Beijing-Tianjin-Hebei Research Articles

Impact of meteorological conditions and reductions in anthropogenic emissions on PM2.5 concentrations in China from 2016 to 2020

Many efforts have been made to control PM2.5 pollution in China during the National 13th Five-Year Plan and PM2.5 concentrations significantly declined nationwide. Meteorological conditions and pollution emissions play the most important roles in PM2.5 pollution. However, extant quantitative estimations of the contributions of meteorological conditions and anthropogenic emission reductions during the period were mostly based on surface observations data. Using a reanalysis dataset from 2016 to 2020, our results reveal that the annual average PM2.5 concentrations have been reduced yearly in the four key regions: the Beijing-Tianjin-Hebei (BTH) region, Yangtze River Delta (YRD), Pearl River Delta (PRD) and central China. The frequency of stagnation days decreased in 2020 in the YRD and PRD, while it did not show significant fluctuations in the BTH region and central China. Through the sensitivity simulation experiments in 2016 and 2020, the implementation of the emission regulations led to PM2.5 pollution reductions of 6.59 and 5.12 μg m−3, respectively in the BTH region and central China, of which the worsening meteorological conditions offset 61.46% (4.05 μg m−3) and 19.53% (1.00 μg m−3) respectively. However, the impacts of favorable weather conditions and effective anthropogenic restrictions jointly contributed to the improvement in air quality in the YRD and PRD. Anthropogenic controls explained 81.95% (3.75 μg m−3) of the total 4.58 μg m−3 reduction in the YRD and 52.10% (1.86 μg m−3) of the total 3.57 μg m−3 reduction in the PRD. The findings provide a perspective on the causes of pollution events and would help formulate more effective emission reduction policies in the future.

Positive Effect Observed on Reducing Criteria Pollutant Emissions Provided by Provisional Local Regulations during the 2022 Winter Olympics

This study examined the impact of temporary air quality control measures on reducing pollutants during the 2022 Winter Olympics in China, utilizing real-time monitoring data from 2017 and 2022 to assess spatial and temporal variations in critical air pollutant concentrations. The results showed that concentrations of PM2.5, PM10, CO, SO2, and NO2 in the Beijing–Tianjin–Hebei region during the Olympic Games showed a marked decrease compared to the historical period, with reductions of 36.59%, 20.35%, 33.95%, 28.90%, and 22.70%, respectively. Significant north–south spatial differences were observed in Beijing, Tianjin, and Hebei Province during the Olympic period. The cities of Zhangjiakou, Chengde, Qinhuangdao, Beijing, and Tangshan showed the most significant pollution reduction. Based on assessments conducted during the Olympic period, it was noted that more than 95% of the daily average concentrations of pollutants are below the maximum values set by the World Health Organization for the interim target. Our research shows that provisional regulations effectively control the emission of air pollutants, providing a solid reference and basis for ensuring air quality during major international events.

Study on the Trade-Offs of Land Functions in the Central Plain of China for Sustainable Development

Properly managing the relationship between food security, ecological protection, and urbanization, and coordinating the trade-offs among these three factors for land demand are extremely important for environmental management and sustainable development. In this study, we attempt to analyze the state of land use trade-offs from a dynamic perspective in terms of both potential and efficiency. We have innovatively proposed a new land use trade-off analysis framework integrating the Estimation System for Land Productivity (ESLP) model, machine learning algorithms, ecosystem service value assessment, and spatial analysis method. By applying the framework, the potential and efficiency of the three land use functions of urban development, ecological protection, and agricultural production on the Huang-Huai-Hai (HHH) Plain were comprehensively estimated, and the trade-off relationship between the three land use functions was identified. The results showed a prominent conflict between urban development and agricultural production (around 8%) on the HHH Plain, especially in the Beijing–Tianjin–Hebei urban agglomeration and the southern Jiangsu urban agglomeration. In the mountainous areas, such as northern Hebei and central Shandong, there was an obvious trade-off between ecological land and agriculture land. Most cities had a trade-off between ecological land and urban land (approximately 6% of the study area), but it was relatively more relaxed in comparison. Finally, we found that on the HHH Plain, where land resources are fiercely competitive, spatial planning and land resource control depend not only on the suitability or potential of the land unit, but also on whether the efficiency of land use has reached an appropriate range. The smart way to use land resources is to scientifically trade-off different land use functions and improve the efficiency of land use to achieve maximum benefit.

