Gross Output

Kevin Lewis

July 27, 2021

Source sector and fuel contributions to ambient PM2.5 and attributable mortality across multiple spatial scales
Erin McDuffie et al.
Nature Communications, June 2021


Ambient fine particulate matter (PM2.5) is the world’s leading environmental health risk factor. Reducing the PM2.5 disease burden requires specific strategies that target dominant sources across multiple spatial scales. We provide a contemporary and comprehensive evaluation of sector- and fuel-specific contributions to this disease burden across 21 regions, 204 countries, and 200 sub-national areas by integrating 24 global atmospheric chemistry-transport model sensitivity simulations, high-resolution satellite-derived PM2.5 exposure estimates, and disease-specific concentration response relationships. Globally, 1.05 (95% Confidence Interval: 0.74–1.36) million deaths were avoidable in 2017 by eliminating fossil-fuel combustion (27.3% of the total PM2.5 burden), with coal contributing to over half. Other dominant global sources included residential (0.74 [0.52–0.95] million deaths; 19.2%), industrial (0.45 [0.32–0.58] million deaths; 11.7%), and energy (0.39 [0.28–0.51] million deaths; 10.2%) sectors. Our results show that regions with large anthropogenic contributions generally had the highest attributable deaths, suggesting substantial health benefits from replacing traditional energy sources.

Unwatched Pollution: The Effect of Intermittent Monitoring on Air Quality
Eric Zou
American Economic Review, July 2021, Pages 2101-2126


Intermittent monitoring of environmental standards may induce strategic changes in polluting activities. This paper documents local strategic responses to a cyclical, once-every-six-day air quality monitoring schedule under the federal Clean Air Act. Using satellite data of monitored areas, I show that air quality is significantly worse on unmonitored days. This effect is explained by short-term suppression of pollution on monitored days, especially during high-pollution periods when the city's noncompliance risk is high. Cities' use of air quality warnings increases on monitored days, which suggests local governments' role in coordinating emission reductions.

The impact of childhood lead exposure on adult personality: Evidence from the United States, Europe, and a large-scale natural experiment
Ted Schwaba et al.
Proceedings of the National Academy of Sciences, 20 July 2021


Childhood lead exposure has devastating lifelong consequences, as even low-level exposure stunts intelligence and leads to delinquent behavior. However, these consequences may be more extensive than previously thought because childhood lead exposure may adversely affect normal-range personality traits. Personality influences nearly every aspect of human functioning, from well-being to career earnings to longevity, so effects of lead exposure on personality would have far-reaching societal consequences. In a preregistered investigation, we tested this hypothesis by linking historic atmospheric lead data from 269 US counties and 37 European nations to personality questionnaire data from over 1.5 million people who grew up in these areas. Adjusting for age and socioeconomic status, US adults who grew up in counties with higher atmospheric lead levels had less adaptive personality profiles: they were less agreeable and conscientious and, among younger participants, more neurotic. Next, we utilized a natural experiment, the removal of leaded gasoline because of the 1970 Clean Air Act, to test whether lead exposure caused these personality differences. Participants born after atmospheric lead levels began to decline in their county had more mature, psychologically healthy adult personalities (higher agreeableness and conscientiousness and lower neuroticism), but these findings were not discriminable from pure cohort effects. Finally, we replicated associations in Europeans. European participants who spent their childhood in areas with more atmospheric lead were less agreeable and more neurotic in adulthood. Our findings suggest that further reduction of lead exposure is a critical public health issue.

Strong evidence for the continued contribution of lead deposited during the 20th century to the atmospheric environment in London of today
Eléonore Resongles et al.
Proceedings of the National Academy of Sciences, 29 June 2021


Although leaded gasoline was banned at the end of the last century, lead (Pb) remains significantly enriched in airborne particles in large cities. The remobilization of historical Pb deposited in soils from atmospheric removal has been suggested as an important source providing evidence for the hypothetical long-term persistency of lead, and possibly other pollutants, in the urban environment. Here, we present data on Pb isotopic composition in airborne particles collected in London (2014 to 2018), which provide strong support that lead deposited via gasoline combustion still contributes significantly to the lead burden in present-day London. Lead concentration and isotopic signature of airborne particles collected at a heavily trafficked site did not vary significantly over the last decade, suggesting that sources remained unchanged. Lead isotopic composition of airborne particles matches that of road dust and topsoils and can only be explained with a significant contribution (estimate of 32 ± 10 to 43 ± 9% based on a binary mixing model) of Pb from leaded gasoline. The lead isotopes furthermore suggest significant contributions from nonexhaust traffic emissions, even though isotopic signatures of anthropogenic sources are increasingly overlapping. Lead isotopic composition of airborne particles collected at building height shows a similar signature to that collected at street level, suggesting effective mixing of lead within the urban street canyon. Our results have important implications on the persistence of Pb in urban environments and suggest that atmospheric Pb reached a baseline in London that is difficult to decrease further with present policy measures.

