The impact of PM2.5 pollution on residents’ health and economic loss accounting in China

Reasonable assessment of the health risks and economic losses of urban residents caused by air pollution is of great significance for regional air pollution control, environmental policy planning and implementation, and the construction of health in China. Based on the data of PM2.5 Concentration and population density in 338 Cities of China from 2015 To 2017, this paper estimates the premature death and related disease incidence caused by exposure to PM2.5 Pollution by the means of the Exposure-Response model,and assesses the direct economic losses of PM2.5 Pollution by the methods of the Life Value Method (VSL) and Disease Cost (COI). The results show that: 1) From 2015 To 2017, pM2.5 Mass concentration has improved to some extent, but the overall spatial pollution pattern has not changed significantly. The highly polluted areas are mainly distributed in the Beijing-Tianjin-Hebei regions and their surrounding cities; 2) PM2.5 Pollution has led to a significant reduction in terminal health losses and economic losses. Among them, the number of residents who lost terminal health decreased by 23.9%,the total economic loss of residents decreased by 24.24% from 1 824.96 Billion yuan in 2015 To 1 382.64 Billion yuan in 20173) The increase of urbanization rate exacerbates the impact of PM2.5 Pollution on the health problems and corresponding economic losses, especially in some cities with high pollution and high urbanization level, such as Beijing and Tianjin. In the future, measures should be taken in line with local conditions to strengthen PM2.5 Monitoring and control in key cities and effectively protect the public health of urban residents

Probing the surface acidity of supported aluminum bromide catalysts

Solid acid catalysis is an important class of reactions. The principal advantages of solid acid catalysts as compared to their corresponding fluid acids include minimal waste and ease of product separation. One type of these catalysts is based on aluminum bromide (Al2Br6), which is a stronger Lewis acid than Al2Cl6. In this report, Al2Br6 is grafted on commercial mesoporous silica (CMS), SBA-15 and silica gel to create a solid catalyst similar to the silica-supported Al2Cl6 superacid. These supported Al2Br6 catalysts were characterized by NH3-Temperature Programmed Desorption (TPD), pyridine Diffuse Reflectance for Infrared Fourier Transform Spectroscopy (DRIFTS) and Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR). Formation of acid sites was confirmed and quantified with NH3-TPD. Both Lewis and Brønsted sites were observed with DRIFTS using pyridine as a probe molecule. In addition, thermal stability of acid sites was also studied using DRIFTS. 27Al MAS NMR analysis showed tetrahedral, pentahedral and octahedral co-ordination of Al, confirming that Al2Br6 reacted with –OH groups on silica surface. Performance of these catalysts was evaluated using acid-catalyzed 1-butene isomerization. Conversion above 80% was observed at 200 °C, corresponding to thermodynamic equilibrium

Low temperature direct conversion of methane using a solid superacid

The direct conversion of methane to higher hydrocarbons and hydrogen can be catalyzed using “superacids”: nCH4→CnHm+xH2. The first report of catalytic oligomerization of methane using superacids was that of Olah et al., who demonstrated the superacidity of FSO3H−SbF5, which is a liquid. More recently, Vasireddy et al. showed that gas‐phase HBr/AlBr3 was an active superacid. The only reported solid superacid for methane oligomerization is sulfated zirconia (SZ). Here, we report a new class of Br‐based solid superacids, AlBrx/H‐ZSM‐5 (“ABZ‐5”, x=1 or 2). ABZ‐5 is based on gas‐phase HBr/AlBr3, with the objective of synthesizing a heterogeneous analogue of the gas‐phase superacid HBr/AlBr3. The results show that ABZ‐5 is significantly more active than SZ. Perhaps more significantly, results here show methane conversions of ∼1 % at 300 °C using ABZ‐5. By comparison with SZ, 350 °C is the lowest temperature reported in the literature at which measurable conversions are shown, and the corresponding methane conversions were <0.15. Here, we demonstrate direct conversion of methane using a solid superacid catalyst, AlBrx/H‐ZSM‐5. This solid catalyst is synthesized using a vapor‐phase process in which AlBr3 vapor is grafted on to solid H‐SZM‐5. This catalyst is characterized using NH3‐TPD, XRD, and DRIFTS. Hydrocarbon products observed in the temperature range of 200–400 °C include both C2–C6 hydrocarbons and aromatics

Surfactant-Free Synthesis of Bi_(2)Te_(3)-Te Micro-Nano Heterostructure with Enhanced Thermoelectric Figure of Merit

An ideal thermoelectric material would be a semiconductor with high electrical conductivity and relatively low thermal conductivity: an “electron crystal, phonon glass”. Introducing nanoscale heterostructures into the bulk TE matrix is one way of achieving this intuitively anomalous electron/phonon transport behavior. The heterostructured interfaces are expected to play a significant role in phonon scattering to reduce thermal conductivity and in the energy-dependent scattering of electrical carriers to improve the Seebeck coefficient. A nanoparticle building block assembly approach is plausible to fabricate three-dimensional heterostructured materials on a bulk commercial scale. However, a key problem in applying this strategy is the possible negative impact on TE performance of organic residue from the nanoparticle capping ligands. Herein, we report a wet chemical, surfactant-free, low-temperature, and easily up-scalable strategy for the synthesis of nanoscale heterophase Bi_(2)Te_(3)-Te via a galvanic replacement reaction. The micro-nano heterostructured material is fabricated bottom-up, by mixing the heterophase with commercial Bi_(2)Te_3. This unique structure shows an enhanced zT value of ~0.4 at room temperature. This heterostructure has one of the highest figures of merit among bismuth telluride systems yet achieved by a wet chemical bottom-up assembly. In addition, it shows a 40% enhancement of the figure of merit over our lab-made material without nanoscale heterostructures. This enhancement is mainly due to the decrease in the thermal conductivity while maintaining the power factor. Overall, this cost-efficient and room temperature synthesis methodology provides the potential for further improvement and large-scale thermoelectric applications

A Novel Universal Primer-Multiplex-PCR Method with Sequencing Gel Electrophoresis Analysis

In this study, a novel universal primer-multiplex-PCR (UP-M-PCR) method adding a universal primer (UP) in the multiplex PCR reaction system was described. A universal adapter was designed in the 5′-end of each specific primer pairs which matched with the specific DNA sequences for each template and also used as the universal primer (UP). PCR products were analyzed on sequencing gel electrophoresis (SGE) which had the advantage of exhibiting extraordinary resolution. This method overcame the disadvantages rooted deeply in conventional multiplex PCR such as complex manipulation, lower sensitivity, self-inhibition and amplification disparity resulting from different primers, and it got a high specificity and had a low detection limit of 0.1 ng for single kind of crops when screening the presence of genetically modified (GM) crops in mixture samples. The novel developed multiplex PCR assay with sequencing gel electrophoresis analysis will be useful in many fields, such as verifying the GM status of a sample irrespective of the crop and GM trait and so on