NOx Levels Research Articles

Predicting the Cognitive Ability of Young Women Using a New Feature Selection Algorithm.

Cognitive abilities are the capabilities to perform mental processes that include executive function, comprehension, decision-making, work performance, and educational attainment. This study aimed to investigate the relationship between several biomarkers and individuals' cognitive ability using various machine learning methods. A total of 144 young women aged between 18 and 24years old were recruited into the study. Cognitive performance was assessed using a standard questionnaire. A panel of biochemical, hematological, inflammatory, and oxidative stress biomarkers in serum and urine was measured for all participants. A novel combination of feature selection and feature scoring techniques within a hierarchical ensemble structure has been proposed to identify the most effective features in recognizing the importance of various biomarker signatures in cognitive abilities classification. Multiple feature selection methods were employed in conjunction with different classifiers to construct this model. In this manner, using three filter methods, the scores of each feature were considered. The combination of high-scoring features for each filter method was stored as the primary feature subset. A high-accuracy feature subset was selected by using a wrapper method. The collection of highly scored features from each filter method formed the primary feature subset. A wrapper method was also employed to select a feature subset with high accuracy. To ensure robustness and minimize random variations in the feature subset search process, a repeative tenfold cross-validation was conducted. The most frequently recurring features were determined. This iterative step facilitated the identification of an optimal feature subset, effectively reducing the dimensionality of features while maintaining accuracy. Among the 47 extracted factors, serum level of NOx (nitrite ± nitrate), alkaline phosphatase (ALP), and phosphate as well as blood platelet count (PLT) was entered into the model of cognitive abilities with the highest accuracy of approximately 70.9% using a decision tree classifier. Therefore, the serum levels of NOx, ALP, phosphate, and blood PLT count may be important markers of the cognitive abilities in apparently healthy young women. These factors my provide a simple procedure to identify mental abilities and earlier cognitive decline in healthy adults.

An Examination of Drill Rig NOx Emission

This article creates awareness of greenhouse gases (GHG). The greenhouse gases play a significant role in climate change. The GHG includes NOx which is N2O, NO, and NO2. NOx can be produced from several human activities, including agricultural practices and drill rigs engine activities. However, drill rig emissions have received limited attention in Nigeria compared to agricultural emissions. This article addresses this research gap by examining the production of NOx emissions from drill rigs in Nigeria and its contributing effects. It also discusses the effects of climate change, which include increases in temperature, rainfall, rising sea levels, and the incidence of flooding. Storm aberrations, shortages of usable land, and potable water accompany this. The study adopts a methodology based on the correlation established by Russell (2006) to derive formation emission factors for onshore, offshore, and deep offshore Nigerian wells. The formation emission factors are based on the number of wells drilled in these locations from 2002 to 2004 and the average depth of wells in these locations. The analysis reveals that while NOx levels in Nigeria are currently low, they exhibit a constant upward trend. This observation is significant for a country heavily reliant on the petroleum industry for foreign exchange earnings and economic stability. Furthermore, considering Nigeria's vulnerability to the impacts of climate change and associated hazards, understanding the effect of drill rig NOx emissions and its production becomes crucial. By shedding light on this overlooked aspect, this research contributes to a more comprehensive understanding of the environmental implications and sustainable practices in Nigeria's petroleum sector.

Methanol as a fuel additive: effect on the performance and emissions of a gasoline engine

ABSTRACT The use of alternative fuels, such as alcohol-based fuels, has received a significant attention as a substitute for gasoline in spark-ignition engine. This study examines the influence of methanol-gasoline blends on both performance and emissions of a single-cylinder, spark-ignition engine. The engine is tested under full load conditions and at speeds range varying from 1000 to 3000 rpm. Four fuel blends labeled M0, M10, M20, and M40, were used, where the numbers represent the percentage by volume of methanol in the blend. It has been shown that the addition of methanol improves the power output and the torque of the engine. The highest improvement observed in engine power is 37% for M20 blend. Specific fuel consumption and thermal efficiency have also been improved with increasing methanol blending ratio. M40 showed a decrease in fuel consumption by 38% and an enhancement in thermal efficiency by 95%, at medium speed, compared to pure gasoline. Additionally, the results have shown significant reduction in CO and CO2 emissions, more particularly at low engine speeds (below 2000 rpm), where the addition of methanol (up to M40) has led to reducing CO emission with up to 70% compared to that of M0. However, NOx emissions increased with increasing methanol blending ratio. The highest increase in NOx levels was given by M40 by about 60% at low engine speed.