Coal-Fired Power Plant Retirements in the U.S.
Rebecca Davis, Scott Holladay & Charles Sims
NBER Working Paper, June 2021


We summarize the history of U.S. coal-fired plant retirements over the last decade, describe planned future retirements, and forecast the remaining operating life for every operating coal-fired generator. We summarize the technology and location trends that are correlated with the observed retirements. We then describe a theoretical model of the retirement decision coal generator owners face. We use retirements from the last decade to quantify the relationships in the model for retired generators. Our model predicts that three-quarters of coal generation capacity will retire in the next twenty years, with most of that retirement concentrated in the next five years. Policy has limited ability to affect retirement times. A $20 per MWh electricity subsidy extends the average life of a generator by six years. A $51 per ton carbon tax brings forward retirement dates by about two years. In all scenarios, a handful of electricity generators remain on the grid beyond our forecast horizon.

The Unintended Effects from Halting Nuclear Power Production: Evidence from Fukushima Daiichi Accident
Matthew Neidell, Shinsuke Uchida & Marcella Veronesi
Journal of Health Economics, forthcoming


This paper provides novel evidence of the unintended health effects stemming from the halt in nuclear power production after the Fukushima Daiichi nuclear accident. After the accident, nuclear power stations ceased operation and nuclear power was replaced by fossil fuels, causing an increase in electricity prices. We find that this increase led to a reduction in energy consumption, which caused an increase in mortality during very cold temperatures, given the protective role that climate control plays against the elements. Our results contribute to the debate surrounding the use of nuclear as a source of energy by documenting a yet unexplored health benefit from using nuclear power, and more broadly to regulatory policy approaches implemented during periods of scientific uncertainty about potential adverse effects.

Trade, Competitive Exclusion, and the Slow-Motion Extinction of the Southern Resident Killer Whales
Scott Taylor
NBER Working Paper, July 2021


Orcinus Orca is the world's largest predator, and simultaneously a significant tourist asset and cultural icon for much of the Pacific Northwest. In the past two decades, the Southern Resident Killer whales (SRKW) have declined by more than 25 percent, and this population appears on a slow-motion path towards extinction. This paper combines elements from biology and economics to put forward a new methodology for investigating their collapse and presents empirical work supporting its novel explanation - the Orca Conjecture. The key mechanism is ecological - Gause's law of competitive exclusion - combined with a shock coming from booming trade with Asia. Using three different empirical methods drawn from economics, I find the attendant noise disturbance from increased ship traffic post-1998 has lowered births and raised deaths significantly, placing the SRKW on a slow-motion path towards extinction.

CEO Hometown Favoritism in Corporate Environmental Policies
Wei Li, Qiping Xu & Qifei Zhu
University of Illinois Working Paper, June 2021


Exploiting within-firm variations in plant-level toxic releases, we find evidence that firms pollute significantly less in plants near their CEOs' hometowns, suggesting that managerial hometown attachment affects corporate environmental policies. Plants near CEOs' hometowns achieve lower toxic release by investing more in abatement and waste management activities. Analyses using CEO turnover events provide supportive evidence. Hometown emission reduction is stronger for poorly-governed firms, and is significantly weakened following an exogenous reduction in agency conflicts. These findings suggest that CEOs' personal motives affect corporate pollution when agency issue is severe.

Cleaner air has contributed one-fifth of U.S. maize and soybean yield gains since 1999
David Lobell & Jennifer Burney
Environmental Research Letters, July 2021


Crop productivity is potentially affected by several air pollutants, although these are usually studied in isolation. A significant challenge to understanding the effects of multiple pollutants in many regions is the dearth of air quality data near agricultural fields. Here we empirically estimate the effect of four key pollutants (ozone (O3), particulate matter (PM), sulfur dioxide (SO2), and nitrogen dioxide (NO2)) on maize and soybean yields in the United States using a combination of administrative data and satellite-derived yield estimates. We identify clear negative effects of exposure to O3, PM, and SO2 in both crops, using yields measured in the vicinity of monitoring stations. We also show that while stations measuring NO2 are too sparse to reliably estimate a yield effect, the strong gradient of NO2 concentrations near power plants allows us to more precisely estimate NO2 effects using satellite measured yield gradients. The presence of some powerplants that turn on and others that shut down during the study period are particularly useful for attributing yield gradients to pollution. We estimate that total yield losses from these pollutants averaged roughly 5% for both maize and soybean over the past two decades. While all four pollutants have statistically significant effects, PM and NO2 appear more damaging to crops at current levels than O3 and SO2. Finally, we find that the significant improvement in air quality since 1999 has halved the impact of poor air quality on major crops and contributed to yield increases that represent roughly 20% of overall yield gains over that period.

