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Antibiotic-resistant pathogens pose a significant threat to human health. Several dispersal mechanisms have been described, but transport of both microbes and antibiotic resistance genes (ARGs) via atmospheric particles has received little attention as a pathway for global dissemination. These atmospheric particles can return to the Earth’s surface via rain or snowfall, and thus promote long-distance spread of ARGs. However, the diversity and abundance of ARGs in fresh snow has not been studied and their potential correlation with particulate air pollution is not well explored. Here, we characterized ARGs in 44 samples of fresh snow from major cities in China, three in North America, and one in Europe, spanning a gradient from pristine to heavily anthropogenically influenced ecosystems. High-throughput qPCR analysis of ARGs and mobile genetic elements (MGEs) provided strong indications that dissemination of ARGs in fresh snow could be exacerbated by air pollution, severely increasing the health risks of both air pollution and ARGs. We showed that snowfall did effectively spread ARGs from point sources over the Earth surface. Together our findings urge for better pollution control to reduce the risk of global dissemination of antibiotic resistance genes.

The May 12, 2008 Great Wenchuan Earthquake has resulted in more than 68,858 deaths and losses in the hundreds of billions RMB as of May 30, 2008, and these numbers will undoubtedly increase as more information becomes available on the extent of the event. Immediately after the earthquake, the China Earthquake Administration （CEA） responded quickly by sending teams of experts to the affected region, eventually including over 60 staff members from the Institute of Engineering Mechanics （IEM）. This paper reports preliminary information that has been gathered in the first 18 days after the event, covering seismicity, search and rescue efforts, observed ground motions, and damage and loss estimates. The extensive field investigation has revealed a number of valuable findings that could be useful in improving research in earthquake engineering in the future. Once again, this earthquake has shown that the vertical component of ground motion is as significant as horizontal ground motions in the near-source area. Finally, note that as more information is gathered, the numbers reported in this paper will need to be adjusted accordingly.

Vegetable gardens are increasingly common in urban areas and can provide numerous societal benefits; however, contamination with potential toxic elements (PTEs) due to urbanization and industrialization is cause for concern. The present study aimed to assess the source of contamination and pollution levels in urban garden soils, as well as the health risks for adults and children consuming vegetables grown in such environments. Various types of vegetable samples and their corresponding soils from 26 community gardens were collected throughout Chengdu City in southwestern China. The results showed that leafy vegetables, particularly lettuce leaves and Chinese cabbage, had relatively higher levels of Cd (0.04 mg/kg FW) and Pb (0.05 mg/kg FW), while higher levels of As (0.07 mg/kg FW), Cr (0.07 mg/kg FW), and Hg (0.003 mg/kg FW) were found in amaranths, tomatoes, and Houttuynia cordatas, respectively. The pollution indices revealed that the vegetable purplish soils were relatively more polluted by Cd and As, and the concentrations of these metals in vegetables were correlated with their concentrations in the soils. Principal component analysis grouped the PTEs in two dimensions that cumulatively explained 62.3% of their variation, and hierarchical clustering identified two distinct clusters indicating that Cr originated from a unique source. The health risk assessment revealed that exposure to As and Cd induced the greatest non-carcinogenic risk, whereas Cr was most likely to cause cancer risks. Furthermore, contaminated vegetable consumption was riskier for children than adults. The critical factors contributing to PTE contamination in vegetable gardens were determined to be vegetable species, total soil element content, soil pH, and soil organic matter content. Overall, Cr and As pollution present the greatest concern, and community health care services must enact more effective regulatory and preventative measures for urban gardens in terms of PTEs.

Earthen sites are easily eroded by the natural environment, resulting in many micro-cracks on the surface. To explore the effects of environmental effects such as drying shrinkage and freeze–thaw on surface cracking, orthogonal tests that imposed these effects on the Zhouqiao site were conducted. Using range analysis, image processing technology, surface strength measurement and microstructure characteristic analysis, this paper explores the effects of soil thickness, water content, dry shrinkage, freeze–thaw cycles and other factors on the morphological characteristics of the site’s surface cracks. The results show that under the action of dry shrinkage, the thickness of soil layer is the primary factor affecting the cracking of earthen soil. The thinner the thickness of soil layer, the lower the moisture content, and the more serious the cracking. The initial moisture content is the most disadvantageous factor affecting the reduction of the surface strength of the earthen soil. The strength around the soil sample is lower than that inside, and there are more cracks. Under the action of freezing and thawing, the main factors affecting the cracking and surface strength reduction of earthen soil are the initial water content and soil layer thickness, and the thicker the soil layer, the smaller the crack development and the lower the surface strength. Scanning electron microscope results show that under dry shrinkage and freeze–thaw conditions, the internal cracks of the soil samples exhibit different shape characteristics. Intergranular cracks appear most often under dry shrinkage conditions, and isolated cracks appear most often in the soil samples from the freeze–thaw cycle test. The cracks caused by these two types of external environment factors damage the earthen soil. According to the tension failure model and the definition of the first frost heaving theory, it can be determined that when the micro pore force F and the maximum frost heaving pressure P Imax are greater than the cohesion of the soil sample, the soil sample will germinate cracks.