The application study of the revised IMPROVE atmospheric extinction algorithm in atmospheric chemistry model focusing on improving low visibility prediction in eastern China

Low visibility event, as a disastrous weather, has great impacts on traffic and transportation, aircraft, and people's daily life, etc. Timely and accurate forecasts of low visibility events are urgently needed and meaningful. The reasonable algorithm of atmospheric extinction in atmospheric chemistry models is the basis for quantitatively predicting low visibility. The revised IMPROVE algorithm (RIMP) of atmospheric extinction is incorporated into the chemistry-weather interacted model GRAPES_Meso5.1/CUACE CW V1 to improve the prediction of low visibility events (LVEs) in the urban agglomerations in eastern China, which is compared with the original IMPROVE algorithm (OIMP) used in this model. The study results show that the RIMP effectively reduces the overestimation of low visibility prediction by OIMP in general, leading to a decrease of root-mean-square errors (RMSEs) and an increase of Threat Score (TS) of visibility <3 km, 5 km, and 10 km overall both at regional and city scales in varying degrees due to its more detailed processing of aerosols' size, optical feature and hygroscopic growth; The improvements of visibility prediction of LVEs by RIMP depends on the combined contribution of high relative humidity (RH) and PM2.5 instead of single high RH or PM2.5. The relative contributions of RH and PM2.5 concentration on different levels of low visibility are different in Beijing-Tianjin-Hebei (BTH) and Yangtze River Delta (YRD) regions due to their different RH and PM2.5, which leads to the different improvement of RIMP in the two regions. The larger improvements by RIMP occur for visibility <5 km in BTH, while in YRD, the larger improvements by RIMP occur for visibility <10 km and >5 km. Moreover, the improvements by RIMP were more evident with higher RH conditions in both regions. The uncertainty created by the extinction algorithm is one important factor of the multiple factors affecting LVEs prediction; accurate modeling of high RH near saturation is also very important for LVEs prediction.

Significantly alleviated PM2.5 pollution in cold seasons in the Beijing-Tianjin-Hebei and surrounding area: Insights from regional observation

PM2.5 pollution has been greatly alleviated in the Beijing-Tianjin-Hebei (BTH) and surrounding area since the implementation of Action Plans for blue skies. Regional air pollution covering multiple cities has recently become common, but an overview from a regional perspective is scarse. In this work, based on PM2.5 chemical composition data collected in “2 + 26” cities during four consecutive autumn-winter seasons (AWS, from October to next March) from October 2016 to March 2020, we determined the main components driving the increase in PM2.5 mass concentration within different PM2.5 concentration regimes. Regionally, in the low PM2.5 regime (daily concentration ≤ 75 μg/m3), the PM2.5 mass remained organic matter (OM)-driven during the four AWSs. In the high PM2.5 regime (daily concentration > 75 μg/m3), regional PM2.5 increase pattern rapidly transformed from OM-driven during the 2016–2017 AWS to secondary inorganics-driven during the latter three AWSs, with nitrate becoming the dominant component, driving PM2.5 increase in almost 90% cities in the region. These transitions not only reflect the effectiveness of policies to control emissions from coal combustion and biomass burning in recent years, but also highlight the need to further reduce nitrogen oxides emissions from diesel vehicles, non-road mobile machinery and industry. Besides, the control of sulfur dioxide and primary organic matter should not be neglected, given the substantial contribution of PM2.5 sulfate under stagnant and humid meteorological conditions, especially in the geographically central and southern parts of the region, and the need for in-depth air quality improvement if the PM2.5 concentration standards are tightened. Considering the dominance of nitrate in driving regional PM2.5 pollution, more research on nitrate formation and its atmospheric and climatic impacts is warranted.

