航空环境工程与科学

阐述了航空对环境的影响及航空环保工程技术,分析了飞机排放对大气的污染及航空噪声的影响;研究了控制飞机排气污染和噪声污染的办法,提出了降低航空污染的技术和管理措施。     

Global atmospheric methane: budget, changes and dangers

A factor of 2.5 increase in the global abundance of atmospheric methane (CH(4)) since 1750 contributes 0.5 Wm(-2) to total direct radiative forcing by long-lived greenhouse gases (2.77 Wm(-2) in 2009), while its role in atmospheric chemistry adds another approximately 0.2 Wm(-2) of indirect forcing. Since CH(4) has a relatively short lifetime and it is very close to a steady state, reductions in its emissions would quickly benefit climate. Sensible emission mitigation strategies require quantitative understanding of CH(4)'s budget of emissions and sinks. Atmospheric observations of CH(4) abundance and its rate of increase, combined with an estimate of the CH(4) lifetime, constrain total global CH(4) emissions to between 500 and 600 Tg CH(4) yr(-1). While total global emissions are constrained reasonably well, estimates of emissions by source sector vary by up to a factor of 2. Current observation networks are suitable to constrain emissions at large scales (e.g. global) but not at the regional to national scales necessary to verify emission reductions under emissions trading schemes. Improved constraints on the global CH(4) budget and its break down of emissions by source sector and country will come from an enhanced observation network for CH(4) abundance and its isotopic composition (δ(13)C, δD(D=(2)H) and δ(14)C). Isotopic measurements are a valuable tool in distinguishing among various sources that contribute emissions to an air parcel, once fractionation by loss processes is accounted for. Isotopic measurements are especially useful at regional scales where signals are larger. Reducing emissions from many anthropogenic source sectors is cost-effective, but these gains may be cancelled, in part, by increasing emissions related to economic development in many parts of the world. An observation network that can quantitatively assess these changing emissions, both positive and negative, is required, especially in the context of emissions trading schemes.     

Analysis of nitro-polycyclic aromatic hydrocarbons in conventional diesel and Fischer-Tropsch diesel fuel emissions using electron monochromator-mass spectrometry

The presence of nitro-polycyclic aromatic hydrocarbons (NPAHs) in diesel fuel emissions has been studied for a number of years predominantly because of their contribution to the overall health and environmental risks associated with these emissions. Electron monochromator-mass spectrometry (EM-MS) is a highly selective and sensitive method for detection of NPAHs in complex matrixes, such as diesel emissions. Here, EM-MS was used to compare the levels of NPAHs in fuel emissions from conventional (petroleum) diesel, ultra-low sulfur/low-aromatic content diesel, Fischer-Tropsch synthetic diesel, and conventional diesel/synthetic diesel blend. The largest quantities of NPAHs were detected in the conventional diesel fuel emissions, while the ultra-low sulfur diesel and synthetic diesel fuel demonstrated a more than 50% reduction of NPAH quantities when compared to the conventional diesel fuel emissions. The emissions from the blend of conventional diesel with 30% synthetic diesel fuel also demonstrated a more than 30% reduction of the NPAH content when compared to the conventional diesel fuel emissions. In addition, a correlation was made between the aromatic content of the different fuel types and NPAH quantities and between the nitrogen oxides emissions from the different fuel types and NPAH quantities. The EM-MS system demonstrated high selectivity and sensitivity for detection of the NPAHs in the emissions with minimal sample cleanup required.     

Asymmetric inter-linkages between green technology innovation and consumption-based carbon emissions in BRICS countries using quantile-on-quantile framework

The role of reliable Carbon emission measures and relevant climate policy is imperative in realizing Sustainable Development Goals. A large extent of the literature concludes the emissions-mitigating effect of green innovations in a linear framework and ignored structural changes, technological revolutions, and socio-economic reforms that create non-linearity. Apart from that, there is a murky relationship between emissions and green innovation, where two-way links exist between both variables. Therefore, this study draws the inter-linkages between green technology innovation (GI) and carbon emissions (consumption-based and terrestrial emissions) in BRICS countries using monthly data from 1990 to 2017. Our preliminary findings strictly reject the preposition of data normality and highlight that the observed relationship is quantile-dependent. Therefore, a complete set of non-linear modeling is employed that included; Quantile unit root, Quantile cointegration, Quantile causality, and Quantile on Quantile regression to unveil hidden unit root, cointegration, causality, and association between variables. The results exhibit that the emissions-mitigating effect of GI is only pronounced at higher emissions quantiles in Brazil, China, India, and Russia, whereas at lower emissions quantile, GI is weekly or positively linked with carbon emissions. On the flipside, higher carbon emissions instigate GI across medium to higher emissions quantiles in Brazil, China, and India. Unlike them, Russia produces different outcomes, where higher emissions are associated with lower GI across all quantiles. The overall results suggest that GI (carbon emissions) mitigate (instigate) carbon emissions (GI) when a country is embodied with higher level of emissions.     

