Mobile Sources Research Articles

Preventive allocation and post-disaster cooperative dispatch of emergency mobile resources for improved distribution system resilience

Repair crews (RCs) and mobile power sources (MPSs) are emergency mobile resources (EMRs) for distribution system repair and restoration. In this paper, an outage management strategy (OMS) is proposed to improve the distribution system resilience against extreme weather events in both preventive and post-disaster stages. In the preventive stage, considering the uncertainty of fault location, the resource allocation problem is formulated as a two-stage stochastic programming to minimize the expected load shedding cost shortly after the disaster. The post-disaster stage is a cooperative dispatch of EMRs, accompanied by dynamic microgrid formation. With the progress of line repair, the MPSs are dispatched to different locations to support microgrids. The optimal repair sequence of faulted lines and scheduling of MPSs are determined in a multi-timeslot dispatch model. The proposed algorithm is validated by IEEE 123-bus test system and a 118-bus real-world system. The simulation results demonstrate that OMS can efficiently restore critical loads via an optimal utilization of mobile resources.

Unequal Health Risks of Integrated Volatile Organic Compounds Emitted From Various Anthropogenic Sources

AbstractVolatile organic compounds (VOCs) emitted from anthropogenic sources are critical precursors to ozone and secondary organic aerosol (SOA), and potential contributors to health risks. However, quantitatively estimating the impact of these source‐derived VOCs on air quality and health is limited by their diverse chemical compositions, resulting in nonselective mass‐based VOC control strategies. To address this issue, we conducted a comprehensive study of typical VOC samples freshly emitted from various flue gases via field‐based measurements and chemical analysis under the same quality control. Our results showed that different source‐specific VOC profiles have unequal sensitivities to chemical reactivity on ozone and SOA formation potential, as well as potential health risks. Mobile sources and residential solid fuel burning were identified as the most sensitive sources of potential secondary pollutants and potential inhalation health risks, respectively. Despite accounting for only 22.7% of the total mass, residential VOCs contributed significantly to both inhalation non‐cancer risk (NCR) (57.4%) and cancer risk (CR) (47.3%). The large inequality between residential VOC emissions and their health risks highlights the necessity of continuously promoting the transition from mass‐based VOC control to effect‐oriented VOC control. This suggests that mobile sources is worth more attention for secondary pollutant formation, while residential solid fuel burning sources should receive more policy priority to reduce health risks.

Electoral Competition between Social Democracy and the Populist Radical Right: How Welfare Regimes Shape Electoral Outcomes

This study examines how the growing competition over immigration and welfare between social democratic parties and populist radical right parties impacts electoral outcomes. The study argues that the historical legacies of the social democratic and conservative welfare regimes influence how voters respond to this competitive struggle. The findings support this argument. In the social democratic regime, populist radical right parties gain more support when they compete over welfare, although Nordic social democratic parties can mitigate this trend by appearing tough on immigration. However, populist radical right parties’ emphasis on welfare is the main source of electoral mobilization, particularly among voters with anti-immigration sentiments. In the conservative regime, the competitive dynamic is less connected to immigration, and populist radical right parties’ welfare discourse appeals primarily to economically vulnerable voters, while social democratic parties lose votes by taking a strict stance on immigration. These results have important implications and suggest that welfare regimes shape voting behaviour differently today than in previous eras.

Characteristics and Source Apportionment of Volatile Organic Compounds in Zhanjiang in Summer

