Quantification of oil and gas methane emissions in the Delaware and Marcellus basins using a network of continuous tower-based measurements

According to the United States Environmental Protection Agency (US EPA), emissions from oil and gas infrastructure contribute 30 % of all anthropogenic methane (CH4) emissions in the US. Studies in the last decade have shown emissions from this sector to be substantially larger than bottom-up assessments, including the EPA inventory, highlighting both the increased importance of methane emissions from the oil and gas sector in terms of their overall climatological impact and the need for independent monitoring of these emissions. In this study we present continuous monitoring of regional methane emissions from two oil and gas basins using tower-based observing networks. Continuous methane measurements were taken at four tower sites in the northeastern Marcellus basin from May 2015 through December 2016 and five tower sites in the Delaware basin in the western Permian from March 2020 through April 2022. These measurements, an atmospheric transport model, and prior emission fields are combined using an atmospheric inversion to estimate monthly methane emissions in the two regions. This study finds the mean overall emission rate from the Delaware basin during the measurement period to be 146–210 Mg CH4 h-1 (energy-normalized loss rate of 1.1 %–1.5 %, gas-normalized rate of 2.5 %–3.5 %). Strong temporal variability in the emissions was present, with the lowest emission rates occurring during the onset of the COVID-19 pandemic. Additionally, a synthetic model–data experiment performed using the Delaware tower network shows that the presence of intermittent sources is not a significant source of uncertainty in monthly quantification of the mean emission rate. In the Marcellus, this study finds the overall mean emission rate to be 19–28 Mg CH4 h-1 (gas-normalized loss rate of 0.30 %–0.45 %), with relative consistency in the emission rate over time. These totals align with aircraft top-down estimates from the same time periods. In both basins, the tower network was able to constrain monthly flux estimates within ±20 % uncertainty in the Delaware and ±24 % uncertainty in the Marcellus. The results from this study demonstrate the ability to monitor emissions continuously and detect changes in the emissions field, even in a basin with relatively low emissions and complex background conditions.

Impact of COVID-19 lockdown on water quality in China during 2020 and 2022: two case surges.

The COVID-19 severely affected the world in 2020. Taking the two outbreaks in China in 2020 and 2022 as examples, the spatiotemporal changes in surface water quality levels and CODMn and NH3-N concentrations were analyzed, and the relationships between the variations in the two pollutants and environmental and social factors were evaluated. The results showed that during the two lockdowns, due to the total water consumption (including industrial, agricultural, and domestic water) decreased, the proportion of good water quality increased by 6.22% and 4.58%, and the proportion of polluted water decreased by 6.00% and 3.98%, the quality of water environment has been improved significantly. However, the proportion of excellent water quality decreased by 6.19% after entering the unlocking period. Before the second lockdown period, the average CODMn concentration exhibited a "falling, rising, and falling" trend, while the average NH3-N concentration changed in the opposite direction. The correlation analysis revealed that the increasing trend of pollutant concentrations was positively correlated with longitude and latitude, and weakly correlated with DEM and precipitation. A slight decrease trend in NH3-N concentration was negatively correlated with the population density variation and positively correlated with the temperature variation. The relationship between the change in the number of confirmed cases in provincial regions and the change in pollutant concentrations was uncertain, with positive and negative correlations. This study demonstrates the impact of lockdowns on water quality and the possibility of improving water quality through artificial regulation, which can provide a reference basis for water environmental management.

Probing environmental and tectonic changes underneath Mexico City with the urban seismic field