Cumulative carbon emissions, emissions floors and short-term rates of warming: implications for policy

A number of recent studies have found a strong link between peak human-induced global warming and cumulative carbon emissions from the start of the industrial revolution, while the link to emissions over shorter periods or in the years 2020 or 2050 is generally weaker. However, cumulative targets appear to conflict with the concept of a 'floor' in emissions caused by sectors such as food production. Here, we show that the introduction of emissions floors does not reduce the importance of cumulative emissions, but may make some warming targets unachievable. For pathways that give a most likely warming up to about 4°C, cumulative emissions from pre-industrial times to year 2200 correlate strongly with most likely resultant peak warming regardless of the shape of emissions floors used, providing a more natural long-term policy horizon than 2050 or 2100. The maximum rate of CO(2)-induced warming, which will affect the feasibility and cost of adapting to climate change, is not determined by cumulative emissions but is tightly aligned with peak rates of emissions. Hence, cumulative carbon emissions to 2200 and peak emission rates could provide a clear and simple framework for CO(2) mitigation policy.     

VOC emission reduction and energy efficiency in the flexible packaging printing processes: analysis and implementation

Volatile organic compound (VOC) emissions into the atmosphere are among the primary environmental problems caused by flexible packaging printing plants. Since 1999, VOC emissions from the use of solvents in various technological processes have been limited by the volatile organic compounds solvents emissions directive, and by directive 2010/75/EU on industrial emissions since 2010. Thus, flexible packaging plants require processing technologies or other solutions to ensure compliance with these requirements. In this paper, combined VOC pollution prevention and treatment alternatives were suggested and were evaluated for their technical, environmental, and economic feasibility. A flexible plastic packaging company that produces over 1920 t/year of plastic packaging for the food industry was selected for detailed analysis. The material and energy flow analysis shows that VOC emissions from the main technological processes reached 112.2 kg/t of production, and a considerable amount of energy (up to 771.6 kWh/t of production) was used. Three integrated pollution prevention and control (IPPC) alternatives of the five analysed in this study were selected and implemented within the company to reduce its VOC emissions and energy consumption. The results indicate that after the implementation of the three suggested economically reasonable IPPC alternatives (replacement of solvent-based with water-based inks; modernisation of the ventilation and lighting system), the VOC emissions decreased to 8.4 kg/t (92.5%) and the total energy consumption for the production of 1 t of flexible packaging decreased to 605.6 kWh/t (21.5%). This study shows that IPPC methods not only significantly reduces VOC emissions from flexible packaging printing processes, but also saves energy and raw materials, and reduces costs.     

Influence of ethanol-diesel blended fuels on diesel exhaust emissions and mutagenic and genotoxic activities of particulate extracts

This study was aimed at evaluating the influence of ethanol addition on diesel exhaust emissions and the toxicity of particulate extracts. The experiments were conducted on a heavy-duty diesel engine and five fuels were used, namely: E0 (base diesel fuel), E5 (5%), E10 (10%), E15 (15%) and E20 (20%), respectively. The regulated emissions (THC, CO, NOx, PM) and polycyclic aromatic hydrocarbon (PAH) emissions were measured, and Ames test and Comet assay, respectively, were used to investigate the mutagenicity and genotoxicity of particulate extracts. From the point of exhaust emissions, the introduction of ethanol to diesel fuel could result in higher brake specific THC (BSTHC) and CO (BSCO) emissions and lower smoke emissions, while the effects on the brake specific NOx (BSNOx) and particulate matters (BSPM) were not obvious. The PAH emissions showed an increasing trend with a growth of ethanol content in the ethanol-diesel blends. As to the biotoxicity, E20 always had the highest brake specific revertants (BSR) in both TA98 and TA100 with or without metabolizing enzymes (S9), while the lowest BSR were found in E5 except that of TA98-S9. DNA damage data showed a lower genotoxic potency of E10 and E15 as a whole.     

