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Humans have altered the earth in unprecedented ways, and these changes have profound implications for global climate change. However, the impacts of human pressures on carbon dioxide (CO2) emissions over long time scales have not yet been clarified. Here, we used the human footprint index (HF), which estimates the ecological footprint of humans in a given location, to explore the impacts of human pressures on CO2 emissions in China from 2000 to 2017. Human pressures (+13.6%) and CO2 emissions (+198.3%) in China are still on the rise during 2000–2017 and are unevenly distributed spatially. There was a significant positive correlation between human pressures and CO2 emissions in China, and northern China is the main driver of this correlation. The increase of CO2 emissions in China slowed down after 2011. Although human pressures on the environment are increasing, high-quality development measures have already had noticeable effects on CO2 emission reductions. [ABSTRACT FROM AUTHOR]

Atmospheric transport of black carbon (BC) from surrounding areas has been shown to impact the Tibetan environment, and clarifying the geographical source and receptor regions is crucial for providing guidance for mitigation actions. In this study, 10 trace volatile organic compounds (VOCs) sampled across Tibet are chosen as proxies to diagnose source regions and related transport of pollutants to Tibet. The levels of these VOCs in Tibet are higher than those in the Arctic and Antarctic regions but much lower than those observed at many remote and background sites in Asia. The highest VOC level is observed in the eastern region, followed by the southern region and the northern region. A positive matrix factorization (PMF) model found that three factors—industry, biomass burning, and traffic—present different spatial distributions, which indicates that different zones of Tibet are influenced by different VOC sources. The average age of the air masses in the northern and eastern regions is estimated to be 3.5 and 2.8 days using the ratio of toluene to benzene, respectively, which indicates the foreign transport of VOC species to those regions. Back-trajectory analyses show that the Afghanistan-Pakistan-Tajikistan region, Indo-Gangetic Plain (IGP), and Meghalaya-Myanmar region could transport industrial VOCs to different zones of Tibet from west to east. The agricultural bases in northern India could transport biomass burning-related VOCs to the middle-northern and eastern zones of Tibet. High traffic along the unique national roads in Tibet is associated with emissions from local sources and neighboring areas. Our study proposes international joint-control efforts and targeted actions to mitigate the climatic changes and effects associated with VOCs in Tibet, which is a climate sensitive region and an important source of global water. [ABSTRACT FROM AUTHOR]

PM 2.5 samples were collected in urban area in Taiyuan for four seasons from August 2009 to April 2010. The Water-soluble inorganic ions (WSI, including F − , Cl − , NO 3 − , SO 4 2 − , Na + , NH 4 + , K + , Mg 2 + , and Ca 2 + ) were analyzed by ion chromatography. The daily PM 2.5 levels in the field samples varied from 49.90 to 477.93 μg/m 3 with the mean of 209.54 μg/m 3 , which all largely exceeded the PM 2.5 24-hour limitation value of 35 μg/m 3 in Environmental Protection Administration of United States and 75 μg/m 3 in Ministry of Environmental Protection of China. The WSI average concentration was 68.86 μg/m 3 and accounted for about 32.86% of PM 2.5 . As the most abundant anion and cation, SO 4 2 − and NH 4 + were 43.53 and 14.78 percent of WSI, respectively. PM 2.5 in Taiyuan was acidic by the micro-equivalents concentration methods but nearly neutral in autumn, and the chemical forms of WSI were mainly NH 4 HSO 4 , (NH 4 ) 2 SO 4 and NH 4 NO 3 . PM 2.5 and WSI levels showed obvious seasonal variation and were the highest in winter in all samples. PM 2.5 , SO 4 2 − , and some coal-related ions such as NH 4 + and Cl − were higher in winter than other seasons, which mainly attributed to more coal combustion for power and indoor heating supply. The ratio analysis showed that Mg 2 + and Ca 2 + were not only from soil dust, but also from coal combustion and industry emission. Biomass burning such as the cornstalk and tree branches led to the highest K + emission in autumn and summer. Wind had a regular influence on the PM 2.5 and WSI, and would transport the soil dust mainly from the northwest and also lead to re-suspension of dust in the air when the wind speed was high. Furthermore, the dustpan topography easily helped the pollutants to concentrate in Taiyuan city, and some coal coking industries might contribute to high PM 2.5 and WSI in Taiyuan. [ABSTRACT FROM AUTHOR]

