[Spatiotemporal Distribution Characteristics of Air Pollution and Health Risks in Key Cities of China].

Based on the monitoring data of five pollutants in 168 key cities under air pollution prevention and control in China from 2015 to 2020, using the MAKESENS model and the aggregate risk index(ARI), this study quantitatively analyzed the spatial and temporal distribution characteristics of air pollution and health risks in China and the six urban agglomerations. The results showed that:① PM2.5 pollution was the most serious pollution in Chinese key cities. Only 15% of the cities' six-year average concentrations of PM2.5 reached the National Secondary Standard, followed by that of NO2; 77% of the cities' six-year average concentrations of NO2 reached the National Secondary Standard. The urban agglomerations of Beijing-Tianjin-Hebei and Fenwei plain had the most serious air pollution, and the six-year average concentrations of PM2.5, SO2, CO, and NO2 were higher than those of other urban agglomerations. ② The concentrations of PM2.5, SO2, CO, and NO2 in key cities of China showed a decreasing trend, whereas the concentration of O3 in other urban agglomerations showed an increasing trend, except in the Chengdu-Chongqing urban agglomeration. The concentration of SO2 in the urban agglomerations of Beijing-Tianjin-Hebei and Fenwei plain changed the most significantly. ③ The health risk of air pollution in the key cities of China generally showed a decreasing trend, with a sharp decline from 2017 to 2018, and the population exposed to extremely high risks dropped from 160 million to 32.54 million. The urban agglomeration in the middle reaches of the Yangtze River had the most significant decline in health risks, whereas the key cities in China faced higher health risks in spring and winter seasons. ④ The Beijing-Tianjin-Hebei and Fenwei plain urban agglomerations had the highest health risks, and the urban agglomeration in the middle reaches of the Yangtze River had the lowest; O3 gradually replaced PM2.5 as the main pollutant affecting the health risk. These results can provide a reference for evaluating the effectiveness of urban air pollution control in China during the 13th Five-Year Plan period.

[Spatial Variation of Surface Ozone Concentration During the Warm Season and Its Meteorological Driving Factors in China].

The concentration of surface ozone (O3) in China increased consistently from 2015 to 2018, and became an important air pollutant, followed by particulate matter. This study uses real-time O3 and meteorological data, obtained in 337 cities in China during the warm seasons (April to September) of 2015 to 2018, to determine the spatial variation of surface O3 and its meteorological driving factors in major cities in China, via trend analysis, spatial autocorrelation, hotspot analysis, and multi-scale geographically weighted regression (MGWR) modeling. The results show that: ① during the warm season, O3 concentrations showed a significant growth trend (P<0.05), with an average growth rate of 0.28 µg·(m3·a)-1, while more than 55% of urban O3 concentrations increased by 0.50 µg·m-3 annually. ② There were significant regional differences in O3 concentration. High values (>60 µg·m-3) were distributed over east China, north China, central China, and northwest China, while low values (<20 µg·m-3) were distributed over south China and southwest China. ③ The spatial agglomeration of O3 concentration has been enhanced year by year, with hotspots mainly distributed over east China and central China. In contrast, there are cold spots in northeast China, southwest China, and southern China. ④Analysis of the MGWR model indicated that temperature, wind speed, cloud coverage, and precipitation all have a significant effect on the distribution of O3, although there are also discrepancies in driving factor priorities between the different regions. Temperature was the main meteorological driving factor of O3 variation during the warm season in China, and its impact on O3 concentration was significantly higher in north China, northwest China, and northeast China than in other regions; overall, there was a significant positive correlation between O3 concentration and temperature, except in Guangxi, Yunnan, and Jiangxi. O3 concentration was negatively correlated with wind speed in most regions of south China, east China, and central China, and positively correlated with wind speed in north China and northeast China. O3 concentration was significantly negatively correlated with cloud cover, except in Liaoning, Shandong, Hebei, Gansu, Guangdong, and some areas in southwest China. O3 concentration was significantly negatively correlated with precipitation, except in the northwest and southwest regions.

[Pollution Characteristics and Exposure Risk Assessment of Perfluoroalkyl Substances in Road Dust, Chengdu].