The role of information and communication technology in encountering environmental degradation: Proposing an SDG framework for the BRICS countries

Sustainability through information and communication technologies is a complex matter, raising interesting debate among researchers. Pursuing the same, this research investigates the impact of information and communication technologies, economic growth, and financial development on carbon dioxide emissions by simultaneously testing the Environmental Kuznets curve (EKC) hypothesis in BRICS countries. In doing so, this study employs Methods of Moments - Quantile Regression, which confirms that the effects of the explanatory variables vary across different quantiles of carbon dioxide emissions. The overall results indicate that economic growth and financial development contribute to carbon dioxide emissions across all quantiles, while information and communication technologies significantly mitigate the level of carbon dioxide emissions only at lower emissions quantiles. Moreover, the results confirm the presence of the EKC hypothesis. Interestingly, the effect of economic growth and information and communication technologies on carbon dioxide emissions is lowest in magnitude at lower quantiles and highest at higher quantiles of carbon dioxide emissions. The empirical findings of DH panel heterogenous causality test confirm bidirectional causality between the model parameters, indicating that any policy intervention concerning explanatory variables significantly causes carbon dioxide emissions and vice versa. The results set out the foundation for policymakers to devise a policy framework to attain the objectives of Sustainable Development Goals (SDGs).     

荔枝全程冷链物流碳足迹测算分析及实证研究

目的针对系统衡量双渠道流通模式下荔枝全程冷链物流的碳排放问题,构建一种计算碳足迹模型,以衡量该过程中的碳排放情况,并对其展开实证研究。方法采用碳排放系数法、投入产出法,测算批发商开设的双渠道流通模式的荔枝采后预冷、流通加工、冷藏运输、贮存、配送、销售以及终端消费者等各环节所产生的碳排放量,并借助Matlab对模型进行优化求解,在设定参数的条件下,以及考虑碳排放的情况下,分别以总成本最小和总碳排放量最小进行运算。结果通过实证可知,总成本均为407.34万元,总碳排放量均为223.14t。通过对断链情况下的荔枝双渠道流通模式碳足迹进行对比分析发现,荔枝在断链的流通模式下的总成本为453.99万元,碳排放量为225.71 t;通过对不同包装下的腐损率进行对比分析发现,在考虑碳排放情况下,腐损率从0上升到30%时,碳排放量上升了4%。结论该模型能有效衡量双渠道流通模式下荔枝全程冷链物流活动的碳足迹,为荔枝运用全程冷链物流的经济效益和环境效益最大化协同的设计和实施提供了支撑。     

Joint decisions on inventory replenishment and emission reduction investment under different emission regulations

Carbon emission regulation policies have emerged as mechanisms to control firms’ carbon emissions. To meet regulatory requirements, firms can make changes in their production planning decisions or invest in green technologies. In this study, we analyse a retailer’s joint decisions on inventory replenishment and carbon emission reduction investment under three carbon emission regulation policies. Particularly, we extend the economic order quantity model to consider carbon emissions reduction investment availability under carbon cap, tax and cap-and-trade policies. We analytically show that carbon emission reduction investment opportunities, additional to reducing emissions as per regulations, further reduce carbon emissions while reducing costs. We also provide an analytical comparison between various investment opportunities and compare different carbon emission regulation policies in terms of costs and emissions. We document the results of a numerical study to further illustrate the effects of investment availability and regulation parameters.     

New tools to control and reduce fugitive emissions

Three main sources of pollutant gas emissions are found in industrial, chemical and petrochemical plants: accidental, canalised (chimney and flare stack), and fugitive sources. The latter may come from liquid or gas storage, regulated processes or various equipment (flanged joints, pumps, valves etc.). Considered individually, the fugitive emissions represent a very low leakage flow, but the amount of volatile organic compound (VOC) fugitive emissions was estimated at 25 million tonnes in 1999.     

CdTe photovoltaics: Life cycle environmental profile and comparisons

We discuss the emissions of cadmium throughout all the life stages of CdTe PV modules, from extracting, refining, and purifying the raw materials to producing, using, and disposing or recycling of the modules. Then, we compare these emissions with those in the life cycle of three different types of crystalline Si PV modules. The energy requirement and energy pay back times (EPBT) of CdTe PV modules are considerably shorter than that of crystalline Si modules, although the latter exhibit higher efficiencies. This difference is primarily due to the energy used to process silicon, a fraction of which is derived from fossil fuels, inevitably producing Cd and many other heavy-metal emissions. The lower energy requirement of CdTe PV results in lower emissions of all pollutants, including cadmium.     

