[Pollution Characteristics and Factors Influencing the Reduction in Ambient PM in Beijing from 2018 to 2020].

Air quality data from 33 environment sites and five regional sites from 2018 to 2020, as well as meteorological data, were used to research PM variation,spatial and temporal change, diurnal variation, and heavy pollutions in Beijing. The annual average mass concentrations of PM in Beijing were 51, 42, and 38 μg·m, which showed great progress in air quality improvement. However, the PM concentration in 2020 was still 8.

Conjugative transfer of mcr-1-bearing plasmid from Salmonella to Escherichia coli in vitro on chicken meat and in mouse gut.

Since mcr-1 was first discovered in 2015, this gene has shown excellent transmission ability and evolutionary characteristics worldwide, leading to major public health and food safety concerns. In this study, chicken meat was used as a food vehicle for the conjugation of mcr-1-bearing Salmonella at different storage temperatures (4 °C, 25 °C, and 37 °C) to simulate mcr-1 transmission during food transportation and storage and determine its efficiency and mechanism. In addition, conjugation experiments were performed in mouse gut to further confirm that mcr-1 is horizontally transferred in vivo during food consumption.

A Facile Route to Synthesis of Hierarchically Porous Carbon Micelle System for Bifunctional Electrochemical Application.

Well-ordered hierarchically porous carbon (HPC) nanomaterials have been successfully synthesized by a facile, efficient, and fast heated-evaporation induced self-assembly (HISA) method. A micelle system was employed as the template by using the HISA method for the first time, which possessed great potential in the large-scale production of HPC materials. Various surfactants, including triblock copolymer Pluronic F127, P123, F108, and cationic CTAB, were used in the polymerization process as templates to reveal the relationship between the structure of surfactants and architecture of the as-prepared HPCs.

Ground ozone concentrations over Beijing from 2004 to 2015: Variation patterns, indicative precursors and effects of emission-reduction.

Based on ozone observation data from urban stations and the Dingling (DL) background station, we investigated the trend of ozone concentrations in Beijing during 2004-2015. For urban stations, both O_1 h and O_8 h increased stably with a clear and significant linear pattern and the increase rate was notably higher during the period of May to Sep. Meanwhile, the variation of O_1 h and O_8 h for the DL station did not demonstrate a regular pattern.

[Different Air Pollution Situations of O₃ and PM₂.₅ During Summer in Beijing].

Two different pollution situations of O₃ and PM₂.₅ during summer in Beijing were analyzed from theperspective of synoptic situations, meteorological elements, precursors, atmospheric oxidation, back-trajectories of air mass and chemical compositions of PM₂.₅.

[PM₂.₅ Background Concentration at Different Directions in Beijing in 2013].

PM₂.₅, background concentration at different directions in 2013 in Beijing was analyzed combining the techniques of mathematical statistics, physical identification and numerical simulation (CMAQ4.7.

[Analysis About Spatial and Temporal Distribution of SO2 and An Ambient SO2 Pollution Process in Beijing During 2000-2014].

Spatial and temporal distribution of SO2 during 2000-2014 was all analyzed based on the SO2 monitoring data that Beijing Municipal Environmental Monitoring Center released and the formation mechanism of a typical air pollution episode in January 2014 was also investigated by combining numerical model CAM(x). Analysis results showed that mass concentration of ρ(SO2) in Beijing in 2014 decreased 69% compared to that in 2000 with an annual gradient from 2000 to 2014 of - 3.5 μg x (m3 x a)(-1).

[Air Quality Characteristics in Beijing During Spring Festival in 2015].

To analyze the impacts of emissions from fireworks on the air quality, monitoring data of PM2.5, PM10, SO2, NO2 chemical compositions of PM2.5 of automatic air quality stations in Beijing during Spring Festival(February 18th-24th) in 2015 were investigated.

[Temporal and spatial distribution characteristics of ozone in Beijing].

Ozone concentrations obtained from 35 automatic air monitoring stations in Beijing were analyzed to investigate their temporal and spatial distribution characteristics. A process with high ozone concentration in summer was analyzed. The results showed that ozone maintained relatively high concentration from May to August while in other months, the ozone concentration was at a low level.