Designing a circular carbon and plastics economy for a sustainable future.

The linear production and consumption of plastics today is unsustainable. It creates large amounts of unnecessary and mismanaged waste, pollution and carbon dioxide emissions, undermining global climate targets and the Sustainable Development Goals. This Perspective provides an integrated technological, economic and legal view on how to deliver a circular carbon and plastics economy that minimizes carbon dioxide emissions. Different pathways that maximize recirculation of carbon (dioxide) between plastics waste and feedstocks are outlined, including mechanical, chemical and biological recycling, and those involving the use of biomass and carbon dioxide. Four future scenarios are described, only one of which achieves sufficient greenhouse gas savings in line with global climate targets. Such a bold system change requires 50% reduction in future plastic demand, complete phase-out of fossil-derived plastics, 95% recycling rates of retrievable plastics and use of renewable energy. It is hard to overstate the challenge of achieving this goal. We therefore present a roadmap outlining the scale and timing of the economic and legal interventions that could possibly support this. Assessing the service lifespan and recoverability of plastic products, along with considerations of sufficiency and smart design, can moreover provide design principles to guide future manufacturing, use and disposal of plastics.

Cost-effective mitigation of nitrogen pollution from global croplands.

Cropland is a main source of global nitrogen pollution1,2. Mitigating nitrogen pollution from global croplands is a grand challenge because of the nature of non-point-source pollution from millions of farms and the constraints to implementing pollution-reduction measures, such as lack of financial resources and limited nitrogen-management knowledge of farmers3. Here we synthesize 1,521 field observations worldwide and identify 11 key measures that can reduce nitrogen losses from croplands to air and water by 30-70%, while increasing crop yield and nitrogen use efficiency (NUE) by 10-30% and 10-80%, respectively. Overall, adoption of this package of measures on global croplands would allow the production of 17 ± 3 Tg (1012 g) more crop nitrogen (20% increase) with 22 ± 4 Tg less nitrogen fertilizer used (21% reduction) and 26 ± 5 Tg less nitrogen pollution (32% reduction) to the environment for the considered base year of 2015. These changes could gain a global societal benefit of 476 ± 123 billion US dollars (USD) for food supply, human health, ecosystems and climate, with net mitigation costs of only 19 ± 5 billion USD, of which 15 ± 4 billion USD fertilizer saving offsets 44% of the gross mitigation cost. To mitigate nitrogen pollution from croplands in the future, innovative policies such as a nitrogen credit system (NCS) could be implemented to select, incentivize and, where necessary, subsidize the adoption of these measures.

Environmental and economic cost-benefit comparison of sponge city construction in different urban functional regions.

This study conducts a life cycle environmental and economic quantification comparison of urban runoff source control facilities (URSCFs) through construction and operation stages in two urban functional regions (i.e., residential area and campus). From the environmental perspective, URSCFs construction in residential area has both higher environmental impacts and benefits than that in campus. The operation stage of URSCFs can observe significant benefit for both residential area and campus. We then develop a set of monetized method to make a comprehensive benefit evaluation (i.e., environmental, economic, and social benefit) of URSCFs. Overall, the two areas have payback time less than thirteen years for their investment which is acceptable when compared with the assumed total service period (30 years). Specifically, the payback time of campus is 5.62 years and residential area is 12.44 years. This implies that the campus has great potential to achieve high cost-benefit ratio and thus the Sponge City construction in campus can implement URSCFs with less engineering and material consumption due to its more spacious site than residential area with high building density. For both residential area and campus, permeable pavement has the highest environmental impact and economic cost because of the concrete consumption. Thus, we recommend that it should be cautious of the construction of concrete permeable pavement and find environmentally and economically alternatives in future URSCFs projects.

The effects on mortality and the associated financial costs of wood heater pollution in a regional Australian city.

OBJECTIVES: To estimate the annual burden of mortality and the associated health costs attributable to air pollution from wood heaters in Armidale. DESIGN: Health impact assessment (excess annual mortality and financial costs) based upon atmospheric PM2.5 measurements. SETTING: Armidale, a regional Australian city (population, 24 504) with high levels of air pollution in winter caused by domestic wood heaters, 1 May 2018 - 30 April 2019. MAIN OUTCOME MEASURES: Estimated population exposure to PM2.5 from wood heaters; estimated numbers of premature deaths and years of life lost. RESULTS: Fourteen premature deaths (95% CI, 12-17 deaths) per year, corresponding to 210 (95% CI, 172-249) years of life lost, are attributable to long term exposure to wood heater PM2.5 pollution in Armidale. The estimated financial cost is $32.8 million (95% CI, $27.0-38.5 million), or $10 930 (95% CI, $9004-12 822) per wood heater per year. CONCLUSIONS: The substantial mortality and financial cost attributable to wood heating in Armidale indicates that effective policies are needed to reduce wood heater pollution, including public education about the effects of wood smoke on health, subsidies that encourage residents to switch to less polluting home heating (perhaps as part of an economic recovery package), assistance for those affected by wood smoke from other people, and regulations that reduce wood heater use (eg, by not permitting new wood heaters and requiring existing units to be removed when houses are sold).