Ozone pollution is intensifying in China, and its related studies are weak in non-focus regions and non-focus cities. Here, we investigated the characteristics and sources of volatile organic compounds (VOCs) at three sampling sites in Zhanjiang. We analyzed 101 VOCs using a gas chromatography-mass spectrometry/hydrogen ion flame detector (GC-MS/FID) and high-performance liquid chromatography (HPLC) using a Summa canister and DNPH adsorption tube. We calculated the ozone formation potential (OFP) of VOCs and used the positive matrix factorization (PMF) model for source apportionment. The results showed that the mean φ(TVOCs) was 1.28×10-7, and the dominant contributors were OVOCs (52%), followed by alkanes (36%), alkenes (7%), halogenated hydrocarbons (2.42%), aromatic hydrocarbons (1.61%), and alkynes (0.78%). The diurnal variation in VOCs was influenced by photochemical reactions; the ratio of aromatic hydrocarbons and alkanes was high in the morning and evening and low at noon, whereas OVOCs had a low ratio in the morning and noon and high in the evening, influenced by primary emissions and the upwind transport of pollutants. The OFP was 3.28×10-7, and the dominant species were formaldehyde, butene, n-butane, butanone, and acetaldehyde.The analysis of X/E values (characterizing the aging degree of air masses) and backward trajectories of air masses showed that during the sampling, when influenced by air masses from the south or southwest, X/E was small, and the aging degree of air masses was high, indicating the influence of regional transport; when influenced by air masses from the east or southeast direction, X/E was large, and the air masses were fresh, and VOCs were mainly from local emissions. Six emission sources of VOCs, including industrial emissions, gasoline vehicle exhaust and gasoline evaporation, regional background and transport sources, biomass combustion, diesel vehicles and marine shipping emissions, and solvent use emission sources, were resolved using the PMF model, with contributions of 36.05%, 28.99%, 13.84%, 10.13%, 7.05%, and 3.95%, respectively.Zhanjiang should strengthen the supervision of formaldehyde, butene, n-butane and butanone, industry sources, and mobile sources as the focus of control.

Contribution of anthropogenic pollutant sources to greenhouse gas emissions: a case study from a developing country.

Anthropogenic greenhouse gas (GHG) emissions are the primary cause of climate change, one of the biggest challenges for humankind. To tackle this problem, the international community is looking for ways to reduce GHG emissions. To create reduction strategies in a city/province/country, there is a need for an inventory that provides emission amounts from different sectors. This study aimed to develop a GHG emission inventory for Karaj, a megacity in Iran, using international guidelines such as AP-42 and ICAO, and IVE software. The emissions of mobile sources were accurately calculated by a bottom-up method. The results showed that power plant with 47% of the total emissions is the primary GHG contributor in Karaj. Residential and commercial units with 27% and mobile sources with 24% of the total emissions play a critical role in emitting GHGs in Karaj. On the other hand, the industrial units and the airport have negligible (2%) contribution to the total emissions. Subsequent estimates showed that GHG emissions per capita and per GDP of Karaj were 6.03 t per person and 0.47 t per thousand US dollars, respectively. These amounts are higher than the global averages (4.97 t per person and 0.3 t per thousand US dollars). The relatively high GHG emissions in Karaj are due to the sole reliance on the consumption of fossil fuels. To reduce emissions, mitigation strategies such as developing renewable energy sources, switching to low-emission transportation, and raising public awareness should be implemented.

Radiation dose-event relationship after intraoperative radiotherapy as a boost in patients with breast cancer.

Intraoperative radiotherapy (IORT) can be used as a boost in combination with external whole breast irradiation. This study reports the clinical and dosimetric factors associated with IORT-related adverse events (AE). Between 2014 and 2021, 654 patients underwent IORT. A single fraction of 20 Gy was prescribed to the surface of the tumour cavity using the mobile 50-kV X-ray source. For skin dose measurement, at least four optically stimulated luminescent dosimeter (OSLD) chips were annealed and attached to the skin edge in the superior, inferior, medial, and lateral locations during IORT. Logistic regression analyses were conducted to identify factors associated with IORT-related AE. With a median follow-up period of 42 months, 7 patients experienced local recurrence, resulting in a 4-year local failure-free survival rate of 97.9%. The median skin dose measured by OSLD was 3.85 Gy (range, 0.67-10.89 Gy), and a skin dose of > 6 Gy was observed in 38 patients (2%). The most common AE was seroma (90 patients, 13.8%). We also found that 25 patients (3.9%) experienced fat necrosis during follow-up, and among them, 8 patients underwent biopsy or excision to exclude local recurrence. IORT-related late skin injury occurred in 14 patients, and a skin dose > 6 Gy was significantly associated with IORT-induced skin injury (odds ratio 4.942, 95% confidence interval 1.294-18.871, p = 0.019). IORT was safely administered as a boost to various populations of patients with breast cancer. However, several patients may experience severe skin injuries, and for older patients with diabetes, IORT should be performed with caution.