The sediments underneath Mexico City have unique mechanical properties that give rise to strong site effects. We investigated temporal changes in the seismic velocity at strong-motion and broadband seismic stations throughout Mexico City, including sites with different geologic characteristics ranging from city center locations situated on lacustrine clay to hillside locations on volcanic bedrock. We used autocorrelations of urban seismic noise, enhanced by waveform clustering, to extract subtle seismic velocity changes by coda wave interferometry. We observed and modeled seasonal, co- and post-seismic changes, as well as a long-term linear trend in seismic velocity. Seasonal variations can be explained by self-consistent models of thermoelastic and poroelastic changes in the subsurface shear wave velocity. Overall, sites on lacustrine clay-rich sediments appear to be more sensitive to seasonal surface temperature changes, whereas sites on alluvial and volcaniclastic sediments and on bedrock are sensitive to precipitation. The 2017 Mw 7.1 Puebla and 2020 Mw 7.4 Oaxaca earthquakes both caused a clear drop in seismic velocity, followed by a time-logarithmic recovery that may still be ongoing for the 2017 event at several sites or that may remain incomplete. The slope of the linear trend in seismic velocity is correlated with the downward vertical displacement of the ground measured by interferometric synthetic aperture radar, suggesting a causative relationship and supporting earlier studies on changes in the resonance frequency of sites in the Mexico City basin due to groundwater extraction. Our findings show how sensitively shallow seismic velocity and, in consequence, site effects react to environmental, tectonic and anthropogenic processes. They also demonstrate that urban strong-motion stations provide useful data for coda wave monitoring given sufficiently high-amplitude urban seismic noise.

Spatial-Temporal Evolution Patterns and Influencing Factors of Hotels in Yellow River Basin from 2012 to 2022

Governmental attention towards the high-quality development of the Yellow River basin has brought new development opportunities for the hotel industry. This study aims to reveal the spatial-temporal evolution patterns and influencing factors of hotels in the Yellow River Basin from 2012 to 2022, based on economic, social, and physical geographic data of 190,000 hotels in the Yellow River flowing. With the help of a GIS technology system, the spatial-temporal evolution patterns of all hotels, star hotels, and ordinary hotels were explored, respectively. Then, the significant influencing factors of these patterns were revealed by using geographic detector and Person correlation analysis. The following conclusions were drawn: (1) the overall scale of the hotel industry in the Yellow River Basin expanded year by year, achieving rapid growth from 2016, and fluctuating around 2020 due to the impact of the novel coronavirus epidemic;the overall spatial distribution had significant regional differences, showing the structural characteristics of "southeast more, northwest less”;(2) there was a great difference in the degree of spatial autocorrelation agglomeration among prefecture-level cities, and the degree of agglomeration of both the hotel industry as a whole and general hotels decreased year by year, showing a random distribution in 2022;star hotels were always distributed randomly. Additionally, a strong synergistic correlation was shown between the number of ordinary hotels and the number of star hotels in local space;(3) overall, the development of the hotel industry was significantly affected by seven factors: structural force, macro force, ecological force, internal power, consumption power, intermediary power, and external power. There were differences in the forces acting on different types of hotels, which gives a pattern recognition in-depth.

Monitoring of the Surfactants in Surface Waters in Slovakia and the Possible Impact of COVID-19 Pandemic on Their Presence

In order to keep the home and occupational environment clean and non-infectious, the consumption of cleaners and disinfectants, including cosmetics, is increasing. Excessive use of these products results in their accumulation in the aquatic environment. Conventional wastewater treatment plants are unable to effectively remove the emergent pollutants, including personal care products. This article is focused on the monitoring of the presence of personal care products in surface waters in two river basins in the Slovak Republic, in terms of the surfactant content. Ecotoxicological evaluation of the selected samples from the monitored river basins was performed by an acute toxicity test using the test organism Daphnia magna. The monitoring results indicate the presence of personal care products in the aquatic environment which poses an ecological and environmental risk. Monitoring in the Hron and Nitra river basins confirmed contamination with the surfactants, to which the measures related to the COVID-19 pandemic contributed. The content of the surfactants in personal care products is significant, and their impact on the aquatic environment is not sufficiently monitored.

INTRODUCTION FROM THE EDITORIAL TEAM

The American South has the highest rate of COVID-19 mortality relating to "unhealthy lifestyle behaviors" that persist in this region, especially among the areas where historically marginalized populations are concentrated (e.g., https://www.cdc.gov/physicalactivity/physical -activity-and-COVID-19.html,<https://www.cdc.gov/physicalactivity/data/inactivity -prevalence-maps/index.html>). Schmitz and McCreary evaluate the influence of the U.S. Army Corps of Engineers in the Apalachicola-Chattahoochee-Flint (ACF) river basin regarding the Florida v. Georgia Supreme Court case. [...]the authors note that the Florida v. Georgia case provides insight for others, particularly geographers, studying the ACF river basin or other transboundary river basins from either analytical or political perspectives.