O3 and PAN in southern Tibetan Plateau determined by distinct physical and chemical processes

Abstract. Tropospheric ozone (O3) and peroxyacetyl nitrate (PAN) are both photochemical pollutants harmful to the ecological environment and human health. In this study, measurements of O3 and PAN as well as their precursors were conducted from May to July 2019 at Nam Co station (NMC), a highly pristine high-altitude site in the southern Tibetan Plateau (TP), to investigate how distinct transport processes and photochemistry contributed to their variations. Results revealed that, despite highly similar diurnal variations with steep morning rises and flat daytime plateaus that were caused by boundary layer development and downmixing of free-tropospheric air, day-to-day variations in O3 and PAN were in fact controlled by distinct physicochemical processes. During the dry spring season, air masses rich in O3 were associated with high-altitude westerly air masses that entered the TP from the west or the south, which frequently carried high loadings of stratospheric O3 to NMC. During the summer monsoon season, a northward shift of the subtropical jet stream shifted the stratospheric downward entrainment pathway also to the north, leading to direct stratospheric O3 entrainment into the troposphere of the northern TP, which traveled southwards to NMC within low altitudes via northerly winds in front of ridges or closed high pressures over the TP. Westerly and southerly air masses, however, revealed low O3 levels due to the overall less stratospheric O3 within the troposphere of low-latitude regions. PAN, however, was only rich in westerly or southerly air masses that crossed over polluted regions such as northern India, Nepal or Bangladesh before entering the TP and arriving at NMC from the south during both spring and summer. Overall, the O3 level at NMC was mostly determined by stratosphere–troposphere exchange (STE), which explained 77 % and 88 % of the observed O3 concentration in spring and summer, respectively. However, only 0.1 % of the springtime day-to-day O3 variability could be explained by STE processes, while 22 % was explained during summertime. Positive net photochemical formation was estimated for both O3 and PAN based on observation-constrained box modeling. Near-surface photochemical formation was unable to account for the high O3 level observed at NMC, nor was it the determining factor for the day-to-day variability of O3. However, it was able to capture events with elevated PAN concentrations and explain its day-to-day variations. O3 and PAN formation were both highly sensitive to NOx levels, with PAN being also quite sensitive to volatile organic compound (VOC) concentrations. The rapid development of transportation networks and urbanization within the TP may lead to increased emissions and loadings in NOx and VOCs, resulting in strongly enhanced O3 and PAN formation in downwind pristine regions, which should be given greater attention in future studies.

Periprostatic adipose tissue (PPAT) supernatant from obese mice releases anticontractile substances and increases human prostate epithelial cell proliferation: the role of nitric oxide and adenosine.

Background: The prostate gland is surrounded by periprostatic adipose tissue (PPAT) that can release mediators that interfere in prostate function. In this study, we examined the effect of periprostatic adipose tissue supernatant obtained from obese mice on prostate reactivity in vitro and on the viability of human prostatic epithelial cell lines. Methods: Male C57BL/6 mice were fed a standard or high-fat diet after which PPAT was isolated, incubated in Krebs-Henseleit solution for 30min (without prostate) or 60min (with prostate), and the supernatant was then collected and screened for biological activity. Total nitrate and nitrite (NOx-) and adenosine were quantified, and the supernatant was then collected and screened for biological activity. NOx- and adenosine were quantified. Concentration-response curves to phenylephrine (PE) were obtained in prostatic tissue from lean and obese mice incubated with or without periprostatic adipose tissue. In some experiments, periprostatic adipose tissue was co-incubated with inhibitors of the nitric oxide (NO)-cyclic guanosine monophosphate pathway (L-NAME, 1400W, ODQ), adenylate cyclase (SQ22536) or with adenosine A2A (ZM241385), and A2B (MRS1754) receptor antagonists. PNT1-A (normal) and BPH-1 (hyperplasic) human epithelial cells were cultured and incubated with supernatant from periprostatic adipose tissue for 24, 48, or 72h in the absence or presence of these inhibitors/antagonists, after which cell viability and proliferation were assessed. Results: The levels of NOx- and adenosine were significantly higher in the periprostatic adipose tissue supernatant (30min, without prostate) when compared to the vehicle. A trend toward an increase in the levels of NOX was observed after 60min. PPAT supernatant from obese mice significantly reduced the PE-induced contractions only in prostate from obese mice. The co-incubation of periprostatic adipose tissue with L-NAME, 1400W, ODQ, or ZM241385 attenuated the anticontractile activity of the periprostatic adipose tissue supernatant. Incubation with the supernatant of periprostatic adipose tissue from obese mice significantly increased the viability of PNT1-A cells and attenuated expression of the apoptosis marker protein caspase-3 when compared to cells incubated with periprostatic adipose tissue from lean mice. Hyperplastic cells (BPH-1) incubated with periprostatic adipose tissue from obese mice showed greater proliferation after 24h, 48h, and 72h compared to cells incubated with culture medium alone. BPH-1 cell proliferation in the presence of PPAT supernatant was attenuated by NO-signaling pathway inhibitors and by adenosine receptor antagonists after 72h. Conclusion: NO and adenosine are involved in the anticontractile and pro-proliferative activities of periprostatic adipose tissue supernatant from obese mice. More studies are needed to determine whether the blockade of NO and/or adenosine derived from periprostatic adipose tissue can improve prostate function.