Spatiotemporal data evolution of regional economy based on spatial econometric models

From the perspective of practical development, under the premise of stable macroeconomic growth in society, influenced by spatiotemporal factors, regional economies inevitably have differences and changes, which affect various aspects of social production and life. In order to understand the spatiotemporal data evolution characteristics of regional economy, promote common regional development and the implementation of coordinated economic development strategies, this article takes the Beijing Tianjin Hebei (BTH for short here) region as an example. By combining spatial econometric models (SEM for short here), this article collects and processes economic development data from 2013 to 2022 in the BTH region, and introduced a spatial weight matrix to conduct High-performance computing and analysis of its regional economic spatial correlation. Based on this, this article conducted in-depth research on the spatiotemporal data evolution characteristics of the BTH regional economy through the description and quantitative analysis of the influencing factors of the BTH regional economy. The empirical analysis results showed that the global Moran index (Global Moran’s for short here) of the BTH region was positive from 2013 to 2022, and the Z-values were all greater than 1.96, indicating a significant spatial correlation in the BTH regional economy. There is an imbalance in economic development in the BTH region, but with the continuous development of the region, its economic balance has improved.

Different Response Mechanisms of N‐Bearing Components to Emission Reduction Across China During COVID‐19 Lockdown Period

AbstractThe response characteristics of secondary inorganic aerosols to COVID‐19 lockdown measures have been extensively reported, while spatial disparities of these response characteristics across China and key deriving mechanisms still remained poorly understood. In our study, a chemical transport model (GEOS‐Chem) was applied to simulate the national concentrations of four N‐bearing components during lockdown periods in 2020 and business‐as‐usual (BAU) period (the same period in 2019). Three distinct regional response mechanisms were distinguished across China. The increases of levels in the northern part of Beijing‐Tianjin‐Hebei (BTH) might be attributable to increased relative humidity (RH) and abundant ammonia (NH3) level (13.5 μg/m3). The dramatic decreases of secondary inorganic nitrogen in Southeast China were contributed by substantial emission reduction (−15.3%) and slightly favorable (pollutant removal) meteorological conditions (−4.36%). The consistent increases of levels, but decreased NH3 levels in tropical regions suggested extremely high RH (84%) and enhanced atmospheric oxidation capacity were dominant factors. The response mechanisms of secondary N‐bearing components showed the distinct characteristics between urban and rural regions, which might be closely associated with variations of emission reduction and meteorology during the COVID‐19 period. The natural experiment demonstrates priority control of NH3 emission might be the primary target for BTH, while the coordinated controls of VOCs and NOx emissions should be exerted in Southeast China especially the tropical regions.

Establishing the emission inventory of biogenic volatile organic compounds and quantifying their contributions to O3 and PM2.5 in the Beijing-Tianjin-Hebei region

O3 and PM2.5 pollution are prominent in the Beijing-Tianjin-Hebei (BTH) region, and volatile organic compounds (VOCs) are important precursors of both. However, few studies has been conducted to establish a high-precision BVOC emission inventory by vegetation types and species for the BTH region yet, and to further analyze the contribution of BVOC emissions to O3 and PM2.5 on this basis. This study established an emission inventory of biogenic volatile organic compounds (BVOCs) in the BTH region using two methods: (a) the coupled method of stock volume conversion and plant function types (PFTs) and (b) MEGAN method. The contributions from different vegetation types to O3 and PM2.5 in the BTH region in July 2018 were simulated with WRF-CMAQ and verified using the O3 and secondary organic aerosol (SOA) formation potential method. Relatively consistent results were obtained using the different inventory establishment and air quality impact analysis methods. Fruiters, crops, shrubs & grasslands, evergreen forests, and deciduous forests emitted 6.25%, 31.18%, 18.27%, 11.42%, and 32.88% of total BVOCs, respectively. The simulation results showed that BVOCs contributed 23.73% to O3 and 37.99% to SOA in the BTH region. Deciduous trees, such as poplar and Quercus, were the main contributors to O3, while Pinus tabulaefoimis and Quercus were the main contributors to SOA.