To study the pollution characteristics and exposure health risk of perfluoroalkyl substances (PFASs) in road dust, 12 PFASs were analyzed by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) in this study. PFAS concentrations in road dust ranged from 0.95 to 111 ng·g-1, with an average concentration of (25.6±37.2) ng·g-1, suggesting large spatial differences between PFASs in road dust. PFAS concentrations on the main roads were significantly higher than on minor roads, and the minor roads downtown displayed higher concentration levels than suburban minor roads. Perfluorobutanoic acid (PFBA) was the predominant compound in Section 1 of Jie-fang Road, Jin-niu-ba Road and Shui-nian-he Road, while perfluroroocantanoic acid (PFOA, 24.8%) and perfluorooctane sulfonate (PFOS, 24.1%) were the main PFASs on other roads, indicating different sources of PFASs in these areas. The total daily dose of PFASs in road dust for children and adults were 0.168 ng·(kg·d)-1 and 0.028 ng·(kg·d)-1, respectively, suggesting higher exposure risk for children than adults. Therefore, more attention should be paid to children's health risk assessment. Daily doses of PFOA and PFOS in road dust for Chengdu residents were lower than the maximum daily intakes recommended by the European Authority, indicating that there was no immediate health risk to local residents.

[Pollution Level and Source Apportionment of Atmospheric Particles PM2.5 in Southwest Suburb of Chengdu in Spring].

In order to understand the characteristics of PM2.5 pollution in the atmosphere of Chengdu southwest suburb, PM2.5 particles in Chengdu southwest suburb were collected and analyzed from March 18 to March 31st, 2015. The results showed that the daily average concentration of PM2.5 in the southwest suburb of Chengdu reached 121.21 µg · m⁻³, and the average daily concentration of 24 samples in 31 PM2.5 samples was over 75 µg · m⁻³, the daily excessive rate was 77%, indicating the PM2.5 pollution in the study area was serious in March. When studying the relationship between atmospheric and meteorological factors, it was found that there was a significant index correlation between PM2.5 concentration and atmospheric visibility, and it had a positive correlation with temperature and humidity, but the correlation was not obvious. NH4⁺ (16.24%), SO4²- (12.58%) and NO3⁻ (9.91%) were dominant in PM2.5 The ratio of NO3⁻/SO4²â» was 0.77, which indicated that the pollution of stationary sources in the southwest suburb was more severe than that of mobile sources. Organic carbon (OC)/elemental carbon (EC) ratios were higher than 2, which indicated the existence of second organic carbon (SOC). Using OC/EC ratio method to estimate the concentration of SOC, it was found that the average concentration of SOC in the southwest suburb of Chengdu in March was 3.49 µ · m⁻³, and the contribution rate of OC was 20.6%, which showed that the main source of OC in the southwest suburb of Chengdu was primary discharge. The correlation analysis of OC and EC showed that the correlation coefficient reached 0.95, indicating that the OC and EC sources were similar and relatively stable, and there was a great impact of local source emissions on Chengdu southwest suburb in spring, and primary discharge played a dominant role, while the contribution of SOC to OC was relatively small, which was consistent with the SOC characteristics obtained by estimation. Using principal component analysis method to analyze the sources of PM2.5 in the southwest of Chengdu, it was found that the main pollution sources of PM2.5 in southwest suburb of Chengdu were coal burning and biomass burning, secondary nitrate/sulfate, soil and dust, vehicle emissions, electronic production source, and mechanical processing source.

[Characteristics of Elements and Potential Ecological Risk Assessment of Heavy Metals in PM2.5 at the Southwest Suburb of Chengdu in Spring].