Environmental and economic impact of using increased fresh gas flow to reduce carbon dioxide absorbent consumption in the absence of inhalational anaesthetics.

BACKGROUND: Increasing fresh gas flow (FGF) to a circle breathing system reduces carbon dioxide (CO2) absorbent consumption. We assessed the environmental and economic impacts of this trade-off between gas flow and absorbent consumption when no inhalational anaesthetic agent is used. METHODS: A test lung with fixed CO2 inflow was ventilated via a circle breathing system of an anaesthetic machine (Dräger Primus or GE Aisys CS2) using an FGF of 1, 2, 4, or 6 L min-1. We recorded the time to exhaustion of the CO2 absorbent canister, defined as when inspired partial pressure of CO2 exceeded 0.3 kPa. For each FGF, we calculated the economic costs and the environmental impact associated with the manufacture of the CO2 absorbent canister and the supply of medical air and oxygen. Environmental impact was measured in 100 yr global-warming potential, analysed using a life cycle assessment 'cradle to grave' approach. RESULTS: Increasing FGF from 1 to 6 L min-1 was associated with up to 93% reduction in the combined running cost with minimal net change to the 100 yr global-warming potential. Most of the reduction in cost occurred between 4 and 6 L min-1. Removing the CO2 absorbent from the circle system, and further increasing FGF to control CO2 rebreathing, afforded minimal further economic benefit, but more than doubled the global-warming potential. CONCLUSIONS: In the absence of inhalational anaesthetic agents, increasing FGF to 6 L min-1 reduces running cost compared with lower FGFs, with minimal impact to the environment.

Carbon reduction potential and cost evaluation of different mitigation approaches in China's coal to olefin Industry.

Coal-based olefin (CTO) industry as a complement of traditional petrochemical industry plays vital role in China's national economic development. However, high CO2 emission in CTO industry is one of the fatal problems to hinder its development. In this work, the carbon emission and mitigation potentials by different reduction pathways are evaluated. The economic cost is analyzed and compared as well. According to the industry development plan, the carbon emissions from China's CTO industry will attain 189.43 million ton CO2 (MtCO2) and 314.11 MtCO2 in 2020 and 2030, respectively. With the advanced technology level, the maximal carbon mitigation potential could be attained to 15.3% and 21.9% in 2020 and 2030. If the other optional mitigation ways are combined together, the carbon emission could further reduce to some extent. In general, the order of mitigation potential is followed as: feedstock alteration by natural gas > CO2 hydrogenation with renewable electricity applied > CCS technology. The mitigation cost analysis indicates that on the basis of 2015 situation, the economic penalty for feedstock alteration is the lowest, ranged between 186 and 451 CNY/tCO2, and the cost from CCS technology is ranged between 404 and 562 CNY/tCO2, which is acceptable if the CO2 enhanced oil recovery and carbon tax are considered. However, for the CO2 hydrogenation technology, the cost is extremely high and there is almost no application possibility at present.

Development of a system dynamics model for polycyclic aromatic hydrocarbons and its application to assess the benefits of pollution reduction.

A dynamic multimedia transport (DMT) model for polycyclic aromatic hydrocarbons (PAHs) was constructed using the system dynamics software STELLA to simulate the transmission and flow of PAHs in different media. Humans are primarily exposed to PAHs via ingestion. Thus, this study used the DMT model to simulate the concentrations of PAHs in food media and the human body and assess the risk of harm to humans. On the basis of the hypothesis of PAH reduction in the Taiwanese steel industry, two scenarios were used (cases I and II), and integration indicators such as the Air Resource Co-Benefit Model of air pollutants, greenhouse gases, and PAHs reduction was established for the cost-benefit analysis of the reduction scenarios. This study not only established Taiwan's PAHs dynamic multimedia transmission model successfully but also performed a reduction scenario on the steel industry. In the year 2025, the total costs for cases I and II will be USD 690 and USD 694 million per year, respectively, and the total benefits will be USD 492 and 1669 million per year, respectively. Therefore, case II is preferable to case I in terms of benefit ratio (2.40 vs. 2.35, respectively).

Neither Knowledge Deficit nor NIMBY: Understanding Opposition to Hydraulic Fracturing as a Nuanced Coalition in Westmoreland County, Pennsylvania (USA).

The expansion of unconventional sources of natural gas across the world has generated public controversy surrounding fracking drilling methods. Public debates continue to reverberate through policy domains despite very inconclusive biophysical evidence of net harm. As a consequence, there is a need to test the hypothesis that resistance to fracking is due to the way it redistributes economic and environmental risks. As in many other communities, opposition to fracking is common in central Westmoreland County, Pennsylvania, (USA) but the rationale underpinning opposition is poorly understood. We test the prevailing assumption in the environmental management literature that fracking opposition is motivated by knowledge deficits and/or not-in-my-backyard (NIMBY) politics. This study uses Q methodology to examine emergent perspectives and sub-discourses within the fracking opposition debate in central Westmoreland County, PA. Q methodology offers a systematic and iterative use of both quantitative and qualitative research techniques to explore frequently overlooked marginal viewpoints that are critical to understanding the fracking problem. The analysis reveals four different narratives of factors amongst people actively involved in locally opposing fracking, labeled (1) Future Fears; (2) NIMBY (3) Community Concerns; and (4) Distrust Stakeholders. The conflicts that emerge across these four factors are indicative of deeper discourse within the fracking debate that signifies diversity in motivations, values, and convictions, and suggests the inadequacy of relying on knowledge deficit and/or NIMBY explanations to fracking politics.

