Emission Standards Research Articles

Dual trigger versus human chorionic gonadotropin trigger for blastocyst quality and cumulative live birth.

To evaluate the difference in the number of euploid blastocysts and cumulative live birth rate (LBR) between dual and human chorionic gonadotropin (hCG) triggers in poor and normal ovarian responders undergoing preimplantation genetic testing (PGT) cycles. This retrospective cohort study was enrolled from July 2018 to December 2021 and followed up until June 2024 at a single reproductive medical center. Overall, 1040 in vitro fertilization (IVF)-PGT and 784 frozen-thawed embryo transfer (FET) cycles were assessed. Dual (triptorelin acetate 0.2 mg and recombinant hCG [rhCG] 250 µg) or hCG (rhCG 250 µg) trigger was used for oocyte maturation in the gonadotropin-releasing hormone antagonist protocol and PGT cycles. We assessed the embryo outcomes and FET cumulative pregnancy outcomes. The number of oocytes retrieved (10.17 ± 5.22 vs 10.27 ± 5.14, P = 0.789), MII oocytes (8.24 ± 4.26 vs 8.28 ± 4.05, P = 0.888), blastocysts (2.16 ± 1.50 vs 2.12 ± 1.49, P = 0.729), euploid blastocysts (1.06 ± 1.14 vs 1.09 ± 1.23, P = 0.726), and the rate of cumulative LBR (24.9% vs 24.9%, P = 1.000) in the dual trigger group were comparable with those in the hCG group. The trigger method was not correlated with higher LBR based on logistic regression analysis (odds ratio[OR] = 1.040 [0.778-1.392], P = 0.790). For poor and normal ovarian responders, the dual trigger, compared with the hCG trigger, did not improve the PGT embryo outcomes and FET cumulative pregnancy outcomes.

Phytoremediation potential of potted plant species against vehicular emissions

Urbanization and industrialization are exponentially deteriorating air quality, ecosystems, and human health. Phytoremediation is cost cost-effective, sustainable, and nature-based solution against air pollution. This study is designed to evaluate four species, Chlorophytum comosum, Rhapis excelsa, Spathiphyllum wallisii, and Ficus benjamina for their phytoremediation potential. The experimental setup consisted of a sealed chamber to place potted plants and equipment, it was also connected to the vehicular exhaust pipe. The Air Pollution Tolerance Index was highest for F. benjamina (12.19) and lowest for Rhapis excels (8.58). C. comosum has the highest VOC removal efficiency (90%, 0.172 ppm h−1). NOx remediation was highest by F. benjamina with 0.057 ppm h−1 (77%) removal efficiency. SOx and CO were remediated more efficiently by C. comosum, as 89%, (0.18 ppm h−1) and 80% (0.23 ppm h−1), respectively. R. excelsa reduced a higher concentration of NH3 (77%, 0.06 ppm h−1) compared to other species. R. excelsa and S. wallisii may serve as bio-indicator species. These findings provide a sustainable, natural, economical, and eco-friendly way to mitigate air pollution. F. benjamina and C. comosum are suitable species for urban landscapes, green spaces, urban plantations, and green walls to curb air pollutants due to traffic and industries.

Legal dissemination protections in community-based participatory health equity research.

There are legal protections for nurse researchers at public universities who employ community-based participatory research (CBPR) in research about social or health inequities. Dissemination of CBPR research data by researchers or participants may divulge unjust laws and create an imperative for university involvement. What are United States-based legal dissemination protections for CBPR health equity nurse researchers? Three case examples employing CBPR are examined: 1) a mixed methods study with participants reporting illegal discrimination in a municipal initiative about capacity building in community-based organizations serving children; 2) a visual methods study exposing potential clean air law violations in environmental justice research; and 3) a study examining workload violations and illegal discrimination among hotel workers. The cases involved participants from protected social class backgrounds. The research is described with respect to: background, funding, research purpose, and research team; research participants' power and legal vulnerability; dissemination of relevant research information balancing vulnerability and power; research dissemination issues; potential legal issues involved; and laws researchers may use. IRB approval was obtained for the studies. Using a social justice ethical framework, studies highlight actual or potential legal aspects of data dissemination in the context of gathering data about injustice. Legal protections for research data dissemination, whistleblower protection, research advancement protection, anti-harassment protection, false claims, defamation, and visual data liabilities are described. Knowledge of legal research data dissemination protections is an essential competency for nurse researchers invested in uplifting social justice.