An overview of air emission intensities and environmental performance of grey cement manufacturing in Canada

Air emissions generated in grey cement manufacturing originate primarily from the combustion of fossil fuels required to heat the kiln and the chemical reaction of raw materials in the pyroprocessing phase. Given that the kiln system is enclosed, air emissions generated, discharge from a single point source kiln stack. Unlike other industries, the point source kiln stack enables the cement sector to accurately monitor and record total air emissions. The largest contributors to air emissions from grey cement manufacturing are carbon dioxide (CO₂), oxides of nitrogen (NO _x ), sulphur dioxide (SO₂) and dust/particulate matter (PM). In Canada, grey cement manufacturing facilities are required to annually report these emissions through the National Pollutant Release Inventory (NPRI). Since CO₂, NO _x , SO₂ and PM are the largest contributors to air emissions, and Canadian grey cement facilities are required to report these emissions, combining NPRI data with annual grey cement production data allows for the development of intensity-based environmental performance indicators. Based on data provided by NPRI, in combination with industry production, we can better understand the environmental performance of Canada’s grey cement manufacturing. On the global stage, intensity-based performance measures provide a useful tool for comparison and demonstrate a strong environmental performance for grey cement production in Canada. As an energy intensive and trade exposed (EITE) grey cement manufacturing is vulnerable to unbalanced environmental policy, which may ultimately result in leakage of production and air emissions to developing countries.     

Climate/chemistry feedbacks and biogenic emissions

The oxidizing capacity of the atmosphere is affected by anthropogenic emissions and is projected to change in the future. Model calculations indicate that the change in surface ozone at some locations could be large and have significant implications for human health. The calculations depend on the precise scenarios used for the anthropogenic emissions and on the details of the feedback processes included in the model. One important factor is how natural biogenic emissions will change in the future. We carry out a sensitivity calculation to address the possible increase in isoprene emissions consequent on increased surface temperature in a future climate. The changes in ozone are significant but depend crucially on the background chemical regime. In these calculations, we find that increased isoprene will increase ozone in the Northern Hemisphere but decrease ozone in the tropics. We also consider the role of bromine compounds in tropospheric chemistry and consider cases where, in a future climate, the impact of bromine could change.     

A theoretical model for the electromagnetic radiation emission during plastic deformation and crack propagation in metallic materials

This paper presents a theoretical model for the electromagnetic radiation (EMR) emissions during plastic deformation and crack propagation in metallic materials. It is shown that under an externally applied stress, edge dislocations within the plastic zone ahead of a crack tip form accelerated electric line dipoles which give rise to the EMR emissions. The dynamic motion of these dislocations becomes overdamped, underdamped or critically damped, depending upon the material/microstructural properties such as mass per unit length of dislocation, line tension, damping coefficient, and distance between the dislocation pinning points. The nature of the EMR signals, viz. exponential decay or damped sinusoidal, is decided essentially by these damping characteristics. The EMR emissions are followed by crack propagation in metallic materials. The EMR has a continuous frequency spectrum with a frequency bandwidth ranging from 10⁸ to 10¹² radians s⁻¹, depending upon the properties of the metals. Screw dislocations do not contribute to the EMR emissions. The paper also presents some experimental results on the EMR emissions in ASTM B265 grade 2 titanium sheets. The nature (damped sinusoidal and exponential decay), amplitude and frequency of the observed EMR emissions are in conformity with the predictions of the theoretical model.     

Quantifying greenhouse-gas emissions from atmospheric measurements: a critical reality check for climate legislation

Emissions reduction legislation relies upon 'bottom-up' accounting of industrial and biogenic greenhouse-gas (GHG) emissions at their sources. Yet, even for relatively well-constrained industrial GHGs, global emissions based on 'top-down' methods that use atmospheric measurements often agree poorly with the reported bottom-up emissions. For emissions reduction legislation to be effective, it is essential that these discrepancies be resolved. Because emissions are regulated nationally or regionally, not globally, top-down estimates must also be determined at these scales. High-frequency atmospheric GHG measurements at well-chosen station locations record 'pollution events' above the background values that result from regional emissions. By combining such measurements with inverse methods and atmospheric transport and chemistry models, it is possible to map and quantify regional emissions. Even with the sparse current network of measurement stations and current inverse-modelling techniques, it is possible to rival the accuracies of regional 'bottom-up' emission estimates for some GHGs. But meeting the verification goals of emissions reduction legislation will require major increases in the density and types of atmospheric observations, as well as expanded inverse-modelling capabilities. The cost of this effort would be minor when compared with current investments in carbon-equivalent trading, and would reduce the volatility of that market and increase investment in emissions reduction.     