Satellite quantification of oil and natural gas methane emissions in the US and Canada including contributions from individual basins

We use satellite methane observations from the Tropospheric Monitoring Instrument (TROPOMI), for May 2018 to February 2020, to quantify methane emissions from individual oil and natural gas (O/G) basins in the US and Canada using a high-resolution (∼25 km) atmospheric inverse analysis. Our satellite-derived emission estimates show good consistency with in situ field measurements (R=0.96) in 14 O/G basins distributed across the US and Canada. Aggregating our results to the national scale, we obtain O/G-related methane emission estimates of12.6±2.1 Tg a-1 for the US and 2.2±0.6 Tg a-1 for Canada, 80 % and 40 %, respectively, higher than the national inventories reported to the United Nations. About 70 % of the discrepancy in the US Environmental Protection Agency (EPA) inventory can be attributed to five O/G basins, the Permian, Haynesville, Anadarko, Eagle Ford, and Barnett basins, which in total account for 40 % of US emissions. We show more generally that our TROPOMI inversion framework can quantify methane emissions exceeding 0.2–0.5 Tg a-1 from individual O/G basins, thus providing an effective tool for monitoring methane emissions from large O/G basins globally.

Measuring Pollution Control and Environmental Sustainable Development in China Based on Parallel DEA Method

The purpose of this study is to explore the impact of pollution control on industrial production efficiency in 31 provinces and cities in the Yellow River and Non-Yellow River basins in China from 2013 to 2017, using the methods of the directional distance function (hereinafter referred to as DDF) and the technology gap ratio (hereinafter referred to as TGR) in parallel, while taking the industrial production sector (labor force, total capital formation, energy consumption and industrial water consumption) and the pollution control sector (wastewater treatment funds and waste gas treatment funds) as input variables. Undesirable outputs (total wastewater discharge, lead, SO2 and smoke and dust in wastewater) and an ideal output variable (industrial output value) are taken as output variables. It is found that the total efficiency of DDF in the Non-Yellow River Basin is 0.9793, which is slightly better than 0.9688 in the Yellow River Basin. Among the 17 provinces and cities with a total efficiency of 1, only Shandong and Sichuan are located in the Yellow River Basin. The TGR values of 31 provinces, cities and administrative regions are less than 1, and the average TGR value of the Yellow River Basin is 0.3825, which is lower than the average TGR value of the Non-Yellow River Basin of 0.5234. We can start by improving the allocation of manpower and capital, implementing the use of pollution prevention and control funds, improving the technical level of industrial production, improving pollutant emission, and increasing output value to improve overall efficiency performance. This study uses the parallel method, taking the industrial production department and the pollution control department as inputs, to objectively evaluate the changes in industrial production efficiency and technology gap in the Yellow River and Non-Yellow River basins, which is conducive to mastering the situation of pollution control and industrial production efficiency, and provides the reference for SDG-6- and SDG-9-related policy making.

Perspectives of Farmers on the Decline in Pinus pinea Nut Yield and the Sustainability of the Production: A Case Study in Kozak Basin in Western Turkey

In the Kozak Basin, which is the most important pine nut production and trade center in Turkey, there has been a significant decrease in production recently. In this study, the perspectives of the farmers in this area were investigated, specifically about reasons for the decrease in yields. For this purpose, a face-to-face survey was conducted with 378 pine nut farmers from the Kozak Basin. It was determined that the average age of the farmers is high, their educational achievement level is low, they generally also work in alternative sectors and almost all of them grow pine nuts in their own pine groves. The farmers’ perception of cooperatives was found to be negative. In general, the local people continue to produce pine nuts in their own pine groves, but nearly half of the participants also worked in other sectors to maintain their standard of living. Farmers attribute the low yield in the Kozak Basin to both abiotic and biotic factors. Mining activities, which are increasing, are seen as a threat to the future of production in the area. Also, there is a growing perception of biotic harm, especially from Western Conifer Seed Bug, Leptoglossus occidentalis. Climate change and air pollution are other prominent factors.