Combustion and emissions characteristics of a diesel engine fuelled with diesel fuel and different concentrations of amino-functionalized multi-walled carbon nanotube

Nanoparticles have recently been used as fuel additives to enhance diesel engine performance and exhaust gas emissions. Amino-functionalized multiwalled carbon nannotubes (NH2-MWCNTs) are catalysts that can be applied in diesel engines because of their promising properties. This study conducted an experimental investigation to determine the impacts of adding NH2-MWCNTs to diesel fuel using a single-cylinder CI engine running at a constant speed (1500 rpm) and various loads. The NH2-MWCNTs were added to diesel fuel at four concentrations of 25, 50, 75, and 100 ppm. Also, the same doses of pristine multiwalled carbon nanotubes (MWCNTs) were added to diesel to be used as a reference for NH2-MWCNTs. Most NH2-MWCNTs blends were preferred in combustion characteristics, engine performance, and exhaust emissions compared to diesel and MWCNTs blends. Thus, there was a considerable increase in cylinder pressure and heat release rate compared to pure diesel. Also, the brake thermal efficiency was increased, and the brake-specific fuel consumption was decreased compared to diesel. Most NH2-MWCNTs combinations appeared to decrease NOx, soot, and CO levels significantly. The NH2-MWCNTs blends are generally favored over the pristine MWCNTs blends in reducing exhaust emissions.

Investigating the influence of plastic waste oils and acetone blends on diesel engine combustion, pollutants, morphological and size particles: Dehalogenation and catalytic pyrolysis of plastic waste

Most research into the treats of plastic wastes have concentrated mainly on single-exposure pathways or products. These practices fail to acknowledge that the complications of carbon particles from engines are produced not only by diesel but by any plastic oils due to the vast amount of contaminants. With the potential to significantly weaken the impact of contaminants, the present study investigates the effects of dehalogenation and catalytic pyrolysis on plastic waste, as well as the risks associated with plastic oil blends on diesel engine. Different types of washing were conducted to effectively dehalogenate plastic waste. After pretreatment, odor compounds were analyzed using GC–MS. Subsequently, various types of pretreated plastic samples underwent catalytic pyrolysis with a 5:1 ratio of HDPE to Al2O3·2SiO2·2H2O. Differences in physico-chemical properties and hydrocarbon compounds of oils were determined. Experiments were performed using different fuel blends in a diesel engine under steady-state conditions, and their effects on combustion, emissions, morphology, and size particles were analyzed. The results show that sample B exhibited a lower toxicity level of 1,3-butadiene compared to other samples, while acetone and terpenes represented the second and third-highest emission levels in flakes, respectively. Sample C started to degrade at low temperatures (<300 °C) due to carbon addition from ethyl acetate solvent into the tertiary carbon chain of the flakes. DAP3 fuel achieved a higher reaction due to its degree of unsaturation and lower viscosity, resulting in the formation of smaller fuel droplets at high injection pressure and heat release rate (HRR). Higher emission levels were observed by DAP1 and D100, exceeding the Euro 5/6 standard limits. However, DAP3 fuel resulted in an average reduction of ∼17.14% and 21.86% in CO and smoke emissions, respectively, accompanied by a slight decrease in NOx and HC levels. Conversely, there were inconsistencies in the emission results observed with DAP2. Compared to D100, both DAP1 and DAP2 exhibited a significant accumulation and coarse particles in the PM10 forms at a peak of ∼83 nm. Whereas the DAP3 showed a smaller mobility Dp with a low nucleation particle peak, which was prone to absorb the unburned HC soot and later change to accumulation mode particles.

