In recent years, increasing wildfire activity in the western US and Canada has driven declining air quality in some regions of the US. Under EPA's Exceptional Events Rule, states are allowed to exempt daily pollution monitor readings impacted by wildfire smoke from determinations of compliance with Clean Air Act air quality standards. As a result, wildfire smoke is leading to a growing divergence between actual and regulatory air quality. This paper reviews treatment of wildfire smoke under the Clean Air Act and the Exceptional Events Rule. It presents quantitative evidence on the effect of the rule on fulfillment of air quality standards, and an analysis of the degree to which smoke that currently leads to air quality violations is driven by out-of-state fires and fires on federal lands. We suggest a modification to the Exceptional Events Rule under which wildfire emissions would be excluded from air quality regulations only if states adopt government-defined best fire management policies, and we discuss the legal and practical feasibility of such a change.

The US Environmental Protection Agency (EPA) bases its estimate of the value of statistical life (VSL) on 17 hedonic wage studies and five contingent valuation studies conducted between 1974 and 1991. We summarize advances in the mortality risk valuation literature since these papers were published, focusing on studies conducted in the United States that value risks to adults. We review hedonic wage, other revealed preference, and stated preference studies, identifying papers that satisfy appropriate validity criteria. We conclude that the recent literature is sufficiently rich to permit a revision of EPA's baseline estimate. Importantly, VSL estimates from both the averting behavior and stated preference studies we review reflect the preferences of a wider range of demographic groups than the current VSL, and newer studies better target causes of death relevant to EPA regulations.

The U.S. EPA's Community Multiscale Air Quality (CMAQ)-adjoint model is used to map monetized health benefits (defined here as benefits of reduced mortality from chronic PM2.5 exposure) in the form of benefits per ton (of emissions reduced) for the U.S. and Canada for NOx, SO2, ammonia, and primary PM2.5 emissions. The adjoint model provides benefits per ton (BPTs) that are location-specific and applicable to various sectors. BPTs show significant variability across locations, such that only 20% of primary PM2.5 emissions in each country makes up more than half of its burden. The greatest benefits in terms of BPTs are for primary PM2.5 reductions, followed by ammonia. Seasonal differences in benefits vary by pollutant: while PM2.5 benefits remain high across seasons, BPTs for reducing ammonia are much higher in the winter due to the increased ammonium nitrate formation efficiency. Based on our location-specific BPTs, we estimate a total of 91,000 U.S. premature mortalities attributable to natural and anthropogenic emissions.

Adjoint modeling, using U.S. EPA's Community Multiscale Air Quality (CMAQ), has been performed to provide location-specific monetized health benefits from the controls of primary PM2.5 and PM2.5 precursors (NO x , SO2, and NH3) across North America. Source-to-health benefit relationships are quantified using a benefit-per-ton (BPT) metric, accounting for the impacts on premature mortality due to long-term exposure to fine particulate matter. In the base analysis, the approach used a 12 km resolution, four 2-week episodes chosen to capture annual responses, emissions for 2016, and the Global Exposure Mortality Model (GEMM) to link exposures to premature mortality. Here, we investigate the impacts those choices have on results using a range of sensitivity analyses. The choice of four representative episodes led to relatively little bias and error. Finer model resolution, investigated by comparing 36, 12, 4, and 1 km simulations over two urban areas, tended to increase BPT estimates, though the impact was inconsistent between different regions. While BPTs and burden estimates were consistent across resolutions over New York City, they sharply increased for Los Angeles, particularly for NOx and ammonia, leading to 90% increase in burden estimates at 1 km resolution. We find that, for primary PM2.5 emissions, better resolved population distribution is the main contributing factor to higher BPTs, but for secondary precursor emissions (ammonia and NOx), higher model resolution that avoids dilution in coarser grids is more important. Changing emissions from 2016 to 2001 and 2028 resulted in fairly consistent primary PM2.5 BPTs but impacted the BPTs for NOx and ammonia more significantly due to changes in SO2 emissions. We found that BPTs tend to stabilize, as emission changes in 2028 lead to a lower deviation from 2016 BPTs compared to changes from the 2001 episode. The role of the epidemiological model also led to relatively modest uncertainties, 15-30% depending on the species, even when different shapes of concentration-response functions were employed. We found the impact of the choice of CRF to be larger or comparable in size to the reported epidemiological model uncertainties for log-linear CRFs. The adjoining approach proved robust to modeling choices in providing BPT estimates that are highly granular across locations and emitted species.

