Average Organic Carbon Content Research Articles

Characteristics and Controlling Factors of the Chang 8 Oil Reservoir in the Yanchi Area of the Ordos Basin: A Case Study of Well G20

In the Ordos Basin, the Chang 8 oil reservoir of the Triassic Yanchang Formation is the main target of oil exploration and development and there are many factors affecting the hydrocarbon accumulation. Well G20 is an important exploration well in the Yanchi area in the northwestern part of the basin, and the core of the Chang 8 reservoir was sampled and tested to determine the source rocks, trace element composition, mineral composition, reservoir physical properties, and oil-bearing properties. The results show that the rock retrieved exhibits delta plain subfacies; the range of the Chang 8 water body was large, with a gentle slope, and the climate was relatively dry. These findings suggest that this reservoir was deposited in an environment in which sedimentary sand body could easily form. The Chang 8 sandstone reservoir pores are dominated by intergranular pores and feldspar intragranular dissolution pores, indicating that the Chang 8 reservoir is a low-porosity and low-permeability reservoir. Chang 7 source rocks from this area have a type I-II1 hydrocarbon-generating potential, with an average total organic carbon (TOC) content of 5.99% and vitrinite reflectance (Ro) value of 0.48%. Combined with the regional sedimentary evolution, tectonic movement, and reservoir distribution, it is considered that due to the lack of lithologic traps or low-amplitude structural traps, G20 produced water in well testing. The Chang 8 oil reservoir in the Yanchi area can be divided into structural reservoirs and structural-lithologic reservoirs. The conventional oil and gas reservoir exploration ideas of “thick sand belt” and “reservoir sweet spot” are not applicable here. The lithology traps or low-amplitude structural traps and areas with good preservation conditions are the main directions for the next phase of exploration in the northwestern part of the Ordos Basin.

Stoichiometric characteristics of carbon, nitrogen and phosphorus in surface sediments of different plant communities in Lake Baiyangdian wetland

白洋淀是雄安新区的核心生态功能区.为探究白洋淀不同植物群落区表层沉积物碳（C）氮（N）磷（P）化学计量特征，采集了96组表层沉积物样品开展对比分析.研究表明：白洋淀湿地表层沉积物总有机碳（TOC）含量均值为39.64 g/kg，范围为14.4~136.82 g/kg，总氮（TN）和总磷（TP）均值分别为2.62和0.75 g/kg，范围分别为0.72~10.57和0.46~1.38 g/kg；不同植物群落区表层沉积物C、N、P化学计量特征存在显著差异，挺水植物分布区表层沉积物TOC和TN含量高于其他区，水田区沉积物TP含量最高；表层沉积物C：N：P比例平均值为141：8：1，C：N比值相对稳定，C：P和N：P比值空间分异性较大；不同水生植物群落区沉积物C、N、P化学计量特征存在差异，挺水植物区沉积物C：P和N：P比值显著高于其他各分区，沉水植物区表层沉积物C：N最大，挺水植物区和沉水植物区C：N：P比例平均值分别为222：13：1和129：6.5：1；白洋淀表层沉积物C、N、P化学计量特征受植物群落生物量、磷氮磷化学计量特征、枯落物分解速率以及人类活动等多个因素影响；与我国东部主要湖泊相比，白洋淀表层沉积物C、N、P含量均处于较高水平，建议在水生植物生长末期收割打捞运出淀外，减少淀内N、P营养盐累积，减缓白洋淀富营养化和沼泽化进程.;Lake Baiyangdian is the main ecological function area of Xiong'an New Area. To explore the stoichiometric characteristics of carbon, nitrogen and phosphorus in surface sediments of different plant communities in Lake Baiyangdian, 96 samples of surface sediment were collected for comparative analysis. Results showed that the average total organic carbon (TOC) contents of the surface sediments were 39.64 g/kg, ranging from 14.4 to 136.82 g/kg, while the average total nitrogen (TN) and total phosphorus (TP) contents were 2.62 and 0.75 g/kg, ranging from 0.72 to 10.57 and 0.46 to 1.38 g/kg, respectively. There were significant differences in carbon and phosphorus stoichiometric characteristics of surface sediments in different plant community regions. TOC and TN contents in surface sediment of emerged aquatic plant areas were higher than those in other areas, and TP contents in surface sediment of paddy fields were the highest. The mean value of the C:N:P ratio in surface sediments was 141:8:1, the C:N ratio was relatively stable, and the C:P and N:P ratios were highly variable. There were significant differences in carbon, nitrogen and phosphorus stoichiometry in sediments of different aquatic plant communities. The ratios of C:P and N:P in surface sediments of emerged aquatic plant areas were significantly higher than those of other regions. The mean C:N:P ratios of emerged aquatic plant area and submerged plants area were 222:13:1 and 129:6.5:1, respectively. The stoichiometric characteristics of carbon, nitrogen and phosphorus in surface sediments of Lake Baiyangdian were affected by many factors, such as plant community biomass, stoichiometric characteristics, decomposition rate and human activities. Compared with the main lakes in eastern China, the contents of carbon, nitrogen and phosphorus in the surface sediments of Lake Baiyangdian were at a higher level. It is suggested to harvest, salvage and transport the aquatic plants out of the lake at the end of the growth period to reduce the accumulation of nitrogen and phosphorus nutrients in the lake and slow down the process of eutrophication and swamping of Lake Baiyangdian.