How does the digital economy affect ecological well-being performance? Evidence from three major urban agglomerations in China

The booming digital economy (DIG) has deeply altered the pattern of people’s lives and production and plays a key role in increasing human well-being and achieving urban sustainability. This study investigates the relationship between the DIG and ecological well-being performance (EWP) in the urban agglomerations of Yangtze River Delta (YRD), Beijing-Tianjin-Hebei (BTH) and Pearl River Delta (PRD) from 2010 to 2020. The main results are as follows. Overall, the DIG can significantly enhance EWP. In terms of spatial spillover effect, there is no spatial spillover effect in BTH and YRD urban agglomerations, and there is a negative spatial spillover effect in PRD urban agglomerations. The overall performance is that the DIG promotes the growth of EWP in the region, while the increase of DIG in the neighboring regions will hinder the enhancement of EWP in the region. In terms of regional heterogeneity, the size of the direct contribution of the DIG to EWP is “PRD > YRD > BTH”. Finally, technological innovation and industrial structure optimization are mechanism variables. This study offers direction for improving EWP.

Spatial–Temporal Patterns of Carbon Sequestration Benefits and Identification of County-Level Compensation Orders in Beijing–Tianjin–Hebei Ecosystems

The role of ecosystems in sequestering carbon is becoming increasingly important as China’s “dual-carbon” strategy and the construction of an ecological civilisation continue to be promoted and implemented. The rapid economic development of the Beijing–Tianjin–Hebei region is accompanied by the problem of excessive carbon emissions. Focusing on enhancing the carbon sequestration benefits of ecosystems and coordinating regional development, this paper adopts the model construction method, spatial correlation analysis, and centre of gravity migration analysis to study the spatial and temporal patterns of ecosystems’ carbon sequestration benefits in the counties of Beijing–Tianjin–Hebei, spatial and spatial aggregation, the pattern of centre of gravity migration, and the sequence of county compensation differentials in the period from 2000 to 2020. The results show (1) the carbon account of the Beijing–Tianjin–Hebei region before the revision shows an overall distribution pattern of “low in the north and high in the south”. However, it is important to take into account the differences in the regional area, regional population, and regional GDP and the fact that the analysis of the amount of ecological compensation does not mechanically take into account the absolute magnitude of each value but rather takes into account all the values and then makes a trade-off for the difference in the value of the difference in the background. The spatial distribution of corrected carbon accounts is more even. (2) The high–high aggregation area of ecological compensation from 2000 to 2020 is mainly distributed in a dozen counties, such as Lulong County and Luan County in the eastern part of the Beijing–Tianjin–Hebei region, while the low–low aggregation area is mainly concentrated in counties such as Weichang County and Longhua County in the western and northern parts of the country, and the scope has a tendency to expand. (3) The centre of gravity of the ecological compensation amount moves roughly within the range of 116°17′30″ E–116°30′30″ E, 38°40′ N–38°50′ N, and the overall change rule of northwest to southeast migration is observed, with reciprocal movement in some years. (4) The top 15 lists of eco-compensation pay areas and payment areas have basically remained stable, with only some internal sorting changes, and the overall amount of payment areas is larger than that of payee areas, with sufficient surplus funds to ensure the smooth implementation of eco-compensation work at the county level in Beijing–Tianjin–Hebei. The findings of this paper are important for coordinating the integrated development of Beijing–Tianjin–Hebei and, at the same time, contributing positively to the realisation of China’s carbon peaking and carbon neutrality goals.

