The impact of stratospheric intrusions (SIs) on Central and Eastern China (CEC) with severe ozone pollution presents a range of uncertainties, underscoring the imperative for sustained research endeavors. In this study, we propose a traceability assessment method that can derive high-resolution critical source areas (CSAs) of SIs by utilizing ambient air quality observations, global ozone (re)analysis data, and customized Lagrangian simulations. This approach enables us to facilitate a meticulous and systematic examination of the impact of direct and indirect SIs on tropospheric and near-surface ozone in six important sub-regions within the CEC during the spring and summer of 2019, as well as the unique circulations driving SIs, from a more refined and targeted tracing perspective. The findings reveal that impacts of indirect intrusions are more efficient at monthly scales, with contributions to tropospheric ozone reaching up to twice the magnitude of direct intrusions. The impacts of direct intrusions are more pronounced at daily scales, primarily occurring in May. In terms of contribution to near-surface ozone, the eastern plains frequently witness ozone exceedance events, with the most substantial impact from SIs observed (e.g., contributing 15.8 % and 16.7 % to near-surface ozone in North China and East China, respectively), showcasing a remarkable ability to capture descending lower-stratospheric air. In contrast, the Loess Plateau and Central China, situated in central and western high-altitude regions, receive more intrusive ozone into the troposphere but exhibit minimal contributions to near-surface ozone. The indirect intrusions that generate the above impact come from three to four CSAs located thousands of kilometers away, evenly distributed latitudinally within the westerlies between 40 and 70° N (spaced 70 longitudes apart). These CSAs are intricately linked to the evolution of synoptic-scale Rossby waves or subtropical westerly jets, with western Siberia or Europe and north Africa identified as the most significant CSAs. Conversely, the CSAs for direct intrusions are relatively concentrated, with those influencing the middle troposphere originating from the Tibetan Plateau and those influencing the lower troposphere predominantly located in Mongolia and central Russia, just a few hundred kilometers from the CEC. These sources are associated with typical atmospheric circulations such as the northeast cold vortex and the South Asian High, where the intensity of the intrusion system plays a more crucial role than its frequency of occurrence. This study provides valuable insights for forecasting and mitigating the impact of SIs on ozone pollution in China and contributes to addressing the broader challenges posed by climate change.

The tumor-associated antigen, mucin4 (MUC4), is overexpressed on various epithelial malignancies, making it a potentially broadly applicable candidate vaccine therapy. In this paper, we report on the creation of a dendritic cell (DC)-based vaccine, using cells transduced with the universal DR-restricted Th helper epitope (PADRE) combined with human leukocyte antigen (HLA)-A1- and HLA-A2-restricted epitopes from MUC4 (rAd-pE-DCs). We examined this vaccine's biologic characteristics and immune activity in vitro, finding that infection with the polyepitope adenovirus did not alter the typical morphology of mature DC and the typical markers of these cells (CD86, CD83, CD80, and HLA-DR) were highly expressed on rAd-pE-DCs. Lymphocytes primed with rAd-pE-DCs generated potent cytotoxic responses. By contrast, lymphocytes primed with a GFP-expressing adenovirus (rAd-GFP-DCs) or mock-transfected DCs were not cytotoxic. Transduction of DCs with an adenovirus encoding PADRE combined with HLA-A1- and HLA-A2-restricted epitopes may be a potential strategy for the immunotherapy of MUC4-associated tumors.

The Beijing-Tianjin-Hebei (BTH) region, with its complex terrain, has serious issues with air pollution. The northern and western parts of the BTH region are surrounded by the Yan Mountains and Loess Plateau (LP), and the south-central part of that region is a large open plain. Such special geographic configuration is prone to result in a concentrated pollution belt along the north-to-south direction on the eastern margin of the plateau, in addition to the influence of pollutant-emission sources and population distribution. In this study, based on an original adaptive nudging constraint method, we quantitatively analyzed the differences in the influence of emission sources under different dynamic and thermal conditions in the BTH region, which is impacted by a special large-scale leeward slope terrain. The mechanism of air pollution vulnerability and the comprehensive effects of terrain–meteorological conditions on air pollution in the BTH region were also discussed. The results indicated that the atmospheric diffusion conditions on the eastern side of the plateau were poor, and a sub-synoptic-scale “vortex sequence”, which was composed of a series of linked vortices, was identified. The corresponding atmospheric pollution convergence line stretched from Beijing to Hebei to Northern Henan in the lower atmosphere. On the eastern edge of the plateau, a “warm cover” formed by a temperature anomaly and a downdraft impeded the vertical diffusion of pollutants. Therefore, pollutants tended to converge at the eastern edge of the plateau, and the pollution belts would move longitudinally north and south along the topography of the eastern slope when south-westerly and north-easterly winds alternated. The movement generated a “train” of pollutants that were transported on the eastern edge of the plateau, which then caused air pollution to persist there. Such terrain–meteorological conditions amplified the effects of emissions by an average of 50% to 150% in the region, leading the eastern side of the LP to become a “naturally vulnerable region” to haze pollution.

