Mobile Sources Research Articles

Monitoring induced microseismicity in an urban context using very small seismic arrays: The case study of the Vendenheim EGS project

Monitoring the seismicity induced by fluid injections in deep geothermal reservoirs is often limited by the significant anthropogenic ambient noise level inherent to most enhanced geothermal system (EGS) projects in urban contexts. We report on the performance of a monitoring network made of three small aperture (72 m) seismic arrays composed of 21 3D nodes. We test the setup for four months (from 12 December 2020 to 8 April 2021) of the Strasbourg sequence of induced earthquakes (2019–2022) related to the EGS Georhin project (Vendenheim, France). The deployment starts a few days after the MLv = 3.6 induced earthquake of 4 December 2020 and covers the early shut-in period of the wells. We use a beamforming technique to characterize the main noise sources, which consist of slow apparent velocities of surface waves emitted from mobile anthropogenic sources (motorway and railway traffic). We detect events with a phase-weighted stacking method, which is efficient when wavefronts illuminate the arrays with a high apparent velocity. Earthquakes associated with these detections are located using a matched field processing technique. The obtained catalog includes 216 seismic events, which represent four times more events than the reference catalog from Le Bureau Central Sismologique Français–Renass (the national academic agency in charge of seismicity monitoring in France), and a reduction of the completeness magnitude from 0.3 to −0.5. The clustering of the seismicity is analyzed using waveform correlation. The enriched catalog reveals intermittent seismic activity during the slow and continuous decrease in fluid pressure after shut-in.

Assessment of the state of the ecosystem of the Lipetsk region

The characteristics of the state of the ecosystem of the Lipetsk Region are presented on the basis of official statistical reporting by the Office of Rospotrebnadzor for the Lipetsk Region, the Lipetsk Center for Hydrometeorology and Environmental Monitoring - a branch of the Central Chernozem UGMS, the Department of Ecology and Natural Resources of the Lipetsk Region. Environmental problems of the Lipetsk region are associated with pollution of atmospheric air,drinking water, soil, and food products by toxic substances. Sources of environmental pollution are ferrous metallurgy, chemical industry, motor vehicles, agricultural production, including livestock. Anthropogenic anomalies of the habitat are becoming one of the main causes of veterinary problems in modern animal husbandry. The purpose of the study: to assess the state of the ecosystem of the territory of the Lipetsk region, including monitoring of surface watercourses in the area of the city of Lipetsk: the rivers Matyra, Voronezh, Lipovka and the Matyr reservoir. For the analysis of water sources for heavy metal contamination with an atomic absorption spectrometer with electrothermal authorization "MGA-1000". Sampling of natural water was carried out according to GOST 17.1.5.05-85. The volume of the sample taken was 250 ml, the filtrate was preserved with nitric acid. Statistical processing of analytical data was carried out by conventional methods.Up to 90% of emissions of harmful substances from stationary and mobile sources of pollution are accumulated by soil, from where toxins migrate into water and plants. The content of zinc slightly exceeded the maximum permissible level in 35% of the selected samples, %, manganese - in 32% and aluminum - in 34% of the selected samples. So the highest content of iron and lead was recorded in the river. Voronezh and in the region of Lipetsk, exceeding the MPC by 1.5 times. To a lesser extent, increases in MPC r. Matyr and Matyr-sky reservoir.

Real-world emission characteristics and inventory of volatile organic compounds originating from construction and agricultural machinery