Analisis Kandungan Karbon pada Vegetasi Mangrove di Desa Lembar Kabupaten Lombok Barat

The mangrove ecosystem is one of the vegetation that has a role as carbon mitigation in coastal areas, especially in port activity areas that can produce large amounts of carbon, such as in Lembar Harbor, Lembar Village, West Lombok Regency. The purpose of this study was to analyze the carbon content in the root and leaf tissue contained in each type of mangrove in the Lembar Harbor Area, Lembar Village, West Lombok Regency. This type of research is descriptive quantitative, with purposive random sampling method, which starts with taking root and leaf samples on each different mangrove species, and testing is carried out based on the Walkley & Black method to obtain tissue carbon content. Based on the results of the study, found 8 (eight) families consisting of 11 species, including: Avicennia lanata, Avicennia marina, Lumnitzera racemosa, Bruguiera gymnorrhiza, Rhizophora stylosa, Ceriops decandra, Scyphiphora hydrophyllaceae, Excoecaria agallocha, Thespesia populnea, Xylocensis, and Ipome pescaprae. The condition of the environmental parameters of the mangrove ecosystem in Lembar Village is still in good condition, in accordance with the quality standards of water health quality, Decree of the State Minister of the Environment Number 51 of 2004 concerning sea water quality standards for biota. The average organic carbon content of root tissue was 43.47 ± 3.10 %C and leaves was 43.87 ± 3.66 %C. The highest organic carbon content in root tissue was found in Xylocarpus moluccensis (47.46 %C), and the lowest was in Ipomea pescaprae (41.49 %C), while the highest organic carbon content in leaf tissue was in Bruguiera gymnorrhiza (50.60 %C), and the lowest was Avicennia lanata (38.99 %C). Based on Tukey's further test that the value of organic content stored in the root and leaf tissue of mangroves was not significantly different (> 0.05) with a statistical test value of 0.76.

On the impact of grassland management on soil carbon stocks: a worldwide meta-analysis

Grasslands occupy 70% of whole agricultural land and hold significant amounts of carbon, a key element in the regulation of Earth's soils fertility, biomass production and climate. Previous work has shown that carbon stocks of grassland soils have been largely depleted worldwide due to missuse or mismanagement but that shifts in management could also potentially increase soil carbon stocks and mitigate against the degradation of natural ecosystems. However, the existing literature points to large discrepancies in the impact of grassland management practices on soil carbon, which the present study investigated. Here we considered 235 experimental sites in 18 countries across the world where shifts in grassland management involved different grazing strategies (free, F vs controlled, C; high, H vs low, L density grazers), grazers exclusion (E), mowing (M) and burning (B). The best performing practice was controlled grazing with high density of grazers (CHG) with an average soil organic carbon content (SOCC) increase of 21% and with 100% of the studies pointing to a SOCC increase. This was followed by E (14.9%; 60%) and FLG (13.3%; 80%). On average, burning grasslands, decreases SOCC by 9.3% but 31% of the studies pointed to an increase, thus indicating discrepancies in the impact of grassland management. CLG and mowing did not significantly impact SOCC. These results also indicated that B decreased SOCC the most under moist to humid climates (−10.9% vs −1.7% under arid to semi-arid), while that E was only beneficial in arid to semi-arid grasslands. Adoption of rotational high-intensity grazing in place of free grazing grasslands, should be seriously considered by policy and decision makers to mitigate against climate change while fostering economic and social development.

Humic fractions as indicators of soil organic matter responses to clear‐cutting in mountain and lowland conditions of southwestern Poland

AbstractClear‐cutting means forest removal (stems only) and is the most common type of forest harvesting but undoubtedly has a negative impact on the C budget in soils. This work aimed to describe responses of soil organic matter (SOM) in the mixed coniferous forest following the removal of trees under temperate climate conditions in lowland and mountain regions in southwestern Poland. Investigated soils are described as Brunic Arenosols derived from sand with an average content of total organic carbon (TOC) in the Oa‐horizons of 244 g·kg−1 in the lowland and Dystric Cambisols derived from gneiss; the average content of TOC in the Oa‐horizons in the mountain regions was 309 g.kg‐1. Analyzed soils were very acidic in the both regions (pH 2.7–3.5 in the topsoil). In the experiment, two replicated soil profiles were located on each site, both taken after clear‐cutting and without any harvesting. Humic fraction was isolated from Oa‐ and A‐horizons; differences between investigated objects were checked with a significance p < 0.05, (n = 16). Using the instrumental analysis, like electron paramagnetic resonance (EPR), proton nuclear magnetic resonance (1H NMR), and Fourier transformed infrared (FTIR) spectroscopy applied to isolated humic fractions, it has been found that clear‐cutting alters C cycling and accelerates decomposition in the forest floor, leading to loss of humic fractions in the investigated soils. In the mountain forests, the more labile, low‐molecular‐weight fulvic fraction decreased as the effect of harvesting practice by 30% in Oa‐horizon and by 54% in A‐horizon. The analysis of stable radicals by EPR showed a decrease in radical concentration observed for humic acids (HA) from mountain clear‐cut areas compared to the undisturbed forest. Results presented in this article have proved there is less aliphatic character of HA molecules from the lowlands, compared to the mountain forest as the effect of clear‐cutting. Changes in plant cover observed as a consequence of deforestation lead to the decrease in concentration of humic fractions with different solubility properties.

