Long-distance Transport Research Articles

Risk assessment of airborne transmission of novel coronavirus (COVID-19) in long-distance transport

Risk assessment of airborne transmission of novel coronavirus (COVID-19) in long-distance transport

The environmental impact of renewable hydrogen supply chains: Local vs. remote production and long-distance hydrogen transport

As a secondary energy source, hydrogen produced by water electrolysis is a promising way to sustainably use electricity generated from primary renewable resources. Thereby, hydrogen is not only a highly relevant feedstock for producing chemical products, such as fertilizers and platform chemicals, but also a valuable energy carrier that can be readily transported and stored. This study explores how transporting renewable hydrogen via pipeline from regions with high renewable energy potential to large consumer centers can help overcome current challenges in ensuring a climate-friendly renewable energy supply. To this end, this work assesses the environmental impacts of cross-border hydrogen supply chains relative to the attained operating hours of local hydrogen production and the required hydrogen transport distance via pipeline. Environmental hotspots along the hydrogen supply chain and the main parameters affecting the overall environmental impact were identified. Remarkably, an environmental trade-off emerges: the most suitable local conditions for producing renewable hydrogen need to be balanced against the distance of hydrogen transport to consumers. Nonetheless, the relevance of the transport distance decreases with an increasing share of renewable energies in the electricity mix for operating the compressor stations of the pipeline network. Considering the ongoing transition towards renewable power generation technologies, our results indicate that long-distance hydrogen transport via pipeline is environmentally justified provided that the share of renewable energies used to operate the compressor stations increases.

Unmanned aerial vehicle observations of the vertical distribution of particulate matter and sulfur dioxide at a regional background site in northwest China

The vertical measurements of atmospheric pollutants are essential for understanding various atmospheric chemical processes and the transmission of air pollutants. Herein, we measured particulate matter (PM) and SO2 concentrations using a six-axis unmanned aerial vehicle (UAV) equipped with portable monitors at the Akedala Background Station in northwest China from the surface to 500 m above the ground level. Twelve-day measurements (68 flights) were conducted from July 13 to 24, 2020. Results showed that the UAV platform could effectively capture the vertical distribution of PM and SO2. During the observation period, the concentrations of PM1, PM2.5, and PM10 in Akedala were 0.1–11.8, 0.2–13.0, and 0.2–21.7 μg/m3, respectively, and SO2 concentrations ranged between 0.1 and 29.4 ppb. The weather condition and backward trajectory indicated that the air mass affecting the station mainly originates from Kazakhstan, southern Russia, and northern Xinjiang.PM and SO2 can be classified into different types based on their vertical profile characteristics, where SO2 mainly showed an incremental distribution, which may be related to the long-distance transport of pollutants. PM mainly showed unimodal distributions, which may be related to the inverse temperature phenomenon and transport of pollutants. Remote sensing data and MIX emission inventory showed the presence of dot emission areas in southern Russia, Kazakhstan, and northern Xinjiang cities, which made important contributions to the air pollutants in Akedala.

Detection and analysis of Lhù'ààn Mân' (Kluane Lake) dust plumes using passive and active ground-based remote sensing supported by physical surface measurements

