[Pollution Characteristics and Emission Factors of PCDD/Fs from Iron and Steel Industry].

The pollution level, emission characteristics, and emission factors of PCDD/Fs from a number of steel plants were investigated in a particular province of China. The results showed that the concentration of PCDD/Fs was at a low level and decreased by 1-2 orders of magnitude compared with that in 2005-2019. In detail, the concentrations of PCDD/Fs ranged from 0.003-0.557 ng·m-3(I-TEQ), and the mean value was 0.165 ng·m-3 for the sintering process. Moreover, the concentrations of PCDD/Fs ranged from 0.006 to 0.057 ng·m-3, and the mean value was 0.025 ng·m-3 for the electric furnace process. In addition, the concentration of PCDD/Fs in the iron and steel industry from 2005 to 2020 increased first and then decreased, especially after the implementation of the new emission standard and the ultra-low emission control of conventional pollutants such as smoke, showing a significant decline. The results of fingerprint analysis showed that 2,3,7,8-TCDF was the largest congener contributing to the mass concentration, and lower chlorinated PCDFs were increased. This result differed from those of previous studies in which highly chlorinated PCDFs and PCDDs dominated, indicating that the generation source of PCDD/Fs had changed. The congener and isomer profiles of PCDD/Fs in flue gas from the sintering process were similar to those in the flue gas from the electric furnace process. Additionally, showing the characteristics of the typical high-temperature thermal process, the de novo synthesis may be the dominant mechanism of formation of PCDD/Fs in the sintering process and electric furnace process. The emission factor was 0.003-0.5 µg·t-1 (I-TEQ), and the average emission factor was (0.18±0.22) µg·t-1 for the sintering process. The emission factor was 0.04-0.5 µg·t-1, and the average emission factor was (0.27±0.23) µg·t-1 for the electric furnace process. These values were far lower than those of the standard toolkit for identification and quantification of dioxin and furan emissions released by UNEP in 2013 and the emission factors in the dioxin emission inventory of China in 2004. It is suggested that the emission factors of PCDD/Fs in the iron and steel industry of China should be studied and updated.

[Analysis of Ozone Pollution Spatio-temporal Evolution Characteristics and Identification of Its Long-term Variation Driving Factor over Hunan Province].

Despite the alleviation of particulate matter (PM), the ambient ozone (O3) concentration is continuously increasing in Hunan province where the investigation of O3 pollution has been rarely reported. Accordingly, the spatio-temporal evolution of O3 pollution was first analyzed based on hourly air quality data observed by national monitoring stations from 2015 to 2020 over 14 cities in Hunan province. Afterwards, the combination of meteorological data from the European Center for Medium-range Weather Forecast (ECMWF) and the generalized additive model (GAM) was applied to investigate the driving factors of the O3 long-term trend during this period. The results presented obvious diurnal, monthly, and seasonal characteristics of O3 variations. High O3 concentrations occurred in May and September monthly, and the peak O3 season was autumn. Furthermore, the 90th percentile O3 increased at a rate of 4.7 µg·(m3·a)-1 temporally, and high O3 values mainly occurred in the north-eastern region spatially, in contrast to the low O3 values in the western region. The modeling results indicated that the increase in O3 was mainly ascribed to precursor emissions. Furthermore, meteorology promoted a rise in O3 with the impact magnitude of 1 µg·(m3·a)-1. Remarkably, meteorology accelerated the O3 increases in spring, summer, and the eastern region, whereas it restrained increases in autumn, winter, and the northwest. The effect of meteorology on PM10 was different from O3 during this period. Overall, this study highlighted the importance of meteorological impacts when regulating emission reduction measures for O3 abatement. It required greater effort regarding O3 mitigation to offset the side-effect from meteorology in meteorology-sensitive seasons and regions. Additionally, the regional corporation is indispensable to reduce O3 transportation from upwind.

Male workers' exposure characteristics of ΣPCDD/F from a municipal solid waste incinerator in south China through hair analysis.

Human hair, flue gas and fly ash from a municipal solid waste incinerator (MSWI) in south China were collected and analyzed for polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF). The ΣPCDD/F level in hair from male workers were higher than those from residents. The Principal Component Analysis (PCA) suggested that ΣPCDD/F in flue gas is an external source of male workers' hair ΣPCDD/F. Results of daily intake of ΣPCDD/F by inhaling flue gas suggested that the inhalation exposure of ΣPCDD/F was at a slight health risk. For the male workers directly exposed to the MSWI power plant, ΣPCDD/F levels in their hair were significantly higher than those who were non-directly exposed. Moreover, a significantly positive relationship was obtained between ΣPCDD/F levels in male workers' hair and the working time. The result of correlation analysis suggested that 1,2,3,4,6,7,8-HpCDD and OCDD could be level indicator congeners to estimate ΣPCDD/F levels. In addition, 2,3,7,8-TCDD could be applied as TEQ indicator congener to characterize the hair of MSWI male workers.

[Discussion of Emissions and Health Risk of Polycyclic Aromatic Hydrocarbons (PAHs) from the Retreading Process of Waste Tires].

The emissions characteristics of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) in ambient air during the waste tire retreading process (open-air storage, mixing, vulcanization, and grinding processes) and in workers' dormitory were analyzed. In addition, the occupational health risk of the workers was evaluated. Results showed that PAHs were detected in all retreading processes and in the workers' dormitory. The highest concentration site was the mixing process, followed by open-air storage and vulcanization process. The lowest concentration point was in the grinding process. The average concentration of PAHs in the workers' dormitory was 11.1 ng·m-3. The PAHs at all sampling points were largely phenanthrene (Phe), fluoranthene (Flu), anthracene (Ant), and pyrene (Pry), which also had a stronger linear correlation with the total PAH concentration. An analysis of the benzene rings showed that three ring and four ring were the majority, while two ring, five ring, and six ring components accounted for less than 10%. Results of the possible influencing factors of the PAHs revealed that the open-air storage and dormitory might be affected by a combustion source, but the mixing, vulcanization, and grinding processes might be affected by rubber oil. The principal component analysis (PCA) and cluster analysis showed that the spatial location of all sites would significantly influence the distribution of PAHs during the tire retreading process. The health risk assessment showed that occupational workers had a lower risk of lifelong cancer, and there was little influence on life expectancy.