On-road measurement of post-catalyst ammonia emissions from gasoline and hybrid vehicles using quantum cascade laser detector.

Ammonia emissions from gasoline vehicles have been confirmed an essential precursor of urban secondary aerosols. To more comprehensively understand the formation mechanisms and better control vehicle-related ammonia, this paper measured the on-road ammonia emissions from six conventional and four hybrid vehicles using a state-of-the-art Quantum Cascade Laser analyzer on urban, rural, and highway routes. The test vehicles emitted 0.01 to 4.27 mg/km of ammonia emissions, with a fleet average of 1.04 mg/km. Compared to the previous laboratory tests, the results of this study were low because of the high emission standards of the vehicles and the near-zero emissions during rural driving. Most test vehicles showed high ammonia emissions during engine warm-up, while some vehicles also had ammonia peaks during dynamic highway driving. On average, hybrid vehicles emitted 60.7% less ammonia emissions than the conventional candidates. It is confirmed that ammonia was formed when incomplete oxidation products presented on a warm catalyst. Engine warm-up, dynamic highway driving, particulate filter regeneration, and hybrid engine re-starting could be important sources. It is hypothesized that the ammonia formed on the upstream catalyst could be consumed by the downstream catalyst at moderate catalyst temperature, resulting in the near-zero ammonia emissions during rural driving.

First direct measurements of the nitrogen isotopic composition of vehicle tailpipe-emitted NH3 and implications for the source apportionment of NH3 in urban atmosphere.

The introduction of three-way catalytic converter (TWC) to meet stringent vehicular NOx emission standards worldwide has led to an unintended consequence of vehicle-derived ammonia (NH3) emission, which might degrade air quality and affect human health, especially in urban areas. The nitrogen stable isotope composition of NH3 (δ15N-NH3) may be a useful tool to trace NH3 sources, but the isotopic signature of vehicle-emitted NH3 is lacking. Here we report the δ15N-NH3 measured from tailpipe exhausts collected directly from 19 different vehicles equipped with TWC using "grab" sample technique optimized to avoid isotopic fractionation. We found a large of range of NH3 concentration (from 1 to 37 ppm, x̄ ± 1σ = 10 ± 8 ppm) and δ15N value (from -38.1 ‰ to 49.0 ‰, x̄ ± 1σ = 1.2 ± 20.9 ‰) for our samples (n = 57). Our results indicate a correlation between δ15N-NH3 and NH3 concentrations (i.e. δ15N-NH3 (‰) = 16.9(± 2.2)In(NH3 concentration; ppm) - 31.7(± 4.7) (R2 = 0.53, P < 0.01) that is associated with the catalyst temperature, which is generally agree with the results of theoretical calculation. After consideration of the vehicle emission evolution, dominant driving condition and tunnel δ15N-NH3 variation, a representative δ15N-NH3 value (meanminmax) of vehicle source is identified as 0.8000-2.20005.2000, which is distinct from (larger than) other NH3 volatilization-related emission sources. Using our newly measured δ15N values and Bayesian mixing model, we approximate the overall contribution of vehicles to ambient NH3 before, during, and after an international event in Beijing was 14.1 %, 7.9 %, and 21.5 %, respectively, which agree well with the course of traffic restriction. Collectively, our findings demonstrate the importance of using vehicle-emitted δ15N-NH3 to quantify vehicular NH3 contribution in urban atmospheres.