Abstract. There is growing recognition that high-latitude dust (HLD), originating from local drainage-basin flows, is the dominant source for certain important phenomena such as particle deposition on snow/ice. The analysis of such local plumes (including a better exploitation of remote sensing data) has been targeted as a key aerosol issue by the HLD community. The sub-Arctic Lhù'ààn Mân' (Kluane Lake) region in the Canadian Yukon is subject to regular drainage-basin, wind-induced dust plumes. This dust emission site is one of many current and potential proglacial dust sources in the Canadian north. In situ ground-based measurements are, due to constraints in accessing these types of regions, rare. Ground- and satellite-based remote sensing accordingly play an important role in helping to characterize local dust sources in the Arctic and sub-Arctic. We compared ground-based passive and active remote sensing springtime (May 2019) retrievals with microphysical surface-based measurements in the Lhù'ààn Mân' region in order to better understand the potential for ground- and satellite-based remote sensing of HLD plumes. This included correlation analyses between ground-based coarse mode (CM) aerosol optical depth (AOD) retrievals from AERONET AOD spectra, CM AODs derived from co-located Doppler lidar profiles, and OPS (optical particle sizer) surface measurements of CM particle-volume concentration (vc(0)). An automated dust classification scheme was developed to objectively identify local dust events. The classification process helped distinguish lidar-derived CM AODs which covaried with vdust(0) (during recognized dust events) and those that varied at the same columnar scale as AERONET-derived CM AOD (and thus could be remotely sensed). False positive cloud events for dust-induced, high-frequency variations in lidar-derived CM AODs in cloudless atmospheres indicated that the AERONET cloud-screening process was rejecting CM dust AODs. The persistence of a positive lidar ratio bias in comparing the CIMEL/lidar-derived value with a prescribed value obtained from OPS-derived particle sizes coupled with dust-speciation-derived refractive indices led to the suggestion that the prescribed value could be increased to optically derived values of 20 sr by the presence of optically significant dust particles at an effective radius of 11–12 µm. Bimodal CM PSDs (see Appendix B for a glossary) from full-fledged AERONET inversions (the combination of AOD spectra and almucantar radiances) also showed CM peaks at ∼ 1.3 and 5–6.6 µm radius: this, we argue, was associated with springtime Asian dust and Lhù'ààn Mân' dust, respectively. Correlations between the CIMEL-derived fine mode (FM) AOD and FM OPS-derived particle-volume concentrations suggest that remote sensing techniques can be employed to monitor FM dust (which is arguably a better indicator of the long-distance transport of HLD).

Angiosperms follow a convex trade-off to optimize hydraulic safety and efficiency.

Intervessel pits are considered to function as valves that avoid embolism spreading and optimize efficient transport of xylem sap across neighbouring vessels. Hydraulic transport between vessels would therefore follow a safety-efficiency trade-off, which is directly related to the total intervessel pit area (Ap ), inversely related to the pit membrane thickness (TPM ) and driven by a pressure difference. To test this hypothesis, we modelled the relative transport rate of gas (ka ) and water (Q) at the intervessel pit level for 23 angiosperm species and correlated these parameters with the water potential at which 50% of embolism occurs (Ψ50 ). We also measured ka for 10 species using pneumatic measurements. The pressure difference across adjacent vessels and estimated values of ka and Q were related to Ψ50 , following a convex safety-efficiency trade-off based on modelled and experimental data. Minor changes in TPM and Ap exponentially affected the pressure difference and flow, respectively. Our results provide clear evidence that a xylem safety-efficiency trade-off is not linear, but convex due to flow across intervessel pit membranes, which represent mesoporous media within microporous conduits. Moreover, the convex nature of long-distance xylem transport may contribute to an adjustable fluid balance of plants, depending on environmental conditions.

Single-use plastic bag alternatives result in higher environmental impacts: Multi-regional analysis in country with uneven waste management

Single-use plastics (SUPs) have been the focus of plastic pollution control, and limiting their use while shifting to other alternatives have been widely promoted in various countries. This study tries to verify the life cycle environmental performances of single-use plastic bag and its alternatives under different scenarios in real world. China is chosen as case study, where provincial variability is prominent in waste disposal, and strictest plastics ban has issued lately in this worldwide biggest market. The study found that HDPE plastic bags have relatively lowest environmental footprints regarding to Acidification Potential, Global Warming Potential, Chemical Oxygen Demand, Eutrophication Potential, Fossil Fuel Depletion Potential and Water Use. Sticking to current waste treatment, large-scale promotion of degradable products will increase environmental impacts by 1.4–22.6 times nationwide. Xinjiang has highest impact of using plastic bag at household level, due to its long-distance transport and high landfill ratio. Henan and Hebei will trigger the most significant changes in Global Warming Potential of 4.6 and 4.4 times if single-use plastic bags are all replaced with other alternatives. Uncertainty and sensitivity test further prove the robustness of results, and extends geographical implications of the findings. These suggest that introduction of new alternatives requires systematic deployment with full life cycle thinking, and SUPs pollution control should be a holistic transformation. Reducing bag weight while ensuring carrying capacity, purchasing local products to shorten transportation distances and shifting towards cleaner energy sources are synergetic ways to reduce the environmental impact of single-use plastic products.