Assessment of light-duty versus heavy-duty diesel on-road mobile source emissions using general additive models applied to traffic volume and air quality data and COVID-19 responses

ABSTRACT Following the outbreak of the COVID-19 pandemic, several papers have examined the effect of the pandemic response on urban air pollution worldwide. This study uses observed traffic volume and near-road air pollution data for black carbon (BC), oxides of nitrogen (NOx), and carbon monoxide (CO) to estimate the emissions contributions of light-duty and heavy-duty diesel vehicles in five cities in the continental United States. Analysis of mobile source impacts in the near-road environment has several health and environmental justice implications. Data from the initial COVID-19 response period, defined as March to May in 2020, were used with data from the same period over the previous two years to develop general additive models (GAMs) to quantify the emissions impact of each vehicle class. The model estimated that light-duty traffic contributes 4–69%, 14–65%, and 21–97% of BC, NOx, and CO near-road levels, respectively. Heavy-duty diesel traffic contributes an estimated 26–46%, 17–63%, and −7–18% of near-road levels of the three pollutants. The estimated mobile source impacts were used to calculate NOx to CO and BC to NOx emission ratios, which were between 0.21–0.32 μg m−3 NOx (μg m−3 CO)−1 and 0.013–0.018 μg m−3 BC (μg m−3 NOx)−1. These ratios can be used to assess existing emission inventories for use in determining air pollution standards. These results agree moderately well with recent National Emissions Inventory estimates and other empirically-derived estimates, showing similar trends among the pollutants. However, a limitation of this study was the recurring presence of an implausible air pollution impact estimate in 41% of the site-pollutant combinations, where a vehicle class was estimated to account for either a negative impact or an impact higher than the total estimated pollutant concentration. The variations seen in the GAM estimates are likely a result of location-specific factors, including fleet composition, external pollution sources, and traffic volumes. Implications: Drastic reductions in traffic and air pollution during the lockdowns of the COVID-19 pandemic present a unique opportunity to assess vehicle emissions. A General Additive Modeling approach is developed to relate traffic levels, observed air pollution, and meteorology to identify the amount vehicle types contribute to near-road levels of traffic-related air pollutants (TRAPs), which is important for future emission regulation and policy, given the significant health and environmental justice implications of vehicle-related pollution along major roadways. The model is used to evaluate emission inventories in the near-road environment, which can be used to refine existing estimates. By developing a locally data-driven method to readily characterize impacts and distinguish between heavy and light duty vehicle effects, local regulations can be used to target policies in major cities around the country, thus addressing local health disbenefits and disparities occurring as a result of exposure to near-road air pollution.

Anthropogenic emission inventory and spatial analysis of greenhouse gases and primary pollutants for the Galapagos Islands.

Climate change and air pollution are critical challenges that humanity is currently facing. Understanding the sources of emissions released into the atmosphere is of great importance to evaluate the local footprint, the impacts of human activities, and the opportunities to develop and implement solutions to mitigate emissions and adapt to climate change particularly in vulnerable places like the Galapagos Islands. In this study, we present an anthropogenic emissions inventory for Santa Cruz, San Cristobal, and Isabela Islands in which emissions were spatially mapped for greenhouse gasses (GHGs) and primary pollutants (PP). Emissions were estimated for the energy stationary sources, energy mobile sources, waste, and other sectors, and emissions for 2019 were spatially distributed along with an uncertainty assessment. Results demonstrated that energy mobile sources which are aerial, terrestrial, and maritime transportation generated the most significant emissions in the Galapagos Islands in terms of PP and GHGs. In fact, maritime transportation was the highest one in 2019, at 41% of total CO2 emissions for Galapagos, with the most predominant PP being NOx and CO. The aerial transportation made up 36% of emissions, and the electricity generation contributed 15%. Emissions from waste and other sectors comprise a smaller percentage relative to the rest of the emission sectors. These results highlight the strong dependency of the islands on fossil fuels for transportation and electricity generation. Alternatives to mitigate and reduce emissions from the islands are discussed. This spatially mapped emissions inventory for the Galapagos Islands represents a powerful tool to make informed decisions to contribute to the long-term sustainability of the archipelago.

A Bayesian Nuclide Identification Algorithm Based on the Energy Spectrum

A fast and reliable nuclide identification algorithm is important to the detection of radioactive materials, and the emergence of a sequential Bayesian algorithm provides a new direction of research on radioactive detection. This article proposes a Bayesian nuclide identification algorithm based on the energy spectrum and deploys the algorithm on a microprocessor for real-time online processing. The algorithm builds a probability model based on the natural background radiation and radioactive source radiation and a decision function based on sequence testing. The processor conducts a posteriori estimation on the collected energy spectrum at fixed time intervals and updates the decision function. A laboratory self-developed CeBr3 detector was used in testing. Four radioactive sources, namely 241Am, 133Ba, 137Cs, and 60Co, were used in experiments with fixed and moving radioactive sources. The experimental results show that the proposed algorithm can rapidly identify mixed and mobile radioactive sources.

