[High Resolution Emission Inventory of Greenhouse Gas and Its Characteristics in Guangdong，China].

Based on the typical city survey data and statistics of Guangdong Province， a 2018-based 3 km×3 km gridded greenhouse gas emissions inventory was developed for Guangdong Province using the combination of top-down and bottom-up emission factor methods. The inventory covered the CO2， CH4， and N2O emissions from energy， industrial processes， agriculture， land use change and forest， waste management， and indirect sources. The results showed that estimates for CO2， CH4， and N2O in Guangdong Province for the year 2018 were 8.5×108， 1.9×106， and 1.1×105 t， respectively， and 8.5×108， 4.0×107， and 3.4×107 t by equivalent carbon dioxide， totaling 9.2×108 t. CO2 was the main greenhouse gas in Guangdong Province， accounting for 92.0% of the total emissions. Energy and indirect sources were the main emission sources， accounting for 77.9% and 7.6%， respectively， totaling 85.5%. Spatial distributions illustrated that most grids were greenhouse gas emissions， whereas some others were greenhouse gas sinks； the greenhouse gas emissions were distributed mainly in the Pearl River Delta region and had certain characteristics of distribution along the road network and channels. The greenhouse gas grids of high emission were mainly the locations of high energy-consuming enterprises such as large power plants， steel mills， and cement plants.

[Emission Trends and Reduction Potential of VOCs from Printing Industry in China].

The printing industry has always been the key source of volatile organic compound(VOC) emissions in China. However, owing to the complexity of raw materials and processes, the fine emission inventory and its future emission reduction potential of VOCs from the printing industry have not been well characterized. In this study, the existing VOCs emission factors of the printing industry were improved, considering the neglected semi/intermediate VOCs(S/IVOCs). An emissions inventory of VOCs from the printing industry in the period of 2011-2020 in China was compiled. Through scenario analysis, the emission of VOCs under different scenarios in 2030 was predicted, and the emission reduction potential was analyzed. VOCs emissions from the printing industry in China increased first and then decreased in the period of 2011-2020. Compared with that in 2011, VOCs emissions increased by 29.6% in 2020, with an average annual growth rate of 3.0%. This was mainly due to the increasing consumption demand in the printing industry market and the lack of effective measures for integrated management of VOCs. The VOCs emission of the printing industry in China in 2020 was 861 Gg. Gravure printing and packaging processing were the two most important processes, accounting for 52.0% and 28.7%, respectively. Guangdong, Jiangsu, and Zhejiang were the largest contributors to VOC emissions, accounting for 44.12% of the total emissions. VOCs emissions of the printing industry in 2030 were 1187 Gg, 684 Gg, and 362 Gg for the baseline scenario, the general control scenario, and the strict control scenario, respectively. Compared to that in 2020, emissions under different control scenarios in 2030 increased by 37.9% and decreased by 20.6% and 57.9%, respectively. Gravure printing and packaging processing are still the focus of emission reduction.

[Characteristics and Health Risk Assessment of Volatile Organic Compounds in Different Functional Zones in Baoji in Summer].