The Nested Air Quality Prediction Model System （NAQPMS） was used to investigate the temporal and spatial variations of PM2.5 over tropospheric central eastern China in January 2013. The impact of regional transport and its implications on pollu- tion prevention and control were also examined. Comparison between simulated and observed PM2.5 showed NAQPMS was able to reproduce the evolution of PM2.5 during heavy haze episodes. The results indicated that regional transport of PM2.5 played an important role in regional haze episodes in the city cluster including Hebei, Beijing and Tianjin （HBT）. The cross-city clusters transport outside HBT and transport among cities inside HBT contributed 20%-35% and 26%-35% of PM2.5 as compared with local emission, in HBT respectively. To meet the Air Quality Standards for Grade II, 90%, 90% and 65% of emissions would have to be cut down in Hebei, Tianjin and Beijing, if non-control strategy was taken in the surround- ing city clusters of HBT. This implicated that control of emissions in one city cluster is not sufficient to reduce regional haze events, and joint efforts among city clusters are essential. Besides regional transports, two-way feedback between bounda- ry-layer evolution and PM2.5 also significantly contributed to the formation of heavy hazes, which contributed 30% of monthly average PM2.5 concentration in HBT.

Due to the record-breaking wildfires that occurred in Canada in 2023, unprecedented quantities of air pollutants and greenhouse gases were released into the atmosphere. The wildfires had emitted more than 1.3 Pg CO 2 and 0.14 Pg CO 2 equivalent of other greenhouse gases (GHG) including CH 4 and N 2 O as of 31 August. The wildfire-related GHG emissions constituted more than doubled Canada’s planned cumulative anthropogenic emissions reductions in 10 years, which represents a significant challenge to climate mitigation efforts. The model simulations showed that the Canadian wildfires impacted not only the local air quality but also that of most areas in the northern hemisphere due to long-range transport, causing severe PM 2.5 pollution in the northeastern United States and increasing daily mean PM 2.5 concentration in northwestern China by up to 2 µg m −3 . The observed maximum daily mean PM 2.5 concentration in New York City reached 148.3 µg m −3 , which was their worst air quality in more than 50 years, nearly 10 times that of the air quality guideline (i.e., 15 µg m −3 ) issued by the World Health Organization (WHO). Aside from the direct emissions from forest fires, the peat fires beneath the surface might smolder for several months or even longer and release substantial amounts of CO 2 . The substantial amounts of greenhouse gases from forest and peat fires might contribute to the positive feedback to the climate, potentially accelerating global warming. To better understand the comprehensive environmental effects of wildfires and their interactions with the climate system, more detailed research based on advanced observations and Earth System Models is essential.

Coseismic landslides are among the most perilous geological disasters in hilly places after earthquakes. Precise assessment of coseismic landslide susceptibility is crucial for forecasting the effects of landslides and alleviating subsequent tragedies. This research formulates a comprehensive landslide hazard assessment model by integrating the Newmark physical model with machine learning techniques. The Jiuzhaigou region serves as the study area, utilizing the comprehensive indicator F s from the Newmark model as a principal feature parameter, which integrates several influencing aspects, including rock strata, moisture content, and slope gradient. Monte Carlo simulations (MCS) mitigate uncertainty in geotechnical parameters, augmenting Newmark model findings’ reliability. The sampling approach utilizes Newmark model outcomes to identify nonlandslide locations for developing six landslide susceptibility models, namely N_XGB, N_RF, Dn_XGB, Dn_RF, and independent XGBoost and RF models. Comparative investigation reveals that the hybrid models N_XGB and N_RF, which amalgamate Newmark model outputs with machine learning methodologies, have enhanced performance. The N_XGB model attains superior accuracy, exhibiting an AUC of 0.96 in the Jiuzhaigou region, markedly surpassing alternative hybrid machine learning models and physical models, moreover, F s as a feature exhibits superior predictive accuracy relative to utilizing Newmark displacement. Validation in the Ludian and Luding region results in model accuracies of 0.88 and 0.86, respectively, indicating robust generalizability across various seismic situations. These findings highlight the benefits of integrating physical principles with data-driven methodologies, providing a comprehensive regional landslide risk assessment and management framework.