Volatile organic compound (VOC) emissions originating from nonroad mobile sources constitute an important but uncertain source of secondary organic aerosols (SOAs) and ozone (O3). In this study, we investigated the emission factors (EFs) of 120 individual VOC species for 40 machines via gas chromatography–mass spectrometry/flame ionization detection and high-performance liquid chromatography. The results showed that the diesel-based VOC EF for the tested machines was 4.18 ± 2.55 (average ± standard deviation) g/kg fuel, dominated by alkanes (38.20 % ± 18.08 %) and oxygenated VOCs (OVOCs; 30.94 % ± 15.71 %). The machine type, rated power, emission standards, and operating conditions affected the emissions of VOCs and their components, and this effect maybe mostly depends on the fuel combustion efficiency. The VOC species were primarily distributed in the C1–C2 and C4–C6 (based on the carbon number) and B4–B6 (based on the saturated vapor concentration) intervals. Furthermore, the estimated formation potential (FP) values of SOAs and O3 from VOCs were 21.02 ± 15.57 mg/kg fuel and 15.96 ± 11.87 g/kg fuel, respectively. VOC control based on the SOA formation potential (SOAFP) and ozone formation potential (OFP) could be more effective in the mitigation of fine particulate matter (PM2.5) and O3 pollution because the top 5 species ranked by percentage contribution accounted for 83.09 % ± 9.59 % and 51.78 % ± 14.38 % of the estimated SOAFP and OFP, respectively. Finally, the emission estimates showed that the VOC emissions originating from construction and agricultural machinery in China (2020) reached 64.05 and 95.24 Gg, respectively. We provide species-specific VOC EFs and detailed emission characteristics to facilitate a comprehensive understanding of gas emissions originating from nonroad mobile sources and an update of emission inventories and atmospheric chemistry models.

Definition of linear regression models to calculate the technical parameters of Italian agricultural tractors

As it is known, the modern agricultural tractor is no longer just a machine capable to pull agricultural trailers and to operate implements but has evolved into a multi-purpose and mobile energy source with standardized interfaces (mechanical, hydraulic and electronic) to connect to a several typologies of agricultural operating machines. It follows that the selection of the most appropriate tractors for the specific production realities is a crucial aspect for farmers, advisors, contractors and farm machinery experts. The tractors choice thus must consider different parameters, concerning not only the cost of the machines but also their dimensions, power, weight, technological level, etc. The availability of simplified models for estimating the purchase investment and sizing the machine in relation to its mechanical characteristics could be a useful tool in the choice of the tractor more suitable for the specific agricultural context. The aim of this study was to collect and to analyse the technical parameters of tractors present on the Italian market (more than 1300 models), divided into: i) four wheel-drive (4WD) standard tractors, ii) two wheel-drive (2WD) standard tractors, iii) narrow track 4WD tractors, iv) Isodiametric specialized 4WD tractors, v) crawler tractors and vi) rubber-tracked tractors), in order to define the most relevant parameter-to-parameter and parameter-to-price relations for updating reference models to calculate the machine price and the weight to engine power ratio. Other relations, including the three-point hitch efficiency with respect to tractor’s weight and the relationship between the rated engine power and its displacement, are proposed in order to provide synthetic tools to characterise and to compare - from the mechanical point of view - the different categories of agricultural tractors.

Multiple sources emission inventory closely integrated with atmospheric environment management: A case study of Guangdong, China

The framework design and compilation methods of air emission inventory cannot connect multiple sets of environmental management statistics. The environmental statistics with different emission results increase the difficulty of policy making by the administrative departments. Based on the existing statistical system of environmental management in Guangdong Province, this study combines traditional compilation method of atmospheric pollution source emission inventory to optimize the classification system of air emission inventory and the integration based on multi-source data of environmental management. The study proposes a four-level classified pollution source system of national economy with Guangdong characteristics as well as a calculation method of multi-source data fusion supporting annually updating. Taking 2020 emission inventory formation as an example, results show that the emissions of SO2, NOx, VOCs, NH3, PM2.5, PM10 and CO in Guangdong Province are about 180, 985, 1,989, 390, 270, 750 and 2844 thousand tons respectively. In this case, SO2 and CO mainly come from industrial sources, NOx and PM2.5 mainly come from mobile sources, VOCs mainly come from natural sources, NH3 mainly comes from agricultural sources, and PM10 mainly comes from dust sources. The study raises a method of uncertainty grading evaluation and conducts a simulation verification of emission inventory accuracy. Results suggest that the emission inventory can reflect the emission status in 2020, but the quality of environmental management data of residential sources, dust sources and eastern Guangdong region still needs to be improved, and the pollution source control strategy of such sources or the region needs to be strengthened.