The situation of air pollution in Guanzhong Plain has been increasing in recent years; hence, it is very important to study the characteristics of volatile organic compounds (VOCs) and their health risks in urban functional zones. We analyzed 115 VOCs using gas chromatography-mass spectrometry/hydrogen ion flame detector (GC-MS/FID) and high performance liquid chromatography (HPLC) at four sampling sites in the traffic, comprehensive, industrial, and scenic zones of Baoji. We analyzed the main components and key species in the different functional zones. Ozone formation potential (OFP),·OH consumption rate (L·OH), and secondary organic aerosol formation potential (SOAFP) were used to evaluate the environmental impact, and the hazard index (HI) and lifetime cancer risk (LCR) methods were employed. The results revealed that the mean values of φ(TVOCs) in the traffic, comprehensive, industrial, and scenic zones were (59.63±23.85)×10-9, (42.92±11.88)×10-9, (60.27±24.09)×10-9, and (55.54±7.44)×10-9, respectively. The dominant contributors at the traffic zone were alkanes, and those at the other functional zones were OVOCs. Acetaldehyde, acetone, n-butane, and isopentane were abundant at different functional zones. According to the characteristic ratios of VOCs, the average ratio of toluene to benzene (T/B) at the traffic, comprehensive, industrial, and scenic zones were 1.84, 2.39, 1.28, and 1.64, respectively, and the ratio of iso-pentane to n-pentane (i/n) was mainly between 1 and 4. The results indicated that VOCs in Baoji were significantly affected by vehicle emissions and gasoline evaporation, biomass and coal combustion, and industrial coatings and foundry. The ratio of m/p-xylene to ethylbenzene (X/E) was lower than 2 at the four functional zones, and the minimum was 1.79 at the scenic zones; the results revealed that X/E was small, and the aging degree of air masses was high, indicating the influence of regional transport. According to the ratio of formaldehyde to acetaldehyde (C1/C2) and the ratio of acetaldehyde to propanal (C2/C3), it was suggested that there may have been evident anthropogenic emission sources, and the photochemical reaction had an important effect on aldehydes and ketones. Environmental impact assessment results revealed that OVOCs and alkenes contributed significantly to OFP and OFP from large to small was as follows:industrial zone>scenic zone>traffic zone>comprehensive zone. The range of L·OH in each functional zone was 8.77-15.82 s-1, with isoprene contributing the most in the industrial zone and acetaldehyde contributing the most at other functional zones. The SOAFP of each functional zone was as follows:scenic zone>comprehensive zone>traffic zone>industrial zone. Toluene, m/p-xylene, and isoprene were the notable species. According to the health risk assessment of EPA, the HI of toxic VOCs in all functional zones was lower than 1, which was at an acceptable level. However, the number of days with HI>1 in industrial zones accounted for 42.86% of the total sampling days, indicating a high risk. The lifetime carcinogenic risk (LCR) of the traffic, comprehensive, industrial, and scenic zones were 1.83×10-5, 1.21×10-5, 1.85×10-5, and 1.63×10-5, respectively, which were all in grade Ⅲ of the rating system, indicating a high probability of cancer risk. Species with LCR greater than 10-6 were formaldehyde; acetaldehyde; 1,2-dibromoethane; 1,2-dichloroethane; 1,2-dichloropropane; and chloroform.

Calculated cancer risks for polycyclic aromatic hydrocarbon mixtures in mainstream smoke of cigarettes sold in China.

China is the world's largest consumer of cigarettes. However, the potential cancer risk posed by polycyclic aromatic hydrocarbons (PAHs) in mainstream cigarette smoke, especially species other than benzo[a]pyrene (BaP) remains unclear. In this study, we collected yield data on multiple PAH species from a variety of cigarettes in the China market and calculated their smoking-related incremental lifetime cancer risk (ILCR) values. The computed ILCRs of the total PAHs (ILCRΣPAHs) for ≥95% of the brands were one order of magnitude higher than the acceptable level. ILCRBaP accounted for only 5.0%-37.7% of ILCRΣPAHs among brands, indicating that using single analyte BaP to represent ΣPAHs would significantly underestimate ILCRΣPAHs. No clear trend of changes in ILCRΣPAHs was found for Chinese cigarettes over multiple years, suggesting that smoking cessation is still the best option to minimize the cancer risk of PAHs. The comparison study showed that rarely reported PAHs from Chinese cigarettes can contribute over half of ILCRΣPAHs for several American cigarettes, highlighting the imperativeness to improve the diversity of analytes for Chinese cigarettes. Adults would need to inhale the air-borne PAHs with a BaP equivalent concentration of at least 53.1 ng/m3 to reach the ILCR value comparable to that obtained from smoking.

[Characteristics and Source Apportionment of Volatile Organic Compounds in Zhanjiang in Summer].

