[Pollution Characteristics and Sources of Water-soluble Ions in PM2.5 in Zhengzhou City].

In order to explore the pollution characteristics, seasonal variations, and sources of water-soluble inorganic ions (WSIIs) in PM2.5 in Zhengzhou, PM2.5 samples were seasonally collected from December 2020 to October 2021; then, combining gaseous pollutants (SO2, NO2, and O3) and meteorological parameters (temperature and relative humidity), nine WSIIs (NO3-, NH4+, SO42-, Ca2+, K+, Na+, Mg2+, F-, and Cl-) were analyzed. The results showed that the annual average concentration of the total water-soluble ions (TWSIIs) was (39.34±21.56) µg·m-3for the four seasons, showing obvious seasonal variations with the maximum value in winter and the minimum value in summer. Annual PM2.5 was slightly alkaline in Zhengzhou, and NH4+ most likely existed in the form of NH4NO3 and (NH4)2SO4. The average sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) were 0.35 and 0.19, respectively, indicating that SO42- and NO3- mainly derived from secondary formation. The main potential source regions of WSIIs obtained by the concentration weight trajectory (CWT) model showed temporal and spatial variations. The significant sources of WSIIs based on principal component analysis (PCA) were dust, secondary generation, combustion, and industrial activities, which were obviously influenced by wind direction and speed in Zhengzhou.

[Air Pollution Characteristics and Quantitative Evaluation of Multi-scale Transport in the Beijing-Tianjin-Hebei Region in January, 2016].

Based on atmospheric monitoring data and the WRF-CAMx model, this study analyzed the characteristics of air pollution and performed a quantitative assessment of PM2.5 cross-border transport in the Beijing-Tianjin-Hebei (BTH) region in January 2016. The results showed that the average concentrations of PM2.5, PM10, SO2, NO2, and CO were 89.5 µg·m-3, 135.61µg·m-3, 57.55µg·m-3, 60.79µg·m-3, and 2.12 mg·m-3, respectively, indicating severe PM2.5 pollution. During the study period, surface-level PM2.5 in each city of BTH region was dominated by local emissions, which accounted for 45.4% to 69.9%. The regional transport contribution was supplemented by transport from within and outside of the BTH region, accounting for 4.8% to 49.7% and 4.9% to 29.6%, respectively. In addition, high wind speeds promoted the diffusion of local PM2.5 pollution and cities with high upwind pollution enhance regional-scale transport to downwind cities. The total inflow, outflow, and net flux of PM2.5 in Beijing (Shijiazhuang) in January 2016 were 1582.96 t·d-1 (2036.89 t·d-1), -1171.09 t·d-1 (-1879.12 t·d-1), and 411.87 t·d-1 (157.77 t·d-1), respectively, indicating that PM2.5 inputs from surrounding cities per unit time were higher than external inputs to the surrounding cities. Furthermore, net PM2.5 flux showed notable vertical evolution; the total net flux of PM2.5 in Beijing and Shijiazhuang below 1782 m ranged from 17.86 to 64.18 t·d-1 and -2.95 to 134.81 t·d-1, respectively, and both peaked 817 m above the ground at 64.18 and 134.81 t·d-1. Moreover, a significant increase the net PM2.5 inflow flux in Zhangjiakou and Shanxi explained the observed net flux peaks in these two cities.

Comparison among soil additives for enhancing Pteris vittata L.: Phytoremediation of As-contaminated soil.

Pot experiments were conducted to assess the effects of monoammonium phosphate (NH4H2PO4) and citric acid (CA) on the arsenic uptake of Chinese brake fern (Pteris vittata L. in two typical arsenic-contaminated soils i.e. fluvo-aquic and brown) from Jiyuan (JY) City and Baoding (BD) City in Northern China. NH4H2PO4 improved the biomass of P. vittata, whereas CA exerted no significant influence. NH4H2PO4 and CA both increased the arsenic uptake of P. vittata by 6.08 and 2.72 times, respectively, in fluvo-aquic soil and 4.20 and 2.52 times, respectively, in brown soil. Moreover, CA, but not NH4H2PO4, promoted the transfer of arsenic from the root to the frond. NH4H2PO4 and CA increased Olsen's arsenic contents in the soils and promoted the transformation of residual arsenic and crystalline Fe/Al oxide-bound arsenic to nonspecifically and specifically sorbed arsenic. This study proved that P. vittata can be used in Northern China. Applying NH4H2PO4 and CA can enhance the effectiveness of P. vittata in the phytoremediation of arsenic-contaminated soils.

[Effects of water stress on protein expression and physiological properties of different genotype wheat (Triticum aestivum L.) sprouts].

