Most climate change policy attention has been addressed to long-term options, such as inducing new, low-carbon energy technologies and creating cap-and-trade regimes for emissions. We use a ...behavioral approach to examine the reasonably achievable potential for near-term reductions by altered adoption and use of available technologies in US homes and nonbusiness travel. We estimate the plasticity of 17 household action types in 5 behaviorally distinct categories by use of data on the most effective documented interventions that do not involve new regulatory measures. These interventions vary by type of action and typically combine several policy tools and strong social marketing. National implementation could save an estimated 123 million metric tons of carbon per year in year 10, which is 20% of household direct emissions or 7.4% of US national emissions, with little or no reduction in household well-being. The potential of household action deserves increased policy attention. Future analyses of this potential should incorporate behavioral as well as economic and engineering elements.
We conducted an emission measurement campaign as a part of a multiyear cookstove intervention trial in two rural locations in northern and southern India. 253 uncontrolled cooking tests measured ...emissions in control and intervention households during three ~3-month-long measurement periods in each location. We measured pollutants including fine particulate matter (PM2.5), organic and elemental carbon (OC, EC), black carbon (BC) and carbon monoxide (CO) from stoves ranging from traditional solid fuel (TSF) to improved biomass stoves (rocket, gasifier) to liquefied petroleum gas (LPG) models. TSF stoves showed substantial variability in pollutant emission factors (EFs; g kg−1 wood) and optical properties across measurement periods. Multilinear regression modeling found that measurement period, fuel properties, relative humidity, and cooking duration are significant predictors of TSF EFs. A rocket stove showed moderate reductions relative to TSF. LPG stoves had the lowest pollutant EFs, with mean PM2.5 and CO EFs (g MJdelivered−1) >90% lower than biomass stoves. However, in-home EFs of LPG were substantially higher than lab EFs, likely influenced by non-ideal combustion performance, emissions from food and possible influence from other combustion sources. In-home emission measurements may depict the actual exposure benefits associated with dissemination of LPG stoves in real world interventions.
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•Measurements of real-world wood and LPG stove emissions of particulate and gaseous pollutants•Quantification of emission factors and optical properties of emitted particles•Fuelwood moisture and ambient relative humidity influence traditional stove emissions.•In-home LPG emissions were substantially higher than those in lab.•Food emissions can have large impact on observed LPG emissions.
Accurate estimation of black carbon (BC) emissions is essential for assessing the health and climate impact of this pollutant. Past emission inventories were associated with high uncertainty due to ...data limitations, and recent information has provided a unique updating opportunity. Moreover, understanding the drivers that cause temporal emission changes is of research value. Here, we update the global BC emission estimates using new data on the activities and emission factors (EFs). The new inventory covers 73 detailed sources at 0.1° × 0.1° spatial resolution and monthly temporal resolution from 1960 to 2017. The estimated annual emissions were 32% higher than the average of several previous inventories, which was primarily due to field-measured EFs for residential stoves and differentiated EFs for motor vehicles. In addition, the updated emissions show an inverse U-shaped temporal trend, which was mainly driven by the interaction between the positive effects of population growth, per capita energy consumption, and vehicle fleet and the negative effects of residential energy switching, stove upgrading, phasing out of beehive coke ovens, and reduced EFs for vehicles and industrial processes. Urbanization caused a significant increase in urban emissions accompanied by a more significant decline in rural emissions.
Europium (Eu) is often regarded as a critical mineral due to its byproduct nature, importance to lighting technologies, and global supply concentration. However, the existing indicator-based ...criticality assessments have limitations to capture Eu's supply chain information and thus fall short of reflecting its true criticality. This study quantified the flows and stocks of Eu in mainland China from 1990 to 2018. Results show that: (1) China's Eu demand decreased by 75% from 2011 to 2018, as a result of the lighting technology transition from fluorescent lamps to light-emitting diodes, which significantly reduced Eu's importance; (2) the supply of Eu mined as a byproduct kept increasing together with the growing rare earth production, which caused a substantial supply surplus being ≈1900 t by 2018; (3) despite the leading role of China in global Eu production, Eu mined in China was exported mainly in the form of intermediate and final products, and ≈90% Eu embedded in domestically produced final products was used for export recently. This study indicates that Eu's criticality is not as severe as previously assessed and highlights the necessity of material flow analysis for a holistic and dynamic view on the entire supply chain of critical minerals.
