Concentrations Of Inorganic Ions Research Articles

An unexpected increase in PM2.5 levels in Xi'an during the COVID-19 pandemic restrictions: The interplay of anthropogenic and natural factors

This study investigated the variations in summer and winter PM2.5 concentrations and chemical composition in urban Xi'an before and during the COVID-19 pandemic restrictions. During the pandemic restrictions, summer daytime PM2.5 concentrations remained comparable to pre-pandemic levels, while a reduction was noted at nighttime. Conversely, winter experienced a significant increase in both daytime and nighttime PM2.5 concentrations. Chemical composition analysis revealed reductions in secondary inorganic ion concentrations but notable increases in crustal matter concentrations during the pandemic restrictions, particularly evident in winter. The reductions in secondary inorganic ion concentrations were likely due to decreased emissions of corresponding anthropogenic precursors in summer, while linked to reductions in transformation efficiencies in winter. The heightened crustal matter concentrations were likely attributed to increased contributions of long-range air mass transport from dusty regions, especially prevalent in winter. Source apportionment using positive matrix factorization analysis provided quantitative insights into the distinct source profiles contributing to PM2.5 before and during the pandemic restrictions, with secondary inorganic-rich sources decreasing and dust-related sources increasing during the pandemic restrictions. Additionally, combustion sources, primarily from coal and biomass burning, showed higher contributions during winter. In conclusion, this study underscores the complex interplay between anthropogenic and natural factors influencing PM2.5 levels in Xi'an. Efforts to mitigate PM2.5 pollution should prioritize reducing anthropogenic emissions and implementing measures to control dust emissions, particularly when dust-related sources significantly contribute to elevated PM2.5 concentrations. These findings provide valuable insights into developing effective strategies for addressing the PM2.5 pollution problem in Xi'an.

Chemical characteristics and formation mechanisms of PM2.5 during wintertime in two cities with different industrial structures in the Sichuan Basin, China

PM2.5 remains one of the critical pollutants involving regional and complex air pollution in many big cities of China, and its improvement has become sluggish in recent years. In this study, we collected PM2.5 samples from two cities, Chengdu and Ya'an, which have different industrial structures in the Sichuan basin during wintertime and investigated the reasons behind their severe PM2.5 pollution. Throughout the entire sampling period, the average PM2.5 concentrations in Chengdu (71.3 ± 24.8 μg/m3) and Ya'an (72.6 ± 27.1 μg/m3) were similar. However, the chemical compositions of PM2.5 showed significant differences. Chengdu exhibited higher concentrations of water-soluble inorganic ions, whereas Ya'an had higher levels of carbonaceous compounds. Both cities experienced an ammonium-rich environment, which promoted the homogeneous generation of secondary pollutants. Moreover, as PM2.5 pollution worsened, the influence of heterogeneous reactions involving SO2 and NOx, as well as the heterogeneous hydrolysis of N2O5, gradually became more pronounced in particle formation. Additionally, adverse meteorological conditions facilitated pollutant accumulation in Ya'an. Using the Positive Matrix Factorization model, we identified 5 sources of PM2.5. The primary source of PM2.5 in both cities was secondary formation (35.4% in Chengdu and 32.5% in Ya'an), while their second-largest contributors varied (26.2% from vehicle emission in Chengdu, and 26.6% from combustion source in Ya'an). These discrepancies highlight the necessity for tailored government interventions, particularly during the winter season. By analyzing the light absorption of the carbonaceous at 370 nm, we discovered that brown carbon was the primary absorber of near-ultraviolet light, with vehicle emissions accounting for the largest portion in Chengdu (37.2%) and combustion emissions being the predominant factor in Ya'an (51.0%). These results could potentially help for having a long-term impact on climate change by simultaneously reducing PM2.5 pollution.