Alternative Analyzers for the Measurement of Gaseous Compounds During Type-Approval of Heavy-Duty Vehicles

Emissions standards describe the fuels, the procedures, and, among others, the analyzers to be used for the measurement of the different compounds during the type-approval of heavy-duty engines and vehicles. Traditionally, NOx, CO, hydrocarbons, and CO2 were the gaseous compounds measured within the Euro standard, with the later addition of CH4 and NH3. Euro 7, introduced in early 2024, expanded those compounds, requiring the measurement of N2O and HCHO. With an increasing number of molecules that need to be measured and introducing carbonless fuels, such as hydrogen, that present different requirements compared to carbon-based fuels, the test procedure needs to be updated. The performances of three laboratory-grade instruments and three portable emissions measurement systems based on Fourier-transformed infrared (FTIR) or quantum cascade laser infrared (QCL-IR) technologies were investigated while measuring from the tailpipe of a Diesel engine and a compressed natural gas (CNG) vehicle. All instruments presented good agreement when emissions of NOx, CO, CH4, NH3, N2O, HCHO, and CO2 were compared using: Z-score, F-test and two tail t-test of student. Water concentration measured by the four FTIRs was also in good agreement. Moreover, the dry emissions of CO2 and CO measured by the laboratory non-dispersive infrared (NDIR) and corrected using water were a few percentages different from those obtained using the regulated carbon-based approach. The results indicate that all the investigated systems are suitable for the measurement of the investigated gaseous compounds, including CO2 and H2O.

Model-Based Two-Stage SCR Urea Injection Strategy for Diesel Engine to Meet Low NOX Emission Regulation

Model-Based Two-Stage SCR Urea Injection Strategy for Diesel Engine to Meet Low NOX Emission Regulation

Energy Consumption Optimization for an Electric Delivery Vehicle

For nearly two centuries, electric drives have been used in transportation. Nevertheless, they were not always favored by designers. The century-long dominance of heat engines led to the disregard of numerous challenges associated with the operation of electric drive systems. One of these issues is the optimization of energy consumption by an electric vehicle. This publication proposes an electronic Energy Consumption Optimizer (ECO) that predictively uses information about the shape of the route and speed limits on its individual sections to control the motor speed and gear changes in the gearbox. This work presents the structure of the optimizer system and the developed control algorithms. Additionally, electric motor excitation control was used, which may have contributed to reducing the power and weight of the electric drive motor. Simulation studies carried out using WLTP test cycles and cycles from real road routes showed the potential to decrease energy consumption for vehicle movement by approximately 10%.

Study on mechanical properties and acoustic emission characteristics of composite rock mass with different thicknesses of weak interlayer.

To study the influence of the thickness of a weak interlayer on the deformation and failure characteristics of composite rock mass. Based on the measured data of sand-mudstone interbedded floor rock mass in the Yima mining area, Henan Province, China. Using quartz sand, gypsum, and cement as similar materials make composite rock-like specimens with weak interlayers. The mechanical properties, deformation evolution process, failure characteristics, and acoustic emission laws of rock samples with different interlayer thicknesses under uniaxial compression were studied using the digital image correlation method and acoustic emission monitoring technology. The results show that: (1) With an increase in the thickness of the weak interlayer, there is a corresponding decrease in the compressive strength of the specimen. When the thickness of the weak interlayer exceeds 5cm, the compressive strength of the composite rock specimen is even less than that of the single weak rock-like. (2) Under uniaxial compression conditions, the strain concentration zone first appears in the weak interlayer part of the composite rock-like specimen. As the pressure continues to increase, the specimen is the first to fail at the position of the maximum strain concentration zone. (3) The thickness of the weak interlayer is an important factor affecting the failure mode of composite rock-like specimens. With the increase of the thickness of the weak interlayer, the composite rock-like specimens change from overall failure to local failure. (4) With the increase of the thickness of the weak interlayer in the middle of the composite rock specimen, the maximum value of the energy released by the single acoustic emission event and the maximum value of the cumulative acoustic emission energy decrease during the compression failure process. The research results can provide a reference for the manufacture of composite rock mass with a weak interlayer and the deformation and failure analysis of composite rock mass.

