

611

313

2.8�

18.02

177

109

134.8�

26.81

154

111

127.4�

17.52

123

8011

0.2�

17.15

126.3

1.67

2.16

7Han

si5

198

153

175.4�

18.45

142

8011

3.8�

25.95

145

103

122.4�

16.43

154

9813

3.4�

21.03

136.25

1.8

2.33

8Agroh

a5

204

167

184.4�

14.72

123

9810

9.4�

9.07

138

107

121.8�

12.87

168

123

148.6�

21.41

141.05

1.86

2.41

9Masudpur

519

914

317

2.2�

22.73

154

123

136.8�

12.99

157

123

142�

13.73

132

111

122.6�

8.44

143.4

1.89

2.45

10Adam

pur

524

520

022

4.4�

19.01

154

111

127.8�

17.03

187

145

168.2�

17.46

198

145

168�

23.07

172.1

2.27

2.94

R. Mehra et al. / Radiation Measurements 46 (2011) 1803e18061804

2009). LR-115 Type II plastic track detector which mainly detects thealpha particles having energy ranging from 1.7 to 4.8 MeVwere usedfor the present study. The detector films of size 1.5 cm� 1.5 cmweresuspended for a period of one year, in bare mode in the dwellings ata height more than 2m above the ground level and about 1 m belowthe ceilings and away form thewalls so that the direct alpha particlesfrom the buildingmaterial of the dwellings do not reach the detectorfilms. Our assumptions for the present study are that a room witha door without window is poorly ventilated, that with one door andonewindowas partially ventilated andwithmore than twowindowsand a door as well ventilated. The detectors were removed andetched using 2.5 N NaOH solution at 60 �C for 90 min. The tracksdensity was counted using an optical microscope at 400� magnifi-cation. The radon concentrationwas calculated from track density inunits Bq m�3 using a calibration constant 0.02 tracks cm�2 day-�1 ¼ 50 Bq m�3 (Eappen et al., 2001).

3. Results and discussion

The measurements for indoor radon concentration levels weremade in 50 dwellings of different ventilation conditions throughoutthe year, covering all the four seasons: winter, spring, autumn andsummer. The results of these measurements are shown in Table 1.The calculations for annual effective dose and mean lifetime fatilityrisk have been made using the conversion factors given elsewhere(Raghavaya, 1994). ICRP assumes 80% occupancy (7000 h/yr) indoorand an equilibrium factor F ¼ 0.4 for dwellings. The conversionfactors of 3 � 10�4 WLM�1 and 3.88 mSv WLM�1 (ICRP, 1993) havebeen used for the calculation of lifetime fatility risk and the annualeffective dose, respectively. The highest average indoor radonconcentration value 172.1 Bqm�3(Adampur) and the lowest averageindoor radon concentrationvalue126.3Bqm�3 (Hisar)was recorded.The winter/summer ratio of the radon concentration has beencomputed for all the dwellings (Table 2). Thewinter/summer ratio ofindoor radon ranges from from0.86 to 2.15with an average of 1.46. Ingeneral radon concentration values recorded for different dwellingsduring winter season are on the higher side than those reported forsummer season for the same dwellings for the present study area.This is because the doors and windows of the dwellings remainclosedmostof the times inwinter comparedwith summerandhencethe ventilation is poor in winter. A similar type of trend has alreadybeen reported for the dwellings of Malwa region of Punjab (Singhet al., 2005). Fig. 1 represents frequency distribution of annualaverage radon concentration among all the dwellings in 10 selectedvillages/towns in the study area. From Table 2 it has been observedthat in general the radon concentration is low for well ventilateddwellings as compared to poorly ventilated dwellings. This isbecause inwell ventilated dwellings the radon can easily escape outand hence does not accumulate inside so the radon level insidebecomes lower in well ventilated houses in comparison to poorlyventilated houses. The calculated value of annual average indoorradon value in the study areas are higher than those reported forindoor radon in dwellings of Malwa region of Punjab by Singh et al.(2005) .The present annual average indoor radon value are higher incomparison to those annual average indoor radonvalues reported forthe some areas of Sirsa district of Haryana byMehra et al. (2009). Themeasured values of radon concentrations are on the lower side thanthose reported for some areas of Himachal Pradesh (Singh et al.,2004). A recent analysis of European case control studies carriedout by (Darby et al., 2005) suggests the increased risk of lung cancerof 8% (3%e16%) per 100 Bq m�2 of radon concentration which isconsistent with that of 11% (0%e28%) found in a recent combinedanalysis of North American studies by (Krewski et al., 2005). Afterdetailed stratification for smoking, it is concluded that there wasstrong evidence of an association between the radon concentration

Fig. 1. Frequency distribution of annual average radon concentration among variousdwellings.

Table

2Indoo

rradon

concentrations(Bqm

�3)duringwinter&su

mmer

season

sfordifferentdwellin

gsof

thestudyarea

.