Concentrations of gaseous elemental mercury (GEM) were continuously monitored from May 2011 to May 2012 at the Wuzhishan State Atmosphere Background Monitoring Station (109°29′30.2″ E, 18°50′11.0″ N) located in Hainan Island. This station is an ideal site for monitoring long-range transport of atmospheric pollutants from mainland China and Southeast Asia to South China Sea. Annual average GEM concentration was 1.58 ± 0.71 ng m during the monitoring period, which was close to background values in the Northern Hemisphere. GEM concentrations showed a clear seasonal variation with relatively higher levels in autumn (1.86 ± 0.55 ng m) and winter (1.80 ± 0.62 ng m) and lower levels in spring (1.16 ± 0.45 ng m) and summer (1.43 ± 0.46 ng m). Long-range atmospheric transport dominated by monsoons was a dominant factor influencing the seasonal variations of GEM. The GEM diel trends were related to the wind speed and long-range atmospheric mercury transport. We observed 30 pollution episodes throughout the monitoring period. The analysis of wind direction and backward trajectory suggested that elevated GEM concentrations at the monitoring site were primarily related to the outflows of atmospheric Hg from mainland China and the Indochina peninsula. The △GEM/△CO values also suggested that GEM was significantly affected by the long-range transport from the anthropogenic sources and biomass burning in Asia and Indochina peninsula. [ABSTRACT FROM AUTHOR]

Coking is regarded as a major source of atmospheric polycyclic aromatic hydrocarbons (PAHs), but few researches have been conducted on the emission characteristics of PAHs from coke production. In this study, emissions of size-segregated particulate matter (PM) and particle-bound PAHs emitted from charging of coal (CC) and pushing of coke (PC) in four typical coke plants were determined. The emission factors on average, sums of CC and PC, were 4.65 mg/kg, 5.96 mg/kg, 19.18 μg/kg and 20.69 μg/kg of coal charged for PM 2.1 (≤ 2.1 μm), PM, PAHs in PM 2.1 and total-PAHs, respectively. PM and PAHs emission from plants using stamp charging were significantly more than those using top charging. The profile of PAHs in PM with size ≤ 1.4 μm (PM 1.4 ) emitted from CC process were similar with that from PC, however, it revealed obviously different tendency for PAHs in PM with size > 1.4 μm, indicating the different formation mechanism for coarse particles emitted from CC and PC. Size distributions of PM and PAHs indicated that they were primarily connected with PM 1.4 , and the contributions of PM 1.4 to PM and PAHs emitted from the plants using stamp charging were higher than those using top charging. Some improved technology in air-pollution control devices should be considered in coke production in future based on the considerable impacts of PM 1.4 and PAHs on human health and ambient air quality. [ABSTRACT FROM AUTHOR]

Short-chain chlorinated paraffins (SCCPs) are candidate persistent organic pollutants (POPs) that are under review by the Stockholm Convention. China is currently the largest producer and consumer of chlorinated paraffins (CPs). To study the environmental behavior and fate of SCCPs in the soils of urban and suburban regions, the SCCP concentrations in 88 topsoils and 15 soil columns from land of different use types (e.g., woodland, vegetable field, paddy field and greenbelt) from Guangzhou and Chengdu have been determined. The SCCP concentrations in topsoils from Guangzhou (range: 1.45–25.5 ng g − 1 dry weight (dw), average: 10.3 ng g − 1 dw) were much higher than those from Chengdu (range: 0.218–3.26 ng g − 1 dw, average: 1.43 ng g − 1 dw). When compared to previously reported SCCP levels for topsoils from other areas, the SCCP concentrations measured in the present work were quite low. Much higher SCCP concentrations were observed in the greenbelt topsoils from Chengdu relative to the values measured from woodlands and vegetable and paddy fields. The composition profiles suggest that C 10 Cl 6–10 and C 11–13 Cl 6–8 were the major groups of SCCPs in topsoils from the woodlands and vegetable and paddy fields in Guangzhou and Chengdu. Vertical variations of the SCCP concentrations in the soil columns suggest that less chlorinated SCCPs (Cl 5–6 -SCCPs) are more capable of migrating to the deeper-layer soils than more chlorinated ones (Cl 9–10 -SCCPs). The SCCP concentrations displayed little dependence on organic matter (OM) for most topsoils ( p > 0.05), indicating that OM is not the controlling factor in the distribution of SCCPs in the soils. Capsule This study analyzed the occurrence, homologue patterns and vertical migration of SCCPs in the topsoils of two Chinese cities with different industrial structures and climate conditions. [ABSTRACT FROM AUTHOR]