Variation of temperature extremes in wintertime over Beijing-Tianjin-Hebei region in the era of sharp decline of Arctic sea ice

The more frequent winter temperature extremes have exerted significant negative impacts on the coordinated development of the Beijing-Tianjin-Hebei(BTH) region of China during the recent decades. To more deeply understand the extreme temperature events(ETEs) in the region, in this study, the temperature intra-seasonal variability(TSV) and ETEs are investigated based on the observation data. Our results suggest that the TSV of wintertime over the BTH region has significantly amplified in the era of sharp decline of Arctic sea ice during 1990/1991–2020/2021, which is reflected by a polarization between warm and cold extremes, particularly increasing cold nights and temperature whiplash events. The amplified TSV is mainly driven by the abnormal atmospheric circulation triggered by rapidly melting autumn Arctic sea ice. The synergistic effects of obviously weakened polar vortex, significantly strengthened Ural Blocking High (UH) and Siberian High (SH), and increased days of extreme negative phase of Arctic Oscillation (AO), which are conducive to the inverted Ω type circulation at 500 hPa, may cause more cold extremes and enhance the TSV in the BTH region since 1990/1991 winter. While global warming favors more frequent warm extremes in this region. We hope this study can help reduce the impact of ETEs and provide some scientific support for the coordinated development of the BTH region.

Compliance relationship analysis between environmental governance attention and environmental quality in the Beijing–Tianjin–Hebei region

This study analyzes the changes and allocation characteristics of environmental governance attention in the Beijing–Tianjin–Hebei region based on the government work report from 2002 to 2020 and explores the compliance relationship between environmental governance attention and environmental quality. The results show that the allocation of local government environmental governance attention shows high consistency with that of the central government, and the overall environmental governance attention shows a fluctuating upward trend. There is a long-term stable co-integrated relationship between environmental governance attention and environmental quality in the Beijing–Tianjin–Hebei region, as well as a two-way Granger causality relationship in the short term. The non-linear influence of environmental governance attention on the environmental quality in the Beijing–Hebei–Tianjin region can be described using the LSTR2 model. During 2004–2016, environmental governance attention often had non-linear effects on the environmental quality. Since 2016, there has been a stable linear relationship between environmental governance attention and environmental quality. Finally, some policy suggestions on improving the local performance evaluation system and establishing a collaborative environment system for the Beijing–Tianjin–Hebei region have been put forward for the government.

Nonlinear effect of NOx concentration decrease on secondary aerosol formation in the Beijing-Tianjin-Hebei region: Evidence from smog chamber experiments and field observations

During the COVID-19 lockdown in the Beijing-Tianjin-Hebei (BTH) region in China, large decrease in nitrogen oxides (NOx) emissions, especially in the transportation sector, could not avoid the occurrence of heavy PM2.5 pollution where nitrate dominated the PM2.5 mass increase. To experimentally reveal the effect of NOx control on the formation of PM2.5 secondary components (nitrate in particular), photochemical simulation experiments of mixed volatile organic compounds (VOCs) under various NOx concentrations with smog chamber were performed. The proportions of gaseous precursors in the control experiment were comparable to ambient conditions typically observed in the BTH region. Under relatively constant VOCs concentrations, when the initial NOx concentration was reduced to 40% of that in the control experiment (labelled as NOx,0), the particle mass concentration was not significantly reduced, but when the initial NOx concentration decreased to 20 % of NOx,0, the mass concentration of particles as well as nitrate and organics showed a sudden decrease. A “critical point” where the mass concentration of secondary aerosol started to decline as the initial NOx concentration decreased, located at 0.2–0.4 NOx,0 (or 0.18–0.44 NO2,0) in smog chamber experiments. The oxidation capacity and solar radiation intensity played key roles in the mass concentration and compositions of the formed particles. In field observations in the BTH region in the autumn and winter seasons, the “critical point” exist at 0.15–0.34 NO2,0, which coincided mostly with the laboratory simulation results. Our results suggest that a reduction of NOx emission by >60% could lead to significant reductions of secondary aerosol formation, which can be an effective way to further alleviate PM2.5 pollution in the BTH region.