Pepper mild mottle virus can infect and traffick within Nicotiana benthamiana plants in non-virion forms

Virions are responsible for the long-distance transport of many viruses, such as Pepper mild mottle virus (PMMoV). Emerging evidence indicates viral traffic in the form of ribonucleoprotein complexes (RNP), yet comprehensive analysis is scarce. In this study, we inoculated plants with PMMoV-GFP, both with and without the coding sequence for the coat protein (CP). PMMoV-GFP was detected in systemic leaves, even in the absence of the CP, despite the presence of much smaller infection areas. Moreover, using leaf extracts from PMMoV-infected plants to perform a root-irrigation experiment, we confirmed that PMMoV can infect plants through root transmission. Diluting the leaf extracts significantly diminished infectivity, and attempts to compensate for the dilution of other components by adding virions above the original level proved ineffective. Our findings strongly indicate that PMMoV can infect and traffick within plants in non-virion forms. Future studies should aim to identify the specific forms involved.

Watershed-scale provenance heterogeneity within Eocene nonmarine basin fill: Southern Greater Green River Basin, western USA

Weathering, erosion, and sediment transport in modern landscapes may be investigated via direct observation of attributes such as elevation, relief, bedrock lithology, climate, drainage organization, watershed extent, and others. Studies of ancient landscape evolution lack this synoptic perspective, however, and instead must rely more heavily on downstream records of fluvial deposits. Provenance analysis based on detrital grain ages has greatly enhanced the utility of such records but has often focused broadly on regional to continental scales. This approach may overlook important details of localized watersheds, which could lead to significant misinterpretation of past sediment dispersal patterns. The present study, therefore, explores the impact of geographic and stratigraphic sampling density on detrital zircon provenance, based on a high-density investigation of U-Pb ages (N = 23, n = 4905) obtained from a narrow chronostratigraphic range (∼2 m.y.) within a relatively small (∼25,000 km2) area of an Eocene nonmarine sedimentary basin. Based on multi-dimensional scaling and DZmix modeling, these strata comprise seven distinct, approximately isochronous detrital zircon (DZ) chronofacies, defined as “. . . a group of sedimentary rocks that contains a specified suite of detrital zircon age populations” (Lawton et al., 2010). Four of these DZ chronofacies reflect long-distance transport from extrabasinal source areas. DZ chronofacies CO-1 and CO-2 are interpreted to derive from a primary sediment source in central Colorado (USA), corroborating previously proposed long-distance sediment transport via the Aspen paleoriver. DZ chronofacies ID-1 and ID-2 are interpreted to have been delivered to the basin from central Idaho by the Idaho paleoriver. In contrast, DZ chronofacies UT-1 and UT-2 are interpreted to reflect local drainage from the Uinta Uplift south of the basin, and DZ chronofacies WY-1 is interpreted to have been sourced from the Rawlins, Granite, and Sierra Madre uplifts to the north and east via the Toya Puki paleoriver. Lateral transitions between different DZ chronofacies in some cases occur over distances as little as 5 km, implying that depositional systems carrying sand from disparate watersheds directly competed to fill available basin accommodation. The results of this study reveal a high degree of complexity of Eocene rivers that converged on the Greater Green River Basin, indicating that their deposits contain a rich record of fine-scale landscape evolution across much of the Laramide foreland and Cordilleran orogen. These results illustrate the need for adequate sample density when assessing basin-scale provenance and offer a cautionary consideration for researchers using sandstone (and incorporated authigenic cement) in other nonmarine basins as the basis for paleoaltimetry or detrital thermochronology studies.

Research and analysis of the operation of vehicles with various propulsion systems, including costs and CO<sub>2</sub> emissions

The article analyzes and evaluates costs, transport time and CO2 emissions by selected vans. The research was carried out on the example of three models of Iveco Daily vehicles powered by: diesel oil, electricity and compressed natural gas (CNG). The result of the research presented in the article is the determination of the operating costs of vehicles powered by various energy sources and the level of CO2 emissions. The comparative analysis was carried out on real data for the established transport task. Vehicles with engines powered by compressed natural gas are characterized by the highest savings in terms of transport costs. As the authors pointed out, this may be due to the fact that this type of engines, despite the low interest of buyers at the moment, may gain much more popularity in the future. On the other hand, in relation to vehicles with electric motors, the cost of transport is the highest, which means that this type of technology is ineffective in relation to long-distance transport.