PM2.5 samples were collected at the southwest suburb of Chengdu in spring (in May 2012 and 2014). The mass concentrations of PM2.5 were determined by the weight method, and 24 chemical elements in PM2.5 were analyzed by XRF. To study the pollution characteristics and sources of chemical elements, and the potential ecological risk of heavy metals in PM2.5, the Geo-accumulation Index, Enrichment Factor, and Potential Ecological Risk Index methods were applied, respectively. The results indicated that the mass concentrations of PM2.5 in spring at the southwest suburb of Chengdu were very high, compared with American EPA's Standard and National Standard level-Ⅱ. The detection of chemical element composition in PM2.5 showed that K and S were the main elements, whereas the contents of Ga, Cs, Co, Cd, and V were the lowest. The differences of elemental concentrations in PM2.5 showed relatively large differences, when compared with domestic and foreign representative cities. Se, Cd, As, Br, S, Pb, Cl and Zn were present at an extremely high level of geo-accumulation degree, which revealed that the pollution coming from human activities was serious. The analysis results of enrichment factor showed that Se, Cd, As, Br, Cl, Pb, Zn and S elements were highly enriched or hyper accumulated, Cu, Cs, Ni, Ga and Co elements were moderately enriched, and they were mainly from human activities rather than soil dust. Cr, Mn, Ca and V elements were mildly enriched, and they were from both natural sources and human activities. Na, Ti, Al, Si and Mg elements were scarcely enriched, and they were mainly from natural sources. The ecological risk assessment of heavy metals showed that the order of potential ecological risk inedx of heavy metals in PM2.5 was Cd > As > Pb > Cu > Zn > Ni > Co > Cr > Mn > V > Ti, while the ecological harm degree of Cd was extremely strong, and the whole potential ecological risk degree was very strong.

[Characteristics of Water-Soluble Inorganic Ions in PM2.5 Emitted from Coal-Fired Power Plants].

To characterize the primary PM2.5 emission from coal-fired power plants in China, and to quantitatively evaluate the effects of flue gas denitrification and desulfurization on PM2.5 emission, a pulverized coal fired (PC) power plant and a circulating fluidized bed (CFB) plant were selected for measuring the mass concentration and water-soluble ion composition of PM2.5 in flue gas. The results showed that the mass concentration of PM2.5 generated from the CFB was much higher than that from the PC, while the mass concentrations of PM2.5 emitted from these two plants were very similar, because the CFB was equipped with an electrostatic-bag precipitator (EBP) with higher PM2.5 removal efficiency than the common electrostatic precipitator (ESP). Although the total concentration of water-soluble ions in PM2.5 generated from the PC was lower than that from the CFB, the total concentration of water-soluble ions in PM2.5 emitted from the PC was much higher than that from the CFB, which implied that PM2.5 emission from the PC was greatly affected by the flue gas treatment installations. For example, the flue gas denitrification system produced H2SO4 mist, part of which reacted with the excessive NH3 in the flue gas to form NH4HSO4 in PM2.5 and to increase the acidity of PM2.5. In addition, the escaping of desulfurization solution during the flue gas desulfurization process could also introduce NH4+ and SO2- into PM2.5. Therefore, although the main water-soluble ions in PM2.5 generated from both of the plants were Ca2+ and SO(4)2-, the major cation was changed to NH4+ when emitted from PC.

[Characteristics of water soluble inorganic ions in fine particles emitted from coal-fired power plants].

Currently, China suffers from serious pollution of fine particulate matter (PM2.5). Coal-fired power plant is one of the most important sources of PM2.5 in the atmosphere. To achieve the national goals of total emission reductions of sulfur dioxide (SO2) and nitrogen oxides (NO(x)) during the 11th and 12th Five-Year Plan, most of coal-fired power plants in China have installed or will install flue gas desulfurization (FGD) and flue gas denitrification (DNO(x)) systems. As a result, the secondary PM2.5, generated from gaseous pollutants in the atmosphere, would be decreased. However, the physical and chemical characteristics of PM2.5 in flue gas would be affected, and the emission of primary PM2.5 might be increased. This paper summarized the size distributions of PM2.5 and its water soluble ions emitted from coal-fired power plants, and highlighted the effects of FGD and DNO(x) on PM2.5 emission, especially on water soluble ions (such as SO4(2-), Ca2+ and NH4+) in PM2.5. Under the current condition of serious PM2.5 pollution and wide application of FGD and DNO(x), quantitative study on the effects of FGD and DNO(x) installation on emission characteristics of PM2.5 from coal-fired power plants is of great necessity.

[Pollution Level and Sources of Organic Phosphorus Esters in Airborne PM2.5 in Chengdu City].