GIS and Remote Sensing-Based Approach for Monitoring and Assessment of Plastic Leakage and Pollution Reduction in the Lower Mekong River Basin

Determination of plastic leakage sources and pathways is essential in plastic pollution mitigation. Finding ways to stem land-sourced plastic waste leakage requires understanding its sources. Spatial analysis conducted in a geographic information system (GIS) environment and remote sensing investigation uncovered insights into the distribution of plastic leakage in the lower Mekong River basin (LMRB). The main objectives of this approach were: (i) to map plastic leakage density using multi-source geospatial data;and (ii) to identify plastic leakage source hotspots and their accumulation pathways by incorporating hydrological information. Mapping results have shown that plastic leakage density was highly concentrated in urban areas with a high intensity of human activities. In contrast, the major pathways for plastic leakage source hotspots were the high morphometric areas directly influenced by facilities, infrastructure, and population. The overall efforts in this study demonstrate the effectiveness of the proposed novel method used for predicting plastic leakage density and its sources from land-based activities. It is also accomplished using multi-geospatial data with GIS-based analysis to produce a graphical model for plastic leakage waste density in each region that non-technical personnel can easily visualize. The proposed method can be applied to other areas beyond the LMRB to improve the baseline information on plastic waste leakage into the river.

Predictive Modeling Analysis - Tropical Cyclones and El Niño/La Niña Relationship in India

India experienced two of the major cyclones in the month of May and June, in the midst of the outbreak of COVID-19. Super cyclone on May 20, hit east coast of India, West Bengal and Odisha. Thereafter Cyclone Nisarga hit west coast of Maharashtra on June 2. Later on it was needed to put people in cyclone shelters in the context of COVID-19. It has become an extremely challenging task. While maintaining social distancing the cyclone shelter capacity is reduced to around 40 percent. Tropical Cyclones are one of the dearest and exceedingly baneful natural calamities happen around the world. Generally tropical cyclones are formed over warm ocean surfaces;consist of high sea surface temperature (SST), lower magnitudes of vertical wind shear and larger magnitudes of low-level relative curl of the velocity field, carioles' force along with middle tropospheric relative humidity. If we see cyclones formed in the Bay of Bengal are greater in numbers than those formed in the Arabian Sea. In order to predict the occurrence of tropical cyclone precisely, it is important to understand the various factors that act upon tropical cyclone activities. For seasonal forecasting of tropical cyclone activities we will use El Niño-Southern Oscillation (ENSO) as one of the vital predictors. The phenomenon to understand the relationship between tropical cyclone activity in various ocean basins and the El NiñoSouthern Oscillation (ENSO) has gone up during the last two decades. In this paper impact of El Niño-Southern Oscillation (ENSO) combining El Niño(warm phase of ENSO) and La Niña(cool phase of ENSO) events on frequency of Tropical Cyclone over the Bay of Bengal, the Arabian Sea and land mass of India during April to December over the period 1950-2015 has been studied based on statistical models. Aggregated frequency of tropical cyclone and ONI index in Niño 3.4 region has been used as the measures of frequency of tropical cyclone and ENSO events. It has been found that La Niña events significantly enhance tropical cyclone activity during pre-monsoon and monsoon seasons (April to September), particularly during the monsoon season (July-August-September). The amount of enhancement has been quantified.

Biogeography of northeastern Atlantic Neogene chitons (Mollusca, Polyplacophora): New data from the Pliocene of Portugal