Effects of adding different proportions of soft rock on the dynamic change of the quality of aeolian sandy soil

Evolution process of quality of soft rock and sand compound soil and exploration of its stability were studied. In the present study different proportions (1 : 1, 1 : 2, 1 : 5, 0 : 1) of soft rock and sand compound soil as the research object were selected. Tthe particulate organic carbon, microbial organic carbon, effective phosphorus, quick-acting potassium, nitro nitrogen and ammonium nitrogen in the compound soil were analyzed. Results showed that after 9 years of planting, the organic carbon content of particles with 0 : 1 treatment was the lowest, at 1.73 g/kg, and the treatment of 1 : 5 and 1 : 1 increased significantly by 74.74 and 94.90%, respectively. In the 20 - 30 cm soil layer, the lowest organic carbon content of particles with 1 : 2 treatment was 1.92 g/kg, and there was no significant difference between the other three treatments, with 0 : 1, 1 : 5 and 1 : 1 treatment increased by 46.20, 29.27 and 34.07%, respectively compared to 1 : 2 treatment. With developed root system, the biomass of the root system was greater than the biomass left on the ground after harvest, and the average content of organic carbon of the particles increased first and then decreased later. The microbial community in the compound soil was significantly improved, and the carbon content of microorganisms in the treatment of 1 : 1, 1 : 2 and 1 : 5 was significantly higher than that of whole sand by 85, 165 and 143%, respectively, after multi-year of cultivation. The soil root microbial community showed a benign development. With the increase of planting years, the incorporation of soft rock accelerates the process of natural succession of soil quality. Compared with sandy land, compound soil has significantly improved storage of available phosphorus and available potassium nutrients. Compound soil has been cultivated for 9 years compared with 6 years, with the ratio of 1 : 1, 1 : 2, 1 : 5 and 0 : 1, the effective phosphorus content increased significantly by 141, 181, 169 and 63% respectively, the available potassium content increased significantly by 141, 181, 169 and 63% respectively. Compound soil has been cultivated for 9 years compared with 6 years, with the ratio of 1 : 1, 1 : 2, 1 : 5, and 0 : 1, the nitrate nitrogen content increased significantly by 40, 130, 135 and 120%, respectively. Nitro nitrogen is easily soluble in water, and the higher the proportion of sand in the compound soil, the easier the loss of nitrous nitrogen content in the soil. After multiple years of cultivation, the ammonium nitrogen content in the compound soil decreased, with a significant decrease of 35 (p < 0.05), 34 (p < 0.05), 45 (p < 0.05) and 37% (p < 0.05), respectively. Due to the disruption of harvest, the exposure of the surface soil is high, which causes ammonium nitrogen to evaporate. Bangladesh J. Bot. 50(3): 837-845, 2021 (September) Special

Geological Characteristics and Exploration Prospect of Black Shale in the Dongyuemiao Member of Lower Jurassic, the Eastern Sichuan Basin, China

China has yielded huge commercial production from the marine organic-rich shale but shows a slow exploration process in the lacustrine organic-rich shale. Multiple lacustrine shales in the Lower Jurassic of the eastern Sichuan Basin, rich in organic matters, are potential targets for shale hydrocarbon exploration and development. An investigation of the Dongyuemiao member, Lower Jurassic, was firstly conducted utilizing the macroscopic and microscopic analyses on outcrops and drilling cores to reveal the characteristics of sedimentary subfacies, mineral compositions, organic matter content and types, thermal maturity level, and reservoir quality. The dark shales in the Dongyuemiao member can be grouped into four general categories: shore, shallow, semi-deep, and deep lacustrine shales. The semi-deep and deep lacustrine shales generally have higher values in thickness (>20 m), average total organic carbon (TOC) content (>1.5 wt.%), and average porosity (>2%) relative to shore and shallow lacustrine shales. All four categories of shales primarily consist of type II kerogen and have thermal maturity levels exceeding the vitrinite reflectance value of 0.9–1.0% (or the Tmax of ∼440°C). Thermally powered pore generation generally promoted the pore system as indicated by the positive correlation between porosity and Tmax. Notably, the semi-deep lacustrine shale in the vicinity of the Qiyueshan Fault Zone shows abnormally high porosity and low oil saturation index (OSI) at Tmax>∼465°C potentially due to the promoted hydrocarbon expulsion through multiscale fractures. Except for the vicinity of the Qiyueshan Fault Zone, the semi-deep and deep lacustrine shales generally show the better exploration prospect relative to the shore and shallow lacustrine shales. Additionally, the high content of clay minerals (>40 wt%) reduced the brittleness of the semi-deep and deep lacustrine shales which may challenge the artificial hydraulic fracturing.