Abstract: Coking is one of the most important emission sources of polycyclic aromatic hydrocarbons (PAHs) in China. However, there is little information available on the emission characteristics of PAHs from fugitive emission during coking, especially on the specific processes dominating the gas–particle partitioning of PAHs. In this study, emission characteristics and gas–particle partitioning of PAHs from fugitive emission in four typical coke plants (CPs) with different scales and techniques were investigated. The average concentrations of total PAHs from fugitive emission at CP2, CP3 and CP4 (stamp charging) were 146.98, 31.82, and 35.20 μg m−3, which were 13.38-, 2.90- and 3.20-fold higher, respectively, than those at CP1 (top charging, 10.98 μg m−3). Low molecular weight PAHs with 2–3 rings made up 75.3% of the total PAHs on average, and the contributions of particulate PAH to the total BaP equivalent concentrations (BaPeq) in each plant were significantly higher than the corresponding contributions to the total PAH mass concentrations. The calculated total BaPeq concentrations varied from 0.19 to 10.86 μg m−3 with an average of 3.14 μg m−3, and more efficient measures to control fugitive emission in coke plants should be employed to prevent or reduce the health risk to workers. Absorption into organic matter dominated the gas–particle partitioning for most of the PAHs including PhA, FluA, Chr, BbF, BkF and BaP, while adsorption on elemental carbon appeared to play a dominant role for AcPy, AcP and Flu. [Copyright &y& Elsevier]

Abstract: The potential for Hg release during municipal solid waste incineration (MSWI) is attracting increased attention due to high volume of municipal waste being treated by incineration in China. Emission amounts have been estimated using emission factors developed for other countries. To fine tune our emission estimate total mercury (THg) and mercury speciation were measured using isokinetic sampling in eight plants, of which six used grate furnace combustor (GFC) and two circulation fluidized bed combustors (CFBCs). Results showed that average THg concentration (19.5±13.6μg/Nm3) in flue gas at the facilities that used CFBC was significantly lower than that at those using GFC (51.4±28.3μg/Nm3, p =0.002). Gaseous oxidized mercury (GOM), gaseous elemental mercury (GEM, Hg0), and particulate mercury (Hgp) represented 95.5±3.8%, 4.1±3.9% and 0.4±0.3% in GFC, and 63.8±8.6%, 33.6±10.5% and 2.6±1.9% in CFBC, respectively. The measured average THg emission factor for the 8 MSWI plants was 208±130mg/t in the Pearl River Delta (PRD) region, with 217±158mg/t and 188±17.7mg/t were from GFC and CFBC, respectively. Using the average emission factor the estimated total mercury emissions from MSWI were 4.67±2.91t in China, and 770±65.5kg in the PRD region in 2010. Of these, 4240±210kg, 408±231kg and 14.8±14.1kg, and 688±37kg, 78.9±40.6kg and 3.2±3.0kg were GOM, Hg0, and Hgp, respectively. Mercury emissions will continue to increase as the amounts of MSW being incinerated increases. [Copyright &y& Elsevier]

Twenty-one carbonyl compounds were measured simultaneously at four hotel ballrooms in urban Guangzhou during the autumn, 2002. In each ballroom, measurements were carried out in business hours in the evening (20:30–24:00) on 7 consecutive days without any disturbance of the ballroom''s normal operation. Nineteen out of the 21 target carbonyl compounds were identified in indoor and outdoor air. In the outdoor environment, formaldehyde was the most abundant carbonyl, followed by acetaldehyde, and there existed a strong correlation between formaldehyde and acetaldehyde. In the indoor air, however, acetaldehyde was the most abundant carbonyl, its concentrations seemed to be affected significantly by smoking. The indoor concentrations of carbonyls were found higher than their outdoor counterparts with only a few exceptions. Further studies concerning the indoor/outdoor ratios and mutual correlation of the carbonyls indicated that apart from direct emission from indoor materials and infiltration of outdoor air, other anthropogenic sources, e.g. tobacco smoke, also significantly contributed to carbonyl compounds. The possible sources of some high molecular weight carbonyls, e.g. nonanaldehyde, were also discussed briefly. Preliminary estimate of the exposures and risks due to carbonyls in the ballrooms was made, which indicated that long-term exposure in such places might cause increased chance of developing cancers. [Copyright &y& Elsevier]

