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気候変動リスク情報創生プログラム（創生D)

ラオス・ベトナムにおける 上下水道サービスのWTPとVSL

大野栄治（名城大学 教授） 森杉雅史（名城大学 教授） 大西暁生（東京都市大学 准教授）

RECCA-S8-創生D 研究交流会 日程：2013年9月3日

場所：RESTEC

Mekong River

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Current Situation of Mekong River • The water level of Mekong River is lowering. • The United Nations has announced that the amount of water

intake of Asia will increase 24% in these 15 years, and that industrialization makes people of 1.1 billion inaccessible to secure water resource.

• What is the cause? ⇒ drastic economic development? ⇒ global climate change? ⇒ dams construction?

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Extreme Climate Change

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Huge Dams Construction

http://www.japanfocus.org/-Michael-Richardson/3210

Quality of Water and Life • Water quality becomes worse. • WHO (2004) reported that, in developing countries, - 1.8 million people died of diarrhea, and - about 90% of which is caused by polluted water. • People in the developing countries need to have access to good

quality water in sufficient quantity, water purification technology and availability and distribution systems for water.

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Some Fundamental Statistics (2008)

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Source: WHO (2010)

Member state Population (2010 for Japan, 2008 for others)

Gross national income per

capita (2008, PPP $)

Access to improved

drinking-water sources

(%)

Access to improved sanitation

(%)

Japan 128,056,000 34,115 100 100

China 1,345,751,000 5,962 89 55

Cambodia 14,805,000 2,066 61 29

Laos 6,320,000 2,204 57 53

Myanmar 50,020,000 1,159 71 81

Thailand 66,405,000 8,100 98 96

Vietnam 87,375,000 2,783 94 75

Mortality Risk by Each Specific Cause

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Source: WHO (2004) and Ohno et.al. (2009)

Cause-specific mortality Average of 6 countries on the

basin of Mekong River

Japan

Cardiovascular diseases 330/100,000 12/100,000

Cancer 127/100,000 250/100,000

Digestive diseases 41/100,000 15/100,000

Diarrheal diseases 36/100,000 0.51/100,000

HIV / AIDS 38/100,000 0.04/100,000

Road traffic accidents 21/100,000 9/100,000

Self-inflicted injuries 13/100,000 24/100,000

Violence and war 13/100,000 0.52/100,000

Objective of Study • Implementation of water supply and sewage systems is the

most effective for reduction of diarrhea mortality risk due to water pollution, especially for these countries.

• Our fundamental questions are as; - can sufficient benefits be obtained to cover the full cost? - can residents pay themselves for the full cost without ODA? • The cost benefit analysis of the implementation must be

carried out. • Therefore …

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Aim of Study

• To provide basic data for the cost benefit analysis of countermeasures against diarrheal diseases in Laos and Vietnam.

• To estimate WTP-function, as the function of

mortality risk reduction level, by using CVM. • To measure VSL concerning diarrhea mortality

risk by using WTP-function.

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Interview Survey • 2,825 samples were got

around Vientiane City in Laos, 2011.

• 1,000 samples were got

around Ho-Chi-Minh City in Vietnam, 2010.

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Basic Statistics of Respondents in Laos

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Sex Proportion Age Proportion Annual

income

Proportion

male 60.0% under 19 1.7% under 99$ 5.1%

female 40.0% 20-29 33.7% 100-299$ 8.4%

total 100.0% 30-39 29.5% 300-499$ 9.2%

40-49 22.0% 500-999$ 18.3%

50-59 10.3% 1,000-1,499$ 22.2%

over 60 2.8% 1,500-1,999$ 13.5%

total 100.0% 2,000-2,999$ 11.0%

over 3,000$ 12.3%

total 100.0%

Basic Statistics of Respondents in Vietnam

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Sex Proportion Age Proportion Annual

income

Proportion

male 53.3% under 19 0.3% under 99$ 1.5%

female 46.7% 20-29 15.2% 100-299$ 0.9%

total 100.0% 30-39 28.5% 300-499$ 3.2%

40-49 30.8% 500-999$ 13.5%

50-59 19.4% 1,000-1,499$ 27.5%

over 60 5.8% 1,500-1,999$ 23.7%

total 100.0% 2,000-2,999$ 22.9%

over 3,000$ 6.8%

total 100.0%

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Main Questionnaire Sheet of CV-survey ■Your death risk from diarrhea or diseases of the

various digestive organs will be 100/100,000 in a year without the service described above.