Macroeconomic analysis of a new green hydrogen industry using Input-Output analysis: The case of Switzerland

Hydrogen is receiving increasing attention to decarbonize hard-to-abate sectors, such as carbon intensive industries and long-distance transport, with the ultimate goal of reducing greenhouse gas (GHG) emissions to net-zero. However, limited knowledge exists so far on the socio-economic and environmental impacts for countries moving towards green hydrogen. Here, we analyse the macroeconomic impacts, both direct and indirect, in terms of GDP growth, employment generation and GHG emissions, of green hydrogen production in Switzerland. The results are first presented in gross terms for the construction and operation of a new green hydrogen industry considering that all the produced hydrogen is allocated to passenger cars (final demand). We find that, for each kg of green hydrogen produced, the operational phase creates 6.0, 5.9 and 9.5 times more GDP, employment and GHG emissions respectively compared to the construction phase (all values in gross terms). Additionally, the net impacts are calculated by assuming replacement of diesel by green hydrogen as fuel for passenger cars. We find that green hydrogen contributes to a higher GDP and employment compared to diesel, while reducing GHG emissions. For instance, in all the three cases, namely, ‘Equal Cost’, ‘Equal Energy’ and ‘Equal Service’, we find that a green hydrogen industry generates around 106%, 28% and 45% higher GDP, respectively; 163%, 43% and 65% more full-time equivalent jobs, respectively; and finally 45%, 18% and 29% lower GHG emissions, respectively, compared to diesel and other industries. Finally, the methodology developed in this study can be extended to other countries using country-specific data.

Aerial monitoring of atmospheric particulate matter produced by open-pit mining using low-cost airborne sensors

Mining is an economic activity that entails the production and displacement of significant amounts of atmospheric particulate matter (PM) during operations involving intense earthcrushing or earthmoving. As high concentrations of PM may have adverse effects on human health, it is necessary to monitor and control the fugitive emissions of this pollutant. This paper presents an innovative methodology for the online monitoring of PM10 concentrations in air using a low-cost sensor (LCS, <300 USD) onboard an unmanned aerial vehicle. After comprehensive calibration, the LCS was horizontally flown over seven different areas of the large Riotinto copper mine (Huelva, Spain) at different heights to study the PM10 distribution at different longitudes and altitudes. The flights covered areas of zero activity, intense mining, drilling, ore loading, waste discharge, open stockpiling, and mineral processing. In the zero-activity area, the resuspension of PM10 was very low, with a weak wind speed (3.6 m/s). In the intense-mining area, unhealthy concentrations of PM10 (>51 μgPM10/m3) could be released, and the PM10 can reach surrounding populations through long-distance transport driven by several processes being performed simultaneously. Strong dilution was also observed at high altitudes (> 50 m). Mean concentrations were found to be 22–89 μgPM10/m3, with peaks ranging from 86 to 284 μgPM10/m3. This study demonstrates the potential applicability of airborne LCSs in the high-resolution online monitoring of PM in mining, thus supporting environmental managers during decision-making against fugitive emissions in a cost-effective manner.

Preservation of Simmental bull sperm at 0°C in Tris dilution: effect of dilution ratio and long-distance transport.