Characteristics of Microorganisms and Antibiotic Resistance Genes of the Riparian Soil in the Lanzhou Section of the Yellow River

Riparian soil is a critical area of watersheds. The characteristics of biological contaminants in riparian soil affect the pollution control of the watershed water environment. Thus, the microbial community structure, antibiotic resistance genes (ARGs), and mobile genetic elements (MGEs) in the riparian soil of the Lanzhou section of the Yellow River were investigated by analyzing the characteristics of soil samples collected from farmland, mountains, and industrial land. The results showed that the Proteobacteria, Bacteroidetes, and Actinobacteria were the dominant phyla in the riparian soil of Lanzhou section of the Yellow River. The microbial structure in the riparian soil was significantly correlated with the land use type (P < 0.05). The α diversity index of bacterial communities in land types was in the order of farmland > mountain > industry. Sulfonamide-typed ARGs were the most dominant genes in the soil of the Lanzhou section of the Yellow River Basin, among which the sul1 gene had the highest abundance, 20-36 000 times that of other detected ARGs. Moreover, the total absolute abundance of ARGs in industrial soil was the highest. Principal coordinate analysis (PCoA) displayed that the ARGs characteristics had a significant correlation with land types (P < 0.05), and intl1 and tnpA-04 drove the diffuseness of sulfonamide and tetracycline ARGs, respectively. Redundancy analysis (RDA) demonstrated that the content of inorganic salt ions and total phosphorus in the soil of the riparian zone of the Yellow River Lanzhou section were the main environmental factors, modifying the distribution of the microbial structure. Halobacterota and Acidobacteriota were the main microflora that drove the structural change in ARGs.

Study on the Influence of Salinity, TDS, GWL and Land Use in the Coastal Region of Kebumen Regency with a Statistical Approach

This study investigates the impact of salinity levels, total dissolved solids (TDS), groundwater levels (GWL), and land use patterns in the coastal region of Kebumen Regency, employing a statistical approach. Coastal areas are often vulnerable to salinity variations, which can significantly affect the surrounding ecosystems and land utilization. The research aims to discern the correlation between TDS, salinity levels, GWL and land use practices in this specific region, employing statistical analysis as a means of quantifying and understanding these relationships. Total dissolved solids (TDS) represent the concentration of inorganic salts, minerals, and ions in water bodies and play a crucial role in the overall water quality of coastal areas. Salinity levels, on the other hand, directly affect TDS and are influenced by factors such as tidal patterns and freshwater input. Groundwater levels affect salinity and TDS. Land use practices, including agricultural, residential, and industrial activities, profoundly impact coastal ecosystems and are often influenced by salinity levels. This study utilizes statistical methods to analyze the complex interplay between TDS, salinity, GWL, and land use in the Kebumen Regency coastal region. By examining data related to TDS, salinity, GWL, and land utilization, this research seeks to contribute valuable insights into the sustainable management of coastal environments. The findings of this study are expected to inform decision-making processes for the benefit of local communities and ecosystems, guiding future policies and practices for the preservation and balanced development of coastal areas in Kebumen Regency

Characteristics, source analysis, and health risk of PM2.5 in the urban tunnel environment associated with E10 petrol usage.

The increase in the number of motor vehicles has intensified the impact of traffic sources on air quality. Our aim was to illustrate the characteristics of PM2.5 emissions from vehicles fueled with E10 (a blend of 10% ethanol and 90% gasoline). A 21-day PM2.5 sampling in a fully enclosed urban tunnel and the component analysis were completed, and the characteristics, sources, and health risks of tunnel PM2.5 were studied. Moreover, the PM2.5 pH and its sensitivity were investigated by the thermodynamic model (ISORROPIA-II). In addition, exposure models were used to assess the health risks of different heavy metals in PM2.5 to humans through respiratory pathways. The two-point Cu/Sb ratio (entrance: 4.0 ± 1.4; exit: 4.4 ± 1.7) was close to the diagnostic criteria indicating a significant impact from brake wear. NO3-, NH4+, and SO42- constituted the main components of water-soluble ions in PM2.5 of the tunnel, accounting for 83.0-84.6% of the total concentration of inorganic ions. The organic carbon/elemental carbon ratio of the tunnel was greater than 2, indicating that the contribution of gasoline vehicle exhaust was significant. The average emission factors of PM2.5 in the fleet was 31.4 ± 16.6 mg/(veh·km). The pH value of PM2.5 in a tunnel environment (4.6 ± 0.3) was more acidic than that in an urban environment (4.9 ± 0.6). The main sensitive factors of PM2.5 pH in the urban atmosphere and tunnel environment were total ammonia (sum of gas and aerosol, NH3) and temperature, respectively. The results of the health risk assessment showed that Pb posed a potential carcinogenic risk, while As and Cd presented unacceptable risks for tunnel workers. The non-carcinogenic risk index of heavy metals of PM2.5 in the tunnel environment exceeded the safety threshold.