The risk associated with human exposure to short-chain chlorinated paraffins (SCCPs) via dietary intake are of great concern because of the bioaccumulation potential of SCCPs in biota and adverse effects. Fish are an important food source for human beings. However, there is a paucity of studies on human exposure to SCCPs via fish consumption. In this study, SCCPs were measured in frequently consumed river fish from the Pearl River Delta, and farmed freshwater fish and wild sea fish from the Yangtze River Delta. Lipid-normalized SCCP levels in river fish ranged from 3000 to 41,000 ng/g lipid weight (lw), with an average of 16,000 ± 12,000 ng/g lw. SCCP concentrations in farmed fish were significantly lower than those in river fish (p < 0.05), but significantly higher than those in sea fish (p < 0.05). Homologue patterns of SCCPs in river fish, farmed fish and sea fish were similar, with C 10 - 11 Cl 6-7 SCCPs being the predominant homologues. SCCP concentrations in river fish increased significantly with increasing lipid content (p < 0.01), indicating that lipid content was a controlling factor influencing SCCP concentrations. Body length and weight also played important roles in SCCP concentrations in river fish, as SCCP concentrations decreased with the increase of body length and weight of breams, keeled mullets and tilapias. Although risk assessment implied no significant risk for human exposure to SCCPs via consuming fish collected in this study, the estimated daily intakes indicated that the consumption of sea fish was safer than farmed freshwater fish. • SCCP levels increased as sea fish < farmed freshwater fish < river fish. • C 10-11 Cl 6-7 SCCPs were the major homologues in different fish species. • SCCP levels in river fish were significantly correlated with lipid contents. • Body length, weight and trophic levels also affected SCCP levels in river fish. • Risk of human exposure to SCCPs via consumption of the fish studied was low. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are widespread in the environment and pose a serious threat to the soil ecosystem. In order to better understand the health risks for residents exposed to PAH-contaminated soil, 173 surface soil samples were collected in Shanxi Province, China, to detect the levels of 16 priority PAHs. The spatial distribution patterns of PAHs were explored using interpolation and spatial clustering analysis, and the probable sources of soil PAHs were identified for different land-use covers. The results indicate that the soil Σ16 PAH concentration ranged from 22.12 to 1337.82 ng g - 1 , with a mean of 224.21 ng g - 1 . The soils were weakly to moderately contaminated by high molecular weight PAHs (3-5 ring) and the Taiyuan-Linfen Basin was the most polluted areas. In addition, the concentration of soil PAHs on construction land was higher than that on other land-use covers. Key sources of soil PAHs were related to industrial activities dominated by coal burning, coking, and heavy traffic. Based on the exposure risk assessment of PAHs, more than 10% of the area was revealed to be likely to suffer from high carcinogenic risks for children. The study maps the high-risk distribution of soil PAHs in Shanxi Province and provides PAH pollution reduction strategies for policy makers to prevent adverse health risks to residents.

The continued development of the automotive industry has led to a rapid increase in the amount of waste rubber tires, the problem of "black pollution" has become more serious but is often ignored. In this study, the emission characteristics, health risks, and environmental effects of volatile organic compounds (VOCs) from a typical, recycled rubber plant were studied. A total of 15 samples were collected by summa canisters, and 100 VOC species were detected by the GC/MS-FID system. In this study, the total VOCs (TVOCs) concentration ranged from 1000 ± 99 to 19,700 ± 19,000 µg/m 3 , aromatics and alkanes were the predominant components, and m/p-xylene (14.63 ± 4.07%-48.87 ± 3.20%) could be possibly regarded as a VOCs emission marker. We also found that specific similarities and differences in VOCs emission characteristics in each process were affected by raw materials, production conditions, and process equipment. The assessment of health risks showed that devulcanizing and cooling had both non-carcinogenic and carcinogenic risks, yarding had carcinogenic risks, and open training and refining had potential carcinogenic risks. Moreover, m/p-xylene and benzene were the main non-carcinogenic species, while benzene, ethylbenzene, and carbon tetrachloride were the dominant risk compounds. In the evaluation results of L OH , m/p-xylene (25.26-67.87%) was identified as the most key individual species and should be prioritized for control. In conclusion, the research results will provide the necessary reference to standardize the measurement method of the VOCs source component spectrum and build a localized source component spectrum.