Previously unaccounted atmospheric mercury deposition in a midlatitude deciduous forest
Daniel Obrist et al.
Proceedings of the National Academy of Sciences, 20 July 2021


Mercury is toxic to wildlife and humans, and forests are thought to be a globally important sink for gaseous elemental mercury (GEM) deposition from the atmosphere. Yet there are currently no annual GEM deposition measurements over rural forests. Here we present measurements of ecosystem–atmosphere GEM exchange using tower-based micrometeorological methods in a midlatitude hardwood forest. We measured an annual GEM deposition of 25.1 µg ⋅ m−2 (95% CI: 23.2 to 26.7 1 µg ⋅ m−2), which is five times larger than wet deposition of mercury from the atmosphere. Our observed annual GEM deposition accounts for 76% of total atmospheric mercury deposition and also is three times greater than litterfall mercury deposition, which has previously been used as a proxy measure for GEM deposition in forests. Plant GEM uptake is the dominant driver for ecosystem GEM deposition based on seasonal and diel dynamics that show the forest GEM sink to be largest during active vegetation growing periods and middays, analogous to photosynthetic carbon dioxide assimilation. Soils and litter on the forest floor are additional GEM sinks throughout the year. Our study suggests that mercury loading to this forest was underestimated by a factor of about two and that global forests may constitute a much larger global GEM sink than currently proposed. The larger than anticipated forest GEM sink may explain the high mercury loads observed in soils across rural forests, which impair water quality and aquatic biota via watershed Hg export.

Floating macrolitter leaked from Europe into the ocean
Daniel González-Fernández et al.
Nature Sustainability, June 2021, Pages 474–483


Riverine systems act as converging pathways for discarded litter within drainage basins, becoming key elements in gauging the transfer of mismanaged waste into the ocean. However, riverine litter data are scarce and biased towards microplastics, generally lacking information about larger items. Based on the first ever database of riverine floating macrolitter across Europe, we have estimated that between 307 and 925 million litter items are released annually from Europe into the ocean. The plastic fraction represented 82% of the observed litter, mainly fragments and single-use items (that is, bottles, packaging and bags). Our modelled estimates show that a major portion of the total litter loading is routed through small-sized drainage basins (<100 km2), indicating the relevance of small rivers, streams and coastal run-off. Moreover, the major contribution of high-income countries to the macrolitter inputs suggests that reducing ocean pollution cannot be achieved only by improving waste management, but also requires changing consumption habits and behaviour to curb waste generation at source. The inability of countries with well-developed recovery systems to control the leakage of waste into the environment further supports the need to regulate the production and use of plastic on a global scale.

Impacts of the Clean Air Act on the Power Sector from 1938-1994: Anticipation and Adaptation
Karen Clay et al.
NBER Working Paper, June 2021


The passage of landmark government regulation is often the culmination of evolving social pressure and incremental policy change. During this process, firms may preemptively adjust behavior in anticipation of impending regulation, making it difficult to quantify the overall economic impact of the legislation. This study leverages newly digitized data on the operation of virtually every fossil-fuel power plant in the United States from 1938-1994 to examine the impacts of the 1970 Clean Air Act (CAA) on the power sector. This unique long panel provides an extended pre-regulation benchmark, allowing us to account for both anticipatory behavior by electric utilities in the years leading up to the Act’s passage and reallocative effects of the CAA across plant vintages. We find that the CAA led to large and persistent decreases in output and productivity, but only for plants that opened before 1963. This timing aligns with the passage of the original 1963 CAA, which provided the federal government with limited authority to “control” air pollution, but signaled impending federal regulation. We provide historical evidence of anticipatory responses by utilities in the design and siting of plants that opened after 1963. We also find that the aggregate productivity losses of the CAA borne by the power sector were substantially mitigated by the reallocation of output from older less efficient power plants to newer plants.

Ecosystem services benefits from the restoration of non-producing US oil and gas lands
William Haden Chomphosy et al.
Nature Sustainability, June 2021, Pages 547–554


Fossil fuel infrastructure has important land-use impacts within the United States, including the environmental consequences of affected land that persists beyond the lifespan of wells. Here, we estimate the ecoregion-specific fifty-year present-value net benefits of restoring lands that are associated with non-producing wells in the conterminous United States on the basis of select ecosystem services—agricultural sales and carbon sequestration. We identify more than 430,000 restorable wells that occupy more than 800,000 ha of land. The present value of ecosystem services benefits was US$21 billion (2018) while the restoration costs were US$7 billion. Deciduous forests, grasslands and Mediterranean ecoregions had large net benefits, whereas arid and semi-arid regions were often negative. Focusing on select ecoregions of the United States would provide higher returns on investment in the form of environmental and economic benefits. Although our results suggest an ecoregional hierarchy, the restoration of all abandoned fossil fuel lands will have benefits at the local, regional and national scales, including food security, protection of biodiversity and restoration-related job opportunities.


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