New territories for fan studies: The insurrection, QAnon, Donald Trump and fandom

The following roundtable is a recorded and edited discussion between four fan studies researchers that took place in March 2022. Having all worked with QAnon and the insurrection in the context of fan studies, our discussion took its departure from the US insurrection on January 6, 2021, as QAnon fans, Trump fans, and other right-wing groups stormed the US Capitol building while live-streaming their endeavor to social media. The discussion draws out some main perspectives that may guide our future thinking in the context of fandom, complicity, and politics and points toward new cultural and social territories for research into fandom and fan practices. Centrally, as fandom enters into the domain of politics and conspiracy theories, it seems increasingly unfruitful to distinguish between fan practices and participatory culture. Instead, participatory culture’s primary mode seems to be deeply driven by fan practices, that is, textual poaching and enunciative and textual productivity (Jenkins, 2013; Fiske, 1992). Instead, understanding this amalgamation of fan practices into other social domains can help us make sense of current phenomena in the seeming growth of conspiracy theory communities and right-wing movements alike. Participatory culture is a source of great creativity, playfulness, and mobilization of social and political movements, but, as Jenkins pointed out as early as 2006 “has benefited third parties, revolutionaries, reactionaries, and racists alike” (Jenkins, 2006, p. 221). In some instances, it seems that these online communities are driven by fan practices, in other instances fan communities are weaponized in order to serve a political agenda. While research into fandom and politics (see Hinck, 2019; Jenkins et al., 2020, Sandvoss, 2012, etc.) and toxic cultures (Proctor et. al., 2018) is certainly not new, it seems that the current transmedial landscapes drive participation and complicity in very specific ways that fan studies would do well to focus on in the coming years.

Dynamic modelling and control system design of micro-high-temperature gas-cooled reactor with helium brayton cycle

It is possible to use the micro-high-temperature gas-cooled reactor with helium Brayton cycle (Mi-HTR) as a mobile micro-nuclear power source to provide a stable power supply. Because the Mi-HTR is a highly integrated system, the devices involved are highly coupled and mutually constrained. Therefore, the dynamic model of 5 MW Mi-HTR was established through theoretical derivation. Compared with the design value, the maximum error of steady-state calculation results is less than 2%, and the temperature error is less than 1 K. The transient behaviour is consistent with the experimental trend. The maximum relative error of flow is less than 1.5%, and the maximum relative error of pressure is less than 2.8%. On this basis, the characteristics of Mi-HTR such as large time delay, nonlinear, strong coupling and parameter time-varying are obtained by analysing the dynamic characteristics. The steady-state operation scheme of Mi-HTR is proposed. The reactor outlet helium temperature control, the electric power/rotor speed control, and the precooler/intercooler outlet helium temperature control are designed. A dynamic control model for Mi-HTR is established. The designed control system can cope with the 33% step change of external load.

A Multi-Round Game-Based Source Location Privacy Protection Scheme With AUV Enabled in Underwater Acoustic Sensor Networks

With a growing demand for the development of smart ocean projects, the Internet of Underwater Things (IoUT) integrating multiple networks will gradually become the mainstream, particularly for civil, commercial, and military scenarios. During development, however, the security aspect cannot be ignored. Faced with possible future battles on the ocean, this study focuses on underwater source location privacy protection for both static and mobile sources. By combining the Ekman drift model, location privacy protection is converted into multi-round gaming between the source and adversary, in which two ways of gaming on nodes, autonomous underwater vehicle (AUV), and adversary are adopted to protect the static source location. Because the location of the mobile source, such as underwater intelligent agent, changes regularly, the protection for this type of source is focused on the trajectory, preventing the mobile source from being tracked. This paper aims to protect the location privacy of the static source first and then initial attempts to protect the dynamic source location privacy. By fuzzing the remaining semantic information after the mobile source passes by, the trajectory of the mobile source is protected, thereby protecting its location privacy. Compared with existing algorithms, the simulation results of the proposed scheme indicate the probability that the source has been captured. Furthermore, the results show that the period of safety of the proposed algorithm is longer than that of a multi-hop-based location privacy protection scheme but shorter than that of an autonomous underwater vehicle based scheme. Although the difference in the energy consumption of the nodes among the compared schemes is little increased, the delay varies significantly.

Evolution hydrothermal aging mechanism for Ag/CeO2 catalysts in regeneration of catalytic diesel particulate filter with DFT calculation.

