Characteristics and Source Apportionment of Volatile Organic Compounds in a Coastal Industrial Area: A Case Study in the Yangtze River Delta of China.

In recent years, the coastal area in East China has experienced elevated volatile organic compounds (VOCs) levels during specific periods. VOCs have become one of the major atmospheric pollutants in these areas. In this study, 64 compounds including alkanes, alkenes, halohydrocarbons, aromatics, and oxygenated VOCs (OVOCs) were obtained by the TO-15 method through a 12-month campaign in industrial, urban and suburban areas in the Yangtze River Delta of China. The overall trends of total VOC (TVOC) concentrations at eight sampling sites were as follows: winter > autumn > spring > summer. The proportion of VOC categories was various at industrial sites, while OVOCs and halohydrocarbons had high proportions at urban sites and suburban sites, respectively. Coating, vehicle emission, petrochemical source, industrial source, and gasoline volatilization were identified as the major VOC emission sources by the positive matrix factorization model. Petrochemical and coating sources were the prime VOC sources at industrial sites. Aromatics contributed the most ozone formation potential at industrial sites, while OVOCs provided the main contributions at both urban and suburban sites during four seasons. According to the health risk assessment, a high probability of non-carcinogenic risk existed at three industrial sites. Special attention should be given to certain VOCs, such as acrolein and 1,2-dibromoethane in industrial areas.

VOC characteristics and their source apportionment in a coastal industrial area in the Yangtze River Delta, China.

Volatile organic compounds (VOCs) are important precursors of secondary organic compounds and ozone, which raise major environmental concerns. To investigate the VOC emission characteristics, measurements of VOCs based on proton transfer reaction-mass spectrometry during 2017 were conducted in a coastal industrial area in Ningbo, Zhejiang Province, China. Based on seasonal variation in species concentration, the positive matrix factorization (PMF) receptor model was applied to apportion the sources of VOCs in each season. The PMF results revealed that unknown acetonitrile source, paint solvent, electronics industry, biomass burning, secondary formation and biogenic emission were mainly attributed to VOC pollution. Biomass burning and secondary formation were the major sources of VOCs and contributed more than 70% of VOC emissions in spring and autumn. Industry-related sources contributed 8.65%-31.2% of the VOCs throughout the year. The unknown acetonitrile source occurred in winter and spring, and contributed 7.6%-43.73% of the VOC emissions in the two seasons. Conditional probability function (CPF) analysis illustrated that the industry sources came from local emission, while biomass burning and biogenic emission mainly came from the northwest direction. The potential source contribution function (PSCF) model showed that secondary formation-related source was mainly from Jiangsu Province, northeastern China and the surrounding ocean. The potential source areas of unknown acetonitrile source were northern Zhejiang Province, southern Jiangsu Province and the northeastern coastal marine environments.

Size-segregated physicochemical properties of inhalable particulate matter in a tunnel-ventilated layer house in China.

This study investigated the physicochemical properties of the particles in a typical commercial laying hen barn in Southeast China. Mass concentrations and size distributions of the particulate matter (PM) and the key components (incl. organic carbon (OC), element carbon (EC), and the water-soluble inorganic ions (WSIIs)) were analyzed. The result shows that the mass concentrations of PM accumulated along with the airflow inside the house, with the total mass of the sampling particles increasing from 843.66 ± 160.74 µg/m3 at the center of the house to 1264.93 ± 285.70 µg/m3 at the place close to exhaust fans. The particles with the aerodynamic equivalent diameter, Dp > 9 µm, coarse particles (2.1 µm < Dp ≤ 9 µm), fine particles (Dp ≤ 2.1 µm) accounted for around 50%, 40%, and 10% of the total mass of the sampling particles, respectively. Mass closure analysis shows secondary inorganic ions (NH4+, SO42- and NO3-) were abundant in the fine-mode fraction and OC accounted for more than 40% of the coarse particles. Size distribution analysis shows that the three secondary inorganic ions were bimodally distributed, and the rest tested components were unimodally distributed. The ratios of OC/EC in fine particles were smaller than those in the coarse particles. The equivalent concentration of WSIIs indicated that fine particles were slightly acidic, and the large size particles were slightly alkaline. Knowledge gained from this study will lead to a better understanding of physicochemical properties, sources, and formation of PM.

Atmospheric wet deposition of trace metal elements: Monitoring and modelling.