Production–Living–Ecological Spatial Function Identification and Pattern Analysis Based on Multi-Source Geographic Data and Machine Learning

Land use cannot be simply understood as land cover. The same land may carry different functions, such as production, living, and ecological applications; the dominant function of land will affect and restrict other uses. Disorderly urbanization and industrialization have led to an intensification of conflicts among the production, living, and ecological functions of land, which is a major constraint on regional sustainable development. This paper took the perspective of land-use function and used multi-source data such as Sentinel remote-sensing imagery, VIIRS night-time light data, and POIs to classify land-use functions on a large scale in the Beijing–Tianjin–Hebei (BTH) urban agglomeration. The specific research process was as follows. Firstly, the BTH region was multi-scale-segmented based on Sentinel remote-sensing data. Then, the spectral, texture, shape, and socio-economic features of each small area after segmentation were extracted. Moreover, a PLES land-use classification system oriented towards land-use function was established, and a series of representative samples were selected. Subsequently, a random forest model was trained using these samples; then, the trained model was used for the large-scale analysis of land use in the entire BTH region. Finally, the spatial distribution patterns and temporal–spatial evolution characteristics of PLES in the BTH region from 2016 to 2021 were analyzed from the macro level to the micro level.

Reductions of multiple air pollutants from coking industry through technology improvements and their impacts on air quality and health risks in a highly industrialized region of China

The Beijing-Tianjin-Hebei (BTH) region, a highly industrialized area in China, boasts a concentration of coking plants that constitute a vital component of the steel industry. In recent years, the Chinese government has implemented measures including backward production capacity elimination (BPCE), ultra-low emission technology transformation (ULET), and deep treatment of volatile organic compounds (DTV), to promote technological progress in the coking industry and mitigate the impact of pollutant emissions. This study focuses on the emission trends, reduction effects of various measures, and the impact on air quality and human health in the regional scale. The findings reveal that in 2015, the emissions of PM, SO2, NOx and VOCs of the coking industry in BTH region were 29.15, 9.64, 26.62 and 82.99 Gg (1000 tons/year) respectively. However, by 2019, these emissions had significantly decreased by 19.95, 5.78, 18.69, and 22.53 Gg, respectively. Of these reductions, ULET contributed about 80.3 % of NOx and SO2, and 57.4 % of PM. Meanwhile, DTV and BPCE contributed 49.2 % and 50.7 % of VOCs emission reduction, respectively. Despite the improvement effect on PM2.5, SO2, and NO2 is limited, the substantial decrease in VOCs (particularly benzene) resulted in a significant reduction in the coking industry's contribution to the atmospheric benzene concentration, dropping from 15.9 % in 2015 to 11.6 % in 2019. Moreover, the lifetime cancer risk (LCR) contribution of benzene inhalation in the BTH region also decreased from 1.7 × 10−6 to 1.2 × 10−6. Looking ahead to 2025, the continued implementation of DTV will be expected to reduce VOCs emissions by 24.41Gg. This will bring the industry's contribution to the benzene concentration down to 6.8 % and the cancer risk of the population to an acceptable level (LCR < 1 × 10−6). Additionally, the deep treatment of VOCs in coking plants will significantly reduce the health risks faced by people living in the vicinity of the plants.