Synthesis of Satellite and Surface Measurements, Model Results, and FRAPPÉ Study Findings to Assess the Impacts of Oil and Gas Emissions Reductions on Maximum Ozone in the Denver Metro and Northern Front Range Region in Colorado

AbstractThe Denver Metro/Northern Front Range area has been designated a severe nonattainment area (NAA) for O3. Previous research associated with the 2014 Front Range Air Pollution and Photochemistry Éxperiment field campaign and a 2017 O3 source apportionment modeling analysis point to north‐south gradients in oil and gas (O&G) impacts on O3, with greater contributions to the north and a dominance of mobile sources to the south. Recent analysis of Atmospheric Infrared Sounder satellite methane enhancement and ethane trends in the area show ∼50% and ∼70% reductions in methane and ethane, respectively, from 2013 to 2020. These are consistent with reductions in O&G volatile organic compound (VOC) emissions estimated in the most recent O3 State Implementation Plan but inconsistent with a timeline of top‐down methane flux estimates for limited periods from 2012 to 2021. Reductions in annual fourth maximum eight‐hour O3 concentrations from 2012 to 2019 are 5 ppb greater at Fort Collins West (FTCW) to the north than at Chatfield Reservoir to the south. Bayesian correlation analyses and partial correlations between FTCW O3 and ethane conditioned for tropospheric NO2 from the Aura satellite Ozone Monitoring Instrument suggest that most of the 9‐ppb reduction here is due to declines in O&G emissions, and 9 ppb is comparable to estimated O&G VOC contributions on high‐concentration days in the northern portion of the study area. The gradient in trends suggests that significant O&G emissions reductions have benefited locations in the central and northern portions of the NAA.

Route-based chemical significance and source origin of marine PM2.5 at three remote islands in East Asia: Spatiotemporal variation and long-range transport

We explored the route-based chemical significance, spatial distribution, temporal variation, and source origin of fine particles (PM2.5) in East Asia. Marine PM2.5 was sampled at three remote islands in the Taiwan Strait (TS) and the South China Sea (SCS) to identify their chemical significance. High PM2.5 concentrations concurred with LRT of northerly polluted air. Moreover, daytime PM2.5 levels were mostly greater than nighttime. Secondary inorganic aerosols (SIAs) accounted for 42.4–79.9% of water-soluble ions (WSIs) in PM2.5, which were commonly higher in spring and winter. Although crustal elements suppressed the metallic contents of PM2.5, trace elements (V, Cr, Mn, Ni, Zn, and Cd) came dominantly from anthropogenic origins. Additionally, OC/EC ratios >2.0 were observed due to higher organic carbon (OC) than elemental carbon (EC) during the Asian Northeastern Monsoons (ANMs) commonly in spring and winter. Levoglucosan and oxalic acid were, respectively, the most abundant anhydrosugars (ASs) and organic acids (OAs) in PM2.5, and both descended from the north to the south. The mass ratios of malonic and succinic acids (M/S) were in the range of 0.95–1.41, suggesting a high correlation of marine PM2.5 with secondary organic aerosols (SOAs). Source resolution of PM2.5 showed that sea salts, fugitive dust, mobile sources, secondary sulfate and nitrate were the major sources of PM2.5. In particular, anthropogenic origins and biomass burning (BB) contributed notably to PM2.5 during the ANMs. Overall, compared to natural sources (21–48%), anthropogenic sources (25–57%) contributed more to marine PM2.5 in East Asia.