[Possible Sources of PCDD/Fs in Atmosphere of a Certain District in Guangdong].

This paper analyzed 17 polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs) by HRGC/HRMS in the flue gas of a certain municipal solid waste incinerator(MSWI) and its surrounding air and other possible sources in Guangdong. It discussed the feature of homologs and main toxic monomers in all samples. It also investigated the relationship among surrounding area, MSWI and possible sources using principle component analysis (PCA) and cluster analysis. The results showed that the concentration of PCDD/Fs was higher in the flue gas than the ambient air, moreover non-effect suffered by prevailing wind direction. The possible sources might be tyre factory and open burning based on spot survey. The concentration of PCDD/Fs was lower in tyre factory than upwind station, but higher at open burning spot than outdrop monitoring station. The analysis of homologs showed that OCDD, 1,2,3,4,6,7,8-HpCDD and 1,2,3,4,6,7,8-HpCDF were the main materials in the flue gas and air, meanwhile OCDF was also found in atmosphere. There was similar feature of 17 PCDD/Fs between surrounding monitoring station and tyre factory, and the same between flue gas and open burning. The further analysis showed that the linearly dependent coefficients of 1,2,3,7,8-PeCDD and 2,3,4,6,7,8-HxCDF were 0.95 and 0.75, respectively. It showed the strong correlation of two monomers in all ambient air samples. The PCA and cluster analysis showed that MSWI influenced the surrounding air, tyre factory had an impact on upwind station, and open burning had a lower effect on outdrop monitoring station.

[Emission of PCDD/Fs from Crematories and Its Influencing Factors].

To analysis the influencing factors for the emssions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) as structure of crematory, air pollution control device (APCD) and funeral objects, etc, we collected and measured the PCDD/Fs emissions in flue gas from 13 crematories in China. Then we proposed some supervision suggestions on measures of pollution control and management. The results indicated that the emission levels of PCDD/Fs (as the toxic equivalent concentration, TEQ) was ranged in a large gap from 0.027 to 15.8 ng x m(-3), and the average was 3.2 ng x m(-3). Emissions factor of PCDD/Fs (as TEQ) from 13 crematories varied between 45.9 and 22 236 ng x body(-1), and the average was 4 738 ng x body(-1). The emissions of PCDD/Fs from flat incinerators were generally lower, whereas higher ratio up to the national discharge standard, than that of car type incinerators. Congener distribution of PCDD/Fs in flue gas from 13 crematories were different from each other. Since the emission of PCDD/Fs from some crematories remains in high level, it is necessary to control pollution from the source, improve the pollution control technology, and strengthen government supervision, by following measures: 11 cremating funeral objects separately from corpse; 22 adding one

[Concentrations and distribution characteristics of PCDD/Fs in spent etching solution and its copper salt recycling products].

Concentrations of 17 PCDD/Fs congeners in spent etching solution and its copper salt recycling products were determined by the high resolution gas chromatography-high resolution mass spectrometry (HRGC-HRMS). The PCDD/F concentrations and corresponding WHO-TEQ (toxic equivalent quantity) values were in the range of 0-3 460 pg.L (mean= 616 pg.L-1) and 0-246 pg.L-1 (mean = 42.9 pg.L-1) , respectively, in the spent etching solution, and 1.08-24.6 ng.kg-1 (mean = 8.83 ng.kg-1) and 0.112-0.715 ng.kg-1 (mean = 0.338 ng.kg-1), respectively, in the copper salt products. The established purification treatment technique could remove most of the PCDD/Fs in the etching solution. Of the copper products, higher PCDD/F concentrations were detected in industrial products than in feed grade and plating grade products. Similar distribution characteristics were found for PCDD/ Fs in all copper salt products as the followings: 1. PCDFs were more abundant than PCDDs, 2. high chlorinated congeners were more abundant than low chlorinated congeners, except for 2,3,7,8-TCDF in the copper sulfate products.

[Characterization of water-soluble inorganic ions in PM2.5 and PM1.0 in summer in Guangzhou].

PM2.5 and PM1.0 samples were collected simultaneously during July of 2008 in Guangzhou. The concentrations of water-soluble inorganic ions (Na+, NH4+, K+, Mg2+, Ca2+, F-, Cl-, NO3-, and SO4(2-)) were determined by ion chromatography. Meteorological parameters, atmospheric scattering, visibility, and concentrations of trace gases (SO2, NO2, and O3) for this period were also recorded. The results showed the total water-soluble inorganic ions concentrations were (25.5 +/- 10.9) microg x m(-1) and (22. 7 +/- 10.5) microg x m(-3) in PM2.5 and PM1.0, which occupied (47.9 +/- 4.3)% and (49.3 +/- 4.3)% of PM mass respectively. Sulfate was the most abundant ion and contributed (25.8 +/- 4.0)% of PM2.5 mass and (27.5 +/- 4.5)% of PM1.0 mass respectively. High temperature and high ozone level favored the formation of sulfate from sulfur dioxide, while the high relative humidity favored the formation of nitrate were observed. Moreover, sulfate, nitrate, and ammonium in PM2.5 and PM1.0 had great impact on the scattering coefficient and visibility degradation.