More or Less Ice? Shipping in the Russian Arctic and the Role of Climate Change

Melting sea ice has often been presented as a primary driver for development of Arctic shipping, but what role has it played for policies to develop the Northern Sea Route? It may look paradoxical that Russia has embarked on an ambitious icebreaker construction program, given climate change. In Russia, there have been contradictory assessments of further climate developments in the Arctic. Representatives of the nuclear icebreaker fleet have argued that a new cooling period will soon occur, whereas Russian climate science is dominated by unidirectional climate change. Nevertheless, there is agreement that more icebreakers are needed, since shipping activity is expected to increase, and an extended navigation season is an indisputable goal. Nuances in Russian climate science do not seem to play any role in policy planning for Arctic shipping. Shipping through the Arctic emits less greenhouse gases than navigation on conventional southerly routes, which may be used as an argument in favor of the Northern Sea Route. It is doubtful, though, that this will change priorities of international shipping companies, especially as long as international shipping is not subject to emissions standards. Many other considerations will have precedence. Obviously, Russia’s war in Ukraine and the ensuing international tension is affecting trade patterns and investments in the Russian Arctic. In this situation climate change plays less of a role in the development of shipping in the Russian Arctic. But even before the war climate change was less important than often assumed in the international literature.

Extended Failure Mode and Effects Analysis for Development of Hot Desert Test Cycle Proposal

ABSTRACTA growing number of gigawatt‐scale photovoltaic (PV) power plants are being established in hot desert regions worldwide, which are favored for their vast available land, high solar irradiance, long sunshine hours, and relatively low maintenance needs. This study combines insights from global PV experts on degradation rates, failure mode and effects analysis (FMEA), and desert weather conditions to develop a hot desert test cycle (HDTC). The average degradation rate for PV modules installed in hot desert regions over the past 10 years is estimated to be around 1.63% per year. Eighteen failure modes were identified and analyzed using FMEA. According to the results, the main degradation mechanisms include UV light‐induced degradation (UVLID), thermomechanical failures in interconnects and fingers, light‐elevated temperature‐induced degradation (LeTID), and abrasion of the glass and antireflection coatings. A radar map comparison shows that desert environments experience UV exposure, ambient, and module temperatures that are more than twice as high as those in moderate climates. The HDTC protocol was developed based on FMEA results and desert‐specific weather conditions. It includes tests for desert UV exposure, temperature cycles, mechanical loads, and sand/brush abrasions. To ensure consistency across countries, there is a plan to establish an internationally recognized standard that complements existing IEC standards. As the industry grows, desert regions are expected to place greater emphasis on adopting desert‐specific testing standards for the qualification and evaluation of PV modules.

Investigation of size-segregated particulate matter and carbonaceous components in Phnom Penh, Cambodia.

This study investigated the size-segregated carbonaceous components of particulate matter (PM), including ultrafine particles (UFP or PM0.1), across three distinct urban settings in Phnom Penh, Cambodia: an educational site (University of Health Sciences, UHS), an institutional site (Ministry of Environment, MoE), and a residential area near a landfill. A cascade impactor-type sampler equipped with an inertial filter was used to collect size-segregated particles down to UFPs. Carbonaceous species, including organic carbon (OC) and elemental carbon (EC), were analyzed using a thermal/optical carbon analyzer to determine their composition and ratios. The results indicated no significant differences in mass concentration between weekdays and weekends at all sites; however, PM profiles varied across the location. The UHS site displayed higher EC levels in UFP, with concentrations suggesting significant local vehicular emissions, underscored by a lower OC/EC ratio (2.39 ± 1.13) compared to other sites. In contrast, the landfill site exhibited higher OC components in finer particles, suggesting emissions from organic sources such as waste burning and cooking activities, evidenced by higher OC/EC ratios across all particle sizes (e.g., OC/EC ratio in UFP at 3.78 ± 0.98). The MoE site presented a balanced profile with moderate levels of both OC and EC, influenced by its proximity to natural dispersion factors like the Tonle Sap River. Additionally, air mass backward trajectory analysis integrated with hotspot data indicated transboundary influences, particularly from agricultural burning in surrounding provinces, including Vietnam. Therefore, both local and transboundary emissions influenced the PM levels in Phnom Penh city.