РОЗРАХУНКОВИЙ МЕТОД ОЦІНКИ ВПЛИВУ ТРАНСПОРТНИХ ЗАСОБІВ НА ПОВІТРЯНЕ СЕРЕДОВИЩЕ

Introduction. The negative impact of vehicles is primarily occurs not only in big cities and on roads in megacities, but also on public roads with heavy traffic. The specifics of mobile sources of pollution (cars) occurs in their low location, spatial distribution and close proximity to populated areas. All this leads to the fact that motor vehicles create big and persistent zones in which environmental standards of air pollution are exceeded several times. Problem statement. Actually, in Ukraine there are evaluation methods for determining the assessment of the impact on the air environment in the area affected by roads. Gross emissions of pollutants and warming gases from vehicles are determined exclusively by statistical data on fuel consumption by internal combustion engines of motor vehicles of legal entities and individuals. Purpose. Clarify the estimates of gross emissions of pollutants and warming gases in exhaust gases from the vehicles while driving on roads, including the implementation of EURO V European standards, with determination of the objective level of negative impact on the air environment. Materials and methods. Analytical, information-searching. Results. The paper presents the procedure for the evaluation of pollutants and warming gas emissions during the operation of vehicles driving on public roads. Conclusions. The performed analysis will allow us to evaluate the impact on the air environment in the area affected by roads highways by evaluation method, the procedure for assessment the emissions of pollutants and warming gases from vehicles driving on public roads has been determined.

Simulation and Estimation of the Inter-Source Category and/or Inter-Pollutant Emission Offset Ratios for a Heavy Industry City

Kao-Ping Air Basin (KPAB) is a heavy industrial area, and also the first and only air quality total quantity control district in Taiwan. Pollutant emission offsetting is an important tool to reduce pollution source emissions and improve air quality in the total quantity control district. In this study, an air quality model was employed to evaluate the sensitivity of SOX, NOX, and primary PM2.5 emissions from point, mobile, and fugitive sources on PM2.5 concentrations in KPAB. The findings show that the emission offset ratios of mobile PM2.5-to-point PM2.5 and fugitive PM2.5-to-point PM2.5 were both greater than one in urban areas (1.3 and 2.0, respectively) and both less than one in non-urban areas. The offset ratios of point SOX-to-point PM2.5 and point NOX-to-point PM2.5 were significantly greater than one, especially those in urban areas (20 and 60, respectively) were higher than those in non-urban areas by more than 2–4 times. No matter whether in urban or non-urban areas, the offset ratio of mobile NOX-to-point NOX was close to one, and the offset ratios of point NOX-to-point PM2.5 and mobile NOX-to-point PM2.5 were similar. The above findings were closely related to the proximity of point sources to densely populated urban areas in KPAB.

Deactivation of Cu SCR catalysts based on small-pore SSZ-13 zeolites: A review

Increasingly stringent regulation towards nitrogen oxides (NOx) emission is foreseen across the world to mitigate their detrimental effects on environment and human health. Selective catalytic reduction (SCR) of NOx with NH3 is regarded as the most efficient technology for NOx abatement in both mobile and stationary sources. As the state-of-art SCR catalyst, transition metals supported on small-pore zeolites, especially Cu on chabazite SSZ-13 (Cu-SSZ-13), have been successfully applied to NOx abatement in road transport. Their application can be expanded to stationary sources due to the gradual phase-out of petrol/diesel vehicles worldwide between 2030 and 2035. Accordingly, the stability and activity of such catalysts need to be revisited and tuned to accommodate the complex operating conditions in various industries such as wider temperature windows and the more complex compositions of the exhausts. This review focuses on the poisoning and deactivation of zeolite-based SCR catalysts, especially Cu-SSZ-13. State-of-the-art of different mechanisms of deactivation (including hydrothermal ageing, sulphur poisoning, hydrocarbon poisoning and chemical poisoning) are discussed critically, attempting to establish the link between current zeolite-based SCR catalysts and the possible application demands in industries.

Microplastic ingestion affects hydrogen production and microbiomes in the gut of the terrestrial isopod Porcellio scaber.

Microplastic (MP) is an environmental burden and enters food webs via ingestion by macrofauna, including isopods (Porcellio scaber) in terrestrial ecosystems. Isopods represent ubiquitously abundant, ecologically important detritivores. However, MP-polymer specific effects on the host and its gut microbiota are unknown. We tested the hypothesis that biodegradable (polylactic acid [PLA]) and non-biodegradable (polyethylene terephthalate [PET]; polystyrene [PS]) MPs have contrasting effects on P. scaber mediated by changes of the gut microbiota. The isopod fitness after an 8-week MP-exposure was generally unaffected, although the isopods showed avoidance behaviour to PS-food. MP-polymer specific effects on gut microbes were detected, including a stimulation of microbial activity by PLA compared with MP-free controls. PLA stimulated hydrogen emission from isopod guts, while PET and PS were inhibitory. We roughly estimated 107 kg year-1 hydrogen emitted from the isopods globally and identified their guts as anoxic, significant mobile sources of reductant for soil microbes despite the absence of classical obligate anaerobes, likely due to Enterobacteriaceae-related fermentation activities that were stimulated by lactate generated during PLA-degradation. The findings suggest negative effects of PET and PS on gut fermentation, modulation of important isopod hydrogen emissions by MP pollution and the potential of MP to affect terrestrial food webs.