A Study of Socio-Economic Impact of Soft Approaches of Climate Adaptation using Changing Fuel Practice in Indoor Air at Rural Sites in India

Majority of India’s rural population depends on biomass burning for cooking and heating purposes on traditional cook stoves called Chullah which results into indoor air pollution. The sampling for this study was carried out in two villages of India viz. Budhwada, Madhya Pradesh (M.P.) and Baggi, Himachal Pradesh (H.P.). Both the regions are significantly different in terms of culture, traditions, topography and daily practices and hence this study helped in understanding the contrast between these regions. The concentrations of carbonaceous aerosols viz. OC (Organic Carbon) and EC (Elemental Carbon) were evaluated for different fuel use in four different houses of each village. Introducing the concept of soft approaches, the residents were asked to bring certain changes in their practices by cooking either with solid biomass or Liquefied Petroleum Gas (LPG) as fuel. The overall average concentration of OC was found to be higher for Budhwada (M.P.) at 124.34 ± 34.68 µg/m3 than at Baggi, (H.P.) with value 105.26 ± 35.63 µg/m3 whereas the reverse was true for the average concentration of EC with value 62.98 ± 20.75 µg/m3 at Baggi, (H.P.) and 55.51 ± 15.51 µg/m3 at Budhwada (M.P.). The average OC and EC concentrations from solid biomass fuel (dung cake) burning at Budhwada (M.P.) was respectively higher by 56.14% and 33.57% as compared to the LPG usage. Similarly, in Baggi (H.P.) village with LPG usage, a significant reduction was observed in OC and EC concentrations (76.69% and 70.10% respectively) when compared with fuelwood burning. House-wise and time-wise variations of carbonaceous aerosols at both the sites confirmed that their concentrations are lower in houses with greater ventilation and higher in cooking times (morning and evening). In Budhwada (M.P.), the concentrations of K+, Ca2+ and SO42- ions decreased significantly from dung cake to LPG use by 67.91%, 76.98% and 51.85% respectively. In Baggi (H.P.), K+ ion concentration was decreased by 63.4% from fuelwood to LPG use. A questionnaire survey conducted on the residents also corroborated the above findings where the residents agreed that LPG use has health benefits over solid biomass fuel usage but the challenges such as supply of LPG into rural interiors, financial feasibility, etc. were of serious concern. Also, changing the contemporary mindset of rural population is a challenging task.

The influences of sedimentary environments on organic matter enrichment in fine-grained rocks of the Paleogene Shahejie formation in Nanpu Sag, Huanghua Depression, Bohai Bay Basin

The fine-grained rocks in the Paleogene Shahejie Formation in Nanpu Sag, Huanghua Depression, Bohai Bay Basin, are extremely important source rocks. These Paleogene rocks are mainly subdivided into organic-rich black shale and gray mudstone. The average total organic carbon contents of the shale and mudstone are 11.5 wt.% and 8.4 wt.%, respectively. The average hydrocarbon (HC)-generating potentials (which is equal to the sum of free hydrocarbons (S1) and potential hydrocarbons (S2)) of the shale and mudstone are 39.3 mg HC/g rock and 28.5 mg HC/g rock, respectively, with mean vitrinite reflectance values of 0.82% and 0.81%, respectively. The higher abundance of organic matter in the shale than in the mudstone is due mainly to paleoenvironmental differences. The chemical index of alteration values and Na/Al ratios reveal a warm and humid climate during shale deposition and a cold and dry climate during mudstone deposition. The biologically derived Ba and Ba/Al ratios indicate high productivity in both the shale and mudstone, with relatively low productivity in the shale. The shale formed in fresh to brackish water, whereas the mudstone was deposited in fresh water, with the former having a higher salinity. Compared with the shale, the mudstone underwent higher detrital input, exhibiting higher Si/Al and Ti/Al ratios. Shale deposition was more dysoxic than mudstone deposition. The organic matter enrichment of the shale sediments was controlled mainly by reducing conditions followed by moderate-to-high productivity, which was promoted by a warm and humid climate and salinity stratification. The organic matter enrichment of the mudstone was less than that of the shale and was controlled by relatively oxic conditions.

Organic geochemical characteristics and shale oil potential of the middle Eocene early-mature shale in the Nanpu Sag, Bohai Bay Basin, Eastern China

The decline of proven conventional petroleum resources in the shallow portions of the Nanpu sag has shifted attention to the exploration of deep unconventional oil and gas resources there, especially the shale oil resources in the middle Eocene shales of the Shahejie Formation (MES shales). In this study, to assess the oil potential of the MES shales, we carried out a systematical geochemical and basin modeling characterization. The results show that the MES shales have low maturity and are at the early stage of hydrocarbon generation, with a mean vitrinite reflectance of 0.64% and low ratio of C27 18α(H)-22, 29, 30-trisnorneohopane to C27 17α(H)-22, 29, 30-trisnorhopane (0.44–1.18). The MES shales contain abundant organic matter (OM), with an average total organic carbon content of 2.21 wt %. Biomarker analyses show that the OM in the MES shales derived mainly from floating macrophyte and aquatic algae, microalgae and bacteria. The sapropelinite group in the MES shales is predominant in the organic macerals, and the kerogen is sapropelic and dominated by types I and II1. Biomarker analyses also reveal that the MES shales were deposited in the stratified water column as suggested by the presence of gammacerane, under relatively warm and wet climatic conditions. The anoxic conditions built up in the water column facilitated the OM preservation, although slight microbial degradation resulted in relatively high carbon preference index values. Modeling results based on geochemical data and basin analyses show that considerable quantities of hydrocarbons remain in the low-maturity MES shales. The preliminary estimate of the quantity of shale oil resources in the Gaoliu area of Nanpu sag is approximately 1.78 × 108 t. Nanpu sag have good shale oil potential, and shale oil exploration may be more feasible for MES shales, especially in the context of in-situ heating technology.