In this study, the multi-year data of meteorology and O₃ from remote sensing and ground observations are applied to characterize the 3-D changes of O₃ in the troposphere over central and eastern China (CEC) induced by the tropical cyclones (TCs) in the tropical and subtropical ocean regions over Northwest Pacific. The CEC-regional average of near-surface O₃ levels is significantly elevated with 6.0 ppb in the large coverage by the TCs in the subtropical ocean, while the TCs in the tropical ocean alter near-surface O₃ weakly, indicating the latitudinal-located TCs in the subtropical offshore ocean could largely influence the O₃ variations over CEC. The sub-seasonal change with the positive and negative anomalies of near-surface O₃ is induced by the tropical TCs from June to July and from August to October. The peripheral circulation of TCs in the subtropical offshore ocean persistently enhances the O₃ concentrations over CEC during the season of East Asian summer monsoons. The positive O₃ anomalies maintain from the entire troposphere to the lower stratosphere over CEC in the peripheries of subtropical TCs, while the tropical TCs cause the positive O₃ anomalies merely in the lower troposphere. The O₃ transport and accumulation, photochemical production and stratospheric intrusion are climatologically confirmed as the major meteorological mechanisms of TCs affecting the O₃ variations. This study reveals that the downward transport of stratospheric O₃ of TCs in the subtropical ocean exerts a large impact on the atmospheric environment over CEC, while the regional O₃ transport and photochemical productions dominate the lower troposphere over CEC with less impact of stratospheric intrusion from the TCs in the tropical ocean region. These results present the climatology of tropospheric O₃ anomalies in China induced by the TCs over the Northwest Pacific with enhancing our comprehension of the meteorological impact on O₃ variations over the East Asian monsoon region.

Regional PM_2.5 transport is an important cause of atmospheric environment change. However, the variations in regional PM_2.5 transport on a synoptic scale with meteorological drivers have been incomprehensively understood. Therefore, this study is targeted at the quasi-weekly oscillation (QWO) of regional PM_2.5 transport over central and eastern China (CEC) with the influence of synoptic-scale disturbance of the East Asian winter monsoon (EAWM) circulation. By constructing the data of daily PM_2.5 transport flux in CEC in the winters of 2015–2019, we utilize the extended empirical orthogonal function (EEOF) decomposition and other statistical methods to extract the moving spatial distribution of regional PM_2.5 transport over CEC, recognizing the QWO in regional PM_2.5 transport with the spatial–temporal variations over CEC. The source–receptor relationship in regional transport of PM_2.5 is identified with the 2 d lag effect of the North China Plain, as the upwind source region, on the PM_2.5 pollution change in the Twain-Hu Basin, as the downwind receptor region in central China. The QWO of regional PM_2.5 transport over CEC is regulated by the synoptic-scale disturbance of the EAWM circulation with the periodic activities of the Siberian high. These findings provide new insights into the understanding of regional PM_2.5 transport with the source–receptor relationship and the meteorological mechanism in atmospheric environment change.

The influence of the underlying surface on the atmospheric environment over rivers and lakes is not fully understood. To improve our understanding, this study targeted the Twain-Hu Basin (THB) in central China, with a unique underlying surface comprising a dense “water network” over rivers and lakes. In this study, the Weather Research and Forecasting Model with Chemistry (WRF-Chem) was used to simulate the impact of this dense “water network” on a wintertime heavy PM_2.5 pollution event in the THB. On this basis, the regulating effects of density and area of the lake groups, with centralized big lakes (CBLs) and discrete small lakes (DSLs), on PM_2.5 concentrations over the underlying surface of the dense “water network” in the THB were clarified, and the relative contributions of thermal factors and water vapor factors in the atmospheric boundary layer to the variation of PM_2.5 concentrations were evaluated. The results show that the underlying surface of dense “water networks” in the THB generally decreases the PM_2.5 concentrations, but the influences of different lake-group types are not uniform in spatial distribution. The CBLs can reduce the PM_2.5 concentrations over the lake and its surroundings by 4.90–17.68% during the day and night. The ability of DSLs in reducing PM_2.5 pollution is relatively weak, with the reversed contribution between −5.63% and 1.56%. Thermal factors and water vapor–related factors are the key meteorological drivers affecting the variation of PM_2.5 concentrations over the underlying surface of dense “water networks”. The warming and humidification effects of such underlying surfaces contribute positively and negatively to the “purification” of air pollution, respectively. The relative contributions of thermal factors and water vapor–related factors are 52.48% and 43.91% for CBLs and 65.96% and 27.31% for DSLs, respectively. The “purification” effect of the underlying surface with a dense “water network” in the THB on regional air pollution highlights the importance of environmental protection of inland rivers and lakes in regional environmental governance. In further studies on the atmospheric environment, long-term studies are necessary, including fine measurements in terms of meteorology and the environment and more comprehensive simulations under different scenarios.