Enhancing photocatalytic degradation of crystal violet dye with g‐C3N4/ZnTiO3 nanocomposites synthesized via a facile approach

AbstractPhotocatalysts that exhibit exceptional performance could be further enhanced for wastewater treatment, particularly in the degradation of organic pollutants and reduction of inorganic heavy metal ions concentrations. This study employed sol–gel techniques was used to create a Type II scheme g‐C3N4/ZnTiO3 (CZT‐2, CZT‐4, and CZT‐6) photocatalyst. FT‐IR, UV‐DRS, XRD, SEM, BET, HR‐TEM, and XPS analysis were conducted to investigate the physical and chemical properties of the g‐C3N4/ZnTiO3 photocatalyst's. An investigation was conducted to evaluate the photocatalytic performance of the synthesized samples. The samples exhibit remarkable efficacy in the degradation of organic contaminants. Among them, CZT‐2 showcased superior photocatalytic performance in the solar light‐induced photodegradation of crystal violet. The photocatalytic activity of g‐C3N4/ZnTiO3 has been significantly enhanced through the establishment of a Type‐II scheme at the interface. This innovative approach efficiently facilitates the separation of photogenerated electron–hole pairs, thereby boosting the photodegradation activity. The discussion also included the chemical process between photocatalysts and crystal violet. The mechanism of the crystal violet‐photocatalyst reaction was also discussed. After undergoing five cycles of reuse, the photocatalyst that was manufactured demonstrated remarkable stability, leading to a reduction in the cost associated with wastewater treatment. The as‐synthesized g‐C3N4/ZnTiO3 composites are very safe for the environment, which suggests that the CZT‐2 composite is very good at getting rid of pollutants.

Treatment of membrane-concentrated landfill leachate by heterogeneous chemical and electrical Fenton processes with Iron-loaded granular activated carbon catalysts

The composition of the membrane-concentrated landfill leachate (MCLL) is complex with a high concentration of organic matter and inorganic ions. In this study, a chemical and an electro-Fenton system were constructed to treat MCLL from a mature landfill using granular activated carbon loaded with iron oxides as heterogeneous Fenton catalysts. In the chemical Fenton treatment optimized by orthogonal experiments, the COD and colour removal rates were 93.9% and 80.2%. For the electro-Fenton system, the best COD, colour, and TN removal rates of MCLL reached 95.7%, 99%, and 94.9% with an energy consumption (EC) of 0.098 kWh·(g COD)−1 under the condition of pH 6, applied voltage 8 V, the reaction time 4 h, and the catalyst dosage 16.67 g L−1. Various spectral analyses confirmed that refractory organic matter and toxic substances in the MCLL were effectively degraded. The synergistic effect study of the factors in chemical Fenton indicated that as far as the effect on COD removal is concerned, heterogeneous Fenton system > catalyst adsorption > activated carbon/H2O2 system > activated carbon adsorption. The results of free radical quenching experiments illustrate that a large amount of ·OH was produced in the chemical heterogeneous Fenton system, while both ·OH and active chlorine play important roles in the removal of pollutants for the electro-Fenton system. MCLL can be disposed of costly and effectively by chemical and electrical Fenton processes with Iron-loaded granular activated carbon catalysts.

Iodide, iodate & dissolved organic iodine in the temperate coastal ocean

The surface ocean is the main source of iodine to the atmosphere, where it plays a crucial role including in the catalytic removal of tropospheric ozone. The availability of surface oceanic iodine is governed by its biogeochemical cycling, the controls of which are poorly constrained. Here we show a near two-year time series of the primary iodine species, iodide, iodate and dissolved organic iodine (DOI) in inner shelf marine surface waters of the Western English Channel (UK). The median ± standard deviation concentrations between November 2019 and September 2021 (n=76) were: iodide 88 ± 17 nM (range 61-149 nM), iodate 293 ± 28 nM (198-382 nM), DOI 16 ± 16 nM (<0.12-75 nM) and total dissolved iodine (dIT) 399 ± 30 nM (314-477 nM). Though lower than inorganic iodine ion concentrations, DOI was a persistent and non-negligible component of dIT, which is consistent with previous studies in coastal waters. Over the time series, dIT was not conserved and the missing pool of iodine accounted for ~6% of the observed concentration suggesting complex mechanisms governing dIT removal and renewal. The contribution of excess iodine (I*) sourced from the coastal margin towards dIT was generally low (3 ± 29 nM) but exceptional events influenced dIT concentrations by up to ±100 nM. The seasonal variability in iodine speciation was asynchronous with the observed phytoplankton primary productivity. Nevertheless, iodate reduction began as light levels and then biomass increased in spring and iodide attained its peak concentration in mid to late autumn during post-bloom conditions. Dissolved organic iodine was present, but variable, throughout the year. During winter, iodate concentrations increased due to the advection of North Atlantic surface waters. The timing of changes in iodine speciation and the magnitude of I* subsumed by seawater processes supports the paradigm that transformations between iodine species are biologically mediated, though not directly linked.