Temporal trends of the concentration and sources of secondary organic aerosols in PM2.5 in Shanghai during 2012 and 2018

Based on the concentrations of the carbonaceous components and the typical organic tracers in 682 p.m.2.5 samples collected in Shanghai from 2012 to 2018, the temporal trends of the concentrations and potential sources of the secondary organic aerosols in PM2.5 in Shanghai were investigated. The annual average concentrations of organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC) all showed a decreasing trend along with the PM2.5 concentration. The annual concentration of total carbon (TC) in 2018 (4.3 μg m−3) was about 34% of that in 2012. Compared with that in 2013, the concentrations of isoprene and sesquiterpene SOA tracers in 2018 decreased by 48% and 43%. Meanwhile, the concentration of monoterpene SOA tracers kept stable in 2 ng m−3 to 3 ng m−3, and the concentration of toluene SOA tracer decreased slightly from 1.3 ng m−3 in 2013 to 1.0 ng m−3 in 2018. Correlation analysis with levoglucosan suggested that biomass burning should be an important source of sesquitertene in Shanghai. It was found that the 2-MGA/2-MTLs ratio of the isoprene tracers was more strongly affected by the ambient temperature but not NOx in Shanghai. The concentration of secondary organic carbon (SOC) estimated with OC/EC-based, WSOC-based and tracer-based methods showed a decreasing trend during the study period, but the contribution of SOC to OC was increasing. Anthropogenic aromatic volatile organic compounds was the increasingly important contributor to the SOC in PM2.5, and should be the key pollutants to be controlled to further improve the air quality in Shanghai.

Secondary Organic Aerosols in PM2.5 in Bengbu, a Typical City in Central China: Concentration, Seasonal Variation and Sources

To investigate the concentration, seasonal variation, and sources of secondary organic aerosols (SOAs) in the inland areas of central China, 244 seasonal PM2.5 samples were collected from January to October 2019 at one urban site and one suburban site simultaneously in Bengbu of Anhui Province. Concentrations of organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and typical organic tracers, including saccharides, tracers of SOAs from isoprene, terpenes, and toluene, were measured. Results showed that Bengbu has high pollution levels of organic aerosols, with annual average OC concentrations of about 9.5 μg m−3. About 60% of the OC in PM2.5 in Bengbu was water soluble. Different seasonal trends were found for the SOA tracers of isoprene, monoterpene, seisquiterpene, and toluene. The highest seasonal average concentration of the isoprene SOA tracers was observed in summer and of the monoterpene and seisquiterpene SOA tracers in autumn. A stronger correlation was found between the 2-methylglyceric acid-to-2-methyltetrol ratio (MGA/MTL) and ambient temperature than that between MGA/MTLs and NOX concentration, suggesting that temperature has an important impact on the MGA/MTL ratio besides NOX concentration. The OC/EC-based method, WSOC-based method, tracer yield method, and positive matrix factorization (PMF)-based method were used to estimate the concentration and sources of secondary organic carbon (SOC), and the PMF-based method was believed to be able to give reasonable results. SOC was the main contributor of WSOC in PM2.5 in Bengbu, while biomass burning made an important contribution to WSOC in autumn and winter (~40%). SOC was mainly associated with SOA tracers in summer and mainly associated with secondary ions in spring and winter, suggesting different formation mechanisms in different seasons.

First Measurements of Carbonaceous Aerosol across Urban, Rural and Residential Areas in Jeddah City, Saudi Arabia

Concentrations of black carbon (BC), organic carbon (OC), and total suspended particulate matter (TSP) were simultaneously assessed in urban, rural and residential areas in Jeddah city for one year from January to December 2017. It was aimed in the present study to provide information about the spatial and seasonal variability of these aerosol species in Jeddah, and insight into sources, processes and effects of meteorological conditions. To the best of our knowledge, this is the first study investigating the variability of carbonaceous aerosols (OC and BC) in Saudi Arabia. The average concentrations of OC, BC, and TSP varied spatially and temporally. The annual average concentrations of OC, BC, and TSP were 134.05, 7.16, and 569.41 μg m−3 and 34.32, 5.14, and 240.64 μg m−3 and 10.67, 4.39 and 101.31 μg m−3 in the urban, residential and rural areas, respectively. Moreover, there was a clear seasonal variation in the concentration of carbonaceous aerosols; the highest concentrations were recorded in February and September, while the lowest concentrations of OC were recorded during April, May and August in the urban, residential and rural sites, respectively. Nevertheless, the lowest concentrations of BC were recorded during March in the urban and residential sites and during November in the rural site. The relative concentrations of OC and BC to the TSP were relatively high, and they have a significant correlation with prevalent wind speed (−0.636, and −0.581 in the urban area), (−0.539 and −0.511 in the residential area), and (−0.508 and −0.501 in the rural area), respectively. The marked differences in the concentrations of BC and OC were reflected on OC/BC ratio, which is a good representative of different source types. This preliminary study showed that the potential local sources were emissions from traffic (fossil fuel), biomass burning, anthropogenic activities (e.g. car drifting and outdoor cooking), and industrial activities. The present study suggest the presence of highly inefficient combustion sources and highlight the need for the regulation of such emissions.