Based on extensive new material, 2088 valves resulting from search sampling of ~500 kg of sediment, the Pliocene chiton biodiversity of the Mondego Basin (Portugal) is reassessed. Twelve species were identified, assigned to seven genera. Eight species are new for the Pliocene of Portugal, as well as two of the genera: Hanleya, Acanthochitona. Two taxa are described as new: Ischnochiton loureiroi n. sp. and Lepidochitona rochae n. sp. Until now, the polyplacophoran European Neogene record was too poorly known to be of help in generating a clear picture of the Miocene to present-day biogeography of the group. This new wealth of data from western Iberia, in conjunction with recent data from the Loire Basin Upper Miocene assemblages (France), allows clarification the Late Miocene to Recent eastern Atlantic and Mediterranean biogeography of the Polyplacophora. The northern range of warm-water northeast Atlantic and Mediterranean Polyplacophora experienced a sharp contraction since, at least, Late Miocene to Early Pliocene times. Warm-water chiton species represented in the Upper Miocene of the Loire Basin of NE France (European-West African Province) and the Pliocene of the Mondego Basin of central-west Portugal (Pliocene French-Iberian Province) are today confined to the southern Mediterranean-Moroccan Molluscan Province.UUID: http://zoobank.org/a2a550c0-caed-449a-aa45-9492c45f882e

What Are Lake Beaches Made of? An Assessment of Plastic Beach Litter on the Shores of Como Bay (Italy)

Featured ApplicationThis research aims at understanding the sources of plastic litter in a freshwater body, assessing the possible production of secondary microplastics (MPs).Plastic waste dispersion is a well-recognized environmental threat, despite continuous efforts towards improving waste disposal management over the last few decades. Plastic litter is known to strongly impact upon water bodies and shorelines, affecting the health of ecosystems and impacting upon the aesthetic value of sites. Moreover, plastic waste that is abandoned on beaches contributes towards different degradation processes that potentially lead to the formation of secondary microplastics (MPs), with likely cascade effects upon the whole ecosystem. In this view, this study aims to characterize the plastic beach litter found on the shores of the western basin of Como Lake (Italy) to better understand the origin of MPs in littoral sediments, including the recognition of object typologies and the chemical characterization of polymers using Fourier-transformed infrared analysis (FTIR). The results highlighted that the most abundant polymers on beaches are polypropylene (PP) and polyethylene (PE), representing 73% of the collected polymers. This confirms that floating, low-density polymers are more likely to accumulate on beaches. Moreover, almost 66% of litter is represented by commonly used manufactured items (disposable objects, packaging, and everyday items). This evidence, combined with the analysis of the main environmental features of the sampling sites (the main winds, distance to urban areas, and the presence of tributaries) indicate that abundance of beached litter is mainly linked to beach accessibility and the local winds. These results highlight that multiple factors affect the environmental fate of plastic litter and give insights into the assessment of secondary microplastics in beach sediments.

Stakeholders’ Perspective on Groundwater Management in Four Water-Stressed Mediterranean Areas: Priorities and Challenges

Recent studies highlight the fragility of the Mediterranean basin against climate stresses and the difficulties of managing the sustainable development of groundwater resources. In this work, the main issues related to groundwater management have been identified from the stakeholder’s perspective in the following four representative water-stressed Mediterranean areas: the coastal aquifer of Comacchio (Italy), the Alto Guadalentín aquifer (Spain), the alluvial aquifer of the Gediz River basin (Turkey), and the Azraq aquifer (Azraq Wetland Reserve, Jordan). This has been achieved by designing a methodology to involve and engage a representative set of stakeholders, including a questionnaire to learn their point of view concerning the current management of aquifer systems and their experience with the already available tools for groundwater resource management, such as monitoring networks and numerical models. The outcome of the survey has allowed us to identify both particular and common challenges among the four study sites and among the various groups of stakeholders. This information provides valuable insights to improve the transfer of scientific knowledge from the research centers to the authorities managing the groundwater resources and it will help to plan more effective research activities on aquifer management. The proposed methodology could be applied in other aquifers facing similar problems.

