环境健康价值评估中的年龄效应研究

Study on the Age Effects on Environmental Health Valuation

在环境健康价值评估研究中,统计寿命价值和年龄之间的关系是理论和实证研究焦点之一,也是重要的学术问题。长久以来,环境政策效益评估中是否应该赋予老年人较低的统计寿命价值一直存在广泛争议,且尚未得到一致性结论。通过设计选择实验,对北京市空气质量改善的健康效益进行了抽样调查,并采用MNL模型对北京市约500个居民的调查数据进行回归分析,估算了不同年龄人群对健康风险减少的支付意愿,针对中国人群中统计寿命价值和年龄之间的关系进行实证探讨。结果表明:一方面,在总体样本中设置年龄虚拟变量,回归结果表明年龄变量系数的符号均显著为负,即年龄因素对减少空气污染带来的死亡风险降低的支付意愿具有显著的影响,年龄越大支付意愿相对越小;另一方面,不同年龄人群分组样本结果显示,统计寿命价值与年龄之间呈现"倒U型"关系,统计寿命价值在中国存在"老年折扣"现象。研究结果可为我国环境政策的健康效益分析中如何考虑年龄的影响提供重要依据。

The relationship between the value of statistical life （VSL） and age is one of the important academic issues in the theoretical and empirical studies of environmental health valuation. For several decades, proposals to apply lower value of statistical life for older adults have drawn attention to the benefit analysis of environmental policies, which is widely and controversially debated with no unanimous consensus. Based on the health benefit of air quality improvement in Beijing, is estiwated an in -person survey of 500 residents is conducted with the choice experiment method, and the willingness to pay for health risk reduction using the MNL model. Thus, an empirical study focusing on the relationship of the VSL and age in Chinese context can be analyzed in this paper. Using the age dummy in the total sample modeling, it is fourd that the coefficients of age variable are significantly negative, indicating that age is one of the dominant factors of the willingness to pay for air - related mortality reduction and the elderly are less willing to pay. Further analyzing the willingness to pay of the age - group subsamples, an inverted U shape relationship is found between the VSL and age, showing the evidence of ＂senior discount＂ phenomenon of VSL in Chinese context. The results provide important information on how to consider the age effect on the health benefit analysis of environmental policies in China.