Effect of Physico-Chemical Parameters and Inorganic Nutrient Ions in Relation with Seasonal Algal Diversity of River Ichhamati, West Bengal, India.

The present study reflects seasonal algal diversity as a source of food for fishes in the river Ichhamati during October 2021 to August 2022. To understand the seasonal algal pattern in the river Ichhamati, physicochemical parameters of river water such as Hardness, Conductivity, pH, Total Dissolve Solids, Turbidity, Dissolve Oxygen, Salinity, Turbidity, Total Alkalinity, Salinity, Biological Oxygen Demand as well as biologically significant inorganic ion concentrations in river water namely sodium, potassium, calcium, carbonate, bicarbonate, nitrate, chloride were also evaluated during study period. It is found that physico-chemical parameters and inorganic ions in river water play an important and significant role in seasonal algal growth. Throughout the study period it was established that river Ichhamati is not very rich in floral diversity. During study time it was observed that dominant group of algae in this river are Chlophytes, Cyanophytes and Bacilariophyceae, including Species of Oscillatoria Nostoc, Klebsormidium, Spirogyra, Lyngbya, Chlorococcum, Chlorella, Diatoms in all seasons. During spring, summer and monsoon Conductivity, salinity, TDS and hardness of river water is high. Ichhamati contained adequate Na+, K+ and NO3- in summer and monsoon season. High rate of bio-mineralisation during winter was found due to presence of high calcium ion concentration and also high TDS along with high salinity as well as high hardness of river water.

Mechanisms of inhibition of prevailing spoilage bacteria Weissella viridescens in sauced duck product by e-beam irradiation synergistic modified atmosphere packaging

This study investigated the inhibitory mechanism of prevailing spoilage bacteria Weissella viridescens in sauced duck products by e-beam irradiation synergistic modified atmosphere packaging (MAP). After four days of storage, the sauced duck necks were inoculated with W. viridescens and reached a colony count of 5.52 log (CFU/g). The yield factor was significantly higher than in the control group (P < 0.05), indicating its strong spoilage potential. The e-beam radiation synergytic with the MAP treatment may kill W. viridescens by rupturing the cell membrane, increasing intracellular leakage of UV-absorbing substances, inhibiting Na+/K+-ATPase and Ca2+/Mg2+-ATPase activities on the cell membrane, reducing the membrane potential, and increasing extracellular Ca2+, Na+, K+, and Mg2+ inorganic salt ion concentrations, thereby extending the shelf life of sauced duck necks. The transcriptome analysis revealed a significant enrichment of differentially expressed genes in the key pathways, including ABC transporter, quorum sensing, and purine metabolism, suggesting that W. viridescens activity is mainly affected by cell membrane transporter function and nucleotide metabolism regulation, effectively inhibiting its growth. This study provides a theoretical basis for applying synergistic sterilization by e-beam irradiation and MAP in foodstuffs.

3D POROUS COMPOSITE SCAFFOLDS WITH HIGH CALCIUM PHOSPHATE CONTENT AND ADDITION OF INORGANIC IONS FOR BONE REGENERATION APPLICATIONS