Ozone pollution is intensifying in China, and its related studies are weak in non-focus regions and non-focus cities. Here, we investigated the characteristics and sources of volatile organic compounds (VOCs) at three sampling sites in Zhanjiang. We analyzed 101 VOCs using a gas chromatography-mass spectrometry/hydrogen ion flame detector (GC-MS/FID) and high-performance liquid chromatography (HPLC) using a Summa canister and DNPH adsorption tube. We calculated the ozone formation potential (OFP) of VOCs and used the positive matrix factorization (PMF) model for source apportionment. The results showed that the mean φ(TVOCs) was 1.28×10-7, and the dominant contributors were OVOCs (52%), followed by alkanes (36%), alkenes (7%), halogenated hydrocarbons (2.42%), aromatic hydrocarbons (1.61%), and alkynes (0.78%). The diurnal variation in VOCs was influenced by photochemical reactions; the ratio of aromatic hydrocarbons and alkanes was high in the morning and evening and low at noon, whereas OVOCs had a low ratio in the morning and noon and high in the evening, influenced by primary emissions and the upwind transport of pollutants. The OFP was 3.28×10-7, and the dominant species were formaldehyde, butene, n-butane, butanone, and acetaldehyde.The analysis of X/E values (characterizing the aging degree of air masses) and backward trajectories of air masses showed that during the sampling, when influenced by air masses from the south or southwest, X/E was small, and the aging degree of air masses was high, indicating the influence of regional transport; when influenced by air masses from the east or southeast direction, X/E was large, and the air masses were fresh, and VOCs were mainly from local emissions. Six emission sources of VOCs, including industrial emissions, gasoline vehicle exhaust and gasoline evaporation, regional background and transport sources, biomass combustion, diesel vehicles and marine shipping emissions, and solvent use emission sources, were resolved using the PMF model, with contributions of 36.05%, 28.99%, 13.84%, 10.13%, 7.05%, and 3.95%, respectively.Zhanjiang should strengthen the supervision of formaldehyde, butene, n-butane and butanone, industry sources, and mobile sources as the focus of control.

A comprehensive approach to quantify the source identification and human health risk assessment of toxic elements in park dust.

In this research, enrichment factor (EF) and pollution load index were utilized to explore the contamination characteristics of toxic elements (TEs) in park dust. The results exhibited that park dust in the study area was mainly moderately polluted, and the EF values of dust Cd, Zn, Pb, Cu and Sb were all > 1. The concentrations of Cr, Cu, Zn and Pb increased with the decrease of dust particle size. The investigation results of chemical speciation and bioavailability of TEs showed that Zn had the highest bioavailability. Three sources of TEs were determined by positive matrix factorization model, Pearson correlation analysis and geostatistical analysis, comprising factor 1 mixed sources of industrial and transportation activities (46.62%), factor 2 natural source (25.56%) and factor 3 mixed source of agricultural activities and the aging of park infrastructures (27.82%). Potential ecological risk (PER) and human health risk (HHR) models based on source apportionment were exploited to estimate PER and HHR of TEs from different sources. The mean PER value of TEs in the park dust was 114, indicating that ecological risk in the study area was relatively high. Factor 1 contributed the most to PER, and the pollution of Cd was the most serious. There were no significant carcinogenic and non-carcinogenic risks for children and adults in the study area. And factor 3 was the biggest source of non-carcinogenic risk, and As, Cr and Pb were the chief contributor to non-carcinogenic risk. The primary source of carcinogenic risk was factor 2, and Cr was the cardinal cancer risk element.

Characteristics of Soil Heavy Metal Pollution and Health Risk Assessment in Urban Parks at a Megacity of Central China.

In this study, we compared the concentrations of the heavy metals Cd, Cr, Cu, Zn, Ni, and Pb in the surface soils of urban parks in Wuhan, Hubei Province, with those in the surface soils of urban parks worldwide. The soil contamination data were assessed using enrichment factors and spatial analysis of heavy metals using inverse distance weighting and quantitative analysis of heavy metal sources with a positive definite matrix factor (PMF) receptor model. Further, a probabilistic health risk assessment of children and adults using Monte Carlo simulation was performed. The average Cd, Cr, Cu, Zn, Ni, and Pb concentrations in the surface soils of urban parks were 2.52, 58.74, 31.39, 186.28, 27.00, and 34.89 mg·kg-1, respectively, which exceeded the average soil background values in Hubei. From the inverse distance spatial interpolation map, heavy metal contamination was primarily observed to be present to the southwest of the main urban area. The PMF model resolved four sources: mixed traffic and industrial emission, natural, agricultural, and traffic sources, with relative contributions of 23.9%, 19.3%, 23.4%, and 33.4%, respectively. The Monte Carlo health risk evaluation model demonstrated negligible noncancer risks for both adult and child populations, whereas the health effects of Cd and Cr on children were a concern for cancer risks.