Financial and environmental costs of reusable and single-use anaesthetic equipment.

BACKGROUND.: An innovative approach to choosing hospital equipment is to consider the environmental costs in addition to other costs and benefits. METHODS.: We used life cycle assessment to model the environmental and financial costs of different scenarios of replacing reusable anaesthetic equipment with single-use variants. The primary environmental costs were CO 2 emissions (in CO 2 equivalents) and water use (in litres). We compared energy source mixes between Australia, the UK/Europe, and the USA. RESULTS.: For an Australian hospital with six operating rooms, the annual financial cost of converting from single-use equipment to reusable anaesthetic equipment would be an AUD$32 033 (£19 220), 46% decrease. In Australia, converting from single-use to reusable equipment would result in an increase of CO 2 emissions from 5095 (95% CI: 4614-5658) to 5575 kg CO 2 eq (95% CI: 5542-5608), a 480 kg CO 2 eq (9%) increase. Using the UK/European power mix, converting from single-use (5575 kg CO 2 eq) to reusable anaesthetic equipment (802 kg CO 2 eq) would result in an 84% reduction (4873 kg CO 2 eq) in CO 2 emissions, whilst in the USA converting to reusables would have led to a 2427 kg CO 2 eq (48%) reduction. In Australia, converting from single-use to reusable equipment would more than double water use from 34.4 to 90.6 kilolitres. CONCLUSIONS.: For an Australian hospital with six operating rooms, converting from single-use to reusable anaesthetic equipment saved more than AUD$30 000 (£18 000) per annum, but increased the CO 2 emissions by almost 10%. The CO 2 offset is highly dependent on the power source mix, while water consumption is greater for reusable equipment.

Economic and environmental sustainability of submerged anaerobic MBR-based (AnMBR-based) technology as compared to aerobic-based technologies for moderate-/high-loaded urban wastewater treatment.

The objective of this study was to assess the economic and environmental sustainability of submerged anaerobic membrane bioreactors (AnMBRs) in comparison with aerobic-based technologies for moderate-/high-loaded urban wastewater (UWW) treatment. To this aim, a combined approach of steady-state performance modelling, life cycle analysis (LCA) and life cycle costing (LCC) was used, in which AnMBR (coupled with an aerobic-based post-treatment) was compared to aerobic membrane bioreactor (AeMBR) and conventional activated sludge (CAS). AnMBR with CAS-based post-treatment for nutrient removal was identified as a sustainable option for moderate-/high-loaded UWW treatment: low energy consumption and reduced sludge production could be obtained at given operating conditions. In addition, significant reductions can be achieved in different aspects of environmental impact (global warming potential (GWP), abiotic depletion, acidification, etc.) and LCC over existing UWW treatment technologies.

Can China diminish its burden of non-communicable diseases and injuries by promoting health in its policies, practices, and incentives?

China has rapidly progressed through epidemiological and demographic transitions and is now confronting an increasing burden from non-communicable diseases and injuries. China could take advantage of what has been learnt about prevention and control of non-communicable diseases and injuries, which is well summarised in the WHO best buys (a set of affordable, feasible, and cost-effective intervention strategies in any resource setting), to improve individual and population health. Implementation of these strategies could allow China to exceed the incremental gains in decreasing non-communicable diseases and injury burdens of high-income countries, and greatly shorten the interval needed to achieve decreased morbidity and mortality in its population. With the lessons learnt from other countries and its own programmes and policies, China could provide a health model for the world.

Implications of ammonia emissions from post-combustion carbon capture for airborne particulate matter.

Amine scrubbing, a mature post-combustion carbon capture and storage (CCS) technology, could increase ambient concentrations of fine particulate matter (PM2.5) due to its ammonia emissions. To capture 2.0 Gt CO2/year, for example, it could emit 32 Gg NH3/year in the United States given current design targets or 15 times higher (480 Gg NH3/year) at rates typical of current pilot plants. Employing a chemical transport model, we found that the latter emission rate would cause an increase of 2.0 µg PM2.5/m(3) in nonattainment areas during wintertime, which would be troublesome for PM2.5-burdened areas, and much lower increases during other seasons. Wintertime PM2.5 increases in nonattainment areas were fairly linear at a rate of 3.4 µg PM2.5/m(3) per 1 Tg NH3, allowing these results to be applied to other CCS emissions scenarios. The PM2.5 impacts are modestly uncertain (±20%) depending on future emissions of SO2, NOx, and NH3. The public health costs of CCS NH3 emissions were valued at $31-68 per tonne CO2 captured, comparable to the social cost of carbon itself. Because the costs of solvent loss to CCS operators are lower than the social costs of CCS ammonia, there is a regulatory interest to limit ammonia emissions from CCS.