Carbon capture, utilization, and storage (CCUS) are a critical set of strategies to decarbonize the industrial and power sectors and to mitigate global climate change. Pipeline infrastructure connecting CO2 sources and sinks, if not planned strategically, can cause environmental and social impacts by disturbing local landscapes. We investigated the impacts of these considerations on optimal CO2 pipeline routing and sink locations by modifying and leveraging an open-source CCUS infrastructure model, SimCCS. We expanded SimCCS from a cost-minimizing to a multiobjective framework, explicitly incorporating environmental protection objectives. We estimated trade-offs between private costs and environmental and social impacts. Using a version of the model focused on the southeastern United States, we modeled seven scenarios with varying weights given to environmental impacts to evaluate how the pipeline network responds to the multiobjective optimization. We found that the optimal path is sensitive to environmental and social impact considerations in that a small increase in pipeline length (and cost) significantly avoids large environmental and social impacts. We hope such a tool can be used to improve the pipeline permitting and siting processes and contribute to the achievement of decarbonization goals with minimal environmental impacts.

Carbon Capture and Storage (CCS) is a pivotal technology for reducing greenhouse gas emissions. While developments have been made in capture and storage capabilities , the planning and development of an optimized transport pipeline network for linking emission sources to storage sites remains understudied. This study aims to extend the capabilities of SimCCS, a widely-used CCS planning tool, to incorporate environmental, social, and cultural considerations alongside economic costs of pipeline networks. Utilizing multi-objective optimization, we introduce an additional objective function that minimizes environmental and social impacts. This function integrates spatial data layers representing critical habitats, protected areas, and other socio-ecological factors. Preliminary results illustrate the model's capacity for multi-objective optimization. The annual expense for maintaining a sample pipeline network increased from $434 million to $622 million, with pipeline lengths of 1986 kilometers and 2878 kilometers, respectively, when shifting focus from cost to environmental and social impacts. This research contributes a more comprehensive framework for the planning of future CCS infrastructure that is both economically and environmentally sustainable.

On January 27, 2022, the Advanced Manufacturing Office (AMO) at the US Department of Energy issued a Request for Information seeking to better understand industrial decarbonization priorities and opportunities. We agree with the need for a better understanding of which emerging technologies are or will be crucial to decarbonize the US industry—especially sectors considered hard to decarbonize, such as the cement, iron, and steel sectors. We also acknowledge the importance of crosscutting technologies, such as blue and green hydrogen and carbon capture, utilization, and storage (CCUS), that would allow for substantial emissions reductions in the different industrial sectors.

Millions of abandoned wells are scattered across the United States, causing significant methane emissions and creating a variety of health and environmental hazards. Governments are increasingly interested in decommissioning such wells via tougher regulations or direct spending, but want to do so efficiently. However, information on the costs of decommissioning wells is very limited. In this analysis, we provide new estimates of the costs of decommissioning oil and gas wells and the key drivers of those costs. We analyze data from up to 19,500 wells and find that median decommissioning costs are roughly $20,000 for plugging only, and $76,000 for plugging and surface reclamation. In rare cases, costs exceed $1 million per well. Each additional 1,000 feet of well depth increases costs by 20 percent, older wells are considerably more costly than newer ones, natural gas wells are nine percent more expensive than wells that produce oil, and costs vary widely by state. Surface characteristics also matter: each additional 10 feet of elevation change in the 5-acre area surrounding the well raises costs by three percent. Finally, we find that contracting in bulk pays off: each additional well per contract reduces decommissioning costs by three percent. These findings suggest that regulators can adjust bonding requirements to better match the characteristics of each well.

