改变总量管制与交易：使污染市场与公共卫生目标保持一致

Issue Brief 25-09 byJohnson Kakeu,Ethan Ziegler, andBrandon Holmes— June 2025 1.Introduction trade is not the only regulatory strategy available.Direct command-and-control regulations—such assetting specific technology standards or emissionlimits for pollutants—also provide a pragmatic startingpoint (Stavins 2004). In fact, given the technical andinstitutional complexities involved in multipollutantassessment, establishing robust command-and-controlframeworks may serve as a foundation from which atransition to a market-based multipollutant cap-and-trade system could be built over time. Air pollution is the leading environmental cause of deathand disease globally (Wright and Pant, 2024). In 2021,household and ambient air pollution was the secondleading risk factor for premature death, killing over 8.1million people (Health Effects Institute 2024). Even inan energy-intensive world, many of these deaths areavoidable and can be prevented through the properunderstanding and regulation of pollutants. This issue brief is associated with an accompanyingworking paper about the detailed structure of amultipollutant permit model (Kakeu 2025). Despitethe technical and institutional barriers that havehindered the adoption of multipollutant regulationsin recent history, there are many benefits associatedwith transitioning to multipollutant frameworks. Thisgoes beyond replacing single-pollutant cap-and-trade systems with multipollutant ones; an overallrestructuring of the methodologies, communication,research, and action on and about the health effects ofair pollution to a more holistic perspective is imperative. Although PM2.5and ozone are considered to be thedeadliest pollutants, there are hundreds of pollutantsthat can be harmful to human health (Ingram 2024).Currently, governmental bodies and policies take afragmented approach to the research and regulationof these pollutants; different departments regulatedifferent pollutants, and pollutants are studied andregulated independent of one another (Greenbaum andShaikh 2010). This fragmentation in regulation includescap-and-trade systems, which are used to manage theemissions of different pollutants such as CO2, SO2, andNO2. 2.Multipollutant Air QualityManagement This issue brief will explore the concept of implementinga multipollutant cap-and-trade program, as opposedto the traditional single-pollutant model. This systemwould provide heterogeneous firms with a variety ofemission permits to choose from, each representinga specified bundle of pollutants. Such a model wouldallow governments to regulate the total amount of eachpollutant emitted while simultaneously accounting forthe effects of pollutant interactions. While this issuebrief focuses on the potential for a multipollutant cap-and-trade model, it is important to note that cap and Since the dawn of modern environmental regulationsin the United States and United Kingdom in the 1950sand 1960s, governments across the world have begunmanaging their emissions in some capacity. This hasmanifested in countries regulating their pollutantsseparately from one another. The Clean Air Act in theUnited States, the basis for much environmental policydomestically and internationally, includes a clause Scientific research has demonstrated that this mixtureof substances can heighten the negative health effectsof the pollutants (Kortenkamp and Faust 2018). This canbe proven by dose addition; within a mixture, individualcomponents contribute proportionally to their dose andpotency, even with little individual impact. Experimentshave demonstrated that the negative effects of achemical mixture occur even when all contributingsubstances were present at or below their no observedadverse effect level. Even if pollutants are not harmfulindividually, a mixture of pollutants above a certainthreshold could pose a health risk, as shown in Figure 1. separating air quality standards for each “criteriapollutant.” Since pollutants are examined independentlyof one another, their methodologies can be centeredaround the characteristics of each pollutant; quantifyingtheir health and environmental effects becomesmore straightforward than a scenario where thosemethodologies must account for other pollutants too(Dominici et al. 2010). Despite the relative ease of single-pollutant researchand policymaking, it would be more efficient andeffective to regulate air quality based on a multipollutantframework. Single-pollutant frameworks fail toadequately reflect the cumulative and interactive natureof pollutant exposures and their associated healthrisks. While it is true that specific pollutants may buildup in certain areas, meaning different populations orcommunities are affected differently based on location,air masses will always contain a complex variety ofpollutants (Kosmicki and Long 2016; Cushing et al.2018). Single-pollutant frameworks fall short in the sensethat they do not account for the mixture of multiplepollutants. When examining the hea