Organic phosphorus esters ( OPEs ) in atmospheric PM2.5 in Chengdu city was quantitatively determined by using gas chromatography-mass spectrometry. The distribution characteristic was discussed, back trajectory model and correlation analysis were used to study the sources of OPEs in PM2.5 in Chengdu city. The results showed that the annual average concentration of Σ7OPEs in atmospheric PM2.5 in Chengdu city was 6.46 ng x m(-3) for the urban site and was 9.38 ng x m(-3) for the suburb site. Due to the waste material recycling industries in the suburb area and the perennial dominant wind direction in Chengdu, the concentration of Σ7OPEs at suburb site was higher than that at urban site (P = 0.013). The atmospheric mixed degree influenced the distribution of OPEs in rural and urban area. The source of Σ7OPEs in atmospheric PM2.5 in Chengdu city was mainly from endogenous pollution which was mainly affected by the local sources around the samoling sites. while the contribution of the exogenous pollution was small.

[Influencing factors of mercury emission flux from forest soil at Tieshanping, Chongqing].

To study the effect of environmental influencing factors on soil mercury emissions, intact surface soil samples (0 to 5 cm) were collected from a Masson pine forest in Tieshanping, Choningng to conduct controlled experiments, and soil mercury emission flux was measured by dynamic flux chambers under different conditions. The results showed that the mercury emission significantly increased with the enhancement of solar radiation, air temperature, and soil water content. The mercury emissions in sunlight were 3 to 9 times higher than those in shade, but the latter condition should be more similar to the actual condition in the field. The mercury emission flux was significantly higher in summer than in spring and autumn, and was the lowest in winter. Higher in air temperature, soil water content had a stronger effect on soil mercury emission. Removal of litterfall significantly decreased soil mercury emission, mainly because the mercury content of litterfall was higher than that in mineral soil layer. In addition, soil mercury emission had an obvious trend of decay during a day, indicating that relatively low mercury content in forest soil might be a limiting factor of mercury emission. The mercury emission flux in the daytime measured in this study was( 14.3 +/- 19.6) ng. (m2 .h) -1 in summer, (3.50 +/-5. 36)ng- (m2 h)-1 in spring and autumn, and (1.48 +/-3. 27)ng- (m2 h)-1 in winter. The steady-state results above might therefore be overestimation of the actual emission in the field.

[Monitoring nitrogen deposition on temperate grassland in Inner Mongolia].

Nitrogen deposition on temperate steppe was monitored from November 2011 to October 2012 in Taipusi County, Inner Mongolia. The dry deposition of gaseous nitrogen compounds was calculated based on online-monitored atmospheric concentrations of NH3 and NO2 and dry deposition velocity simulated by CMAQ model. The wet deposition, dry deposition of particle, and throughfall deposition were also estimated by collecting rainfall, dust fall, and throughfall samples and the chemical analysis of NH4+ and NO3-concentrations. Results showed that the total deposition of nitrogen was up to 3.43 g x (m2 x a)(-1), which might be harmful to the ecosystem. The wet deposition accounted for about 44% of the total deposition, while dry deposition of gases and particle accounted for 38% and 18%, respectively. Since the deposition contributed more than wet deposition, a great attention should be paid on dry deposition monitoring. However, the very simple method for total deposition monitoring based on throughfall seemed not suitable for grassland because the monitored throughfall deposition was much lower than the total deposition. In addition, reduced nitrogen (NH4+ and NH3) contributed to 71% of the total deposition, while oxidation nitrogen (NO3- and NO2) was only 29%. Therefore, NH3 emission reduction should be considered as important as nitrogen oxides (NO3x) for controlling nitrogen deposition.

[Preliminary study of PBDE levels in house dust and human exposure to PBDEs via dust ingestion].

