Association between Long-Term Exposure to PM_(2.5) Inorganic Chemical Compositions and Cardiopulmonary Mortality: A 22-Year Cohort Study in Northern China

Particulate matter with diameters≤2.5μm(PM_(2.5))has been identified as a significant air pollutant contributing to premature mortality.Nevertheless,the specific compositions within PM_(2.5) that play the most crucial role remain unclear,especially in areas with high pollution concentrations.This study aims to investigate the individual and joint mortality risks associated with PM_(2.5) inorganic chemical compositions and identify primary contributors.In 1998,we conducted a prospective cohort study in four northern Chinese cities(Tianjin,Shenyang,Taiyuan,and Rizhao).Satellite-based machine learning models calculated PM_(2.5) inorganic chemical compositions,including sulfate(SO_(4)^(2–)),nitrate(NO_(3)^(–)),ammonium(NH_(4)^(+)),and chloride(Cl^(-)).A time-varying Cox proportional hazards model was applied to analyze associations between these compositions and cardiorespiratory mortality,encompassing nonaccidental causes,cardiovascular diseases(CVDs),nonmalignant respiratory diseases(RDs),and lung cancer.The quantile-based g-computation model evaluated joint exposure effects and relative contributions of the compositions.Stratified analysis was used to identify vulnerable subpopulations.During 785,807 person-years of follow-up,5812(15.5%)deaths occurred from nonaccidental causes,including 2932(7.8%)from all CVDs,479(1.3%)from nonmalignant RDs,and 552(1.4%)from lung cancer.Every interquartile range(IQR)increase in SO_(4)^(2–)was associated with mortality from nonaccidental causes(hazard ratio:1.860;95%confidence interval:1.809,1.911),CVDs(1.909;1.836,1.985),nonmalignant RDs(2.178;1.975,2.403),and lung cancer(1.773;1.624,1.937).In the joint exposure model,a simultaneous rise of one IQR in all four compositions increased the risk of cardiorespiratory mortality by at least 36.3%,with long-term exposure to SO_(4)^(2–)contributing the most to nonaccidental and cardiopulmonary deaths.Individuals with higher incomes and lower education levels were found to be more vulnerable.Long-term exposure to higher levels of PM_(2.5) inorganic compositions was associated with significantly increased cardiopulmonary mortality,with SO_(4)^(2–)potentially being the primary contributor.These findings offer insights into how PM_(2.5) sources impact health,aiding the development of more effective governance measures.

Comparison of inorganic chemical compositions of atmospheric TSP,PM10 and PM2.5 in northern and southern Chinese coastal cities

To compare the inorganic chemical compositions of TSP（total suspended paniculate）,PM10（particulate matter with an aerodynamic diameter less than 10 μm） and PM2.5（particulate matter with an aerodynamic diameter less than 2.5 μm） in southern and northern cities in China,atmospheric particles were synchronously collected in Dalian（the northern city）and Xiamen（the southern city） in spring and autumn of 2004.The mass concentrations,twenty-three elements and nine soluble ions were assessed.The results show that in Dalian,the mass concentrations of Mg,Al,Ca,Mn and Fe in spring were 4.0-10.1,2.6-8.0,4.1-12,1.2-3.6 and 2.9-7.9 times higher,respectively,than those in Xiamen.The dust storm influence is more obvious in Dalian in spring.However,in Xiamen,heavy metals accounted for 13.9%-17.9%of TSP,while heavy metals contributed to 5.5%-9.3%of TSP in Dalian.These concentrations suggest that heavy metal pollution in Xiamen was more serious.In addition,the concentrations of Na＋,Cl-,Ca2＋ and Mg2＋ were higher in Dalian due to the influence of marine aerosol,construction activities and soil dust.The NO3-/SO42- ratios in Dalian（0.25-0.49） were lower than those in Xiamen（0.51-0.62）,indicating that the contributions of vehicle emission to particles in Xiamen were higher.Coefficient of divergence values was higher than 0.40,implying that the inorganic chemical composition profiles for the particles of Dalian and Xiamen were quite different from each other.

SOME FEATURES OF RING 94S-A KUROSHIO DETACHED EDDY IN THE SOUTH CHINA SEA

Distribution of current and chemical tracers along two hydrographic sections across Ring 94S, a Kuroshio detached eddy in the South China Sea, were studied. Results suggest that while currents on its offshore side maintained quasi-geostophic, a balance was no reach on its onshore side. It is then suggested that interaction Ring 94S with the slope might play an important role that could break down the quasi-geostrophic balance and caused deformation of the current field. 18O distribution supports previous discussion that water mass inside the ring is of Kuroshio origin. Distributions of chemical tracer reveal strong stirring effect at the edge of Ring 94S, which may play an important role in vertical exchange across the thermocline.

Controlled preparation and self-assembly of NdVO_4 nanocrystals

Phase-pure t-NdVO_4 nanocrystals with different shapes have been synthesized by facile and repeatable hydrothermal methods. The as-synthesized t-NdVO_4 nanoparticles were characterized by various techniques of X-ray diffraction（XRD）. scanning electron microscope（SEM） and transmission electron microscope（TEM）. The growth process and assembly behavior of t-NdVO_4 nanorod arrays were investigated. The results show that the morphology of t-NdV04 nanocrystals is greatly related to the pH value of precursor solution and that strong basic solution is not in favor of the formation of t-NdVO_4 nanoparticles. Due to the strong adhesive action and stabilization of OH^-ions to some crystal faces of NdVO_4, neodymium vanadate crystallite grows into oriented short nanorods and then into nanorod arrays. The shape, crystalline and dimension of NdVO_4 nanocrystals can be effectively governed in our work.

Hydrothermal synthesis and optical properties of Zn_(1-x)Mn_xS nanorods

Zn1-xMnxS （x = 0-0.05） nanorods were successfully synthesized through a hydrothermal route. The morphology, composition and microstructure of Zn1-xMnxS nanorods were characterized respectively by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and Raman spectrometer. The optical properties of Zn1-xMnxS nanorods were determineded by UV-Vis absorption spectroscopy and photo- luminescence （PL） emission spectroscopy. The results show that the introduction of Mn^2＋ on interstitial sites in ZnS lattice has significant influence on the Raman spectra, UV-Vis absorption spectra and PL emis- sion spectra. With the increase of Mn^2＋, the lengths of the sampled nanorods become shorter and the morphologies of the products show disorder accompanied by some nanoparticles. The absorption band edge shifts to longer wavelength. The intensity of the ZnS-related emission gradually becomes weaker, whereas, the Mn^2＋-related broad emission spectra located at 580 nm gradually red-shifts and increases. Occupation of Zn^2＋ sites in the lattice by Mn^2＋ ions results in lattice distortion and influences the energy level structure of ZnS. The Mn doping is found responsible for the changes in the defect-related emission of the ZnS nanorods.