Improved emission factors and speciation to characterize VOC emissions in the printing industry in China.

Printing industry is one of the most important sources of industrial volatile organic compound (VOC) emissions in China, and is thus a key industrial sector in terms of VOC control. However, process-based VOC emission and speciation from the printing industry have not been well identified, mainly owing to the poor emission factors (EFs) and diversity of source profiles. In this study, we systematically characterized process-based VOC emissions from the printing industry for the period of 2010-2019, through the establishment of improved emission factors and composite source profiles. VOC emissions from the printing industry were found to continuously increase from 2010 to 2018, reaching their maximum in 2018 at 939.8 Gg, but started to decrease afterwards. The substantial growth is driven by the large demand for ink and adhesive and the absence of effective control measures in the printing industry. The total VOC emissions and ozone formation potential (OFP) in China in 2019 were 916.1 Gg and 1834.5 Gg, respectively. Gravure printing and the compound process were the processes that contributed the most to both emissions and OFP. Rapidly developing provinces such as Guangdong, Jiangsu, and Zhejiang were the largest contributors to emissions. Oxygenated VOCs (OVOCs) accounted for most of the VOC emissions, followed by alkanes and aromatics, while aromatics were the dominant groups for total OFP, followed by alkenes/alkynes and OVOCs. Ethyl acetate, toluene, isopropanol, isopentane, and n-pentane were the top five VOC species in terms of emissions, while toluene, ethyl acetate, 1,3-butadiene, isopentane, and 1-butene were the top five species in terms of OFP. Scientific and precise control policy were proposed, involving four aspects: environmental access, emission standards, classification and management, and research on source substitution. We believe our study will provide an important reference for the systematic characterization and control policy of VOC emissions from other industries.

Research progress on microplastics in wastewater treatment plants: A holistic review.

Wastewater treatment plants (WWTPs) discharge metric tons of microplastics (MPs) daily to aquatic and terrestrial environments worldwide. Herein we provide a holistic review on MPs in the WWTPs, highlighting recent advances in sampling and analysis, improved understanding of their sources, occurrence, and degradation in treatment steps, and the potential risks MPs pose after being discharged in treated effluent and sludge. We discuss the merits and limitations of the various sampling and analytical approaches to determine MPs in major WWTP compartments; highlight new research on MP profiles (abundance, physical characteristics, and compositions) in raw sewage, treated effluent, and waste sludge, which are of particular interest when assessing MP sources, removal rates, and fate; and emphasize mechanisms of MP fragmentation and degradation within WWTPs as well as the potential sorption of wastewater contaminants to the MPs. We find that robust and standardized methods for determining MPs in WWTP samples is still urgently needed, and that complete removal of MPs from wastewater by WWTPs is not guaranteed, although the vast majority of MPs end up in sludge. Areas of research that deserve further attention include the fate of small (<20 µm) MPs, abiotic and biotic fragmentation of MPs in the WWTPs, and more empirical data with concentrations on a mass basis.

Carbonyls from commercial, canteen and residential cooking activities as crucial components of VOC emissions in China.

Cooking in China supply the large population with nutrition and, as a commercial activity, it also promotes the economic growth of Chinese society. The specific cooking styles in China can produce complex volatile organic compound (VOC) emissions. The resulting adverse effects on the environment and human health of carbonyls from cooking should not be ignored. We quantitatively evaluated the contribution of carbonyls to common VOCs (carbonyl/VOC ratio) from cooking activities in China through the establishment and comparison of the source profiles, emission factors (EFs), emission amount and ozone formation potential (OFP). It was found that carbonyls are crucial components of VOCs from commercial, canteen and residential cooking activities (COC, CAC and REC, respectively). The carbonyl/VOC ratio from cooking activities in China had EFs, emissions, and a total OFP of 22-65 %, 23-34 %, and 49-104 %, respectively. The high OFP was due to the high OFP emissions intensity (OFPEI) and maximum incremental reactivity (MIR) values of carbonyls. This indicates that to alleviate O3 pollution, OFP-based control measures that target carbonyls might be more efficient than measures that target common VOCs. Priority should be given to emission controlling COC emissions, specifically those from medium- and large-scale catering. Formaldehyde, acetaldehyde, and hexanal were the key carbonyl species that form O3 in the environment. Our findings imply that cooking-emitted carbonyls should not be overlooked in investigations of O3 formation and that these compounds should be subject to strict regulations.