Biomass Accumulation, Contaminant Removal, and Settling Performance of Chlorella sp. in Unsterilized and Diluted Anaerobic Digestion Effluent

Microalgae demonstrate significant efficacy in wastewater treatment. Anaerobic digestion effluent (ADE) is regarded as an underutilized resource, abundant in carbon, nitrogen, phosphorus, and other nutrients; however, the presence of inhibitory factors restricts microalgal growth, thereby preventing its direct treatment via microalgae. The purpose of this study was to dilute ADE using various dilution media and subsequently cultivate Chlorella sp. to identify optimal culture conditions that enhance microalgal biomass and water quality. The effects of various dilution conditions were assessed by evaluating the biomass, sedimentation properties, and nutrient removal efficiencies of microalgae. The results demonstrate that microalgal biomass increases as the dilution ratio increased. The microalgae biomass in the treatments diluted with simulated wastewater was significantly higher than that with deionized water, but their effluent quality failed to meet discharge standards. The treatment diluted with deionized water for 10 times exhibited abundant microbial biomass with strong antioxidant properties. The corresponding total phosphorus concentration in the effluent (6.96 mg/L) adhered to emission limits under the Livestock and Poultry Industry Pollutant Emission Standards (8 mg/L), while ammonia nitrogen concentration (90 mg/L) was near compliance (80 mg/L). The corresponding microbial biomass, with a sludge volume index (SVI30) of 72.72 mL/g, can be recovered economically and efficiently by simple precipitation. Its high protein (52.07%) and carbohydrate (27.05%) content, coupled with low ash (10.75%), makes it a promising candidate for animal feed and fermentation. This study will aid in understanding microalgal growth in unsterilized ADE and establish a theoretical foundation for cost-effective ADE purification and microalgal biomass production.

The uniqueness of pollutant emission and fuel consumption test results for road vehicles tested on a chassis dynamometer

The article considers the issues of non-repeatability of exhaust emission and fuel consumption test results for road vehicles tested on a chassis dynamometer. Empirical results of passenger car tests on a chassis dynamometer in the WLTC (Worldwide Harmonized Light Vehicles Test Cycle) test were used. Tests were conducted in four repeated sets to assess the repeatability of the test results. The road emission of hydrocarbons, non-methane hydrocarbons, carbon monoxide, nitrogen oxides, particulate matter and carbon dioxide, the road number of particulate matter and operational fuel consumption were determined. The coefficient of variation of the values measured in the four tests was determined, taken as a measure of the repeatability of the test results. The coefficient of variation of the road emission of carbon dioxide and operational fuel consumption is the lowest. No significant differences were found in the values of the measured exhaust emission.

Development of a Chemical Sensor Device for Monitoring Hazardous Gases Generated in the Semiconductor Manufacturing Process

The semiconductor industry plays a crucial role in various fields but also contributes to environmental degradation. Throughout the semiconductor chip manufacturing process, hazardous gases are released at each stage, despite stringent treatment procedures. These gases can be categorized into four groups: acidic and alkaline gases, volatile organic compounds, flammable and corrosive gases, and greenhouse gases. To meet stricter emission standards, further advancements in gas sensor technology are essential. This review examines recent research on monitoring these gases, highlighting the capabilities and limitations of existing sensor technologies. Additionally, the paper discusses current challenges in gas sensing research and proposes future directions for improving technologies.

Evaluating health risks of PM2.5-bound heavy elements in Faridabad, Haryana (India): an industrial perspective.

