Dominant contribution of combustion-related ammonium during haze pollution in Beijing.

Aerosol ammonium (NH), mainly produced from the reactions of ammonia (NH) with acids in the atmosphere, has significant impacts on air pollution, radiative forcing, and human health. Understanding the source and formation mechanism of NH can provide scientific insights into air quality improvements. However, the sources of NH in urban areas are not well understood, and few studies focus on NH/NH at different heights within the atmospheric boundary layer, which hinders a comprehensive understanding of aerosol NH.

Biochemical Characterization and Functional Analysis of Glucose Regulated Protein 78 from the Silkworm .

The glucose regulated protein (GRP78) is an important chaperone for various environmental and physiological stimulations. Despite the importance of GRP78 in cell survival and tumor progression, the information regarding GRP78 in silkworm L. is poorly explored.

Tracer-based characterization of fine carbonaceous aerosol in Beijing during a strict emission control period.

Strict emission controls were implemented in Beijing and the surrounding regions in the North China Plain to guarantee good air quality during the 2014 Asia-Pacific Economic Cooperation (APEC) summit. Thus, the APEC period provides a good opportunity to study the sources and formation processes of atmospheric organic aerosol. Here, fine particles (PM, particulate matter with a diameter of 2.

Source and formation process impact the chemodiversity of rainwater dissolved organic matter along the Yangtze River Basin in summer.

Rainwater dissolved organic matter (DOM) plays an important role in the biogeochemical cycle and evolution of organic matter in the land-atmosphere interface. To better understand their sources and molecular composition in the atmosphere, rainwater samples were collected at six different locations along the Yangtze River Basin. Based on the application of a combined approach including excitation-emission matrix (EEM) fluorescence and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), various sources (terrestrial, anthropogenic, and autochthonous sources) of rainwater DOM were revealed.

Latitudinal difference in the molecular distributions of lipid compounds in the forest atmosphere in China.

Lipids are important biogenic markers to indicate the sources and chemical process of aerosol particles in the atmosphere. To better understand the influences of biogenic and anthropogenic sources on forest aerosols, total suspended particles (TSP) were collected at Mt. Changbai, Shennongjia, and Xishuangbanna that are located at different climatic zones in northeastern, central and southwestern China.

Molecular characterization and spatial distribution of dicarboxylic acids and related compounds in fresh snow in China.

Low molecular weight organic compounds are ubiquitous in the atmosphere. However, knowledge on their concentrations and molecular distribution in fresh snow remains limited. Here, twelve fresh snow samples collected at eight sites in China were investigated for dicarboxylic acids and related compounds (DCRCs) including oxocarboxylic acids and α-dicarbonyls.

Distinctive Sources Govern Organic Aerosol Fractions with Different Degrees of Oxygenation in the Urban Atmosphere.

Understanding how the sources of an atmospheric organic aerosol (OA) govern its burden is crucial for assessing its impact on the environment and adopting proper control strategies. In this study, the sources of OA over Beijing were assessed year-around based on the combination of two separation approaches for OA, one from chemical fractionation into the high-polarity fraction of water-soluble organic matter (HP-WSOM), humic-like substances (HULIS), and water-insoluble organic matter (WISOM), and the other from statistical grouping using positive matrix factorization (PMF) of high-resolution aerosol mass spectra. Among the three OA fractions, HP-WSOM has the highest O/C ratio (1.

The complete chloroplast genome sequences of (Plantaginaceae).

Two complete chloroplast genomes of (_A and _B), representing two distinct clades in China, were sequenced and assembled in this study. The circular genomes were 152,763 and 152,713 bp in length and exhibit a typical quadripartite structure of the large single-copy (LSC, 82,983/82,949 bp) and small single-copy (SSC, 18,294/18,278 bp) regions, separated by a pair of inverted repeats (IRs, both 25,743 bp). Both two cp genomes identically contain 133 genes, including 88 protein-coding genes, 37 , and eight genes.

Variations in physicochemical properties of airborne particles during a heavy haze-to-dust episode in Beijing.

The variations in physicochemical properties of airborne particles collected during a typical transition from haze to dust were investigated using single particle analysis with transmission and scanning electron microscopes combined with online measurement of chemical compositions of airborne particles in Beijing in February 2013. The transition was divided into three phases based on the weather condition. During haze pollution (Phase 1), gaseous and particle pollutants enhanced gradually.

Summertime fluorescent bioaerosol particles in the coastal megacity Tianjin, North China.

Primary biological particles are an important subset of atmospheric aerosols. They have significant impacts on climate change and public health. Tianjin is a coastal megacity in the North China Plain, which is affected by both anthropogenic activities and marine air masses.