■Your death risk from diarrhea or diseases of the various digestive organs will be X/100,000 in a year with the service described above.

(1) When the annual fee of the service is 1 dollar, 1. You will receive the services. 2. You will not receive the services. (2) When the annual fee of the service is 3 dollars, 1. You will receive the services. 2. You will not receive the services. (3) When the annual fee of the service is 5 dollars, 1. You will receive the services. 2. You will not receive the services. …… and so on.

Death Risk is the number of people who has been died by diarrhea every 100,000 population annually. Water Service supplies safer water and decreases the death risk. With the service, the death risk is changed as; case1) X=80, 60 (for 1st , 2nd) case2) X=80, 40 case3) X=60, 20 case4) X=40, 20 case5) X=60, 80 case6) X=40, 80 case7) X=20, 60 case8) X=20, 40

Evaluation Model (logit model based on random utility theory)

Choice probability: , , Utility function: , where : suggested annual fee to buy the water service, : unknown parameters.

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[ ]VPyes ∆−+

=exp1

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[ ]tbaVVV noyes ln⋅+=−=∆

yesno PP −=1

tba,

WTP and WTP-function

Willingness to pay: , WTP-function: , where : reduction level of mortality risk, : unknown parameters.

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−=

baWTPmedian exp

[ ]rWTP ∆⋅+= lnβα

r∆βα ,

Estimated WTP-function in Laos

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Estimated WTP-function in Vietnam

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Δr 0

WTP

・

・ WTP1

WTP2

Δr1 Δr2

WTP-function

1VSL

2VSL

rWTPVSL ∆≡ /

Definition of VSL

Measured Values of WTP and VSL in Laos

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Δr

[per year]

WTP

[US$ per year]

VSL

[US$]

20/100,000 9.580 47,898

40/100,000 11.131 27,827

60/100,000 12.038 20,064

80/100,000 12.682 15,853

Measured Values of WTP and VSL in Vietnam

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Δr

[per year]

WTP

[US$ per year]

VSL

[US$]

20/100,000 41.932 209,660

40/100,000 47.256 118,141

60/100,000 50.371 83,952

80/100,000 52.581 65,726

List of Precedent Studies on VSL

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Researchers (year) Subject (method) VSL estimates Yamamoto et.al. (1994) Water pollution (CVM) 21.69-34.38 mil. US$

Imanaga (2001) Traffic accident (CVM) 3.75 mil. US$ Takeuchi et.al. (2001) Traffic accident (CVM) 1.63 mil. US$ Matsuoka et.al. (2002) Air pollution (CVM) 3.14-4.32 mil. US$

Imanaga (2003) Air pollution (CVM) 1.20 mil. US$ Kabutoyama et.al. (2003) Traffic accident (Standard Gamble) 1.28 mil. US$

Matsuoka et.al. (2003) Air pollution (CVM) 4.59 mil. US$ Furukawa et.al. (2004) Traffic accident (Wage Risk) 7.23-9.06 mil. US$

Kei et.al. (2004) Traffic accident (CVM) 2.44 mil. US$ Koshi (2004) Traffic accident (CVM) 12.82 mil. US$

Itaoka et.al. (2005) Traffic accident (CVM) 0.93-3.15 mil. US$ MLIT of Japan (2005) Traffic accident (CVM) 1.44 mil. US$

Tsuge et.al. (2005) Traffic accident (CVM) 3.15 mil. US$ Kashima (2006) Traffic accident (CVM) 8.18 mil. US$

Cabinet office of Japan (2007) Traffic accident (CVM) 1.90 mil. US$ Ohno et.al. (2009) Heat stroke (CVM) 0.95-1.12 mil. US$ Okuyama (2009） Marine accident (CVM) 0.57-1.03 mil. US$

Maeno (2010） Industrial accident (Wage Risk) 45.71-91.43 mil. US$ Miyasato (2010） Industrial accident (Wage Risk) 9.23-24.10 mil. US$

Concluding Remarks • The resident’s WTP-function for each reduction level

of mortality risk has been derived. • It has been indicated that the VSL varies according to

reduction level of mortality risk; 15,853 - 47,898 US$ in Laos and 65,726 - 209,660 US$ in Vietnam.

• By comparison with GDP per capita, these VSLs are

about 14 (7 - 22) times in Laos and about 49 (24 - 75) times in Vietnam.

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Thank you