The Coupling Coordination and Interaction Mechanism of Land Ecological Security and High-Quality Economic Development in the Beijing–Tianjin–Hebei Region

Land ecological security (LES) and high-quality economic development (HED) are mutually influential. China has three world-class urban agglomerations; the Beijing–Tianjin–Hebei (BTH) region is one of them. It is an important platform for participating in international competition and cooperation. To promote regional sustainable development, it is critical to study the coupling coordination and interaction mechanism of LES–HED subsystems over time and space in the BTH region. This study involved the construction of an aggregated index system to obtain a comprehensive understanding of the subsystems, and then investigated the coupling coordination degree (CCD) of the LES–HED subsystems from 2007 to 2018 using a CCD model. Additionally, a panel vector autoregressive (PVAR) model was applied to analyze the interactive mechanism of the LES–HED subsystems. Finally, a model of the degree of relative development was used to classify the types of regional development. The results showed that the CCD of the LES–HED subsystems in the BTH region had significant spatial and temporal differences. The spatial distribution could be characterized as low in the central area and high in the peripheral area, and the evolutionary law of CCD in the system was from lower to higher levels over time. In addition, improvements in LES promoted HED, but the impact of HED on LES was limited. The development patterns within the cities of the study area included three development types, including an slightly lagging type of LES, a slightly lagging type of HED, and a significantly lagging type of HED. Given the spatial variability of the coupled and coordinated development of LES–HED subsystems, it is necessary to implement different development strategies. This study can inform decisions promoting the coordinated development of LES–HED subsystems for sustainable regional development.

Pathways to achieve carbon emission peak and carbon neutrality by 2060: A case study in the Beijing-Tianjin-Hebei region, China

Global climate change, rapid urbanization, and drastic economic development pose many threats and challenges to humanity, increasing the need for sustainable development, urban ecological management, and low-carbon transformations. Comprehensive simulation models rarely involve all the aspects of carbon emissions, carbon sequestration, population, economic, and energy sections. Firstly, this study evaluated the changes of the carbon neutrality rate in the Beijing-Tianjin-Hebei (BTH) region from 2000 to 2019. Then, a Carbon Neutrality Simulation Model (CNSM) was built using system dynamics. Finally, an optimal development scenario and pathways were identified for the BTH region based on scenario analysis. The results revealed that: (1) Carbon emissions first increased rapidly and then stabilized, carbon sequestration did not significantly change, and carbon neutrality rate decreased. (2) The baseline scenario (S1) did not reach the “dual carbon” target with carbon emissions increasing to 832.62 Mt in 2030 and 914.26 Mt in 2060, whereas the carbon neutrality rate increased to 17.96 % in 2030 and 22.69 % in 2060. (3) Among the single-factor scenarios (S2–S7), the industrial restructuring scenario (S3) had the greatest carbon reduction potential, reaching the carbon peak target. (4) Among the multi-factor scenarios, all the three baseline economic scenarios (S8–S10) reached carbon peak target in 2043, 2029, and 2022. The high constraint scenario (S10) reached the carbon neutrality target, as the optimal development scenario for the BTH region. All the results provide scientific evidences to achieve carbon neutrality target and regional sustainable development.

Research on the economic collaborative development evaluation in the Beijing-Tianjin-Hebei region based on hesitant triangular fuzzy information

Beijing, Tianjin and Hebei are located in the Bohai Rim region of Northeast Asia, China. It is the region with the largest economic scale and strongest economic vitality in northern China. Due to historical development and administrative division, the economic strength of Beijing and Tianjin is strong, while the economic strength of Hebei Province is weak. The economic development of the Beijing-Tianjin-Hebei region is severely uneven. The “Beijing-Tianjin-Hebei Coordinated Development Strategy” is proposed and elevated to a national strategy in this context, aiming to explore the path of coordinated economic development in the Beijing-Tianjin-Hebei region, promote economic cooperation, balance economic differences, and enhance the overall economic strength of the Beijing Tianjin Hebei region through national leadership. The economic collaborative development evaluation in the Beijing-Tianjin-Hebei region is a classical multiple attribute decision making (MADM) problems. Recently, the TODIM and Evaluation based on Distance from Average Solution (EDAS) method has been used to cope with MADM issues. The hesitant triangular fuzzy sets (HTFSs) are used as a tool for characterizing uncertain information during the economic collaborative development evaluation in the Beijing-Tianjin-Hebei region. In this paper, the hesitant triangular fuzzy TODIM-EDAS (HTF-TODIM-EDAS) method is built to solve the MADM under HTFSs. In the end, a numerical case study for economic collaborative development evaluation in the Beijing-Tianjin-Hebei region is given to validate the proposed method. The main contributions of this paper are summarized: (1) the HTF-TODIM-EDAS method is proposed under HTFSs. (2) The MADM method is designed based on the information entropy and HTF-TODIM-EDAS method under HTFSs. (3) A numerical case study for economic collaborative development evaluation in the Beijing-Tianjin-Hebei region is given to validate the proposed method. (4) A comparison between proposed method and existing methods is carried out to check its effectiveness.