Investigation on Carbon Sequestration Capacity of Typical Subtropical Evergreen Broad-leaved Forest in Jiulianshan Nature Reserve

Nine investigation sample plots (each 20m×20m) were set up to investigate the biomass and soil bulk density of three typical subtropical evergreen broad-leaved forests (Castanopsis eyrei, Schima superba, Cyclobalanopsis glauca) in Jiulianshan National Nature Reserve in Jiangxi Province in 2015 and 2020. The vegetation carbon density and carbon storage, soil carbon density and carbon storage, the carbon density and carbon storage of the investigation sample plots were calculated according to the organic carbon content of vegetation and soil. In addition, the changes in carbon sequestration capacity of three typical subtropical evergreen broad-leaved forests in Jiulianshan National Nature Reserve in Jiangxi Province in 2015 and 2020 were analyzed. The investigation results had shown that:Compared with 2015, the average organic carbon content of Castanopsis eyrei, Cyclobalanopsis glauca, and Schima superba of Jiulianshan National Nature Reserve in Jiangxi Province increased by 10.36%, 10.13% and 7.73% in 2020. The average organic carbon content of leaf, branch, stem and root increased also by 10.60%, 10.38%, 11.13% and 5.29% respectively. The soil organic carbon content of different soil layers in 2020 and 2015 were all decrease with the increase of soil depth. Compared to 2015, the organic carbon content increased while the soil bulk density decreased in 2020.The average carbon density of the forest vegetation layer in the investigation plots of Jiulianshan National Nature Reserve in Jiangxi Province had increased from 82.63t/hm2 in 2015 to 108.94t/hm2 in 2020. The carbon density of the arbor layer had increased from 76.11t/hm2 in 2015 to 106.09t/hm2 in 2020, while the carbon density of the shrub layer, herbaceous layer and litter layer in 2020 was lower than that in 2015. In 2015 and 2020, the carbon density of different vegetation layers in the three typical subtropical evergreen broad-leaved forest of Castanopsis eyrei, Schima superba and Cyclobalanopsis glauca were all ranked as arbor layer, shrub layer, litter layer and herbaceous layer.The average soil carbon density (calculated by 10cm) at different depths in 2020 and 2015 in Jiulianshan National Nature Reserve of Jiangxi Province all decreased with the increase of the soil depth. The total average soil carbon density in 2020 was 168.03t/hm2, which was 35.4%% lower than that of 2015(288.05t/hm2).The average carbon storage in the sample plot (20m×20m) in Jiulianshan National Nature Reserve in Jiangxi Province decreased from 13771.04kg in 2015 to 10688.11kg in 2020 with a decrease of 22.38%. The average carbon storage of vegetation decreased from 3305.20kg in 2015 increased to 4357.60kg in 2020 with an increase of 31.8%, while the average soil carbon storage decreased from 10137.04kg in 2015 to 6475.51kg in 2020 whit a decrease of 36.1%.

Ambient Levels, Emission Sources and Health Effect of PM2.5-Bound Carbonaceous Particles and Polycyclic Aromatic Hydrocarbons in the City of Kuala Lumpur, Malaysia

With increasing interest in understanding the contribution of secondary organic aerosol (SOA) to particulate air pollution in urban areas, an exploratory study was carried out to determine levels of carbonaceous aerosols and polycyclic aromatic hydrocarbons (PAHs) in the city of Kuala Lumpur, Malaysia. PM2.5 samples were collected using a high-volume sampler for 24 h in several areas in Kuala Lumpur during the north-easterly monsoon from January to March 2019. Samples were analyzed for water-soluble organic carbon (WSOC), organic carbon (OC), and elemental carbon (EC). Secondary organic carbon (SOC) in PM2.5 was estimated. Particle-bound PAHs were analyzed using gas chromatography-flame ionization detector (GC-FID). Average concentrations of WSOC, OC, and EC were 2.73 ± 2.17 (range of 0.63–9.12) µg/m3, 6.88 ± 4.94 (3.12–24.1) µg/m3, and 3.68 ± 1.58 (1.33–6.82) µg/m3, respectively, with estimated average SOC of 2.33 µg/m3, contributing 34% to total OC. The dominance of char-EC over soot-EC suggests that PM2.5 is influenced by biomass and coal combustion sources. The average of total PAHs was 1.74 ± 2.68 ng/m3. Source identification methods revealed natural gas and biomass burning, and urban traffic combustion as dominant sources of PAHs in Kuala Lumpur. A deterministic health risk assessment of PAHs was conducted for several age groups, including infant, toddler, children, adolescent, and adult. Carcinogenic and non-carcinogenic risk of PAH species were well below the acceptable levels recommended by the USEPA. Backward trajectory analysis revealed north-east air mass brought pollutants to the studied areas, suggesting the north-easterly monsoon as a major contributor to increased air pollution in Kuala Lumpur. Further work is needed using long-term monitoring data to understand the origin of PAHs contributing to SOA formation and to apply source-risk apportionment to better elucidate the potential risk factors posed by the various sources in urban areas in Kuala Lumpur.

