Chemical characterization of PM2.5 from a southern coastal city of China:applications of modeling and chemical tracers in demonstrationof regional transport

An intensive sampling campaign of airborne fine particles (PM2.5) was conducted at Sanya, a coastal city in Southern China, from January to February 2012. Chemical analyses and mass reconstruction were used identify potential pollution sources and investigate atmospheric reaction mechanisms. A thermodynamic model indicated that low ammonia and high relative humidity caused the aerosols be acidic and that drove heterogeneous reactions which led to the formation of secondary inorganic aerosol. Relationships among neutralization ratios, free acidity, and air-mass trajectories suggest that the atmosphere at Sanya was impacted by both local and regional emissions. Three major transport pathways were identified, and flow from the northeast (from South China) typically brought the most polluted air to Sanya. A case study confirmed strong impact from South China (e.g., Pearl River Delta region) (contributed 76.8% to EC, and then this result can be extended to primary pollutants) when the northeast winds were dominant. The Weather Research Forecasting Black carbon model and trace organic markers were used to apportion local pollution versus regional contributions. Results of the study offer new insights into the atmospheric conditions and air pollution at this coastal city

Single RGB Image 6D Object Grasping System Using Pixel-Wise Voting Network

A robotic system that can autonomously recognize object and grasp it in a real scene with heavy occlusion would be desirable. In this paper, we integrate the techniques of object detection, pose estimation and grasping plan on Kinova Gen3 (KG3), a 7 degrees of freedom (DOF) robotic arm with a low-performance native camera sensor, to implement an autonomous real-time 6 dimensional (6D) robotic grasping system. To estimate the object 6D pose, the pixel-wise voting network (PV-net), is applied in the grasping system. However, the PV-net method can not distinguish the object from its photo through only RGB image input. To meet the demands of a real industrial environment, a rapid analytical method on a point cloud is developed to judge whether the detected object is real or not. In addition, our system shows a stable and robust performance in different installation positions with heavily cluttered scenes

Decreasing concentrations of carbonaceous aerosols in China from 2003 to 2013

Carbonaceous aerosols were characterized in 19 Chinese cities during winter and summer of 2013. Measurements of organic carbon (OC) and elemental carbon (EC) levels were compared with those from 14 corresponding cities sampled in 2003 to evaluate effects of emission changes over a decade. Average winter and summer OC and EC decreased by 32% and 17%, respectively, from 2003 to 2013, corresponding to nationwide emission control policies implemented since 2006. The extent of carbon reduction varied by season and by location. Larger reductions were found for secondary organic carbon (SOC, 49%) than primary organic carbon (POC, 25%). PM2.5 mass and total carbon concentrations were three to four times higher during winter than summer especially in the northern cities that use coal combustion for heating

Impact of the Emission Control of Diesel Vehicles on Black Carbon (BC) Concentrations over China

In order to reduce black carbon (BC) emissions from diesel vehicles, a regional atmospheric chemistry model (WRF-Chem) was used to investigate the effects of installing a high-efficiency device for vehicle exhaust control, a diesel particulate filter (DPF), on diesel vehicles in China. To reduce the uncertainty of estimation, three sensitivity experiments were designed and conducted for different emission scenarios. The first experiment uses the standard black carbon emissions of diesel vehicles without engaging in any emission control actions (referred to as CTRL), and the other two experiments were conducted using different DPF devices to reduce BC emissions by 65% (CASE1) and 39% (CASE2), respectively. The results show that the model simulation reasonably represents the measured BC concentrations. The highest BC concentrations occurred in large cities of the North China Plain (NCP) and present important seasonal variations. The results suggest that the reduction in diesel vehicle emissions has great benefits for reducing BC pollution not only in winter but also in other seasons. Sensitivity studies show that in CASE1, the average BC concentrations decreased about similar to 6% in January and by more than 10% in the other seasons. The greatest reduction exceeded 50%. In CASE2, the average BC concentrations decreased by about similar to 3.5% in January and by more than 7% in the other seasons. This study suggests that adding DPF to a diesel vehicle can have a significant influence on reducing BC concentrations in China. Thus, this study provides a practical basis by which diesel vehicle emissions can be reduced

Short-Term Weather Patterns Modulate Air Quality in Eastern China During 2015-2016 Winter