Critical-sized bone defects remain challenging in the clinical setting. Autologous bone grafting remains preferred by clinicians. However, the use of autologous tissue is associated with donor-site morbidity and limited accessibility to the graft tissue. Advances in the development of synthetic bone substitutes focus on improving their osteoinductive properties. Whereas osteoinductivity has been demonstrated with ceramics, it is still a challenge in case of polymeric composites. One of the approaches to improve the regenerative properties of biomaterials, without changing their synthetic character, is the addition of inorganic ions with known osteogenic and angiogenic properties. We have previously reported that the use of a bioactive composite with high ceramic content composed of poly(ethyleneoxide terephthalate)/poly(butylene terephthalate) (1000PEOT70PBT30, PolyActive, PA) and 50% beta-tricalcium phosphate (β-TCP) with the addition of zinc in a form of a coating of the TCP particles can enhance the osteogenic differentiation of human mesenchymal stromal cells (hMSCs) (3). To further support the regenerative properties of these scaffolds, inorganic ions with known angiogenic properties, copper or cobalt, were added to the coating solution.β-TCP particles were immersed in a zinc and copper or zinc and cobalt solution with a concentration of 15 or 45 mM. 3D porous scaffolds composed of 1000PEOT70PBT30 and pure or coated β-TCP were additively manufactured by 3D fibre deposition. The osteogenic and angiogenic properties of the fabricated scaffolds were tested in vitro through culture with hMSCs and human umbilical vein endothelial cells, respectively. The materials were further evaluated through ectopic implantation in an in vivo mini-pig model. The early expression of relevant osteogenic gene markers (collagen-1, osteocalcin) of hMSCs was upregulated in the presence of lower concentration of inorganic ions. Further analysis will focus on the evaluation of ectopic bone formation and vascularisation of these scaffolds after implantation in a mini-pig ectopic intramuscular model.

Origin and Function of Amino Acids in Nectar and Nectaries of Pitcairnia Species with Particular Emphasis on Alanine and Glutamine.

Floral nectar contains sugars and numerous other compounds, including amino acids, but little is known about their function and origin in nectar. Therefore, the amino acid, sugar, and inorganic ion concentrations, as well as the activity of alanine aminotransferase (AlaAT) and glutamine synthetase (GS) in nectar, nectaries, and leaves were analyzed in 30 Pitcairnia species. These data were compared with various floral traits, the pollinator type, and the phylogenetic relationships of the species to find possible causes for the high amino acid concentrations in the nectar of some species. The highest concentrations of amino acids (especially alanine) in nectar were found in species with reddish flowers. Furthermore, the concentration of amino acids in nectar and nectaries is determined through analyzing flower color/pollination type rather than phylogenetic relations. This study provides new insights into the origin of amino acids in nectar. The presence of almost all amino acids in nectar is mainly due to their transport in the phloem to the nectaries, with the exception of alanine, which is partially produced in nectaries. In addition, active regulatory mechanisms are required in nectaries that retain most of the amino acids and allow the selective secretion of specific amino acids, such as alanine.

Effects of aerosol water content and acidity on the light absorption of atmospheric humic-like substances in winter

Atmospheric humic-like substances (HULIS) could affect regional climate due to their strong light-absorbing capacity. Daily fine particulate matter (PM2.5) samples were collected from December 18, 2016 to January 8, 2017 at an urban site in Chongqing, Southwest China. The mean concentration of HULIS in terms of carbon (HULIS-C) was 6.4 ± 3.4 μg m−3, accounting for 72% of water-soluble organic carbon. The mass absorption efficiency at 365 nm (MAE365) and absorption Ångström index (AAE) of atmospheric HULIS were 2.8 ± 0.30 m2 g−1 C and 4.6 ± 0.37, respectively. Good correlations between the light absorption coefficients of HULIS at 365 nm (Abs365) and the concentrations of K+, elemental carbon, NO3−, and NH4+ were observed, with correlation coefficients higher than 0.83, indicating that biomass burning and secondary formation were potential sources of light-absorbing HULIS, as evidenced by abundant fluorescent components related to less-oxygenated HULIS. Comparing the changes in Abs365 values, concentrations of major water-soluble inorganic ions and carbonaceous compounds in PM2.5, and environmental factors during the clean and pollution periods, we found that extensive biomass burning during the pollution period contributed significantly to the increase of Abs365 values. Moreover, the aerosol pH during the pollution period was close to 4, and NO2 concentration and aerosol water content were about 1.6 and 2.7 times higher than those during the clean period, respectively, which were favorable to form secondary HULIS through aqueous phase reactions in the presence of high NOx, resulting in an evident increase in its light absorption. Knowledge generated from this study is critical for evaluating the regional radiative forcing of brown carbon in southwest China.