This study aimed to assess the impact of the dilution ratio of Tris diluent, storage at 0°C, and long-distance transportation on the spermatozoa of Simmental cattle. It also validated the feasibility of the regional distribution of fresh semen. In experiment 1, semen was diluted at four dilution ratios (1:6, 1:9, 1:12, and 1:15) to determine the optimal dilution ratio of Tris diluent. In experiment 2, we assessed sperm viability, progressive motility (objectively assessed by computer-assisted sperm analyzer), and acrosome intactness in Tris dilutions kept at constant 0°C for 1, 3, 6, 9, and 12 days. We compared them to Tianshan livestock dilutions (Commercial diluent). In experiment 3, semen was diluted using Tris diluent, and sperm quality was measured before and after long-distance transport. Artificial insemination of 177 Simmental heifers compared to 156 using Tianshan Livestock dilution. The outcomes demonstrated that 1:9 was the ideal Tris diluent dilution ratio. The sperm viability, Progressive Motility, and acrosome integrity of both Tris and Tianshan dilutions preserved at 0°C gradually decreased over time. sperm viability was above 50% for both dilutions on d 9, with a flat rate of decline. The decrease in acrosome integrity rate was faster for Tianshan livestock dilutions than for Tris dilutions when stored at 0°C for 1 to 6 days. There was no significant difference (p>0.05) in sperm viability between semen preserved in Tris diluent after long-distance transportation and semen preserved in resting condition. The conception rates for Tris dilution and Tianshan livestock dilution were 49.15% and 46.15% respectively, with no significant difference (p>0.05). This shows that Tris diluent is a good long-term protectant. It has been observed that fresh semen can be successfully preserved for long-distance transport when stored under 0°C conditions. Additionally, it is feasible to distribute semen regionally.

Heterogenous Slippery Surfaces: Enabling Spontaneous and Rapid Transport of Viscous Liquids with Viscosities Exceeding 10 000 mPa s.

Superhydrophobic and slippery lubricant-infused surfaces have garnered significant attention for their potential to passively transport low-viscosity liquids like water (1 mPa s). Despite exciting progress, these designs have proven ineffective for transporting high-viscosity liquids such as polydimethylsiloxane (5500 mPa s) due to their inherent limitations imposed by the homogenous surface design, resulting in high viscous drags and compromised capillary forces. Here, a heterogenous water-infused divergent surface (WIDS) is proposed that achieves spontaneous, rapid, and long-distance transport of viscous liquids. WIDS reduces viscous drag by spatially isolating the viscous liquids and surface roughness through its heterogenous, slippery topological design, and generates capillary forces through its heterogenous wetting distributions. The essential role of surface heterogeneity in viscous liquid transport is theoretically and experimentally verified. Remarkably, such a heterogenous paradigm enables transporting liquids with viscosities exceeding 12 500 mPa s, which is two orders of magnitude higher than state-of-the-art techniques. Furthermore, this heterogenous design is generic for various viscous liquids and can be made flexible, making it promising for various systems that require viscous liquid management, such as micropatterning.

Mesenchymal Stem Cell Utilization for In Vitro Donor Liver Machine Perfusion Preservation: Current Status and Future Directions.

Liver transplantation is the only effective treatment for end-stage liver disease. Currently, the shortage of high-quality donors has led to the exploration of the use of marginal organs. However, several factors limit the in vitro long-term preservation and long-distance transport of livers, which can also lead to ischemia-reperfusion injuries, resulting in poor prognosis. Therefore, an efficient and convenient strategy to improve this situation is urgently required. Normothermic machine perfusion (NMP) is expected to improve the liver environment in vitro and provide better evaluation indices for organ repair mechanisms. Mesenchymal stem cells (MSCs) can repair damaged hepatocytes or exert their protective effects via paracrine mechanisms, such as the release of extracellular vesicles (EVs). We hypothesized that combining the regenerative ability of MSCs and the significant advantages of NMP may improve the quality and utilization rate of organs, especially marginal organs. In this study, we review different strategies for liver preservation in vitro, as well as their strengths and weaknesses. We also introduce MSCs, derived EVs, and MSCs applications in liver preservation in vitro. Finally, we discuss the current challenges and future trends of MSCs applications for in vitro liver preservation. We envision novel bioreactor designs that employ 3D cell culturing and offer the possibility to reconstruct MSCs microenvironments to promote cell growth and biofunction expression. Large-scale MSCs production can be combined with normothermic machine perfusion to enhance in vitro liver preservation, thereby promoting donor organ function to benefit recipients in need of liver transplantation.