The roles of anthropogenic emissions and weather conditions in air pollution over eastern China have been widely discussed but still controversial. Here we focus on the impact of the intraseasonal variability of midtropospheric weather circulations on air quality during 2015-2016 winter. We use the European Center for Medium-Range Weather Forecasts reanalysis data to calculate westerly wind index (WI) and meridionality in the midtroposphere and also calculate the intensity of Siberian High at the surface. The results suggest that there were lower WI, higher meridionality, and strengthened Siberian High in January 2016 compared with the conditions in December 2015. Lower WI and higher meridionality imply for wavier midtropospheric weather circulations and stronger surface northerly winds, thereby causing more southward cold fresh air advection and resulting in the lower PM2.5 concentrations over eastern China in January 2016. Sensitivity experiments conducted by the Weather Research and Forecasting Chemical model show that the intraseasonal weather variability dominantly causes lower PM2.5 concentrations in January 2016. It not only counteracts increments in PM2.5 concentrations induced by the increased emission but also reduces PM2.5 concentrations by an extra 25-100g/m(3). We also simulate two extreme weather patterns and compare their effects on PM2.5 concentrations. Difference in these two weather patterns induces changes in PM2.5 concentrations by 50-200g/m(3) over eastern China and the maximal change exceeding 200g/m(3). These findings suggest that understanding the variability of the dominant midtropospheric circulation is the key to successfully forecasting short-term air quality over eastern China in winter. Plain Language Summary The subseasonal variation of PM2.5 concentrations is dominantly induced by the intraseasonal variability of weather circulations during 2015-2016 winter. In the early winter (December 2015), a straight westerly wind prevails at the midtroposphere, confining cold air within the high latitudes and causing the accumulation of PM2.5 concentrations in eastern China, while in the late winter (January 2016), a north-to-south oriented airflow at the midtroposphere allows cold air advection to eastern China, reducing PM2.5 concentrations. Consequently, the intraseasonal weather variability leads to the maximal reduction of PM2.5 concentrations by 50-200g/m(3). These findings suggest that understanding the variability of the midtroposphere circulation patterns is the key to successfully forecasting and improving air quality in winter

Impact of the Green Light Program on haze in the North China Plain, China

As the world's largest developing country, China has undergone ever-increasing demand for electricity during the past few decades. In 1996, China launched the Green Light Program (GLP), which became a national energy conservation activity for saving lighting electricity as well as an effective reduction of the coal consumption for power generation. Despite the great success of the GLP, its effects on haze have not been investigated and well understood. This study focused on assessing the potential coal saving induced by the improvement of luminous efficacy, the core of the GLP, and on estimating the consequent effects on the haze in the North China Plain (NCP), where a large number of power plants are located and are often engulfed by severe haze. The estimated potential coal saving induced by the GLP can reach a massive value of 120-323 million tons, accounting for 6.7 %-18.0 % of the total coal consumption for thermal power generation in China. There was a massive potential emission reduction of air pollutants from thermal power generation in the NCP, which was estimated to be 20.0-53.8 Gg for NOx and 6.9-18.7 Gg for SO2 in December 2015. The potential emission reduction induced by the GLP plays important roles in the haze formation, because the NOx and SO2 are important precursors for the formation of particles. To assess the impact of the GLP on haze, sensitivity studies were conducted by applying a regional chemical-dynamical model (WRF-CHEM). The model results suggest that in the case of lower-limit emission reduction, the PM2.5 concentration decreased by 2-5 mu g m(-3) in large areas of the NCP. In the case of upper-limit emission reduction, there was much more remarkable decrease in PM2.5 concentration (4-10 mu g m(-3)). This study is a good example to illustrate that scientific innovation can induce important benefits for environment issues such as haze

Unraveling the process of aerosols secondary formation and removal based on cosmogenic beryllium-7 and beryllium-10

The secondary formation and diffusion processes of aerosol are extraordinarily complex and significantly impact the environment and human health. Therefore, exploring the process of aerosol formation and diffusion based on independent new tracer has always been a concern. The Be-7 and Be-10, which are generated only by the action of cosmic rays, are chemically stable and adsorbed on aerosol for transmission, so they have the potential characteristics of aerosol tracers. Here, we obtained the daily resolution atmospheric Be-7, Be-10, and Be-10/Be-7 without dust interference in Xi'an autumn and winter (heavy pollution period in a typical polluted area) by accelerator mass spectrometry. It is found that during the rapid formation of secondary aerosols (SA) under the stable Be-10/Be-7 ratio, which indicates the stable atmospheric vertical structure, the concentration of Be-7 and Be-10 is significantly negatively correlated (R-2 > 0.9) with the aerosol concentration. Therefore, SA relative content in aerosols can be estimated by the dilution amount of Be-7 and Be-10 to reveal the secondary-formation process of aerosol (33% average contribution to aerosols during the winter heavy air pollution period). Furthermore, we also revealed the physical removal process of aerosols based on Be-7, Be-10, and Be-10/Be-7, including precipitation removal and diffusion of vertical atmospheric movement caused by stratospheric air intrusion. In summary, meteoric cosmogenic 7Be and 10Be will provide a new way to study the secondary chemical formation and physical removal of aerosols

Metabonomics Study of Essential Hypertension and Its Chinese Medicine Subtypes by Using Gas Chromatography-Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy

A metabonomic study was performed to investigate the metabolic mechanism of essential hypertension and its Chinese medicine subtypes, including “Yin-deficiency and Yang-hyperactivity syndrome” (YDYHS) and “Yin-Yang deficiency syndrome” (YYDS). Plasma samples from 22 healthy volunteers, 31 hypertensive patients with YDYHS, and 29 hypertensive patients with YYDS were analyzed by 1H-NMR spectroscopy and gas chromatography coupled with mass spectrometry (GC-MS). The three groups were distinctly classified by principal components analysis (PCA) and partial least squares discriminant analysis (PLS-DA). According to identified biomarkers and their related pathways, abnormal glucose metabolism might be the main common pathway from YDYHS to YYDS, and sympathetic nervous system activation would play an important role in the pathogenesis of YDYHS, while a low metabolic rate usually occurred in YYDS