With drought-resistant wheat (Triticum aestivum) cultivar Changwu 134 and drought-sensitive cultivar Zhengyin 1 as test materials, and by using -1.2 MPa PEG 6000 to treat their seeds, this paper studied the protein expression and physiological properties of the sprouts under different soil moisture conditions. SDS-PAGE analysis showed that water stress induced the production of two new proteins with molecular weights of 39.5 kDa and 23.0 kDa in Changwu 134 but not in Zhengyin 1 sprouts. Under normal water supply, the expression of the protein with molecular weight of 48.5 kDa in the sprouts of both Changwu 134 and Zhengyin 1 increased with sprout growth. This protein was preliminarily named as water-sensitive protein, due to its water-sensitivity and of newly discovered protein. The determinations of physiological properties showed that under water stress, the sprouts of drought-resistant Changwu 134 had higher root/shoot ratio and higher relative water content, but lower relative membrane permeability and lower malondlaldehyde content than those of drought-sensitive Zhengyin 1.

[Investigations of microscopic morphology of individual inhalable particulates in Macao in summer].

By means of high resolution field emission scanning electron microcopy (FESEM) and image analysis (IA), microscopic morphologies and the number-size and volume-size distributions of different types of individual inhalable particles collected in Macao in summer of 2007 were investigated. The results showed that the soot aggregates and mineral particles were ubiquitous in the PM10 of Macao in July, 2007. The mineral particles mostly showed an irregular morphology and the soot aggregates displayed chain-like and fluffy morphology. The soot aggregates accounted for approximately 30%-40% in average by number, and the mineral particles accounted for approximately 20%. The relatively higher percentages of more soot aggregates implied that emission from motor vehicle exhausts was serious in Macao during summer. The number-size distributions revealed that the majority of the particles in PM10 of Macao were fine particles, with the equivalent diameter being concentrated in a range from 0.2-0.4 microm. A distinct spatial difference existed in the types of particles collected at different sampling sites. Soot particles dominated the busy transportation sites and the tunnel site, while the mineral particles had a higher proportion at the dock site.

[Morphology and bioreactivity of PM10 in air of Zhengzhou].

PM10 was collected at the urban and suburban sites of Zhengzhou city during autumn. High solution field emission scanning electron microscopy (FESEM) and image analysis (IA) were used to analyse the morphology and size distribution of individual particles in PM10. Plasmid DNA assay was employed to investigate the bioreactivity of PM10. The results showed that the coal fly ash particles were dominated in the PM10 at the urban site while mineral particles were dominated at the suburban site. The number-size distribution showed that the PM10 at the urban site was mainly concentrated in the range of 0.1 microm to 0.4 microm, but the PM10 at the suburban site was scattered in a relatively wider size range. The volume-size distribution demonstrated that the PM10 from both urban and suburban sites occurred mainly in the size range > 1 microm. These facts showed that by number the fine particles were prevailing in the PM10, while by volume (mass) the coarse particles had a major contribution to the total PM10. The results from plasmid assay showed that the bioreactivity of the urban PM10 was obviously higher than that of the suburban PM10.

[Physical and chemical characteristics of individual mineral particles in an urban fog episode].

Field emission scanning electron microscopy (FESEM) and scanning electron microscopy with energy dispersive X-ray detector (SEM-EDX) were used to study the four aerosol samples collected in Beijing air during the fog and non-fog episodes in winter. Size-distribution of mineral particles in fog sample displayed two major peaks at the size range of 0.1-0.3 microm and 1-2.5 microm. EDX analyses indicated that the major chemical compositions varied greatly in the individual mineral particles of the fog and non-fog episodes, especially the sulfur. A total of 9 different mineral categories were classified, namely, "Si-rich", "Ca-rich", "S-rich", "Fe-rich", "Mg-rich", "Al-rich", "Ti-rich", "K-rich" and "Cl-rich". About 55% of the "Ca-rich" in the fog samples comprised of Ca (50% +/- 1.2%)and S (37% +/- 1.6%) and about 72% of the "S-rich" comprised of S (44% +/- 1.5%) and Ca (33% +/- 2%), illustrating that particles with abundant sulfur were also enriched with abundant calcium. It is suggested that the "Ca-rich" alkali minerals could alleviate acidity of the fog water in Beijing air. The S/Ca mean ratio of mineral particles in the fog sample was 6.11, being 8 times higher than the S/Ca mean ratio of the non-fog samples (0.73). This result showed that sulfuration on the surfaces of aerosol particles was extremely severe, and that the conversion efficiency from SO2 to sulfates was relatively high.