Trace elements (TEs), a group of atmospheric pollutants, have attracted considerable attention from scientists and government administrators worldwide. The wet deposition fluxes of nineteen trace elements (NTE) were monitored at Wanqingsha, a coastal site in the Pearl River Delta, for three consecutive years (2016.9-2019.8). Significant seasonal differences in NTE between wet and dry seasons were observed. The fluxes of crustal elements (Ca, Na, Al, Mg, K, Fe, Zn and Ba) were significantly higher than those of anthropogenic elements, accounting for over 99 % of the total annual wet deposition of 19 elements. Analysis of PM2.5 and rainfall samples reveals that both the fraction of each TE in the PM2.5 (CQ) and the Apparent Scavengance Ratio for TE (ASR, defined as the concentration ratio in rain and PM2.5) follow lognormal distributions. The logCQ variation for each element is relatively small but shows substantial differences, with means ranging from -5.48 to -2.03, while the logASRs for all elements show similar means (varying from 5.86 to 7.64) and an extremely wide range of variation. The influences of meteorological factors on CQ and ASR were also investigated. A simple box model framework was constructed to reasonably simplify the TE removal process by precipitation. The corresponding regression analysis showed significant correlations between NTE and the precipitation rate, PM2.5 concentration, ASR, and CQ, with R2 ranging from 0.711 to 0.970. By substituting the effects of environmental factors on ASR and CQ into the above relationship, temporal variations in NTE can be predicted. The reliability of the model was demonstrated by comparing model simulations with observations over three years. For most elements, the models can predict the temporal variation of NTE quite accurately, and even for the worst predictions, such as Al, Mg, K, Co and Cd, where predictions exceed observations by only an order of magnitude.

Surface ozone changes during the COVID-19 outbreak in China: An insight into the pollution characteristics and formation regimes of ozone in the cold season.

The countrywide lockdown in China during the COVID-19 pandemic provided a natural experiment to study the characteristics of surface ozone (O3). Based on statistical analysis of air quality across China before and during the lockdown, the tempo-spatial variations and site-specific formation regimes of wintertime O3 were analyzed. The results showed that the O3 pollution with concentrations higher than air quality standards could occur widely in winter, which had been aggravated by the emission reduction during the lockdown. On the national scale of China, with the significant decrease (54.03%) in NO2 level from pre-lockdown to COVID-19 lockdown, the maximum daily 8-h average concentration of O3 (MDA8h O3) increased by 39.43% from 49.05 to 64.22 µg/m3. This increase was comprehensively contributed by attenuated NOx suppression and favorable meteorological changes on O3 formation during the lockdown. As to the pollution states of different monitoring stations, surface O3 responded oppositely to the consistent decreased NO2 across China. The O3 levels were found to increase in the northern and central regions, but decrease in the southern region, where the changes in both meteorology (e.g. temperature drops) and precursors (reduced emissions) during the lockdown had diminished local O3 production. The spatial differences in NOx levels generally dictate the site-specific O3 formation regimes in winter, with NOx-titration/VOCs-sensitive regimes being dominant in northern and central China, while VOCs-sensitive/transition regimes being dominant in southern China. These findings highlight the influence of NOx saturation levels on winter O3 formation and the necessity of VOCs emission reductions on O3 pollution controls.

Research progress of the POP fugacity model: a bibliometrics-based analysis.

With the emergence of environmental issues regarding persistent organic pollutants (POPs), fugacity models have been widely used in the concentration prediction and exposure assessment of POPs. Based on 778 relevant research articles published between 1979 and 2020 in the Web of Science Core Collection (WOSCC), the current research progress of the fugacity model on predicting the fate and transportation of POPs in the environment was analyzed by CiteSpace software. The results showed that the research subject has low interdisciplinarity, mainly involving environmental science and environmental engineering. The USA was the most paper-published country, followed by Canada and China. The publications of the Chinese Academy of Sciences, Lancaster University, and Environment Canada were leading. Collaboration between institutions was inactive and low intensity. Keyword co-occurrence analysis showed that polychlorinated biphenyls, organochlorine pesticides, and polycyclic aromatic hydrocarbons were the most concerning compounds, while air, water, soil, and sediment were the most concerning environmental media. Through co-citation cluster analysis, in addition to the in-depth exploration of traditional POPs, research on emerging POPs such as cyclic volatile methyl siloxane and dechlorane plus were new research frontiers. The distribution and transfer of POPs in the soil-air environment have attracted the most attention, and the regional grid model based on fugacity has been gradually improved and developed. The co-citation high-burst detection showed that the research hotspots gradually shifted from pollutant persistence and long-range transport potential to pollutant distribution rules among the different environmental media and the long-distance transmission simulation.