[Effects of Tropical Cyclones on Ozone Pollution in the Pearl River Delta in Autumn].

Based on the tropical cyclone track data in the northwest Pacific Ocean from 2015 to 2020, meteorological observation data, and ozone concentration monitoring data in the Pearl River Delta (PRD), the impacts of four tropical cyclones, namely the westbound tropical cyclone (type A), East China Sea tropical cyclone (type B), offshore tropical cyclone (type C), and offshore tropical cyclone (type D), on ozone concentration in the PRD were analyzed. The results showed that:under the influence of the type A tropical cyclone, the risk of regional ozone concentration exceeding the standard exhibited little change. Under the influence of the type B tropical cyclone, the risk of ozone exceeding the standard in the PRD was obviously increased. Under the influence of the type C tropical cyclone, the risk of regional ozone exceeding the standard obviously increased, but the increase was weaker than that of the type B tropical cyclone. The type D tropical cyclone was far away from the Chinese mainland and had little influence on ozone concentration in the PRD. When the type A or type C tropical cyclones occurred, the average daily maximum 8-hour average ozone concentration (MDA8) in the PRD region increased by approximately 5 µg·m-3, and the ozone MDA8 in some cities may have decreased. When the type B tropical cyclone occurred, the regional ozone MDA8 increased by 19 µg·m-3 on average, and the ozone concentration in all cities increased significantly. Among them, the average increase in ozone MDA8 in Zhuhai and Jiangmen was relatively large, with an increase of greater than 20 µg·m-3. Generally speaking, the ozone concentration in cities in the western PRD was more affected by tropical cyclones. When the type B tropical cyclone occurred, solar radiation increased, sunshine duration lengthened, cloud cover decreased, air temperature rose, and relative humidity decreased in the PRD, all of which were beneficial to photochemical reactions. Meanwhile, downward flow increased in the boundary layer, and downward flow transported high-concentration ozone to the ground, which promoted the increase in ozone concentration on the ground. When type A or type C tropical cyclones occurred, the change in meteorological conditions was not entirely conducive to the increase in ozone concentration, and in some cases, even adverse meteorological conditions such as rainfall occurred, which led to the risk of regional ozone exceeding the standard being less than that of the type B tropical cyclone. Affected by tropical cyclones, sunshine hours and air temperature in western cities of the PRD increased more than those in eastern cities, which was more conducive to ozone generation.

Trophic transfer of methylmercury and brominated flame retardants in adjacent riparian and aquatic food webs: 13C indicates biotransport of contaminants through food webs.

Biomagnification of persistent toxic substances (PTSs) in food chains is of environmental concern, but studies on biotransport of PTSs across aquatic and riparian food chains are still incomplete. In this study, biomagnification of several PTSs including methylmercury (MeHg), polybrominated diphenyl ethers (PBDEs), and 1,2-bis (2,4,6-tribromophenoxy) ethane (BTBPE) was investigated in adjacent aquatic and riparian food webs. Concentrations of MeHg and PBDEs ranged from 2.37 to 353 ng/g dry weight (dw) and not detected (Nd) to 65.1 ng/g lipid weight (lw) in riparian samples, respectively, and ranged from Nd to 705 ng/g dw and Nd to 187 ng/g lw in aquatic samples, respectively. Concentrations of MeHg were significantly correlated with δ13C (p < 0.01) rather than δ15N (p > 0.05) values in riparian organisms, while a significant correlation was observed between concentrations of MeHg and δ15N (p < 0.01) in aquatic organisms. Biomagnification factors (BMFs) and trophic magnification factors (TMFs) of PBDE congeners were similar in riparian and aquatic food webs, while BMFs and TMFs of MeHg were much higher in aquatic food web than those in riparian food web. The results indicate the biotransport of MeHg from aquatic insects to terrestrial birds, and δ13C can be a promising ecological indicator for biotransport of pollutants across ecosystems.