The quality of urban soil is closely related to the safety of public places and the guarantee of food quality. This study investigated the level, distribution, source, and carcinogenic risk of 16 U.S. EPA (Environmental Protection Agency) priority polycyclic aromatic hydrocarbons (PAHs) in urban, agricultural, and montane soil in Taiyuan. The ∑16PAHs level varied from 104.78 to 6594.63 ng g -1 with a mean of 922.93 ng g -1 , and 47.73% of the soil samples were severely contaminated, with a concentration higher than 600 ng g -1 . PAHs with higher molecular weight (≥4 rings) were dominant in PAHs profiles accounting for 80.92%. In the spatial distribution of PAHs, hotspots of ∑16 PAHs were observed near the industries, indicating pollutants emitted by the industries directly affect the surrounding soil quality. The sources identified by positive matrix factorization (PMF) indicated: coal combustion (40.77%), vehicle exhausts (32.94%), biomass combustion (14.89%), and coking source (11.40%). Coal-related sources (coal and coking sources) were the major contributors (52.17%) to PAHs and carcinogenic risk (46.48%) assessed by BaP toxic equivalent concentration in total soils. Therefore, the extensive usage of coal was the leading factor for PAH pollution and health risk in Taiyuan soil.

Short-chain chlorinated paraffins (SCCPs) are a series of new persistent organic pollutants, posing a risk of significant adverse effects to biota. Increasing attention has been paid to SCCP pollution in China as large amounts of chlorinated paraffin (CP) products containing SCCPs have been produced and used there. However, knowledge of the bioaccumulation of SCCPs in marine organisms from the Pearl River Estuary (PRE), Southern China, is still scarce. In this study, SCCP concentrations were measured in seawater, sediments, and marine organisms from the PRE. SCCP concentrations ranged from 180 to 460 ng/L in seawater, from 180 to 620 ng/g dry weight (dw) in sediments, and from 870 to 36,000 ng/g lipid weight (lw) in marine biota samples. C 10-11 SCCPs were the predominant homologues in all the samples, with an average abundance of 68% in seawater, 57% in sediments, and 56-77% in marine organisms. However, chlorine patterns of SCCPs in seawater, sediments, and marine organisms were different. Cl 8-10 SCCPs dominated in sediments, whereas Cl 5-7 SCCPs were the predominant SCCP homologues in water and most organism species. The logarithm bioaccumulation factors (BAFs) of SCCPs ranged from 1.6 to 3.0, and increased significantly with the increase of K ow values for most marine biota species, indicating that K ow was the major factor controlling the bioaccumulation of SCCPs and that SCCPs with higher lipophilicity were more prone to being bioaccumulated from water. Opposite to that observed for log BAFs, biota-sediment accumulation factors of specific SCCPs (range: 0.01-30) decreased significantly with the increase of K ow values. The biomagnification factor of total SCCPs for oyster-mangrove crab was 2.40, implying the potential biomagnification of SCCPs for benthos in the PRE., (Copyright © 2019 Elsevier B.V. All rights reserved.)

China is the largest coke producer and exporter in the world, and it has been a major concern that large populations of coke workers are exposed to the associated air pollutants such as volatile organic compounds (VOCs). This study aimed to preliminarily quantify the potential exposure to VOCs emitted from two representative coking plants and assess the potential health risks. Air samples from various stages of coking were collected from the topside of coke ovens and various plant areas and then analyzed for benzene, toluene, ethylbenzene, and xylene (BTEX). The time-weighted average (TWA) concentrations were used to quantify the coke oven emission (COE). The TWA concentrations for benzene were 705.6 and 290.4 μg m(-3) in plant A and plant B, respectively, which showed a higher exposure level than those reported in other countries. COE varied on the topside of coke ovens during charging and pushing processes, from 268.3 to 1197.7 μg m(-3) in plant A and 85.4-489.7 μg m(-3) in plant B. Our results indicate that benzene exposure from the diffusion of tar distillation also exerts significant health risks and thus should also be concerned. Charging and pushing activities accounted for nearly 70 % of benzene dose at the topside, and the benzene exposure risks to the coke oven workers in China were higher than those reported by US EPA. Compared to the reported emission sources, the weight-based ratios of average benzene to toluene, ethylbenzene, and xylene in different COE air samples showed unique characteristic profiles. Based on the B/T ratios from this work and from literatures on several major cities in northern China, it was evident that COE contributes significantly to the severe pollution of VOCs in the air of northern China. Future more rigorous studies are warranted to characterize VOC emission profiles in the stack gas of the coking processes in China.