环境税内生假定下合理税率及其动态优化研究—以大气污染物征税为例

Investigating an appropriate environmental tax rate that promotes emissions reduction and social welfare maximization simultaneously is of great significance to achieve the overall goals of China’s environmental tax policy. In this research, we aim to dissect the decision-making process of enterprises’ technology selection in the context of environmental tax implementation as well as the influencing mechanisms of enterprise behaviors on the utilities of consumers, and further probe into the appropriate environmental tax rate along with its dynamic evolvement with an assumption that environmental tax is endogenous. To this end, the internal mechanisms and conditions of environmental taxation encouraging enterprises to adopt pollution-reduction technologies are first studied following the thought of cost-benefit analysis. Then the complicated transmission mechanism of enterprises’ technology selection affecting the utilities of consumers is clearly identified. Subsequently, we deduce a mathematical model to measure the appropriate environmental tax rate, which is assumed to have endogenous relationships with some economic factors such as enterprises’ technology selections and the green preferences of consumers, and then uncover the evolution law of the appropriate environmental tax rate with the changes of these factors. At last, taking the environmental taxation for air pollutants in Hubei province as an example, we simulate the dynamic evolution path of the appropriate environmental tax rate based on a series of deep field surveys. The solutions of these works can not only well extend the theoretical analytical framework for exploring optimal environmental tax rate, but also provide some scientific theoretical foundations for formulating and adjusting the environmental tax rate to local governments.

探析能同时促进污染减排与社会福利最大化的合理环境税率，对保障我国环境税总体目标的顺利实现具有重要意义。本项目深入剖析环境税实施背景下企业技术选择的决策机理，以及该行为决策对消费者效用的影响机制，进而探究环境税内生假定下的合理税率及其动态演化路径。具体来看：首先，遵循成本收益分析思路，构建企业边际减排成本的内生变动模型，探析环境税激励企业减排技术采用的内在机理与发生条件。随后，刻画消费者效用与企业技术选择行为之间的内在关系，识别企业减排技术投资对消费者效用影响的传导机制。在此基础上，构建环境税内生假定下合理税率的数理模型，揭示合理环境税率随企业技术选择行为、消费者绿色偏好等因素变动的演化规律。最后，以湖北省大气污染物征税为例，基于实地调研，模拟其合理环境税率的动态演化路径。上述问题的解决，不仅可拓展最优环境税率研究的理论框架，而且能够为政府部门合理制定与优化调控环境税率提供科学的决策参考。

2018年1月1日我国环境税法正式实施。考虑到各地区在环境承载力、污染物排放状况和经济社会生态发展目标等方面的差异，我国环境税法对各种污染物设定了较大浮动幅度的税额区间。为此，本研究解析了环境税实施后企业技术选择的决策机理，深入剖析企业减排技术投资对消费者效用影响的传导过程，并构建环境税内生假定下合理税率的模型，运用湖北省电力、水泥、钢铁等典型企业调研数据，测算了大气污染物的合理税率，探讨了其动态调整路径。结果发现，湖北省目前针对大气污染物的征税额度相对偏低，大部分企业会选择缴税而非绿色技术改造。在当前技术水平以及消费者绿色偏好水平，二氧化硫和氮氧化物的税率应该分别设定在4.4元/污染当量、4.8元/污染当量，才能够实现有效激励企业进行绿色技术改造并提升消费者福利的目标。从长远来看，在居民收入稳步增长和绿色技术前沿不断取得突破的前提下，2030年左右大气污染物税率达到最大值，12-18元/污染当量；随后，下降至10元/污染当量，并保持相对稳定的水平。截止2022年底，项目组成员基本按照计划完成了项目申报时拟定的目标，并在国内外重要学术期刊上发表论文21篇，相关研究成果已整理成咨询报告供相关部门参考；培养了10名硕士博士研究生，其中7名毕业。