Realistic metrics and methods for testing household biomass cookstoves are required to develop standards needed by international policy makers, donors, and investors. Application of consistent test ...practices allows emissions and energy efficiency performance to be benchmarked and enables meaningful comparisons among traditional and advanced stove types. In this study, 22 cookstoves burning six fuel types (wood, charcoal, pellets, corn cobs, rice hulls, and plant oil) at two fuel moisture levels were examined under laboratory-controlled operating conditions as outlined in the Water Boiling Test (WBT) protocol, Version 4. Pollutant emissions (carbon dioxide, carbon monoxide, methane, total hydrocarbons, and ultrafine particles) were continuously monitored. Fine particle mass was measured gravimetrically for each WBT phase. Additional measurements included cookstove power, energy efficiency, and fuel use. Emission factors are given on the basis of fuel energy, cooking energy, fuel mass, time, and cooking task or activity. The lowest PM(2.5) emissions were 74 mg MJ(delivered)(-1) from a technologically advanced cookstove compared with 700-1400 mg MJ(delivered)(-1) from the base-case open 3-stone cookfire. The highest thermal efficiency was 53% compared with 14-15% for the 3-stone cookfire. Based on these laboratory-controlled test results and observations, recommendations for developing potentially useful metrics for setting international standards are suggested.
The corrected ultraviolet-visible light spectrum was used to calculate the color of synthetic rubies with different light path lengths, and the influence of light path length and standard light ...source on the color of synthetic ruby was studied. The results show that the difference in colour between the o light direction and the e light direction of the synthetic ruby decreases as the length of the light path increases. At the same time, as the length of the light path increases, the lightness L* decreases, and the hue angle h° increases. The chroma C* first increases as the length of the light path increases, and then begins to decrease under the influence of the continuous decrease in lightness. The color difference ΔE*
reaches the maximum when the light path length is around 10 mm, and the standard light source has the greatest influence on the color difference ΔE*
. As the length of the light path continues to increase, the influence of the standard light source on the color difference ΔE*
decreases. In the ultraviolet-visible light spectrum, the strong absorption band of Cr
at 545 nm is the main cause of the color of the ruby. The larger the area of the band at 545 nm, the lower the lightness and the higher the hue angle, which means the ruby colour is redder.
Waste electrical and electronic equipment (WEEE) has received extensive attention as a secondary source of metals. Because WEEE also contains toxic substances such as heavy metals, appropriate ...management of these substances is important in the recycling and treatment of WEEE. As a basis for discussion toward better management of WEEE, this study characterizes various types of WEEE in terms of toxic metal contents. The fate of various metals contained in WEEE, including toxic metals, was also investigated in actual waste treatment processes. Cathode-ray tube televisions showed the highest concentration and the largest total amount of toxic metals such as Ba, Pb, and Sb, so appropriate recycling and disposal of these televisions would greatly contribute to better management of toxic metals in WEEE. A future challenge is the management of toxic metals in mid-sized items such as audio/visual and ICT equipment because even though the concentrations were not high in these items, the total amount of toxic metals contained in them is not negligible. In the case of Japan, such mid-sized WEEE items as well as small electronic items are subject to municipal solid waste treatment. A case study showed that a landfill was the main destination of toxic metals contained in those items in the current treatment systems. The case study also showed that changes in the flows of toxic metals will occur when treatment processes are modified to emphasize resource recovery. Because the flow changes might lead to an increase in the amount of toxic metals released to the environment, the flows of toxic metals and the materials targeted for resource recovery should be considered simultaneously.
