Zhang Guoxing, Chen Zhanglei, Li Jiexun, Su Bin, Gao Yang, Yu Lean
School of Management, Lanzhou University, Lanzhou 730000, China.
Department of Decision Sciences, Western Washington University, Bellingham, WA 98225, USA.
PNAS Nexus. 2024 May 17;3(5):pgae199. doi: 10.1093/pnasnexus/pgae199. eCollection 2024 May.
Air pollution control in the United States has evolved into a comprehensive policy system spanning from the federal to the state level over time. A unified quantitative analysis of policy intensity can shed light on the policy evolution across different levels, the influence of partisan and regional factors on policy, and the relationships with emissions of major pollutants. By harnessing the policy text of the Clean Air Act (CAA) at the federal level and State Implementation Plans (SIPs) at the state governments (1955-2020), we deployed a Natural Language Processing approach to define a policy intensity index to systematically quantify the US air policy landscape. Our findings highlight that the 1970 CAA amendment carries the most vigorous intensity as it established a holistic control system for the first time. Subsequent years witnessed a general trend of partisan polarization, eventually leading to a graduate convergence between red and blue states. Blue states demonstrated a closer alignment with federal directives and a superior efficacy in pollutant reduction. Regionally, the Northeast displays the highest overall policy intensity, and the West exhibits the highest coordination with the federal benchmarks, making these regions outperform others in air pollution control. Our study not only discusses policy implications for air pollutant reductions considering partisan and regional differences but also provides a novel measurement tool to quantify policies for assessing disparities and synergies.
随着时间的推移，美国的空气污染控制已发展成为一个从联邦到州层面的全面政策体系。对政策强度进行统一的定量分析，可以揭示不同层面的政策演变、党派和地区因素对政策的影响，以及与主要污染物排放的关系。通过利用联邦层面的《清洁空气法》（CAA）和州政府的《州实施计划》（SIPs）（1955 - 2020年）的政策文本，我们采用自然语言处理方法定义了一个政策强度指数，以系统地量化美国的空气政策格局。我们的研究结果表明，1970年的《清洁空气法》修正案强度最大，因为它首次建立了一个整体控制系统。随后几年呈现出党派两极分化的总体趋势，最终导致红州和蓝州逐渐趋同。蓝州与联邦指令的一致性更高，在污染物减排方面效果更佳。在地区上，东北部的总体政策强度最高，西部与联邦基准的协调性最高，使得这些地区在空气污染控制方面优于其他地区。我们的研究不仅讨论了考虑党派和地区差异的空气污染减排政策含义，还提供了一种新颖的测量工具来量化政策，以评估差异和协同效应。