A comprehensive exploration on the health risk quantification assessment of soil potentially toxic elements from different sources around large-scale smelting area.

Non-ferrous metal smelting activities have always been considered as one of the foremost anthropogenic sources of potentially toxic elements (PTEs). The enrichment factor (EF) and pollution load index (PLI) were used to evaluate the pollution level of soil PTEs; positive matrix factorization (PMF), correlation analysis, and geostatistics were utilized to quantify the sources of soil PTEs; and potential ecological risk (PER) and human health risk (HHR) of different sources from farmland, construction land, and natural land were quantifiably determined via combined PTE sources with PER and HHR assessment models. Taking the smelting area of Daye City as an example, the evaluation results of EF and PLI showed that the soil PTE pollution in the study area was serious, especially Cd and Cu. And four sources were quantitatively allocated as agricultural practices (12.14%), traffic emissions (23.07%), natural sources (33.46%), and industrial activities (31.33%). For PER, industrial activities were the largest contributor to PER, accounting for 55.66%, 56.30%, and 55.36% of farmland, construction land, and natural land, respectively, and Cd was the most dangerous element. In terms of HHR, industrial activities were also the cardinal contributors under the three land use types. Children were exposed to serious non-carcinogenic risks under three land use patterns and slight carcinogenic risk in construction land (1.06E - 04). Significantly, the carcinogenic risk of children in farmland (9.06 × 10-5) was very close to the threshold (1 × 10-4), which requires attention. Both non-carcinogenic and carcinogenic risk for adults were all at acceptable levels. The health risks (carcinogenic and non-carcinogenic risks) of children from four different sources were distinctly higher than those of adults. Consequently, strict management and control of industrial activities should be given priority, and the management of agricultural practices should not be ignored.

External Exposure to BTEX, Internal Biomarker Response, and Health Risk Assessment of Nonoccupational Populations near a Coking Plant in Southwest China.

Benzene, toluene, ethylbenzene and xylene isomers (BTEX) have raised increasing concern due to their adverse effects on human health. In this study, a coking factory and four communities nearby were selected as the research area. Atmospheric BTEX samples were collected and determined by a preconcentrator GC-MS method. Four biomarkers in the morning urine samples of 174 participants from the communities were measured by LC-MS. The health risks of BTEX exposure via inhalation were estimated. This study aimed to investigate the influence of external BTEX exposure on the internal biomarker levels and quantitatively evaluate the health risk of populations near the coking industry. The results showed that the average total BTEX concentration in residential area was 7.17 ± 7.24 µg m-3. Trans,trans-muconic acid (T,T-MA) was the urinary biomarker with the greatest average level (127 ± 285 µg g-1 crt). Similar spatial trends can be observed between atmospheric benzene concentration and internal biomarker levels. The mean values of the LCR for male and female residents were 2.15 × 10-5 and 2.05 × 10-5, respectively. The results of the risk assessment indicated that special attention was required for the non-occupational residents around the area.

Bioaccumulation and translocation of organophosphate esters in a Mangrove Nature Reserve from the Pearl River Estuary, South China.

Little is known about the distribution and bioaccumulation of organophosphate esters (OPEs) in mangrove ecosystems. In this study, water, sediments, plants and animals were collected from Qi'ao Island Mangrove Nature Reserve to investigate the levels, bioaccumulation and biomagnification of OPEs. Concentrations of ΣOPEs in the mangrove plant Sonneratia apetala (an exotic species) were greater than those in Kandelia obovata (a native species). Translocation factors of OPEs in the two mangrove tree species were greater than 1, indicating that OPEs were mainly absorbed in aboveground tissues. Concentrations of OPEs in mangrove trees and animals were negatively correlated with their log Kow, suggesting that accumulation of OPEs in mangrove biota was influenced by hydrophobicity. A significant difference for concentrations of ΣOPEs was found among the eight mangrove animal species. Concentrations of ΣOPEs in mangrove animals were related with lipid contents, feeding habits and Kow of OPEs. Biota-sediment accumulation factor of OPEs was larger than 1, suggesting that bioaccumulation of OPEs occurred in mangrove animals. The targeted OPEs except isodecyl diphenyl phosphate were not biomagnified in mangrove animals. This study highlights bioaccumulation of OPEs in mangrove biota and suggests further concern about the ecological risk of OPEs to mangrove biota.