US tax law provides nearly $1 billion annually in tax credits for “refined coal”, which is supposed to reduce local air pollution. Eligibility for the credit requires firms to demonstrate legally specified emissions reductions for three pollutants. Firms typically demonstrate eligibility through laboratory tests, but results from the lab can differ from those in practice. Using a nationally comprehensive boiler-level panel dataset, we find that emission reductions in practice are only about half of the levels required, and even then only arise when certain pollution controls are installed. We also show that the policy reduces social welfare, resulting in costs more than seven times the benefits, in part because of a “rebound” effect in which the subsidy increases coal use by extending the operational life of some coal plants. Because the tax credit is up for reauthorization in 2021, our work has immediate policy relevance.

Given the Trump administration’s emphasis on repealing regulations, this article discusses issues related to conducting benefit–cost analyses of regulatory repeal. In particular, the article develops analyses of the repeal and modification of six major rules issued by the Obama administration and compares them to analyses conducted by the Trump administration. The results illustrate the sensitivity of these analyses to several key analytical components, including the social cost of methane emissions and the upper-bound estimates of catastrophic accidents, and also illustrate that the Trump administration’s ranking of the six rules using its preferred metric—the cost savings of repeal—differs from a ranking that uses net benefits. Recommendations are provided for improving regulatory impact analyses, including those conducted for regulatory repeal.

Oil and gas development has grown rapidly in recent years in the United States, generating substantial debate over its risks and benefits. A large body of research has surveyed individuals living in and around producing regions to evaluate their views on the industry, with somewhat mixed results. Here, we present the first detailed analysis on this topic using real-world voting data, drawing from precinct-level results of a 2018 election in Colorado that included a vote on Proposition 112, which would have set very large setback requirements on new oil and gas activity. We find partisan affiliation correlates very strongly with support for oil and gas development, that voters in precincts with higher levels of oil and gas activity are modestly more supportive of the industry, but that this support weakens in precincts where development has grown most rapidly.

We examine how attitudes and willingness to pay (WTP) for climate policies have changed over the past decade in the United States, China, and Sweden. All three countries exhibit an increased willingness to pay for climate mitigation. Ten years ago, Sweden had a larger fraction of believers in anthropogenic climate change and a higher WTP for mitigation, but today the national averages are more similar. Although we find convergence in public support for climate policy across countries, there is considerable divergence in climate attitudes and preferences within countries, particularly the United States. Political polarization explains part of this divergence.

The Amazon rainforest, the world's largest tropical rainforest and an important constituent of the global biosphere, continues degrading by rapid deforestation, which is expected to continue despite policies to prevent it. Current international funding to protect the Amazon rainforest focuses on benefits from reduced carbon emissions. This paper examines an additional rationale for Amazon protection: the valuation of its biodiversity and forests as natural heritage to the international community. To measure the economic value of this benefit, the paper examines U.S. and Canadian households' willingness to pay to help finance Amazon rainforest protection. The analysis finds that mean willingness to pay to avoid forest losses projected to occur by 2050 despite current protective policies is $92 per household per year. Aggregating across all households and considering the area protected, the analysis finds that preserving the Amazon rainforest is worth $3,168 per hectare (95-percent confidence interval $1,580-$4,756), on average, to households in the United States and Canada. Considering households in other developed countries would generate yet larger estimates of aggregate value, likely comparable to the carbon benefits from rainforest protection. The results reveal high values of the Amazon rainforest to people geographically distanced from it, lending support to international efforts to reduce deforestation in the Amazon.

Benefit-cost analyses of environmental, health, and safety regulations often rely on an estimate of the value of statistical life (VSL) to calculate the aggregate benefits of reducing human mortality risk. The VSL represents the marginal rate of substitution between mortality risk and money. Although this concept is well understood by economists, it is viewed by many noneconomists as confusing technical jargon that borders on the immoral. Based on focus groups and a quantitative ranking exercise, this article describes a systematic approach for identifying and testing alternatives to the VSL terminology, with the goal of identifying an alternative term that more clearly communicates the VSL concept to a broad audience.