► Appropriate management of toxic metals contained in WEEE is important during recycling and treatment of WEEE. ► CRT TVs contain large amount of toxic metals with high concentration and thus appropriate management is highly important. ► Mid-sized equipment is a future target for managing toxic metals in WEEE because the total amount is not negligible. ► Changes in the flows of toxic metals will occur when treatment processes are modified to emphasize resource recovery. ► The flows of toxic metals and valuable materials should be managed simultaneously in recycling and treatment of WEEE.
The constantly increasing demand of Rare Earth Elements (REEs) made them to be part of the so-called "critical elements" indispensable for the energy transition. The monopoly of only a few countries, ...the so-called balance problem between demand and natural abundance, and the need to limit the environmental costs of their mining, stress the necessity of a recycling policy of these elements. Different methods have been tested for REEs recovery. Despite the well-known ion-exchange properties of zeolites, just few preliminary works investigated their application for REEs separation and recycle. In this work we present a double ion exchange experiment on a NH
-13X zeolite, aimed at the recovery of different REEs from solutions mimicking the composition of liquors obtained from the leaching of spent fluorescent lamps. The results showed that the zeolite was able to exchange all the REEs tested, but the exchange capacity was different: despite Y being the more concentrated REE in the solutions, the cation exchange was lower than less concentrated ones (16 atoms p.u.c. vs 21 atoms for Ce and La solutions), suggesting a possible selectivity. In order to recover REEs from the zeolite, a second exchange with an ammonium solution was performed. The analyses of the zeolites show that almost all of Ce and Eu remain in the zeolite, while nearly half of La and Y are released. This, once again, suggests a possible selective release of REEs and open the possibility for a recovery process in which Rare Earths can be effectively separated.
A photoacoustic sensor system (PAS) intended for carbon dioxide (CO
) blood gas detection is presented. The development focuses on a photoacoustic (PA) sensor based on the so-called two-chamber ...principle, i.e., comprising a measuring cell and a detection chamber. The aim is the reliable continuous monitoring of transcutaneous CO
values, which is very important, for example, in intensive care unit patient monitoring. An infrared light-emitting diode (LED) with an emission peak wavelength at 4.3 µm was used as a light source. A micro-electro-mechanical system (MEMS) microphone and the target gas CO
are inside a hermetically sealed detection chamber for selective target gas detection. Based on conducted simulations and measurement results in a laboratory setup, a miniaturized PA CO
sensor with an absorption path length of 2.0 mm and a diameter of 3.0 mm was developed for the investigation of cross-sensitivities, detection limit, and signal stability and was compared to a commercial infrared CO
sensor with a similar measurement range. The achieved detection limit of the presented PA CO
sensor during laboratory tests is 1 vol. % CO
. Compared to the commercial sensor, our PA sensor showed less influences of humidity and oxygen on the detected signal and a faster response and recovery time. Finally, the developed sensor system was fixed to the skin of a test person, and an arterialization time of 181 min could be determined.
Household air pollution (HAP) contributes to 3.5-4 million annual deaths globally. Recent interventions using improved cookstoves (ICS) to reduce HAP have incorporated temperature sensors as stove ...use monitors (SUMs) to assess stove use. We deployed SUMs in an effectiveness study of 6 ICSs in 45 Kenyan rural homes. Stove were installed sequentially for 2 weeks and kitchen air monitoring was conducted for 48 h during each 2-week period. We placed SUMs on the ICSs and traditional cookstoves (TCS), and the continuous temperature data were analyzed using an algorithm to examine the number of cooking events, days of exclusive use of ICS, and how stove use patterns affect HAP. Stacking, defined as using both a TCS and an ICS in the same day, occurred on 40% of the study days, and exclusive use of the ICS occurred on 25% of study days. When researchers were not present, ICS use declined, which can have implications for long-term stove adoption in these communities. Continued use of TCSs was also associated with higher HAP levels. SUMs are a valuable tool for characterizing stove use and provide additional information to interpret HAP levels measured during ICS intervention studies.
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