Simulation Investigation on Thermal Characteristics of Thermal Battery Activation Process Based on COMSOL

Current thermal simulation methods are not suitable for small-size fast-activation thermal batteries, so this paper provides an improved simulation method to calculate thermal cell temperature changes using the COMSOL platform. A two-dimensional axisymmetric model of thermal batteries has been established, considering the actual heat release situation and the mobile heat source of thermal batteries. Based on it, the temperature change and electrolyte melting of thermal batteries under high-temperature conditions (50 °C) have been simulated, in which the temperature change law, thermal characteristics, and electrolyte melting characteristics have been analyzed in depth. The results show that the additional heating flakes and insulation design above and below the stack can effectively reduce heat loss. Most of the melting heat of the electrolyte flows in from the negative side. In addition, the thermal battery activation time has been calculated to be 91.2 ms at the moment when all the thermal battery electrolyte sheets begin to melt, and the absolute error was within 10% compared with the experimental results, indicating that the simulation model has high accuracy and can effectively broaden the simulation area of thermal batteries.

Characteristics and Source Apportionment of PM2.5 in the Core Area of Ili River Valley in Spring

To explore the characteristics and sources of PM2.5 in the core area of Ili River Valley in spring, a total of 140 PM2.5 samples were collected at six sampling sites during April 20-29, 2021, and 51 chemical components including inorganic elements, water-soluble ions, and carbon components were analyzed. The results showed that ρ(PM2.5) was at a low level during sampling, ranging from 9 μg·m-3 to 35 μg·m-3. Si, Ca, Al, Na, Mg, Fe, and K were the most abundant elements, accounting for 12% of PM2.5, indicating that PM2.5 was affected by the dust sources in spring. The spatial distribution characteristics of elements depended on the surrounding environments of the sampling sites. The new government area was affected by coal-fired sources, so the value of As concentration was high. Yining Municipal Bureau and the Second Water Plant were greatly affected by motor vehicle sources, so the values of Sb and Sn concentration were higher. The enrichment factor results showed that Zn, Ni, Cr, Pb, Cu, and As were mainly emitted from fossil fuel combustion and motor vehicles. The concentration of water-soluble ions accounted for 33.2% of PM2.5. Among them, ρ(SO42-), ρ(NO3-), ρ(Ca2+), and ρ(NH4+) were (2.48±0.57), (1.22±0.75), (1.18±0.49), and (0.98±0.45) μg·m-3, respectively. The higher Ca2+ concentration also reflected the contribution of dust sources. The ratio of n(NO3-)/n(SO42-) was between 0.63 and 0.85, which indicated that the influence of stationary sources was more important than that of mobile sources. Both Yining Municipal Bureau and the Second Water Plant were affected by motor vehicle exhaust; therefore, their n(NO3-)/n(SO42-) ratios were high. Yining County was in a residential area, and therefore its n(NO3-)/n(SO42-) ratio was lower. The average ρ(OC) and ρ(EC) in PM2.5 were 5.12 μg·m-3(4.67-6.25 μg·m-3) and 0.75 μg·m-3(0.51-0.97 μg·m-3), respectively. Yining Municipal Bureau was significantly affected by motor vehicle exhaust from both sides, so the values of OC and EC concentration were slightly higher than those in other sampling sites. The SOC concentration was calculated by the minimum ratio method, and the results showed that the values of SOC concentration in the New Government Area, the Second Water Plant, and Yining Ecological Environment Bureau were higher than those in other sampling sites. The results of the CMB model showed that PM2.5 in this area mainly came from the contribution of secondary particulate matter and dust sources, which accounted for 33.3% and 17.5%, respectively. Secondary organic carbon (16.2%) was the main contribution source of secondary particulate matter.

