改水与儿童健康:基于中国农村的实证研究

Water Quality Improvement and Child Health in Rural China:An Empirical Study in Rural China

安全饮用水的普及对儿童的健康成长及缓解地区间健康不平等至关重要。自20世纪80年代以来我国在农村地区开展了大规模的改水项目,但鲜有研究评估该项目对儿童健康的长期影响。本文在回顾我国改水项目的发展历程的基础上,采用CHNS 1991年至2011年的纵向追踪数据,首先使用固定效应回归模型对改水项目的长期健康效益进行估计,再进一步分母亲受教育程度与家庭收入对不同样本进行回归,探究改水项目对不同群体长期影响的异质性。此外,为解决家庭改水与儿童健康间的内生性问题,本文还利用工具变量法对模型结果进行稳健性检验。研究发现:调查对象中使用室内自来水的比例从1991年到2011年增长近一倍。从长期来看,改水可以有效提高儿童年龄别身高Z评分(HAZ)。母亲受教育程度较高、家庭收入较低的儿童更能从改水项目中受益,经工具变量法进行估计结果较为稳健。本研究为改水项目对健康的积极影响提供了实证支持,研究结果表明改水项目有助于促进儿童的长期健康且对低收入人口更具积极作用,因此应进一步加大对改水项目的投入。另一方面,为使改水项目产生更大的社会效益,应重视农村女性的教育,加强健康知识的普及。

The access to safe water is essential to the child health and poverty alleviation.To evaluate the impact of the prevalent water quality improvement program in rural China from 1980s’,this paper first sys⁃tematically reviews the literature about the implementation and development of the program.Then using the panel data of CHNS from 1991 to 2011,it estimates the health outcomes by employing the method of fixed effect regression.Meanwhile,given the heterogeneity of the rural population,we further investigate how mother’s literacy and household income moderate the health benefits of the water improvement program.The method of instrumental variable estimation is also employed to strengthen the robustness of the out⁃comes.The results imply that the children from the households with in-house tap water have higher height for age Z score(HAZ)than their counterparts.In particularly,children whose mother has higher education attainment and those from low-income family would benefit the most from the water quality improvement program.The majorities of the estimates are stable across the robustness checks.The findings have signifi⁃cant policy implication.The positive relationship between the water improvement program and child health along with the benefit for the low-income households suggests that investment should be increased to fur⁃ther improve safe water facilities in rural areas.In addition,the positive impact of the water improvement program will be multiplied through increasing the literacy of women and promoting the health education.