[Source Analysis and Composition Characteristics of Water-soluble Ions During Spring Festival in Ningbo].

Water-soluble ions and some trace gases during the Spring Festival in Ningbo were observed using an ion online gas composition and aerosol monitoring system. Combined with meteorological elements data, the source analysis and composition characteristics of water-soluble ions and trace gases were analyzed. The average concentration of ρ(PM2.5) during the observation period was 33.1 µg·m-3, and there was light pollution. The order of concentration of water-soluble ions was NO3->SO42->NH4+>K+>Cl->Na+>Ca2+>Mg2+. The secondary inorganic ions ρ(NO3-), ρ(SO42-), and ρ(NH4+) were the most water-soluble ions, which were 12.5, 10.5, and 7.2 µg·m-3, respectively. According to the PMF source analysis, firecracker combustion, secondary generation (background, industrial source), and dust sources were the major sources of fine particles during the observation period, and their contribution rates of PM2.5 were 21.9%, 64.5%, and 13.6%, respectively. When the secondary generation was the main pollution, NH4+ accounted for 92.2% of the cations. When firecracker combustion was the main pollution from New Year's Eve to the second day, the proportion of K+ions significantly increased. Dust sources were affected by regional transport from the northwest direction. When the dust source was the main pollution, the proportion of K++Ca2+and Na++Mg2+ increased.

Real-time non-refractory PM1 chemical composition, size distribution and source apportionment at a coastal industrial park in the Yangtze River Delta region, China.

This study present real-time measurements of the chemical composition and particle number size distributions (PNSD) of submicron particulate matter (PM1) in winter at a coastal industrial park in the Yangtze River Delta region of China. Positive matrix factorization (PMF) analysis identified three PNSD factors and three organic aerosol (OA) factors. Contributions and potential source regions of these factors were investigated for four typical periods during the PM1 formation and dissipation process. Results show that the relative contributions from aged 250 nm- factor, fresh 35 nm- and 80 nm- factors were strongly affected by local fresh emissions and regional new particle formation. The non-refractory PM1 measured by Aerodyne aerosol chemical speciation monitor is indicative of the chemical composition of aged 250 nm-factor, but not fresh 35 nm- and 80 nm-factors. The contributions of NO3- and SO42- to NR-PM1 were largely dictated by whether the air mass trajectory went over the sea or the continent. NO3- was abundant (up to 44% of NR-PM1) in cold and dry continental air masses, while SO42- formation (up to 39% of NR-PM1) was preferred in humid and warm marine air masses. Among the three OA source factors, more-oxidized oxygenated OA (MO-OOA) was the most abundant OA factor (44-66% of total OA) throughout the entire field campaign, while an enhanced contribution of 39% from hydrocarbon-like OA (HOA) was observed prior to heavy pollution period. On average, secondary components SO42-, NO3-, NH4+, MO-OOA and less-oxidized oxygenated OA (LO-OOA) contributed 90 ± 7% of NR-PM1, while primary components HOA and Cl- accounted for the remaining 10 ± 7%.

Genome Sequence of Sulfide-Dependent Denitrification Bacterium Thermomonas sp. Strain XSG, Isolated from Marine Sediment.

We report the draft genome sequence of Thermomonas sp. strain XSG, isolated from a marine sediment. The genome is 3,047,478 bp long with a GC content of 68.5%. Strain XSG was found to be closely related to strain NBRC 101115 of Thermomonas koreensis.

A locus for autosomal dominant accessory auricular anomaly maps to 14q11.2-q12.

Accessory auricular anomaly is a small excrescence of skin that contains elastic cartilage on different regions of the helix and the face. Previous work has shown that the genetic trait of some patients with the isolated symptom of accessory auricular anomaly is autosomal dominant. To map the gene for autosomal dominant accessory auricular anomaly (ADAAA), we investigated a Chinese family with 11 affected individuals. We performed linkage analysis with microsatellite markers spanning the whole human-genome in the family. The inheritance pattern of the ADAAA family was autosomal dominant with complete penetrance. Two-point linkage analysis revealed significant maximum LOD scores of 4.20(D14S990 and D14S264, sita = 0) in the family. Haplotype construction and multipoint linkage analysis also confirmed the locus and defined the isolated ADAAA locus to a 9.84 cM interval between the markers D14S283 and D14S297. Our study assigned an isolated ADAAA locus to 14q11.2-q12. This is the first ADAAA locus reported to date.