The effect of annealing and photoactivation on the optical transitions of band-band and surface trap states of colloidal quantum dots in PMMA

For optoelectronic applications, colloidal CdSe quantum dots (QDs) have been integrated into solid devices by using optically transparent polymer matrices that embedded the colloidal QDs. We systematically studied the effect of annealing and photoactivation on the band-band (BB) and surface trap state (STS) transitions of colloidal CdSe QDs embedded in polymethylmethacrylate (QDs-PMMA). The QDs-PMMA composites demonstrate enhancement of the STS emissions while their annealing leads to an intensity quench of both BB and STS emissions. The annealing process also causes the red shift of the BB emission. By contrast, photoactivation of QDs-PMMA composites results in the remarkable recovery of luminescence intensity accompanied by blue shift of the emissions. Furthermore, it is found in the photoactivation process that the STS emission can be saturated earlier than the BB emission, which renders it possible to tune the light color of the emissions. The combination of annealing and photoactivation could undoubtedly provide an effective way to precisely tune the colors of light-emitting devices that use colloidal CdSe QDs.     

Can industrial robots reduce carbon emissions? Based on the perspective of energy rebound effect and labor factor flow in China

China is a major robot-use and carbon-emitting country, and it is imperative to explore industrial robots' impact on carbon emissions to achieve the nation's planned low-carbon transition. Previous studies have neglected to consider the energy rebound stimulating effect of adopting industrial robots. To address this gap, we explored the relationships between industrial robots, carbon emissions, and the energy rebound effect by applying a fixed-effects model that considers cross-sectional dependence, using data from 2008 to 2019. We also analyze the moderating effect of labor factor mobility on industrial robots and regional differences in conjunction with the labor substitution effect of industrial robots. Three relevant conclusions are obtained. First, although using industrial robots reduces carbon emissions, it also leads to an energy rebound effect, partially offsetting industrial robots' carbon reduction performance. Second, the resulting emissions reduction and energy rebound effects in the western region are greater than those in eastern and central regions. This suggests that the use of industrial robots in less industrialized regions could yield better emissions reduction effects but requires awareness and mitigation of potential increased energy consumption. Third, labor factor flow negatively moderates the impact of industrial robots on carbon emissions, indicating that labor flow between cities reinforces the emissions reduction effect of industrial robots. The negative moderating effect of labor factor flow is greatest in the western region compared to eastern and central regions. Thus, we need adequate awareness of the energy rebound effect in the use of industrial robots. Meanwhile, removing barriers to labor flow between cities could further stimulate the carbon reduction effect.     

Do innovation in environmental-related technologies cyclically and asymmetrically affect environmental sustainability in BRICS nations?

This study contributes to the current research by identifying the cyclical and asymmetrical impact of innovation in environmental-related technologies on carbon dioxide emissions in BRICS economies, as well as control variables such as fossil fuels, export taxes, household consumption expenditures, and exports, for the period 1990(Q1)-2016 (Q4). Following are some of the key findings. First, the data analysis indicated a significant long-term positive link between negative shocks to innovation in environmental-related technologies and carbon dioxide emissions during the economic downturn. Second, positive shocks to innovation in environmental-related technologies minimize carbon dioxide emissions during the economic upturn. Third, the relationship between innovation shocks in environmental-related technologies and carbon dioxide emissions was counter-cyclical during business cycles. Fourth, impact of positive shocks to innovation in environmental-related technologies on carbon dioxide emissions was more than the impact of negative shocks to innovation in environmental-related technologies on carbon dioxide emissions. Fifth, increasing the export tax serve as an effective measure to mitigate carbon dioxide emissions. Sixth, an increase in exports, use of fossil fuels, and household consumption expenditures contributed to the carbon dioxide emissions. Based on estimated results, the paper suggests policy implications for policymakers to reduce carbon dioxide emissions.     

Valve fugitive emission measurement standards

During the early 1990s emissions from valves were estimated to be responsible for 60–70% of plant fugitive emissions. The implementation of legislation in the US governing emissions of volatile organic compounds (VOCs), together with EU directives, has provided a stimulus for work aimed at reducing fugitive emissions. This has led to extensive work by plant operators and their suppliers to reduce emissions. An agreed procedure for the measurement of emissions, the qualification of valves and subsequent production testing has yet to be finalized. In this feature Dr David Harrison, the UK Principal Expert on the ISO 15848 Valve Fugitive Emissions Working Group (ISO TC 153/SC1/WG10), discusses the ISO standard, and also some of the alternatives in current industrial use.