The present study isfocused on investigating the heavy/toxic metals (Al, Ni, Cr, Pb, Cu, As,Mn, and Zn) of PM2.5 and assessing their associated human health risks. During the study period (July 2022 to July 2023), the PM2.5 samples were collected from two distinct sites in Faridabad (92 samples from site 1 and 85 samples from site 2). In this study, the US EPA's Risk Assessment Guidance for Superfund (RAGS) was followed to evaluate the human health risk associated with PM2.5-bound heavy elements. The annual average of PM2.5 concentrations was 108 ± 16µgm⁻3 at site 1 and 154 ± 11µgm⁻3 at site 2, approximately three to fourtimes higher than the national ambient air quality standards (annual, 40µgm-3). The analysis of enrichment factors (EFs) for the elements Cr, As, Zn, Cu, Mn, Pb, and Ni indicates that the heavy elements associated with PM2.5 primarily originate from anthropogenic sources. The application of the conditional bivariate probability function (CBPF) model for Faridabad revealed local pollution sources contributing to elevated mass concentrations at the receptor site from the southern (S), northwestern (NW), northeastern (NE), southwestern (SW), and southeastern (SE) regions. Furthermore, positive matrix factorization (PMF) analysis identified the predominant sources of PM2.5-bound heavy elements as industrial emissions (41%), vehicular emissions (34%), and combustion processes (25%). After a thorough assessment of health hazards, Cr appeared as a significant carcinogenic risk factor. Children with elevated hazard quotient (HQ) values for Mn and Cr indicated non-carcinogenic health problems. Ultimately, this analysis reinforces the necessity for rigorous monitoring and intervention to safeguard public health from the potentially harmful effects of heavy elements.

Utilizing Waste Biomass from Agricultural and Forestry Sustainable Resources: Biomass Conversion to Functional Adsorbent Material for Efficient Removal of Total Phosphate in Practical Water.

The promotion of the utilization of waste agricultural and forestry resources (AFRs) as a means of combating environmental pollution represents an advanced and necessary development approach with the potential to achieve sustainable development. In this work, an advanced adsorbent with a functional Mg-Al bimetallic layer was prepared using waste sawdust biomass (WSD) as a raw material. The layer serves as the primary active component for adsorbing total phosphate from both simulated and real wastewater. The hierarchical structure of the Mg-Al bimetallic hydroxide-modified waste sawdust biomass (MA@WSD) has an abundance of nanosheets on its surface, providing ample binding sites and an enhanced specific surface area of 175.99 m2/g. Under the optimal conditions, the maximum removal efficiency toward phosphate can reach 99.99%. The adsorption of phosphate by MA@WSD follows the pseudo-second order kinetic (PSOK) model, indicating that chemisorption is the rate-determining step. Moreover, the thermodynamic data demonstrate the spontaneous nature of the adsorption process, indicating the favorable characteristics of the developed material. The adsorption mechanism can be summarized as the collaboration of physical adsorption, electrostatic interaction, and chemical adsorption. The results of the regeneration process indicate that MA@WSD exhibits a retention of 50.3% of its initial adsorption performance following the fifth testing cycle, thereby suggesting its potential for comparable reusability. The MA@WSD performs well in adsorbing total phosphate in real river water, and the removal efficiency of MA@WSD is evidently superior to commercial activated carbon, which is at least 70% higher than that of the commercial activated carbon. Besides, the 5-time average removal efficiency toward total phosphate by MA@WSD is 62.9%, evidently higher than the 29.1% of commercially available activated carbon, indicating its potential as an alternative for treating phosphorus-containing wastewater. The research provides theoretical support for harmless treatment, resource utilization, carbon sequestration, and emission reduction of waste biomass.

The next challenge in emissions control for heavy-duty diesel vehicles: From NOx to N2O