Fifty-two house dust samples were randomly collected in Guangzhou and Haikou City, to analyze the concentrations of Sigma10 PBDEs (sum of BDE 28, 47, 66, 85, 99, 100, 153, 154, 183 and 209), the PBDE composition profiles, and possible influencing factors, and estimate human exposure to PBDEs via dust ingestion for adults and toddlers. The results showed that PBDEs were found in all samples, with the Sigma10 PBDEs concentrations ranging from 544.2 ng/g to 9 654 ng/g, and with median (mean) of 2 547 (3 096) ng/g. The PBDE levels in Guangzhou samples were obviously higher than those in Haikou. No significant correlations between PBDE levels and residential characteristics (number of TVs, computers, and polyurethane foam-contained furniture, time of using TVs and computers) were observed. BDE209, with a mean concentration of 3 021 ng/g, was the dominated congener, contributing 73.70%-99.74% to the Sigma10 PBDEs, with a mean contribution of 96.85%. BDE 47, 99 and 183 were the most abundant congeners of Sigma9 PBDEs (BDE 209 excluded), with a mean contribution of 24.48%, 23.99%, and 21.66%, respectively. There is no notable difference in PBDE composition between Guangzhou and Haikou samples. The estimated exposure for adults and toddlers to PBDEs ranged from 10.59 ng/d to 254.7 ng/d and from 140.1 ng/d to 509.3 ng/d, respectively. Due to their increased dust ingestion rates, toddlers in took more PBDEs via dust ingestion than adults. Dust ingestion was an important human exposure route for PBDEs, especially for toddlers.

Adsorption intrinsic kinetics and isotherms of lead ions on steel slag.

Batch experiments were carried out to investigate the kinetics of adsorption of lead ions by steel slag on the basis of the external diffusion, intra-particle diffusion and adsorption reaction model (pseudo-first-order, pseudo-second-order). The results showed that the controlling step for the adsorption kinetics changed with the varying experimental parameters. When the particle size of steel slag was larger than 120 mesh, intra-particle diffusion of Pb(2+) was the controlling step, and when the initial concentration of Pb(2+) was less than 150 m gL(-1) or the shaking rate was lower than 150 rpm, external diffusion of Pb(2+) was promoted. Contrary to the former experimental conditions the adsorption reaction was the controlling step, and the adsorption followed second-order kinetics, with an adsorption rate constant of 13.26 g mg(-1)min(-1). The adsorption isotherm of Pb(2+) with steel slag followed the Langmuir model, with a correlation coefficient of 0.99.

[Molecularly imprinted technique-flow injection-chemoluminescence system analysis detect phenol in water].

Using phenol as template, acrylamide as monomers, pentaerythritol triacrylate as crosslinking agent, azodiisobutyronitrile as initiating agent, acetomitrile as thinner, we synthesized MIPM in aquosity system with suspension polymerization, on which surface there are some holes. The adsorbance of MIPM to phenol will no longer increased after two hours, it means that it reaches the saturation which were 7.03 micromol x L(-1). The separate genes of MIPM were 1.66 and 1.99 with pyrocatechol and hydroquinone as competitors. The MIPM had the better effect of adsorption and selectivity. Using MIPM as molecule recognizates, we set up a new method which was molecularly imprinted technique-flow injection-chemoluminescence analysis to detect phenol. The result shows that the range of phenol concentration from 1 x 10(-3) microg x L(-1) to 100 microg x L(-1) with adsorbed by MIPM is linearly dependent, which relativity coefficient is 0.9996 and the relative standard deviation is 0.99%, the detection limit is 9 x 10(-4) microg x L(-1). Using the method to detecting phenol from the water samples, the recoveries of phenol is 99%-105%, the result is pretty good.

[Research on the transformation of GBC-918 spectrophotometric data into text data].

This paper introduces the principle of designing resident program which can be used to obtain GBCUV screen pictures. First, the spectrophotometric data of refinery waste water, phenol and aniline were obtained by using GBCUV software. Second, the data mentioned above were transformed into text data with TXTSR.COM and TXZH.EXE. Finally, after the text data of refinery waste water were processed by Kalman filtering, the recoveries of phenol and aniline were in the range of 99.0%-103.8% and 97.8%-100.6% respectively. In conclusion, using this software can enlarge the application of GBC-918 and meet the need of modem spectral analysis.

[Dichotomizing method applied to calculating equilibrium constant of dimerization system].

The arbitrary trivariate algebraic equations are formed based on the combination principle. The univariata algebraic equation of equilibrium constant kappa for dimerization system is obtained through a series of algebraic transformation, and it depends on the properties of monotonic functions whether the equation is solvable or not. If the equation is solvable, equilibrium constant of dimerization system is obtained by dichotomy and its final equilibrium constant of dimerization system is determined according to the principle of error of fitting. The equilibrium constants of trisulfophthalocyanine and biosulfophthalocyanine obtained with this method are 47,973.4 and 30,271.8 respectively. The results are much better than those reported previously.