[Volatile Organic Compounds(VOCs) Emission Inventory from Domestic Sources in China].

A volatile organic compounds(VOCs) emission source classification and accounting system from domestic sources in China was established for the period between 2010 and 2018. Suggestions for the prevention and treatment of VOCs from domestic sources were developed and proposed. The results showed that the total VOCs emission inventory from domestic sources in China in 2018 was 2518 kt. Architectural decoration, asphalt road paving, cooking, and rural household biomass use source were the four largest contributors, accounting for 69.22% of the total emissions. Chemical household products and urban and rural coal use contributed equally, accounting for 10.43% and 9.98%, respectively, whilst car repair accounted for 7.75%. Shandong, Sichuan, Henan, Guangdong, Jiangsu, and Hebei were the six provinces that contributed the most(36.01%). During the 2010-2018 period, China's domestic VOCs emissions increased at a rate of 0.43%, and after reaching a peak in 2013, the emissions began to decline at a rate of 2.23%. The reason for the decline was that, on the one hand, the cleaner energy consumption of residents made a contribution to the gradual reduction of domestic coal and biomass consumption. On the other hand, the gradual saturation of housing construction in some areas, which led to a decrease in the annual construction of the country. It is recommended to promote the comprehensive management of architectural decoration, cooking methods, and car repair, while paying attention to the VOCs emissions from asphalt road paving. Meanwhile, continue to optimize the energy use structure of domestic sources, and promote the pollution control of civil coal and household biomass combustion in accordance with local regulations and multiple measures.

Emission-to-ash detoxification mechanisms of co-combustion of spent pot lining and pulverized coal.

In response to the global initiative for greenhouse gas emission reduction, the co-combustion of coal and spent pot lining (SPL) may cost-effectively minimize waste streams and environmental risks. This study aimed to quantify the emission-to-ash detoxification mechanisms of the co-combustion of SPL and pulverized coal (PC) and their kinetics, gas emission, fluorine-leaching toxicity, mineral phases, and migrations. The main reaction covered the ranges of 335-540 °C and 540-870 °C while the interactions occurred at 360-780 °C. The apparent activation energy minimized (66.99 kJ/mol) with 90% PC addition. The rising PC fraction weakened the peak intensity of NaF and strengthened that of Ca2F, NaAlSiO4, and NaAlSi2O6. The addition of PC enhanced the combustion efficiency of SPL and raised the melting temperature by capturing Na. PC exhibited a positive effect on solidifying water-soluble fluorine and stabilizing alkali and alkaline earth metals. The leaching fluorine concentrations of the co-combustion ashes were lower than did SPL mono-combustion. The main gases emitted were HF, NH3, NOx, CO, and CO2. HF was largely released at above 800 °C. Multivariate Gaussian process model-based optimization of the operational conditions also verified the gas emissions results. Our study synchronizes the utilization and detoxification of SPL though co-combustion and provides insights into an eco-friendlier life-cycle control on the waste-to-energy conversion.

A comprehensive exploration on pollution characteristics and health risks of potentially toxic elements in indoor dust from a large Cu smelting area, Central China.

