“杀手树”有助于理解氮氧化物预算计划的影响吗？（英）

Isaiah Bryant-Sheth, Sagbo Anicet Hounton, Lala Ma, and Lucija Muehlenbachs About the Authors Isaiah Bryant-Shethis a visiting research fellow at the University of Rochester Healthand Environmental Economics Lab. He studies the health effects of pollution andproviding valuation of their cost as an input into policy as well as policy designed toincrease climate resiliency for coastal communities. Sagbo Anicet Hountonis a PhD student in the Department of Economics at theUniversity of Calgary. He studies environmental economics and developmenteconomics with a particular focus on air pollution and health. Lala Mais an associate professor of economics in the Gatton College of Businessand Economics and holds the Carl F. Pollard Professorship in Health Economics atthe University of Kentucky. Her research focuses on estimating the values placed onenvironmental quality as assessed through housing markets and health impacts. Lucija Muehlenbachsis a professor of economics at the University of Calgary anda university fellow at Resources for the Future (RFF). She has published extensivelyon the oil and gas industry, covering topics such as well reactivation, methane leaks,property value impacts, shale-related traffic accidents, wastewater composition, andeffects on water quality. Acknowledgements We thank Kathy Baylis, Daniel Brent, Maureen Cropper, Emily Pindilli, Dave Evans,Art Fraas, Laura Grant, Alan Krupnick, Yusuke Kuwayama, Corey Lang, Joshua Linn,and Dick Morgenstern for comments and Alan Krupnick for the title. We also thankattendees at the annual meetings of the Association of Environmental and ResourceEconomists and the Southern Economic Association for their helpful comments. We aregrateful for financial support from RFF’s call for Retrospective Studies of RegulatoryPerformance and the University of Kentucky Energy Research Priority Area. About RFF Resources for the Future (RFF) is an independent, nonprofit research institution inWashington, DC. Its mission is to improve environmental, energy, and natural resourcedecisions through impartial economic research and policy engagement. RFF iscommitted to being the most widely trusted source of research insights and policysolutions leading to a healthy environment and a thriving economy. Working papers are research materials circulated by their authors for purposes ofinformation and discussion. They have not necessarily undergone formal peer review.The views expressed here are those of the individual authors and may differ from thoseof other RFF experts, its officers, or its directors. Sharing Our Work Our work is available for sharing and adaptation under an Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) license. Youcan copy and redistribute our material in any medium or format; you must giveappropriate credit, provide a link to the license, and indicate if changes were made,and you may not apply additional restrictions. You may do so in any reasonablemanner, but not in any way that suggests the licensor endorses you or your use.You may not use the material for commercial purposes. If you remix, transform, orbuild upon the material, you may not distribute the modified material. For moreinformation, visithttps://creativecommons.org/licenses/by-nc-nd/4.0/. Are “Killer Trees” Helpful for Understanding the Effectsof the NOx Budget Program? Isaiah Bryant-Sheth, Sagbo Anicet Hounton,Lala Ma, and Lucija Muehlenbachs∗ October 22, 2025 Abstract The benefits of an air pollution policy depend on impacts from the targeted pollu-tant itself but also on reactions with other pollutants in the atmosphere. The creationof new “secondary” pollutants may alter the effectiveness of a pollution reduction pol-icy. We examine the NOx Budget Trading Program (NBP), a large emissions tradingprogram that reduced emissions of nitrogen oxides (NOx), with the intended goal ofreducing ground-level ozone, a secondary pollutant, formed through the interaction ofNOx and volatile organic compounds (VOCs). The ability of the NBP to reduce ozonethus depends on the amount of pre-existing VOCs in the atmosphere. VOCs, however,have been historically unmonitored, making it difficult to predict the effectiveness ofNOx reductions. We show that evergreen forest cover, as a major contributor to VOCs,can be used to determine how effective NOx reductions will be in reducing ozone. Areaswith high evergreen forest cover saw the largest ozone reductions, whereas areas withlow evergreen forest cover saw no reductions.Particulate matter, another secondarypollutant, shows much less of a response to the NBP and little correlation with forestcover. Keywords:Environmental policy, pollutant interactions, ozone, forests, VOCs, NOx 1Introduction Policies aimed at reducing air pollution are complicated by atmospheric chemistry. A policythat mitigates emissions of one pollutant will have benefits that depend on not only thedirect impact of the targeted pollutant but also indi