We estimate the impact of shale gas development on particulate matter pollution using a quasi-experimental setting in Pennsylvania where some wells were developed to produce natural gas whereas other wells were permitted but not drilled. In doing so, we utilize a novel empirical approach drawing upon insights from atmospheric chemistry to account for windblown pollution spillovers in a difference-in-differences framework. Utilizing a high frequency, high resolution satellite-based measure of PM pollution between 2000 and 2018, we identify causal increases in PM2.5 concentration ranging from 0.017 & mu;g/m(3) to 0.062 & mu;g/m(3) in the vicinity of over 20,000 wells, resulting in approximately 20 additional deaths between 2010 and 2017.

In 1980, solid waste from oil and gas fields was exempt from US federal hazardous waste regulations (according to the US Environmental Protection Agency's Resources Conservation and Recovery Act, RCRA). However, recent developments in oil and gas extraction from deep shale formations warrant a closer look at this exemption. We obtained lab reports submitted to state regulators to characterize the solid waste generated from 231 shale gas wells in Pennsylvania. Of the 40 chemicals listed as toxic in RCRA, eight were present in our samples and two exceeded RCRA toxicity limits for classification as a hazardous waste (Ba and Cr). We also found overlap with chemicals listed in international lists of toxicity, suggesting that these wastes could pose health problems that would not be regulated by RCRA. Radiation in solid waste is regulated at the state-level; the maximum detected concentrations of radium-226 and radium-228 (51 picocuries/g and 8.87 picocuries/g, respectively) exceed the regulatory limits for landfills in Ohio and New York, however it is common practice to ship waste across state lines. Removing the RCRA oil and gas exemption would increase testing and reporting burdens but would leave most shale waste management practices unchanged while protecting against some hazardous outliers.

Benefit-cost analyses of environmental, health, and safety regulations often rely on an estimate of the value of statistical life (VSL) to calculate the aggregate benefits of reducing human mortality risk. The VSL represents the marginal rate of substitution between mortality risk and money. Although this concept is well-understood by economists, it is viewed by many non-economists as confusing technical jargon that borders on the immoral. Based on focus groups and a quantitative ranking exercise, this article describes a systematic approach for identifying and testing alternatives to the VSL terminology, with the goal of identifying an alternative term that more clearly communicates the VSL concept to a broad audience.

Shale gas pipeline development can have negative environmental impacts, including adverse effects on species and ecosystems through habitat degradation and loss. From a societal perspective, pipeline development planning processes should account for such externalities. We develop a multiobjective binary integer-programming model, called the Multi Objective Pipeline Siting (MOPS) model, to incorporate habitat externalities into pipeline development and to estimate the trade-offs between pipeline development costs and habitat impacts. We demonstrate the utility of the model using an application from Bradford and Susquehanna counties in northeastern Pennsylvania. We find that significant habitat impacts can be avoided for relatively low cost, but the avoidance of the additional habitat impacts becomes gradually and increasingly costly. For example, 10% of the habitat impacts can be avoided at less than a two percent pipeline cost increase relative to a configuration that ignores habitat impacts. MOPS or a similar model could be integrated into the pipeline siting and permitting process so oil and gas companies, communities, and states can identify cost-effective options for habitat conservation near shale gas development.

At a press briefing in mid-August, Bill Wehrum, the appointed head of the US Environmental Protection Agency’s (EPA’s) Air Office, reiterated the Trump administration’s position that ancillary benefits are not to be counted in cost-benefit analysis of major rules, this time in the context of the Affordable Clean Energy (ACE) rule proposed to replace the Obama administration’s Clean Power Plan (CPP). If only the forgone carbon dioxide (CO2) benefits of pulling back on the CPP are counted, the cost savings from ACE outweigh these forgone benefits. But adding the ancillary health benefits that are lost with the ACE rule—the value of 1,400 fine particulate matter (PM2. 5)-associated deaths related to greater coal use under the ACE rule—turns ACE into an economic loser, with net social costs relative to the CPP. At the briefing, Wehrum said:“We’re not dealing with [sulfur dioxide] SO2. We’re not dealing with [nitrogen oxides] NOX. We’re not dealing with particulate matter.… We have abundant legal authority to deal with those other pollutants directly, and we have very aggressive programs in place that directly target emissions of those pollutants. So our view is, if we want to regulate PM, we regulate PM straight up. If we want to regulate SO2, we regulate SO2 straight up.”