High daytime abundance of primary organic aerosols over Mt. Emei, Southwest China in summer.

Organic molecular composition of fine aerosols in the free troposphere is poorly understood. Here, PM (particles with aerodynamic diameters ≤ 2.5 μm) samples were collected at the summit of Mt.

Black carbon in Xiamen, China: Temporal variations, transport pathways and impacts of synoptic circulation.

Black carbon (BC) plays a vital role in atmospheric environment and climate change. Temporal variations and transport pathways of BC in Xiamen, China with the impacts of synoptic circulation were investigated in 2014 with Aethalometer. Annual mean BC concentration was 4270 ng m.

Occurrence of Aerosol Proteinaceous Matter in Urban Beijing: An Investigation on Composition, Sources, and Atmospheric Processes During the "APEC Blue" Period.

Aerosol proteinaceous matter is comprised of a substantial fraction of bioaerosols. Its origins and interactions in the atmosphere remain poorly understood. We present observations of total proteins, combined, and free amino acids (CAAs and FAAs) in fine particulate matter (PM) samples in urban Beijing before and during the 2014 Asia-Pacific Economic Cooperation (APEC) summit.

Implications for biomass/coal combustion emissions and secondary formation of carbonaceous aerosols in North China.

To understand the origins, secondary formation and seasonality of carbonaceous aerosols in North China, we collected PM samples on day- and night-time bases in summer and winter 2016 from a typical metropolis, Tianjin, and studied their carbonaceous components and stable carbon isotope ratios of total carbon (δC). PM ranged from 21.2 μg m to 74.

Primary biogenic and anthropogenic sources of organic aerosols in Beijing, China: Insights from saccharides and n-alkanes.

Sugars and n-alkanes are important organic constituents of atmospheric fine particulate matter (PM). For better understanding their sources and seasonal variations in urban atmosphere, sugar compounds (anhydrosugars, sugars and sugar alcohols) and homologue n-alkanes (C-C) were studied in PM samples collected from September 2013 to July 2014 in Beijing, China. In general, all measured compounds showed the lowest levels in summer.

The organic molecular composition, diurnal variation, and stable carbon isotope ratios of PM in Beijing during the 2014 APEC summit.

Organic tracers are useful for investigating the sources of carbonaceous aerosols but there are still no adequate studies in China. To obtain insights into the diurnal variations, properties, and the influence of regional emission controls on carbonaceous aerosols in Beijing, day-/nighttime PM samples were collected before (Oct. 15th - Nov.

Stable sulfur isotope ratios and chemical compositions of fine aerosols (PM) in Beijing, China.

Pervasive particulate pollution has been observed over large areas of the North China Plain. The high level of sulfate, a major component in fine particles, is pronounced during heavy pollution periods. Being different from source apportionments by atmospheric chemistry-transport model and receptor modeling methods, here we utilize sulfur isotopes to discern the potential emission sources.

High Contribution of Nonfossil Sources to Submicrometer Organic Aerosols in Beijing, China.

Source apportionment of organic carbon (OC) and elemental carbon (EC) from PM (particulate matter with a diameter equal to or smaller than 1 μm) in Beijing, China was carried out using radiocarbon (C) measurement. Despite a dominant fossil-fuel contribution to EC due to large emissions from traffic and coal combustion, nonfossil sources are dominant contributors of OC in Beijing throughout the year except during the winter. Primary emission was the most important contributor to fossil-fuel derived OC for all seasons.

Molecular distributions and compound-specific stable carbon isotopic compositions of lipids in wintertime aerosols from Beijing.

Molecular distributions and stable carbon isotopic compositions (δ(13)C) of n-alkanes, fatty acids and n-alcohols were investigated in urban aerosols from Beijing, northern China to better understand the sources and long-range atmospheric transport of terrestrial organic matter during polluted and clear days in winter. n-Alkanes (C19-C36), fatty acids (C8-C32) and n-alcohols (C16-C32) detected in Beijing aerosols are characterized by the predominance of C23, C16 and C28, respectively. Carbon preference index (CPI) values of n-alkanes, the ratios of the sum of odd-numbered n-alkanes to the sum of even-numbered n-alkanes, are close to 1, indicating a heavy influence of fossil fuel combustion.

Fluorescent water-soluble organic aerosols in the High Arctic atmosphere.

Organic aerosols are ubiquitous in the earth's atmosphere. They have been extensively studied in urban, rural and marine environments. However, little is known about the fluorescence properties of water-soluble organic carbon (WSOC) or their transport to and distribution in the polar regions.