Dynamic Evolution Characteristics and Drivers of Tourism-Related Ecological Security in the Beijing–Tianjin–Hebei Region

Revealing the characteristics of the spatial and temporal evolution of regional tourism-related ecological security and exploring its driving factors are of great theoretical and practical value to promoting the coordinated and sustainable development of the tourism economy and the ecological environment. Taking the Beijing–Tianjin–Hebei region as a case study, this study constructed a tourism-related ecological security evaluation index system based on the DPSIR theoretical framework. The tourism-related ecological security index was measured from 2011 to 2022 and its spatiotemporal characteristics and dynamic evolutionary process were analyzed. Finally, the panel quantile regression model was used to analyze its driving factors. The results show that: (1) in time, the average value of tourism-related ecological security fluctuates and rises, and the differences between the units show a convergent trend, which is mainly manifested in the catching-up effect from low-value cities to higher-value cities; (2) in space, Beijing and its southeastern cities have a high level of tourism-related ecological security, and although the study area is mainly at the less secure level, it is developing continuously and progressively; (3) in terms of the dynamic evolution characteristics, the type transfer of tourism-related ecological security has certain “path dependence” and “self-locking” effects, often occurring between neighboring levels, and the type transfer under the influence of different neighborhoods has significant differences; (4) in terms of driving factors, environmental pollution has a significant inhibitory effect on the level of tourism-related ecological security, and the level of economic development has the largest positive marginal effect on tourism-related ecological security, while other influencing factors such as the level of tourism development have certain differences in terms of their positive role in the promotion of the level of tourism-related ecological security. This study can provide a reference for decisionmakers to promote ecological protection and high-quality tourism development in the Beijing–Tianjin–Hebei region.

Estimating the transboundary budget of sulfate aerosols in Northeast Asia with NASA MERRA aerosol reanalysis data

Using the Modern-Era Retrospective Analysis for Research and Applications Aerosol (MERRAero) reanalysis data, we conducted an estimation of the impact of transboundary-transported sulfate aerosols from China, specifically the Beijing–Tianjin–Hebei (BTH) region and Shandong province, on the sulfate concentrations in Korea between 2004 and 2020. Our analysis revealed that the ground-level sulfate concentration at six sites in Korea experienced a significant decrease of over 40%, from 7.16 μg m−3 to 3.7 μg m−3 after 2013. The MERRAero reanalysis data provided insights into a yearly reduction of 0.8 μg m−3 in sulfate concentration for the BTH and Shandong regions, while Korea showed an annual decrease of 0.2 μg m−3. Notably, the BTH and Shandong regions and Korea displayed the strongest correlation in sulfate concentrations with a one-day lag, particularly during the winter season. With the exception of summer, approximately 49.79 ton km−2 month−1 of sulfate was transported from the BTH and Shandong regions of China to Korea, resulting in a net increase of 9.8 ton km−2 month−1. The highest influx of sulfate occurred in spring at 70.06 ton km−2 month−1. Despite the clear declining trend in sulfate concentrations across the study region, the transboundary transport of sulfate from the BTH and Shandong regions of China to Korea did not exhibit a decreasing trend. This underscores the importance of thoroughly investigating the formation process of these aerosols through photochemical reactions during their long-distance transportation over northeast Asia, in addition to conducting a comprehensive examination of precursor emissions related to secondary aerosols.