Methane, carbon dioxide, hydrogen sulfide, and isotopic ratios of methane observations from the Permian Basin tower network

We describe the instrumentation, calibration, and uncertainty of the network of ground-based, in situ, cavity ring down spectroscopy (CRDS) greenhouse gas (GHG) measurements deployed in the Permian Basin. The primary goal of the network is to be used in conjunction with atmospheric transport modeling to determine methane emissions of the Delaware sub-basin of the Permian Basin oil and natural gas extraction area in Texas and New Mexico. Four of the measurements are based on tall communications towers, while one is on a building on a mountain ridge, with the recent addition of a small tower at that site. Although methane (CH4) is the primary species of interest, carbon dioxide (CO2), hydrogen sulfide (H2S), and the isotopic ratio of methane (δ13CH4) are also reported for a subset of the sites. Measurements were reported following the WMO X2004A scale for CH4 and the WMO X2019 scale for CO2. CRDS instruments were calibrated for CH4 andCO2 in the laboratory prior to deployment. For H2S, data were offset-corrected using the minimum 40 min running mean value of the day, and for δ13CH4, calibrations were based on laboratory data. We describe the characteristics of the dataset with a set of illustrative analyses. Methane and carbon dioxide showed strong seasonality, with a well-defined diurnal cycle during the summer, which was opposed to the winter, when a diurnal cycle was absent. CH4 enhancements to the background, during the winter, are up to twice the summer values, which is attributed to the changes in boundary layer depth and wind speed. The largest CH4 enhancements occurred when winds blow from the center of the Delaware sub-basin, where most of the methane emissions come from. The magnitude of enhancements of CO2 did not present seasonality. H2S enhancements indicated a potential source northeast of the tower (Hobbs, New Mexico) where the inlet is installed. Isotopic ratios of methane indicated that oil and natural gas extraction is the source of local methane in the region. The hourly-averaged data, starting on 1 March 2020 and described in this paper, are archived at The Pennsylvania State University Data Commons at 10.26208/98y5-t941 (Monteiro et al., 2021).

Flood Risk and Exposure: The Case of the Tajuña Valley (Madrid, Spain)

This paper aims to update the exposure to flood risk in a catchment area of the Community of Madrid (Spain) linked to primary sector activities, albeit affected by the urban expansion of the capital. This research starts with the updating of the flood inventory, encompassing episodes documented between 1629 and 2020. The inadequate occupation of the territory means that floods continue to cause significant damage nowadays. It is worth highlighting the two recent floods (2019) that occurred just 15 days apart and caused serious damage to several towns in the basin. The areas at risk of flooding are obtained from the National Floodplain Mapping System, and the maximum and minimum floodable volume in the sector of the Tajuña River basin with the highest exposure to flooding has been calculated. The Sentinel 2 image in false colour (RGB bands 11-2-3, 11-8-3 and 12-11-8) and its transformation to colour properties (Intensity, Hue and Saturation) has made it possible to determine the extension of the riparian vegetation and the irrigated crops located in the alluvial plain. The SPOT 6 image with higher spatial resolution has allowed us to update the mapping of buildings located in areas at risk of flooding. Finally, based on cadastral data, a detailed cartography of built-up areas in areas at risk of flooding is provided. They affect buildings built mainly between the 1960s and 1990s, although the most recent buildings are built on agricultural land in the alluvial plain, even though current regulations prevent the occupation of these lands.

A Mobile Laboratory Enables Fecal Pollution Source Tracking in Catchments Using Onsite qPCR Assays

Onsite molecular diagnostics can revolutionize fecal pollution source tracking. We aimed to validate a method for onsite qPCR assays with a miniature speaker-sized Q qPCR instrument and other portable equipment items. We showed that marker genes for total bacteria (16S) and E. coli (rodA) in 100 mL of river water measured with this method agreed within ±0.3 log10 units with results obtained when using conventional laboratory equipment items. We then deployed the portable method in a mobile laboratory (‘lab in a van’) and quantified HF183 marker genes for human host associated Bacteroides in river water within 3 h of sampling. We also used the mobile laboratory to investigate urban river water and effluents from two storm drains and a retention pond and collected comprehensive microbial and physicochemical water quality data. We found significantly higher HF183 gene levels in the older storm drain compared to the river water (6.03 ± 0.04 vs. 4.23 ± 0.03 log10 gene copies per 100 mL), and a principal component analysis revealed that storm drain effluent retention in a pond beneficially altered water characteristics, making them more like those of the receiving river. In conclusion, onsite qPCR assays can be performed with portable equipment items to quickly test water.