Comparison of seasonality of urban grime in three southern Ontario cities

Urban grime refers to films made of a complex chemical mixture of organics and inorganics deposited on outdoor surfaces. The specific chemical composition of such films can vary considerably due to geographic and seasonal influences. We compared the seasonal change of grime’s water-soluble inorganic ion content in a rural (Thamesford), suburban (Oshawa), and urban city (Toronto) in southern Ontario, Canada. Sodium, calcium, chloride, nitrate, and sulfate amounts in grime were collected and quantified over four seasons in Oshawa, ON and Thamesford, ON and compared with results from a previous study in Toronto to elucidate differences. We found that all three regions displayed a clear seasonality in sodium and chloride consistent with winter road salt inputs and chloride loss in summer. Mole fractions of sulfate were consistently the lowest of the measured ions, and NO3 −/SO4 2− ratios showed a winter–spring minimum and summer–fall maximum. Urban–rural differences in the seasonal changes of ionic mole ratios suggest that additional chloride displacement by nitrate occurs within grime in Toronto that is not present in the two other rural/suburban cities in the same region.

Optimization of sampling conditions to minimize sampling errors of both PM 2.5 mass and its semi-volatile inorganic ion concentrations

Optimization of sampling conditions to minimize sampling errors of both PM _2.5 mass and its semi-volatile inorganic ion concentrations

Development of an efficient method for obtaining lactose and lactulose from whey

Taking into account a wide range of lactulose application in pharmaceutics, baby food production and other fields, along with the importance of technological solutions for its extraction from milk whey, the presented work was carried out to obtain lactulose in one cycle with simultaneous alkaline treatment and desalting of whey by the electromembrane method. Based on the data obtained, an effective method for obtaining a protein concentrate, lactose, and its isomer – lactulose from whey has been developed. The processes of pre-treatment and desalting of milk whey by the electromembrane method were studied and the optimal parameters for the processes implementation were determined. The curves of changes in the concentration of inorganic ions in whey in the desalination process, depending on the degree of demineralization, were plotted.

Effect and mechanism of a concentration-dependent inorganic ion biomimetic periosteum in a repairing bone defect

An inorganic ion functionalized biomimetic periosteum constitutes a new strategy for the design and application of new bone repair materials. However, the effect of cumulative concentration of inorganic ions (e.g. inorganic ion (Si4+)) on bone immune microenvironment in promoting bone repair is still unclear. Here, we used different mesoporous bioactive glass nanoparticles (MBGNs) contents and a methacrylic acid gelatin (GelMA) organic–inorganic double crosslinking techniques to construct low, medium, and high content inorganic ion biomimetic periosteum. As the inorganic ion concentration increased, the compression modulus of LM@G, MM@G, and HM@G (1, 3, and 5 wt% MBGNs, respectively) was 1.6, 3.2, and 2.1 times higher than that of the GelMA hydrogel and the Si4+ release was 35.4 ± 0.4, 59.5 ± 0.2, and 71.5 ± 1.2 ppm in vitro, respectively. The ERK1/2 and p65 inhibition in the HM@G was 51.9% and 40.2% higher than that in the LM@G; however, the stem cell recruitment was about 85.2% lower than that in the LM@G, and the vascular germination degree was 35.4% lower than that in the MM@G. Contradiction between immune regulation and bone repair was found. However, the anti-inflammation in the MM@G was 30.8%, 30.1% higher than that in the LM@G, and stem cell recruitment and vascular sprouting were 3.4 and 1.6 times higher, respectively than those in the HM@G. In summary, the anti-inflammatory effect of MM@G group is stronger than that of LM@G group, and the effect of stem cell recruitment is more significant than that of HM@G group. We not only explore the biological mechanism of Si4+ coordinating macrophages and stem cells to promote bone repair, but also provide research basis for designing inorganic ion based immunofunctional biomaterials.