Geostatistical analysis of the relationship among geomorphology, land cover, and AOD at the local scale in a South American desert region

This work aims to assess the particle matter distribution in Tulum Valley, San Juan, Argentina, during 2019, in relation to geomorphology. Random forest supervised classifications were performed to obtain customized annual landform and seasonal land cover maps using Landsat 8 Surface Reflectance (OLI); Sentinel-1 SAR, SRTM digital elevation images, and a set of spectral indices. Geostatistical analyses, including Linear Mixed Models, were performed considering the ln of the mean, the ln of the standard deviation, and the Angstrom Exponent of the MAIAC Aerosol Optical Depth product as response variables, and landforms, landforms + land cover, Land Surface Temperature, and Moisture Stress Index as explanatory variables. The models allowed statistically significant differentiation of the Aerosol Optical Depth means of the landform and landform + land cover classes. The percentage of residual standard error for the means obtained from the model was up to 4.02%. The Angstrom Exponent values below 0.0858, along with the spatial distribution of the three response variables, indicate that the primary aerosol source in the study area is wind-driven soil/sediment erosion, which shows a strong relationship with emission areas. No long-distance transport of aerosols was observed.

The Potential Role of Ammonia for Hydrogen Storage and Transport: A Critical Review of Challenges and Opportunities

Hydrogen is being included in several decarbonization strategies as a potential contributor in some hard-to-abate applications. Among other challenges, hydrogen storage represents a critical aspect to be addressed, either for stationary storage or for transporting hydrogen over long distances. Ammonia is being proposed as a potential solution for hydrogen storage, as it allows storing hydrogen as a liquid chemical component at mild conditions. Nevertheless, the use of ammonia instead of pure hydrogen faces some challenges, including the health and environmental issues of handling ammonia and the competition with other markets, such as the fertilizer market. In addition, the technical and economic efficiency of single steps, such as ammonia production by means of the Haber–Bosch process, ammonia distribution and storage, and possibly the ammonia cracking process to hydrogen, affects the overall supply chain. The main purpose of this review paper is to shed light on the main aspects related to the use of ammonia as a hydrogen energy carrier, discussing technical, economic and environmental perspectives, with the aim of supporting the international debate on the potential role of ammonia in supporting the development of hydrogen pathways. The analysis also compares ammonia with alternative solutions for the long-distance transport of hydrogen, including liquefied hydrogen and other liquid organic carriers such as methanol.

Ozone and PM2.5 behavior in small cities in southern Brazil

Air pollution is one of the greatest challenges facing humanity today. The number of studies has grown annually, but most of the time they have been conducted in megacities or heavily industrialized regions. In this study, we aimed to evaluate the behavior of O3 and PM2.5 in 5 small cities (&lt; 1500 inhabitants) in southern Brazil, comparing them with reference cities in their micro-regions and with the metropolis Porto Alegre, capital of the state of Rio Grande do Sul. During the short period evaluated, the levels of pollutants in small cities would not differ from those found in the reference cities and were equivalent to the levels in the studied metropolis. Also, during 2 periods (18 to 20 September 2021 and 30 September to 2 October 2021) there were episodes of high levels of PM2.5, superior to the national air quality criteria in 4 of the 5 small cities. The likely origin of the pollutants is the long-distance transport of pollutants from biomass burning in the Amazon. Multiple regression analysis showed little or no influence of local meteorological parameters for O3 and PM2.5 levels, but showed a strong association with pollutant levels in the respective reference cities. Understanding the dynamics of air pollutants in small cities is essential to understand some health outcomes in these populations and has been recently recommended by the World Health Organization.

Multi-Trip Vehicle Routing Problem with Time Windows and Resource Synchronization on Heterogeneous Facilities

Inspired by long-distance road transport in industrial logistics in China, this paper studies a simultaneous loading scheduling and vehicle routing problem over a multi-workday planning horizon. Industrial cargo often requires specialized facilities, and these facilities vary in performance and quantity and are subject to available time constraints. Consequently, achieving coordinated optimization of vehicle routing and loading scheduling becomes a significant challenge in practice. We describe the studied problem as a multi-trip vehicle routing problem with time windows and resource synchronization on heterogeneous facilities. First, we develop a mixed integer programming model in a multi-workday setting to minimize the total travel distance and the number of vehicles. Moreover, a three-phase heuristic approach is developed. An initial solution is constructed using a sequential strategy in the first phase, and then an adaptive large neighbourhood search and a post-optimization procedure based on ejection chains are, respectively, designed to optimize the two hierarchical objective functions. Finally, extensive computational experiments are conducted to demonstrate the effectiveness of the proposed method. Specifically, the research results indicate that in long-distance road transport in industrial scenarios, expanding the planning horizon from a single workday to a multi-workday period could significantly reduce logistics operational costs and improve service quality.