Vitamins C and D Exhibit Similar Antidepressant Effects to Escitalopram Mediated by NOx and FKBPL in a Stress-Induced Mice Model.

The aim of this study was to investigate the potential antidepressant and anxiolytic effects of vitamin C and vitamin D in a stress-induced mouse model of depression, while also exploring the association between these effects and the levels of circulating NOx, periostin, and FKBPL. Our findings revealed that both vitamin C and vitamin D exhibited comparable antidepressant effects to escitalopram, a commonly used antidepressant, without demonstrating any anxiolytic effects. The antidepressant properties of vitamin C and vitamin D were linked to the normalization of Nox and FKBPL levels, while the levels of periostin showed no significant correlation. These results are consistent with previous research, indicating that the antidepressant effects of vitamin C and vitamin D may be attributed to their antioxidant and anti-inflammatory properties, as well as their modulation of neurotransmission and norepinephrine release. Additionally, our study uncovered elevated levels of periostin in stress-induced depression, which were only restored to normal levels by escitalopram, suggesting a potential role for periostin in mood disorders. Furthermore, FKBPL and NOx levels were increased in stress-induced depression and normalized by treatment with vitamin C, vitamin D, and escitalopram, indicating their involvement in the stress response and gene expression regulation. However, it is important to acknowledge certain limitations of our research, such as the use of a single depression induction model and limited dosing regimens. Future investigations should focus on examining these markers in specific brain regions, such as the hippocampus and prefrontal cortex, to gain a more comprehensive understanding of their potential implications for depression. Overall, our findings suggest that vitamin C, vitamin D, and escitalopram may possess antidepressant properties mediated by NOx and FKBPL levels, while emphasizing the potential significance of periostin in the context of depression.

Investigation of Secondary Organic Aerosol Formation during O3 and PM2.5 Episodes in Bangkok, Thailand

In Bangkok, the megacity of Thailand, concentrations of fine particulate matter (PM2.5) have often exceeded the National Ambient Air Quality standards. During severe smog events over Bangkok, the air quality has exhibited moderate to unhealthy atmospheric conditions, according to the air quality index of the United States. To investigate the formation of secondary organic aerosols (SOA), a field campaign to estimate secondary organic carbon (SOC) in Bangkok using the EC tracer method was conducted in January 2021, when the concentrations of PM2.5 were high. The monthly period was classified into three pollution groups, including high pollution, high PM, and low pollution events. The study showed that the correlations between PM2.5 and O3 were negative during both the daytime and night-time. The OC/EC ratios varied from 4.32 to 5.43, while the moderate OC/EC values implied that fossil fuel combustion was the major carbonaceous aerosol in Bangkok. The EC tracer-estimated SOC and POC showed that SOC contributed between 32.5 and 46.4% to OC, while the highest SOC contribution occurred during the low pollution event. The heightened formation of SOA during the low pollution event was perhaps owing to the levels of oxides of nitrogen (NOx). Since Bangkok is more likely to have a NOx-rich photochemical reaction regime, an increase in the NOx level tended to decrease the SOA yield ([NOx] was 21.6 ppb, 20.8 ppb, and 17.1 ppb during the high pollution, high PM, and low pollution events, respectively). Together with the high humidity and high light intensity during the low pollution event, the SOA formation was enhanced. Even though the driving factors of SOA formation over Bangkok remain unclear, the results of this study reveal the significance and urgency of local actions to reduce NOx and O3 towards more habitable and sustainable urban environments.

Assessment of variations in air quality in cities of Ecuador in relation to the lockdown due to the COVID-19 pandemic