Vehicle emissions are a major source of greenhouse gases globally. Dual selective catalytic reduction (SCR), an advanced version of single SCR, is crucial under stricter nitrogen oxide (NOx) emission standards for heavy-duty diesel vehicles (HDDVs). However, the emission characteristics of nitrous oxide (N2O), a byproduct of SCR and a potent greenhouse gas, remain unclear. This study investigates the N2O emissions from HDDVs equipped with single or dual SCR systems using heavy-duty chassis dynamometers under various ambient temperatures, altitudes, and loading masses. The results showed that the brake-specific emissions (EFb) of N2O from HDDVs with single and dual SCRs were 76.28–269.65 mg/kWh and 147.50–170.22 mg/kWh, respectively. Notably, the dual SCR-equipped HDDV emitted 6–22 times more N2O than NOx under all tested conditions. As ambient temperature increased from −10 °C to 25 °C and from 25 °C to 40 °C, the average distance-based emission factors (EFd) of N2O for the single SCR-equipped HDDV increased by 87.73% and 48.26%, respectively. However, the variation was not significant for the dual SCR-equipped HDDV. Under half- and full-load conditions, the average EFd of N2O for the single SCR-equipped HDDV increased by 47.57% and 110.92%, respectively, compared to those without loading. Similarly, N2O emissions for dual SCR-equipped HDDV increased by 41.40% and 65.37% under the same loading variations. As altitude increased from 0 m to 3000 m, the average EFd of N2O for the single SCR-equipped HDDV decreased by 64.31%. Additionally, N2O emissions were significantly affected by SCR temperature, engine power, and nitric oxide (NO)/nitrogen dioxide (NO2) ratio. These findings are crucial for setting future greenhouse gas limits of HDDVs and informing carbon reduction strategies.

Analyzing Morphology and Composition of Coarse Aerosol Particles in Bangkok, Thailand: Implications to Sources and Impacts of Aged Aerosols on Ecosystem Health and Climate Dynamics

AbstractDuring dry seasons, elevated aerosol levels across Thailand pose nationwide problems. Understanding and addressing this issue is challenging due to the dynamic nature of aerosol modification and generation during transport. This study investigates the morphology and elemental compositions of coarse aerosol particles in Bangkok, Thailand, during the dry seasons of 2020/21. Through scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectrometry (EDS), the study reveals a complex mixture of anthropogenic, mineral, biogenic, and marine aerosols. Anthropogenic sources, including biomass burning, vehicular emissions, and industrial activities, contribute to carbonaceous particles like soot aggregates and tar balls. Mineral dust particles, predominantly calcium-rich and aluminosilicate, originate from various sources including construction, industry, and natural processes. Aging processes alter the composition and properties of both carbonaceous and mineral particles, influencing nutrient deposition, carbon sequestration, cloud condensation nuclei formation, and light scattering. These processes have multifaceted impacts on ecosystem health and climate dynamics, highlighting the need for further research and mitigation strategies to address the environmental consequences of aged aerosol particles in urban environments like Bangkok.

Seasonal occurrence and ecological risk assessment of polycyclic aromatic hydrocarbons in the sediments and water in the left-bank canals of Indus River, Pakistan.

This study investigated a pressing environmental concern: the presence, distribution, sources, and ecological implications of sixteen polycyclic aromatic hydrocarbons (PAHs) in the left-bank canals of Kotri barrage-Akram, Pinyari, and Phuleli of the Indus River in Pakistan. These vital waterways, crucial for industrial, domestic, and agricultural activities, are experiencing contamination threats from anthropogenic sources, particularly PAHs. The study collected three water and two sediment samples from each canal in pre-monsoon and post-monsoon seasons. Then the EPA's liquid-liquid extraction method and gas chromatography determined the concentrations of PAHs. The findings of this study reveal alarming contamination levels, with pre-monsoon concentrations ranging from 22.256 to 836.455ng/L in water and 1,459.941 to 43,179.243ng/g in sediments. The post-monsoon concentrations ranged from 60.352 to 5663.058ng/L in water and 2976.770 to 15,238.335ng/g in sediments. The diagnostic ratios and principal component analysis (PCA) identified multiple sources of contamination, including industrial and domestic wastewater discharge, solid waste burning, vehicular emissions, biomass combustion, and petroleum residues. Furthermore, the assessment of the toxic equivalency factor (TEF) underscored the heightened carcinogenic potential of certain PAHs, notably benzo(a)pyrene and benzo(a)anthracene. Thus, the high levels of PAH contamination pose severe health risks to both human populations and aquatic ecosystems, emphasizing the urgency of addressing this issue. Stricter regulations governing industrial and domestic waste discharge, advocacy for cleaner fuel technologies, and the implementation of effective waste management practices must be initiated as crucial strategies in safeguarding the environmental integrity of the left-bank canals and the health of the surrounding communities.