Diurnal Variations in High Time-Resolved Molecular Distributions and Formation Mechanisms of Biogenic Secondary Organic Aerosols at Mt. Huang, East China.

The molecular characteristics and formation mechanism of biogenic secondary organic aerosols (BSOAs) in the forested atmosphere are poorly known. Here, we report the temporal variations in and formation processes of BSOA tracers derived from isoprene, monoterpenes, and β caryophyllene in PM2.5 samples collected at the foot of Mt. Huang (483 m a. s. l) in East China during the summer of 2019 with a 3 h time resolution. The concentrations of nearly all of the detected species, including organic carbon (OC), elemental carbon (EC), levoglucosan, and SIA (sum of SO42-, NO3-, and NH4+), were higher at night (19:00-7:00 of the next day) than in the daytime (7:00-19:00). In addition, air pollutants that accumulated by the dynamic transport of the mountain breeze at night were also a crucial reason for the higher BSOA tracers. Most of the BSOA tracers exhibited higher concentrations at night than in the daytime and peaked at 1:00 to 4:00 or 4:00 to 7:00. Those BSOA tracers presented strong correlations with O3 in the daytime rather than at night, indicating that BSOAs in the daytime were primarily derived from the photo-oxidation of BVOCs with O3. The close correlations of BSOA tracers with SO42- and particle acidity (pHis) suggest that BSOAs were primarily derived from the acid-catalyzed aqueous-phase oxidation. Considering the higher relative humidity and LWC concentration at night, the promoted aqueous oxidation was the essential reason for the higher concentrations of BSOA tracers at night. Moreover, levoglucosan exhibited a robust correlation with BSOA tracers, especially β-caryophyllinic acid, suggesting that biomass burning from long-distance transport exerted a significant impact on BSOA formation. Based on a tracer-based method, the estimated concentrations of secondary organic carbon (SOC) derived from isoprene, monoterpenes, and β caryophyllene at night (0.90 ± 0.57 µgC m-3) were higher than those (0.53 ± 0.34 µgC m-3) in the daytime, accounting for 14.5 ± 8.5% and 12.2 ± 5.0% of OC, respectively. Our results reveal that the BSOA formation at the foot of Mt. Huang was promoted by the mountain-valley breezes and anthropogenic pollutants from long-range transport.

Performance evaluation of a novel relay parallel push-pull ventilation system for long-distance pollution control

The push-pull ventilation system, which uses air supply jets to enhance the transport of airflow, is an effective local ventilation method to control pollutants generated in industrial buildings. However, factors such as the increased scale of industrial plants and the restricted location of exhaust hoods have highlighted the need for long-distance pollutant control. In this paper, a novel relay parallel push-pull ventilation (RPPV) system was proposed to enhance the performance of long-distance local ventilation. Through experiments and numerical simulations, this system was evaluated and compared to the traditional parallel push-pull ventilation (PPV) system. Key performance metrics included the performance coefficient, airflow diffusion height, and energy-saving capability. The results indicated that the RPPV system is a very effective mode of long-distance transport. Firstly, the RPPV system exhibited superior airflow control over extended distances, enhancing airflow control by 30.5%. Importantly, it also managed to at least double the critical velocity, demonstrating the potential for longer control distances. Secondly, the RPPV system could achieve targeted airflow delivery, significantly reducing the diffusion height of supply airflows by up to 57%. Finally, the RPPV system consistently achieved the same airflow control as the PPV system, but with a smaller pull airflow rate, saving up to 40% of the pull airflow rate. These results present a promising solution to the problem of pollutant capture and airflow transport over long distances.