Organic petrological characterisation and facies interpretation of the Upper Triassic (Carnian – Julian) black limestone in the Lesno Brdo area (External Dinarides, Central Slovenia)

Upper Triassic (Carnian - Julian) bedded dark limestone in the Lesno Brdo area, more precisely in the Drenov Grič quarry (Central Slovenia), was investigated in this study to describe its carbonate facies, its geochemical characteristics of the inorganic and organic matter, and to estimate its hydrocarbons generative potential. The site was chosen as a well referenced location of previous lithological and paleontological studies with the aim to fill a gap in the up-to-date knowledge on organic petrology of the investigated rocks termed as the Julian “Carbonate Member” within the Lesno Brdo stratigraphic sequence. The study represents the first multi-analytical organic petrological investigation of Mesozoic carbonate rocks in Slovenia. In the Drenov Grič (DRG) section, 7 microfacies were defined. A total of 38 DRG samples of micritic limestones, marlstones, and a coaly sample were collected from the section. The average total organic carbon (TOC) content of the samples is 0.70 wt% with one outstanding sample DRG-28 with a TOC content of 15.56 wt.%. According to the TOC content, DRG samples are considered as a fair to good source rock for hydrocarbons generation. In addition, the samples with TOC >0.5 wt.% were characterised by the Rock-Eval S1, S2 and S3 peaks, hydrogen and oxygen indices (HI, OI), Tmax and production index (PI) values. According to these data, typical “black” Julian carbonate beds from the Drenov Grič locality are poor source rocks. Based on pyrolysis data (HI versus OI), the type of the organic matter could not be determined, so a micropetrographic examination was performed. . The predominant and the only clearly visible maceral in the DRG samples is vitrinite within the amorphous organic matter. Given the low S2 peaks, thermal maturity was determined by vitrinite reflectance. Vitrinite reflectance results (between 2.71 ± 0.19 %Ro and 3.89 ± 0.17 %Ro) indicate that the organic matter in the DRG samples is in a thermally mature to overmature stage, which is also consistent with the Thermal Alteration Index (TAI) (4- - 4). All 38 samples were also analysed on main and trace elements, focusing on the redox sensitive trace elements (Ni, Mo, Th, U, V and Zn) to supplementary interpret depositional conditions. Overall, the “black” carbonate rocks of the Drenov Grič section show a negligible potential for the generation of hydrocarbons. Their original dispersed organic matter was thermally strongly transformed. Therefore, the investigated carbonate rocks almost completely exhausted their ability to generate a considerable quantity of hydrocarbons. They can therefore be classified as “spent source rocks”, which could conditionally generate some dry gas.

Seasonal Trends of Organic and Elemental Carbon in PM1 Measured over an Industrial Area of Delhi, India

The present study was carried out to investigate the seasonal variation of organic carbon (OC) and elemental carbon (EC) in PM1 during 2018–2019 in the industrial area of Delhi, India. A cascade impactor was used to collect aerosol particles in four different size fractions (≥ PM10, PM2.5–10, PM2.5–1, ≤ PM1). The OC/EC analysis was performed by thermal/optical carbon analyzer (DRI 2001). The highest concentration of aerosol particles was observed in PM1 among four different size fractions (≥ PM10: 37.77 ± 16.07 µg/m3, PM2.5–10: 90.28 ± 41.84 µg/m3, PM2.5–1: 81.65 ± 43.85 µg/m3, and ≤ PM1: 151.75 ± 58.57 µg/m3). The annual average concentration of OC and EC in PM1 was found to be 34.12 ± 22.94 µg/m3 and 13.91 ± 11.45 µg/m3, respectively. Furthermore, a clear seasonal difference in the concentrations of OC and EC was observed. The highest OC and EC concentration were found during post-monsoon (OC: 59.58 ± 21.66 µg/m3) and winter season (EC: 23.90 ± 12.08 µg/m3), respectively. Although the lowest concentration of OC and EC was observed in the monsoon season (OC: 12.08 ± 6.98 µg/m3, EC: 3.88 ± 1.97 µg/m3). The annual average percentage contribution of OC and EC in PM1 was observed to be 22.48 and 9.16%, respectively. Total carbonaceous aerosol (TCA) accounted for 45.18% of PM1. The annual average OC/EC ratio was found to be 2.45, which indicates the secondary organic aerosol (SOA) formation. The OC/EC analysis reveals that OC2 and EC1 were dominant among eight carbon subfractions, which suggest a mixed source of emission. The higher value of inhalation dose of EC was observed during the winter season (309 µg), which can lead to a higher risk of cardiac and respiratory illness.

Influence of Meteorological Conditions and Fire Hotspots on PM0.1 in Northern Thailand during Strong Haze Episodes and Carbonaceous Aerosol Characterization