Long-Term Study of Antibiotic Presence in Ebro River Basin (Spain): Identification of the Emission Sources

Water monitoring is key to determining the presence of potentially hazardous substances related to urban activities and intensive farming. This research aimed to perform a long-term (four years) quantitative monitoring of selected antibiotics (azithromycin, enrofloxacin, trimethoprim and sulfadiazine) both in rivers and wastewaters belonging to the Ebro River basin (North of Spain). The target antibiotics were chosen on the basis of a preliminary multispecies screening. The analysis of the antibiotics was carried out by LC-MS/MS on wastewater-treatment plant (WWTP) effluent, effluents of a slaughterhouse and hospital, rivers downstream and upstream of these WWTPs, and rivers close to extensive farming areas. The ANOVA test was performed to study the significant differences between the points exposed to concrete emission sources and antibiotic concentration. The monitoring, carried out from 2018 to 2020, has been essential to illustrating the presence of the most abundant antibiotics that were detected in the Ebro River basin. Enrofloxacin has appeared in river waters in significant concentrations, especially near intensive farming, meanwhile azithromycin has been frequently detected in wastewaters.

The Characteristics of PM2.5 Pollution Episodes during 2016–2019 in Sichuan Basin, China

Many studies have been conducted to explore the characteristics of PM2.5 pollution events in Sichuan Basin, China. However, they focused on either specific regional pollution events from different aspects or the megacities, such as Chengdu and Chongqing. To provide a panorama gram of PM2.5 pollution episodes in the whole basin area, we identified all the PM2.5 pollution events in 17 cities during 2016-2019 and analyzed the characteristics of these events. In total, 1342 episodes were identified and the characteristics of episode numbers, durations and PM2.5 concentrations were analyzed in each city. We found that the characteristics of the temporal and spatial distribution of the episode numbers and durations were similar to the annual average of PM2.5 concentrations, which were higher in the Southern Sichuan and Western Sichuan Plain spatially and occurred most frequently in winter, followed by spring, autumn and summer. Non-monotonical relationships were obtained between the PM2.5 concentrations and pollution durations and there was a duration threshold in each city. For episodes with durations shorter than the threshold, their PM2.5 concentrations increased with duration. The duration thresholds were 6–8 days and 5–7 days in Southern Sichuan and Western Sichuan Plain, respectively. We also found that the air quality deteriorated in 2019 in most cities. Synthetically considering the numbers, durations and concentrations of pollution episodes, more concerns should be taken for the prevention of PM2.5 pollution in Yibin in the Southern Sichuan, Chengdu and Leshan in the Western Sichuan Plain, Neijiang in the Central Hills, and Bazhong, Dazhou, Nanchong in the Northeastern Sichuan. These results could help understanding the characteristics of PM2.5 episodes in Sichuan Basin and providing implications for pollution control strategies in future.

Promotion and Uptake of Sustainable Consumption and Production (SCP) Practices among Kenyan MSMEs: Key Learnings

This article analyses and assesses the integration of sustainable consumption and production (SCP) practices in the horticultural production of Kenyan micro-, small-, and medium-sized enterprises (MSMEs) within the framework of the EU Switch Africa Green project ‘Green Horticulture at Lake Naivasha’ (GOALAN) in the Lake Naivasha basin, Kenya. The aim of the study is to understand what facilitates and hinders the uptake of SCP practices. Using qualitative and quantitative data collection methods, this article is based on a case study approach. The study looked into (1) 158 MSMEs (project beneficiaries and non-beneficiaries) regarding their adoption and implementation of SCP practices, as well as their encountered challenges, opportunities, and evidenced outcomes;and (2) five ‘best practice’ case studies from the project beneficiary group. Findings indicate some key factors influencing the decision of MSMEs to adopt and implement SCP practices. These factors encompass access to SCP know-how, the identification of potential benefits, access to specialized and reliable markets, access to finance, and access to infrastructure. Based on the findings, the study suggests that to promote the uptake and long-term implementation of SCP practices by horticultural MSMEs, it is key to build the capacity of MSMEs, improve financial capacity to invest in SCP measures, enhance access to markets through establishing new linkages with buyers and customers, and enable infrastructure.