Coordinated restoration optimization of power-gas integrated energy system with mobile emergency sources

In an integrated energy system (IES) composed of multiple subsystems, energy coupling causes an energy supply blockage or shutdown in one subsystem, thereby affecting the energy flow distribution optimization of other subsystems. The energy supply should be globally optimized during the IES energy supply restoration process to produce the highest restoration net income. Mobile emergency sources can be quickly and flexibly connected to supply energy after an energy outage to ensure a reliable supply to the system, which adds complexity to the decision. This study focuses on a power- gas IES with mobile emergency sources and analyzes the coupling relationship between the gas distribution system and the power distribution system in terms of sources, networks, and loads, and the influence of mobile emergency source transportation. The influence of the transient process caused by the restoration operation of the gas distribution system on the power distribution system is also discussed. An optimization model for power-gas IES restoration was established with the objective of maximizing the net income. The coordinated restoration optimization decision-making process was also built to realize the decoupling iteration of the power-gas IES, including system status recognition, mobile emergency source dispatching optimization, gas-to-power gas flow optimization, and parallel intra-partition restoration scheme optimization for both the power and gas distribution systems. A simulation test power-gas IES consisting of an 81-node medium-voltage power distribution network, an 89-node medium-pressure gas distribution network, and four mobile emergency sources was constructed. The simulation analysis verified the efficiency of the proposed coordinated restoration optimization method.

Role of Ce in promoting low-temperature performance and hydrothermal stability of Ce/Cu-SSZ-13 in the selective catalytic reduction of NOx with NH3

With the increase of car ownership, new challenges are posed to the treatment of mobile source exhaust gas, especially denitration (de-NOx). It is urgent to develop highly efficient de-NOx catalyst with a wide working temperature window. In this work, a series of Ce modified Cu-SSZ-13 molecular sieves (Ce/Cu-SSZ-13) are prepared by ion exchange method with different exchange times (x = 1, 2, 4, 8 h), and the role of Ce in promoting low-temperature de-NOx performance and hydrothermal stability of Ce/Cu-SSZ-13 in the selective catalytic reduction (SCR) of NOx are investigated. Both the low-temperature de-NOx performance and the hydrothermal stability of Cu-SSZ-13 are enhanced due to the modification of Ce, especially the Ce/Cu-SSZ-13 with an exchange time of 2 h. Both Ce/Cu-SSZ-13 and Cu-SSZ-13 present more than 95 % NOx conversion in the temperature region of 210–600 °C, and Ce modification significantly improves the NOx conversion in the low-temperature range (120–210 °C). It is revealed that the acidity, the surface Cu2+/Cu+ ratio and the NH3 adsorption amount on Cu-SSZ-13 increase after Ce ion exchange, and the active component Cu2+ migrates to the more stable six-membered ring due to the modification of Ce, all of which have promote the improvement of NH3-SCR de-NOx performance. Furthermore, in the process of hydrothermal aging, the presence of Ce protects the framework of Cu-SSZ-13, acidic sites and active component Cu2+, which greatly improves the hydrothermal stability of Cu-SSZ-13 molecular sieve. In addition, in-situ DRIFTS shows that the developed Ce/Cu-SSZ-13 follows dual mechanisms of Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) to undergo NH3-SCR reaction. This work provides a new idea for improving the low-temperature de-NOx performance and hydrothermal stability of Cu-SSZ-13.

Fugitive Emissions from Mobile Sources—Experimental Analysis in Buses Regulated by the Euro 5 Standard

Fugitive emissions are unintentionally produced by pipeline leakage and evaporation in industrial processes and contribute 5% of Global Greenhouse Gas emissions (GHG). Frictional wear and thermal fatigue in vehicle exhaust pipe couplings and joints can cause leaks that are not visible and difficult to quantify. It is therefore essential to trace and document these sources. In this work, an experimental survey was conducted on buses in accordance with Regulation (EC) N° 715/2007 of the European Parliament. Statistical methods by means of a priori analysis aided by G∗Power 3.1 software was used to define the required sample. Three random sample groups were stratified and fugitive gases were encased and piped into a bronze tube 5 mm in diameter and 500 mm in length. A Horiba PG-300 analyzer was used to analyze the samples using chemiluminescence and infrared methods. The results proved the existence of fugitive emissions in all samples analyzed with variations of (3.000–27.500 ppm) among the samples for CO2, (6.0–138.5 ppm) and (2.0–5.0 ppm) for CO and NOx, respectively. Statistical analysis showed that engine mileage had no significant influence on NOx emissions, while CO and CO2 emissions increased with mileage. Analysis using Response Surface Methodology (RSM) indicated a trend of increasing concentrations of CO2 and CO for both explanatory variables, mileage and usage time.