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Besides organic pollutants, coke production generates emissions of toxic heavy metals. However, intensive studies on heavy metal emissions from the coking industry are still very scarce. The current work focuses on assessing the emission characteristics of heavy metals and their behavior during coking. Simultaneous sampling of coal, coke, residues from air pollution control devices (APCD), effluent from coke quenching, and fly ash from different processes before and after APCD has been performed. The total heavy metal concentration in the flue gas from coke pushing (CP) was significantly higher than that from coal charging (CC) and combustion of coke oven gases (CG). Emission factors of heavy metals for CP and CC were 378.692 and 42.783 μg/kg, respectively. During coking, the heavy metals that were contained in the feedstock coal showed different partitioning patterns. For example, Cu, Zn, As, Pb, and Cr were obviously concentrated in the inlet fly ash compared to the coke; among these metals Cu, As, and Cr were concentrated in the outlet fly ash, whereas Zn and Pb were distributed equally between the outlet fly ash and APCD residue. Ni, Co, Cd, Fe, and V were partitioned equally between the inlet fly ash and the coke. Understanding the behavior of heavy metals during coking processes is helpful for the effective control of these heavy metals and the assessment of the potential impact of their emissions on the environment.

In this study, the health risk of toxic volatile organic compounds (VOCs) species for well drillers, working at an exposure site around a well of underground coal fire site, was presented in a case of Shanxi province. The samples were collected by Teflon sampling bags and measured by gas chromatography-mass spectrometry (GC-MS). The results showed that isopropyl alcohol was the most abundant compound of VOCs, with the geometric mean concentrations of 1700.38 μg/m(3). The geometric mean concentrations of individual BTEX compounds obtained in all of the sampling campaign were 131.64, 10.15, 15.53, and 25.38 μg/m(3) for benzene, toluene, ethyl-benzene, and xylenes, respectively. Relative proportion of BTEX averaged as 8.5:0.7:1:1.6. High B/T ratio (13.0) and low T/E ratio (0.7) was observed in this study. For non-cancer risk in this study, the hazardous quotient (HQ) of 1,2-dibromoethane, 1,3-butadiene, and benzene was 17.91, 1.71, and 43.88, respectively, mean their non-cancer risk was at the level of definite concern. The HQ sum of 20 VOCs was 64.94, much higher than 1. The cancer risk values of benzene (7.01E-04), 1,2-dibromoethane (1.91E-04), carbon tetrachloride (1.55E-04), and 1,3-butadiene (1.09E-04) were greater than 10(-4), indicating that they were all definite risk. The total cancer risk of all VOCs species was 1.39E-03, almost 14 times more than the level of definite risk. The stochastic exposure assessment of all VOCs species total cancer risk using the Monte Carlo simulation analysis shows that 5 and 95 % cancer risks were predicted to be 7.60E-04 and 2.75E-03, respectively. The cancer risk for all VOCs species is unacceptable. The results of sensitivity analysis show that benzene, carbon tetrachloride, and 1,3-butadiene exposure account for more than 98 % contributions to the estimated risk for drillers, indicating that those VOCs species exposure has greater impact than other species on risk assessment. Both combined effects and independent effects of each VOCs species have to be considered.

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Size-segregated samples (< 2.5, 2.5-5, 5-10, and 10-100 µm) and PM 2.5 samples were collected to analyze the watersoluble inorganic ions (WSIs, including F -, Cl -, NO 3 -, SO 4 2-, Na + , NH 4 + , K + , Mg 2+ , and Ca 2+ ), through ion chromatography from January to October in 2017 in Jinzhong. The median concentration of the total WSIs in PM 2.5 was 37 µg m -3 , thereby accounting for 31% of the PM 2.5 , with the lowest level in spring and the highest in autumn. SO 4 2-, NO 3 -, and NH 4 + were the most abundant substances and were primarily on the fine particles (0-2.5 µm), whereas Ca 2+ , Mg 2+ , and Fwere concentrated on the coarse particles (2.5-100 µm). The results of the correlation analysis led to the conclusions that (NH 4 ) 2 SO 4 , NH 4 Cl and K 2 SO 4 were the primary compounds on the fine particles, MgSO 4 and CaSO 4 were the major chemical forms of WSIs on the coarse particles, thus indicating that the formation mechanisms of these compounds were different; however, NH 4 NO 3 and KNO 3 were present in both the types of particles. The particles that were observed in Jinzhong were alkaline during the study period, and their acidity was negligible. The ratio analysis showed that the highest ratio of Cl -/K + was found in winter in both fine and coarse particles; however, no obvious distinction has been made between Mg 2+ /Ca 2+ during the four seasons. The NO 3 -/SO 4 2ratio in coarse particles was observed to be significantly higher than that in fine particles, particularly in summer, thus indicating that the heterogeneous reaction on particles plays a vital role in the formation of NO 3in coarse particles. The PCA analysis showed that the primary factors of WSIs, which were secondary formation, coal combustion, biomass burning, dust particles, and industrial emission. The coal combustion and biomass burning have been considered as the leading emission sources to be controlled for improving air quality in Jinzhong.