Sample

location

Ven

tilation

condition

Winter/Su

mmer

Ratio

Ven

tilation

condition

Winter/Su

mmer

Ratio

Ven

tilation

condition

Winter/Su

mmer

Ratio

Ven

tilation

condition

Winter/Su

mmer

Ratio

Ven

tilation

condition

Winter/Su

mmer

Ratio

Dwellin

g-1

Dwellin

g-2

Dwellin

g-3

Dwellin

g-4

Dwellin

g-5

Ratiya

Poorly

Ven

tilated

2.15

Poorly

Ven

tilated

2.09

Poorly

Ven

tilated

2.01

Poorly

Ven

tilated

2.06

Poorly

Ven

tilated

2.15

Bah

man

wala

Poorly

Ven

tilated

1.65

Partially

Ven

tilated

1.44

Partially

Ven

tilated

1.22

Poorly

Ven

tilated

1.59

Poorly

Ven

tilated

1.51

Fatehab

adW

ellV

entilated

1.16

WellVen

tilated

1.17

WellVen

tilated

1.08

WellV

entilated

0.91

Partially

Ven

tilated

1.21

Jakh

alW

ellV

entilated

1.01

WellVen

tilated

1W

ellVen

tilated

1.1

WellV

entilated

0.86

WellVen

tilated

1.08

Tohan

aPa

rtially

Ven

tilated

1.25

WellVen

tilated

1.11

WellVen

tilated

1.05

WellV

entilated

1.13

Partially

Ven

tilated

1.26

Hisar

WellV

entilated

1.01

WellVen

tilated

1.02

WellVen

tilated

1W

ellV

entilated

0.97

WellVen

tilated

1.23

Han

siPa

rtially

Ven

tilated

1.37

Partially

Ven

tilated

1.49

Partially

Ven

tilated

1.42

Partially

Ven

tilated

1.5

Partially

Ven

tilated

1.42

Agroh

aPa

rtially

Ven

tilated

1.48

Partially

Ven

tilated

1.56

Partially

Ven

tilated

1.54

WellV

entilated

1.55

Partially

Ven

tilated

1.46

Masudpur

WellV

entilated

1.27

Partially

Ven

tilated

1.16

Partially

Ven

tilated

1.16

Partially

Ven

tilated

1.23

WellVen

tilated

1.22

Adam

pur

Partially

Ven

tilated

1.31

Partially

Ven

tilated

1.38

WellVen

tilated

1.23

Partially

Ven

tilated

1.25

Poorly

Ven

tilated

1.54

R. Mehra et al. / Radiation Measurements 46 (2011) 1803e1806 1805

at home and lung cancer. The study by (Darby et al., 2005) revealsthat the radon doseeresponse relation is linear with no thresholdlimited to the individuals from homes with measured radon<200 Bq m�2. Hence, exposure to radon dose even below the rec-ommended action levels also lead to health effects. The presentcalculated values for annual effective dose for study area vary from2.16mSv to 2.94mSvwith an average value of 2.48mSvwhich is lessthan even the lower limit of the suggested action level (3e10 mSv)but at the same time the calculated value for annual effective dose isabout the double of the accepted value of 1.3 mSv per year only forthe internal dose. Thehigh value for annual effective internal dosemight be due to the poor ventilation conditions of the dwellings, useof building materials in construction of houses that are rich inradioactivity and the rate of emanation of radon beneath the soil.Also the most of the houses in the study areawere constructed frommud, soil and other rawmaterials viz. somekind offibrous or organicmaterial (sticks, straw, dung). But a detailed investigation is requiredto reach a final conclusion. The measured values of lifetime fatalityrisk vary from 1.67 to 2.27 with an average value of 1.92.

4. Conclusions

The results of the present study provide a database on indoorradon level in Westran Haryana, India. The annual average indoorradon concentration values measured in Westran Haryana variesfrom 126.3 Bq m�3 to 172.1 Bq m�3 which is higher than the worldaverage of 40 Bq m�3 however these values are below the recom-mended action level (200e300 Bq m�3). The peak values for radonmeasurements were observed in the winter season, since thehouses are kept closed and finally the radon level observed in caseof poorly ventilated houses was higher than that observed in othertypes of houses. The present values for average annual effectivedose ranged from 2.16 mSv to 2.94 mSv with an average value of2.48 mSv which is more than the value (1.30 mSv) due to theexposure to radon (UNSCEAR, 1993) but on the lower side of therecommended action level (3e10 mSv) and hence will pose noneserious health risk.

Acknowledgements

The authors are thankful to the residents of the study area fortheir kind cooperation during the field work. Also the authors are

R. Mehra et al. / Radiation Measurements 46 (2011) 1803e18061806

thankful to the laboratory staff of NIT, Jalandhar, India for theirsupport in accomplishing the work.

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