Large-scale smelting activities release large amounts of potentially toxic elements (PTEs) in fine particles. These particles floating in the air eventually settle on leaves, roads, and even indoors. In smelting areas, indoor environments are generally considered relatively safe. However, these areas are not taken seriously and need to be assessed. This paper systematically studied pollution characteristics, main sources and health risks of ten potentially toxic elements, PTEs (Mn, Ni, Cu, Zn, Hg, Cd, As, Cr, Pb, and Tl), of dust samples from different indoor environments in smelting areas using various methods. Therefore, this study analyzed dust samples from 35 indoor environments. The enrichment factors showed that the indoor dust samples were extremely enriched by Cd and Cu and significantly enriched by Hg, Pb, As, and Zn. The result of the spatial distribution showed that the high-value PTEs were mainly distributed near the Cu smeltery. Three sources were quantitatively assigned for these PTEs, and they were industrial smelting and traffic activities (44.40%), coal-fired activities (18.11%), and natural existence (37.49%). Based on the calculation of health risk, the value of THI for children was 7.57, indicating a significant non-carcinogenic risk. For carcinogenic risk, the values of TCR for children and adults were 2.91×10-2 and 2.97×10-3, respectively, which were much higher than the acceptable risk value 1×10-4. Combining health risk assessment with source discrimination, we found that the industrial discharges and traffic activities were the most main source of non-cancer and cancer risks. Therefore, smelting activities should be more strictly monitored, and traffic emission management should be strengthened.

Multiple drivers, interaction effects, and trade-offs of efficient and cleaner combustion of torrefied water hyacinth.

Developing cleaner and affordable alternatives to the sole reliance on fossil fuels has intensified efforts to improve the thermochemical conversion property of the second-generation lignocellulosic biomass. This study aimed to explore the effects of the two torrefaction temperatures (200 and 300 °C), the two reaction atmospheres (N2/O2 and CO2/O2), and the three heating rates (5, 10, and 15 °C/min) on the combustion regime of water hyacinth (WH). Decomposition behaviors, reaction kinetics, thermodynamics, and mechanisms, evolved emissions and functional groups, and fuel microstructure properties were quantified. The deoxygenation and dehydration reactions acted as the main drivers of the torrefaction process, with the peak degree of deoxygenation of 86.21% for WH torrefied at 300 °C (WH300). WH300 significantly reduced the quantity of oxygen-containing functional groups and altered the fuel microstructure properties. The order of the decomposition rates of the pseudo-components were hemicellulose > cellulose > lignin for both WH and WH torrefied at 200 °C (WH200) and cellulose > lignin > hemicellulose for WH300. The average activation energy fell from 197.71 to 195.71 kJ/mol for WH, 287.90 to 195.97 kJ/mol for WH200, and 226.92 to 184.94 kJ/mol for WH300 when the atmosphere changed from N2/O2 to CO2/O2. The heating rate exerted a stronger control on their combustion behaviors than did the reaction atmosphere. CO2, NO, and NO2 emissions dropped by 46.0, 53.1, and 65.9% for WH200 and 29.6, 42.8, and 62.5% for WH300, respectively, when compared to WH. 473.7 °C, 5 °C/min, and the CO2/O2 atmosphere were the optimal settings for the maximized combustion efficiency. 717.1 °C was determined as the optimal setting for the minimized combustion emissions. Our study can yield new insights into the large-scale and cleaner combustion of the torrefied water hyacinth.

Spatially Resolved Emission Factors to Reduce Uncertainties in Air Pollutant Emission Estimates from the Residential Sector.

The residential sector is a major source of air pollutant emission inventory uncertainties. A nationwide field emission measurement campaign was conducted in rural China to evaluate the variabilities of realistic emission factors (EFs) from indoor solid fuel combustion. For a total of 1313 burning events, the overall average EFs (±standard deviation) of PM2.5 were 8.93 ± 6.95 and 7.33 ± 9.01 g/kg for biomass and coals, respectively, and 89.3 ± 51.2 and 114 ± 87 g/kg for CO. Higher EFs were found from burning of uncompressed straws, while lower EFs were found from processed biomass pellets, coal briquettes, and relatively clean anthracite coals. Modified combustion efficiency was found to be the most significant factor associated with variations in CO EFs, whereas for PM2.5, fuel and stove differences determined its variations. Weak correlations between PM2.5 and CO indicated high uncertainties in using CO as a surrogate for PM2.5. EFs accurately fit log-normal distributions, and obvious spatial heterogeneity was observed attributed to different fuel-stove combinations across the country. Emission estimation variabilities, which are determined by the interquartile ranges divided by the median values, were notably reduced when spatially resolved EFs were adopted in the inventory.