Atmospheric aerosols play an important role in the radiation balance of the earth–atmosphere system. However, our knowledge of the long-term changes in equivalent black carbon (eBC) and aerosol optical properties in China is very limited. Here we analyze the 9-year measurements of eBC and aerosol optical properties from 2012 to 2020 in Beijing, China. Our results showed large reductions in eBC by 71 % from 6.25 ± 5.73 µg m−3 in 2012 to 1.80 ± 1.54 µg m−3 in 2020 and 47 % decreases in the light extinction coefficient (bext, λ = 630 nm) of fine particles due to the Clean Air Action Plan that was implemented in 2013. The seasonal and diurnal variations of eBC illustrated the most significant reductions in the fall and at nighttime, respectively. ΔeBC / ΔCO also showed an annual decrease from ∼ 7 to 4 ng m−3 ppbv−1 and presented strong seasonal variations with high values in spring and fall, indicating that primary emissions in Beijing have changed significantly. As a response to the Clean Air Action Plan, single-scattering albedo (SSA) showed a considerable increase from 0.79 ± 0.11 to 0.88 ± 0.06, and mass extinction efficiency (MEE) increased from 3.2 to 3.8 m2 g−1. These results highlight the increasing importance of scattering aerosols in radiative forcing and a future challenge in visibility improvement due to enhanced MEE. Brown carbon (BrC) showed similar changes and seasonal variations to eBC during 2018–2020. However, we found a large increase of secondary BrC in the total BrC in most seasons, particularly in summer with the contribution up to 50 %, demonstrating an enhanced role of secondary formation in BrC in recent years. The long-term changes in eBC and BrC have also affected the radiative forcing effect. The direct radiative forcing (ΔFR) of BC decreased by 67 % from +3.36 W m−2 in 2012 to +1.09 W m−2 in 2020, and that of BrC decreased from +0.30 to +0.17 W m−2 during 2018–2020. Such changes might have important implications for affecting aerosol–boundary layer interactions and the improvement of future air quality.

We investigate the rapid formation and evolutionary mechanisms of an extremely severe and persistent haze episode that occurred in northern China during winter 2015 using comprehensive ground and vertical measurements, along with receptor and dispersion model analysis. Our results indicate that the life cycle of a severe winter haze episode typically consists of four stages: (1) rapid formation initiated by sudden changes in meteorological parameters and synchronous increases in most aerosol species, (2) persistent evolution with relatively constant variations in secondary inorganic aerosols and secondary organic aerosols, (3) further evolution associated with fog processing and significantly enhanced sulfate levels and (4) clearing due to dry, cold north-northwesterly winds. Aerosol composition showed substantial changes during the formation and evolution of the haze episode but was generally dominated by regional secondary aerosols (53–67%). Our results demonstrate the important role of regional transport, largely from the southwest but also from the east and of coal combustion emissions for winter haze formation in Beijing. Also, we observed an important downward mixing pathway during the severe haze in 2015 that can lead to rapid increases in certain aerosol species.

Mineral dust can be transported long distances in the lower atmosphere. Satellite measurements and model simulations show that dust generated during a storm in the Taklimakan Desert, China, in 2007 was transported more than once around the globe. Mineral dust is usually transported long distances in the lower troposphere. There are examples of Asian dust being transported across the Pacific Ocean 1 , 2 , 3 , 4 , 5 , 6 , 7 , and traces of Asian dust have also been found in ice and snow cores in Greenland 8 and the French Alps 9 . Here, we use measurements from the Cloud–Aerosol Lidar with Orthogonal Polarization 10 , an air parcel trajectory model and a three-dimensional aerosol transport model to map the transport of dust clouds generated during a storm in China’s Taklimakan Desert during May 2007. We show that the dust-veiled clouds were lofted to the upper troposphere around 8–10 km above the Earth’s surface and transported more than one full circuit around the globe in about 13 days. When the dust reached the northwestern Pacific Ocean for the second time, the subsidence of a large-scale high-pressure system caused it to descend into the lower troposphere; some of the dust was then deposited over the ocean. Our analysis also indicates that the dust particles may have acted as ice nuclei in these high-altitude clouds, leading to the formation of cirrus clouds. We suggest that Asian dust can influence the global radiation budget by stimulating cirrus cloud formation and marine ecosystems by supplying nutrients to the open ocean.