In order to avoid the high cost of existing precious metal catalyst like Pt, Ag/CeO2 was the most promising catalysts for mobile source soot emission control technologies, but there was a clear trade-off between hydrothermal aging resistance and catalytic oxidation performance hindered the application of this catalyst. In order to reveal the hydrothermal aging mechanism of Ag/CeO2 catalysts, the TGA (thermogravimetric analysis) experiments were investigated to reveal the mechanism of Ag modification on catalytic activity of CeO2 catalyst between fresh and hydrothermal aging and were also characterized with the related characterization experiments to in-depth research the lattice morphology and valence changes. The degradation mechanism of Ag/CeO2 catalysts in vapor with high-temperature was also explained and demonstrated based on density functional and molecular thermodynamics theories. The experimental and simulation data showed that the catalytic activity of soot combustion within Ag/CeO2 decreased more significantly after hydrothermal aging than CeO2 due to the less agglomerated, which caused by the decreased in OII/OI and Ce3+/Ce4+ compared with CeO2. As shown in density function theory (DFT) calculation, the decreased surface energy and the increased oxygen vacancy formation energy of the low Mille index surface after Ag modification led to the instability structure and the high catalytic activity. Ag modification also increased the adsorption energy and Gibbs free energy of H2O on the low Miller index surface compared to CeO2, indicating that the desorption temperature of H2O molecules in (1 1 0) and (1 0 0) was higher than (1 1 1) in CeO2 and Ag/CeO2, which led to the migration of (1 1 1) crystal surfaces to (1 1 0) and (1 0 0) in the vapor environment. These conclusions can provide a valuable addition to the regenerative application of Ce-based catalysts in diesel exhaust aftertreatment system the aerial pollution.

Airborne Air Pollutant Emission Characteristics of Mobile Vehicles in Taiwan

This study examines the air pollutant emission characteristics, activity intensity, and trends of mobile sources from 2013 to 2021. The target pollutants include criteria pollutants (fine particulate matters, nitrogen oxides, and hydrocarbons) and hazardous air pollutants (benzene, formaldehyde, and BaP). The results indicated that the activity intensity levels of road mobile sources in Taiwan were148 × 109, 156 × 109, 159 × 109, and 155 × 109 km/year in 2013, 2016, 2019, and 2021, respectively, with the largest proportion attributed to gasoline passenger cars (42.6%), followed by four-stroke motorcycles (32.6%). An emission factor of PM2.5 was estimated by EPA’s MOVES (Motor Vehicle Emission Simulator) model, and the results showed that the emission sequence was diesel > gasoline > motorcycle; the NOx emission factor was estimated using the MOBILE6.2 model, and the results showed that the order was diesel > gasoline > motorcycle; the HC emission factor was compiled with the use of gasoline vehicle dynamometer data, and the results showed that motorcycle > gasoline vehicles. Further results showed that the emission sequence for benzene was motorcycle > gasoline ≥ diesel; the formaldehyde emission sequence was diesel > motorcycle ≥ gasoline. The BaP emission factors of different vehicle types were estimated using MOVES, and the emission factors of old heavy-duty diesel vehicles were the highest.

Study of Mobile Source Pollutants Based on Multi-Source Data Fusion: A Case Study of Zibo City, China

The primary pollutants emitted from mobile sources have become one of the main sources of urban air pollution. In this study, the primary pollutants CO, HC, NOx and PM from mobile sources in Zibo city, China are studied. Firstly, the localized mobile-source pollutant emission factors are corrected using vehicle emission experiments; secondly, multi-source data fusion is performed using road network data, road traffic data, air quality and meteorological data; then, the corrected pollutant emission factors and multi-source data are used to construct a localized emission measurement model and dispersion simulation model, visualize the emission distribution and propose residual concentration correction to accurately obtain the pollutant sharing rate. The results show that the pollutant emission trends are highly coupled with the distribution of urban residents’ working hours. Based on the localized dispersion model used to analyze the pollutant traceability at air monitoring stations, the emission sharing rate of NOx is the largest, and according to the analysis of the changing trend of mobile-source emission sharing rate, the mobile source pollutants in Zibo are mainly influenced by pollutant emissions from road motor vehicles. This study provides data support and a theoretical basis for the management of the transportation industry to carry out exhaust gas control of motor vehicles and non-road mobile machinery and to make decisions related to improving the air environment (delineating the scope of low emission zones).

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.