Comparative Analysis of Real-Emitted Particulate Matter and PM-Bound Chemicals from Residential and Automotive Sources: A Case Study in Poland

The awareness of environmental pollution has been continuously growing in recent decades and is currently reaching its maximum. Europe and most developed countries are determined to ensure safe breathing air for their citizens, and the measures to do so are stricter than ever before. Combustion procedures remain the primary means of producing energy and warmth in Poland. Among the notable constituents of flue gases produced as a result of fuel combustion, solid particles (or particulate matter) hold significant prominence. The paper presents the chemical characterisation of particulate matter emitted from stationary and automotive emission sources. Stationary emission sources included the combustion process of fossil fuels (soft wood, bituminous coal, ecopea coal, culm) in domestic heating units and the process of combustion of bituminous coal in a power plant. Automotive emission sources included light duty and medium duty vehicles fuelled by diesel. Exhaust toxicity tests were carried out maintaining the real conditions of PM emission. In all field measurements particulate matter was gravimetrically measured and collected on quartz or glass fibre filters. Subsequently, the content of carbonaceous fraction, inorganic ions, and metals and metalloids was analyzed using different analytical techniques. The chemical composition of the particulate matter differed depending on the emission source. With respect to stationary combustion sources, the main factors determining solid particle emission are related primarily to the fuel quality. The duty of vehicles was also a factor that influenced the chemical characterisation of the particulate matter emitted from the engines.

Climatology of aerosol properties at an atmospheric monitoring site on the northern California coast

Abstract. Between April 2002 and June 2017, the Global Monitoring Laboratory (GML) of the National Oceanic and Atmospheric Administration (NOAA) made continuous measurements of a suite of in situ aerosol optical properties at a long-term monitoring site near Trinidad Head (THD), California. In addition to aerosol optical properties, between 2002–2006 a scanning humidograph system was operated, and inorganic ion and total aerosol mass concentrations were obtained from filter measurements. A combined analysis of these datasets demonstrates consistent patterns in aerosol climatology and highlights changes in sources throughout the year. THD is predictably dominated by sea salt aerosols; however, marine biogenic aerosols are the largest contributor to PM1 in the warmer months. Additionally, a persistent combustion source appears in the winter, likely a result of wintertime home heating. While the influences of local anthropogenic sources from vehicular and marine traffic are visible in the optical aerosol data, their influence is largely dictated by the wind direction at the site. Comparison of the THD aerosol climatology to that reported for other marine sites shows that the location is representative of clean marine measurements, even with the periodic influence of anthropogenic sources.

Atmospheric Oxidation Capacity and Its Impact on the Secondary Inorganic Components of PM2.5 in Recent Years in Beijing: Enlightenment for PM2.5 Pollution Control in the Future

In recent years, the concentrations of PM2.5 in urban ambient air in China have been declining; however, the strong atmospheric oxidation capacity (AOC) represents challenges to the further reduction of PM2.5 concentration and the continuous improvement of ambient air quality in China in the future, since the overall AOC is still at a high level. For this paper, based on ground observation data recorded in Beijing from 2016 to 2019, the variation in AOC was characterized according to the concentration of odd oxygen (OX = O3 + NO2). The concentrations of the primary and secondary components of PM2.5 were analyzed using empirical formulas, the correlation between AOC and the concentrations of secondary PM2.5 and the secondary inorganic components (SO42−, NO3−, NH4+, and SNA) in Beijing were explored, the impact of atmospheric photochemical reaction activity on the generation of atmospheric secondary particles was evaluated, and the impact of atmospheric oxidation variations on PM2.5 concentrations and SNA in Beijing was investigated. The results revealed that OX concentrations reached their peak in 2016 and reached their lowest point in 2019. The OX concentrations followed a descending seasonal trend of summer, spring, autumn, and winter, along with a spatial descending trend from urban observation stations to suburban stations and background stations. The degree of photochemical activity and the magnitude of the AOC have a large influence on the production of atmospheric secondary particles. When the photochemical reaction was more active and the AOC was stronger, the mass concentrations of the secondary generated PM2.5 fraction were higher and accounted for a higher proportion of the total PM2.5 mass concentrations. In the PM2.5 fraction, SNA accounted for 50.7% to 94.4% of the total mass concentrations of water-soluble inorganic ions in the field observations. Higher concentrations of the atmospheric oxidant OX in ambient air corresponded to a higher sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR), suggesting that the increase in AOC could promote the increase of PM2.5 concentration. Based on a relationship analysis of SOR, NOR, and OX, it was inferred that the relationship between OX and SOR and the relationship between OX and NOR were both nonlinear. Therefore, when establishing PM2.5 control strategies in Beijing in the future, the impact of the AOC on PM2.5 generation should be fully considered, and favorable measures should be taken to properly regulate the AOC, which would be more effective when carrying out further control measures regarding PM2.5 pollution.