ABSTRACT Northern Thailand has long been severely affected by haze from biomass burning containing fine and ultrafine aerosols in the dry period. The carbonaceous PM0.1 comprising elemental carbon (EC) and organic carbon (OC) collected during the haze and non-haze periods in Chiang Mai, Thailand was investigated. The PM0.1 levels during the haze periods were about 3 times higher than the non-haze periods, a significant increase. PM0.1 concentration was strongly correlated with atmospheric relative humidity and the number of forest fire hotspots. Carbonaceous aerosol characteristics in PM0.1 were analyzed with the thermal/optical transmittance (TOT) method following the IMPROVE protocol. The concentrations of OC and EC, distribution of OC and EC and OC/EC ratios in PM0.1 were evaluated. Average OC and EC mass concentrations in PM0.1 were 6.8 ± 2.7 and 1.4 ± 0.5 µg m–3 during the haze periods, significantly higher than those during the non-haze periods; 1.9 ± 0.9 and 0.5 ± 0.2 µg m–3. The OC/EC ratio increased linearly with the number of hotspots. This indicated significant contribution from biomass burning to the PM0.1. This was strongly supported by the 48-hr backward trajectory simulation, that indicated both domestic and transboundary aerosol transports. Because both organic and elemental carbon are the light-absorbing carbonaceous aerosols, the increase during the haze periods contributed to regional air quality and climate. This study enhances the understanding of PM0.1 behavior in Chiang Mai, Thailand, during the haze periods in upper southeast Asia.

Investigation on carbon sequestration capacity of typical subtropical evergreen broad-leaved forest in Wuyi Mountain National Nature Reserve

Three typical substropical evergreen broad-leaved forests (Castanopsis eyrei, Schima superba and Cyclobalanopsis glauca) in Wuyi Mountain National Nature Reserve of Jiangxi Province were selected to investigate its carbon sequestration capacity. The biomass and soil bulk density of sample investigation were get by setting sample investigation, field quadrat sampling, indoor sample making, experimental analysis testing, data statistics and analysis. The organic carbon content of vegetation layer (arbor layer, shrub layer and herbaceous layer, litter layer) and soil layer (0-10cm, 10-20cm, 20-30cm, 30-50cm and 50-100cm) were also get. The carbon density and carbon storage of subtropical evergreen broad-leaved forests vegetation and soil were estimated which including Castanopsis eyrei, Schima superba and Cyclobalanopsis glauca. The investigation results had shown that: The average organic carbon content of each vegetation layer in the investigation plot (400 m2) of Wuyi Mountain National Nature Reserve was arbor layer (54.07%)> shrub layer (52.8%)> herbaceous layer (47.5%), in which the average organic carbon content of the three subtropical evergreen broad-leaved forests in the arbor layer was close 52.97% to 54.87% and the total average content was 54.07%. The average carbon density of the forest vegetation layer was 178.3587t/hm2, the average carbon density of the vegetation layer was arbor layer (176.0273t/hm2)> shrub layer (1.3043t/hm2)> litter layer (0.8144t/hm2)> herbaceous layer (0.2127t/hm2); the average carbon density of each forest species was Castanopsis eyrei (213.5141t/hm2)> Schima superba (168.9069t/hm2)> Cyclobalanopsis glauca (152.6551t/hm2). Investigation sample of subtropical evergreen broad-leaved forest (400 m) in Wuyi Mountain National Nature Reserve, Jiangxi Province2 The average soil bulk density of each soil layer cm 0-100 g/cm was 0.868-1.816 g/cm3 both soil organic carbon content and soil carbon density decreased with the increase of soil depth. The average organic carbon content of each soil layer was between 3.75% and 12.48%, and the average soil carbon density was between 62.85t/hm2 and 146.14t/hm2. The average total carbon density of the soil in the investigated sample plots was 754.77t/hm2, of which the average soil carbon density in investigation sample plots in Castanopsis eyrei, Schima superba and Cyclobalanopsis glauca was 911.49t/hm2, 762.56t/hm2 and 543.22t/hm2 respectively. The average carbon storage of the investigation sample plot (400m2) in Jiangxi Wuyi Mountain National Nature Reserve were Castanopsis eyrei forest (45.0002t) >Cyclobalanopsis glauca forest (36.6087t) > Schima superba forest (28.4850t), the average soil carbon storage(30.1908t) was 4.23 times the average carbon storage(7.1314t).

Carbonaceous Aerosols in PM1, PM2.5, and PM10 Size Fractions over the Lanzhou City, Northwest China

Carbonaceous particles have been confirmed as major components of ambient aerosols in urban environments and are related to climate impacts and environmental and health effects. In this study, we collected different-size particulate matter (PM) samples (PM1, PM2.5, and PM10) at an urban site in Lanzhou, northwest China, during three discontinuous one-month periods (January, April, and July) of 2019. We measured the concentrations and potential transport pathways of carbonaceous aerosols in PM1, PM2.5, and PM10 size fractions. The average concentrations of OC (organic carbon) and EC (elemental carbon) in PM1, PM2.5, and PM10 were 6.98 ± 3.71 and 2.11 ± 1.34 μg/m3, 8.6 ± 5.09 and 2.55 ± 1.44 μg/m3, and 11.6 ± 5.72 and 4.01 ± 1.72 μg/m3. The OC and EC concentrations in PM1, PM2.5, and PM10 had similar seasonal trends, with higher values in winter due to the favorable meteorology for accumulating pollutants and urban-increased emissions from heating. Precipitation played a key role in scavenge pollutants, resulting in lower OC and EC concentrations in summer. The OC/EC ratios and principal component analysis (PCA) showed that the dominant pollution sources of carbon components in the PMs in Lanzhou were biomass burning, coal combustion, and diesel and gasoline vehicle emissions; and the backward trajectory and concentration weight trajectory (CWT) analysis further suggested that the primary pollution source of EC in Lanzhou was local fossil fuel combustion.