This study analyzes the effect of lockdown due to COVID-19 on the spatiotemporal variability of ozone (O3), sulfur dioxide (SO2), and nitrogen dioxide (NO2) concentrations in different provinces of continental Ecuador using satellite information from Sentinel – 5P. The statistical analysis includes data from 2018 to March 2021 and was performed based on three periods defined a priori: before, during, and after lockdown due to COVID-19, focusing on the provinces with the highest concentrations of the studied gases (hotspots). The results showed a significant decrease in NO2 concentrations during the COVID-19 lockdown period in all the study areas: the Metropolitan District of Quito (DMQ) and the provinces of Guayas and Santo Domingo de los Tsáchilas. In the period after lockdown, NO2 concentrations increased by over 20% when compared to the pre-lockdown period, which may be attributable to a shift towards private transportation due to health concerns. On the other hand, SO2 concentrations during the lockdown period showed irregular, non-significant variations; however, increases were observed in the provinces of Chimborazo, Guayas, Santa Elena, and Morona Santiago, which could be partly attributed to the eruptive activity of the Sangay volcano during 2019–2020. Conversely, O3 concentrations increased by 2–3% in the study areas; this anomalous behavior could be attributed to decreased levels of NOx, which react with ozone, reducing its concentration. Finally, satellite data validation using the corresponding data from monitoring stations in the DMQ showed correlation values of 0.9 for O3 data and 0.7 for NO2 data, while no significant correlation was found for SO2.

The Expression of CTLA-4 in Breast Tumors and Tumor-Infiltrating Leukocytes Affects Patients' Systemic Inflammatory Status and Varies According to Their Molecular Subtypes.

Recent evidence has pointed out that the cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) expression is a poor prognosis factor. However, the implications of CTLA-4 expression on circulating inflammatory mediators are unclear for breast cancer. Tumor biopsies and blood samples were collected from 117 breast cancer patients. Oxidative stress parameters were evaluated in plasma samples by measuring the lipoperoxidation profile and nitric oxide metabolites (NOx). Interleukins 12 (IL-12) and 4 (IL-4) were assessed by ELISA. CTLA-4 expression was determined by immunofluorescence assessed by its labeling in tumor-infiltrating leukocytes (TILs) or breast tumors. Correlations between CTLA-4 expression in breast tumors with TCD4/TCD8 infiltrating lymphocyte and inflammation-related genes were performed using data from TIMER 2.0/TCGA databases (n = 2160). CTLA-4 expression in TILs significantly correlated to triple-negative breast tumors. Patients carrying CTLA-4-positive tumors exhibited lower plasmatic NOx levels, and those expressing CTLA-4 in TILs had reduced levels of IL-12 in plasma. No changes in either IL-4 or lipid peroxidation profiles were detected concerning any CTLA4 status. Compared to the Luminal A ones, oxidative stress parameters and cytokines were observed in patients bearing triple-negative tumors. CTLA-4 expression in all breast cancer subtypes positively correlated to TCD4/TCD8 lymphocyte infiltrates, as well as to the pro-inflammatory genes IL12A, IL4, NFKB1, NFKB2, NOS1, NOS2, and NOS3. CTLA-4 expression in both tumor and TILs can affect the systemic inflammatory status of breast cancer patients, especially antitumor molecules such as IL-12 and NOx that correlate to more aggressive disease.

Asociación entre niveles de proteína C-reactiva y óxido nítrico con el pronóstico de pacientes con infarto cerebral agudo

Introducción: La inflamación y alteraciones en la biodisponibilidad del óxido nítrico (NO) han sido involucradas en la fisiopatología de la enfermedad cerebrovascular.&#x0D; Objetivo: El objetivo del estudio fue determinar el valor pronóstico de la medición de metabolitos del NO y marcadores inflamatorios en pacientes con infarto cerebral agudo.&#x0D; Materiales y métodos: Se incluyeron 158 pacientes con diagnóstico de infarto cerebral agudo en un estudio observacional de cohorte. Entre 48 y 72 horas del inicio de los síntomas se tomó una muestra de sangre para determinación del perfil bioquímico, marcadores inflamatorios (PCR, IL1-?, IL6, TNF-?) y nitritos/nitratos plasmáticos. Se realizó seguimiento durante 2 años para determinar la aparición de un nuevo evento (infarto cerebral, infarto de miocardio, falla cardiaca) o muerte de origen vascular. Un análisis de regresión multivariada de Cox permitió determinar los factores asociados independientemente con el desenlace.&#x0D; Resultados: La edad promedio fue 70,5 ± 12,8 años. El 39,2% de los sujetos incluidos presentó el desenlace durante los primeros 24 meses de seguimiento. Los niveles de PCR &gt; 12 mg/L (HR 2,22, IC 95% 1,07-4,59) y el puntaje &gt; 13 en la escala NIHSS al ingreso (HR 2,81 IC 95% 1,46-5,41) se encontraron significativamente asociados con mayor riesgo de presentar un nuevo evento. La combinación de niveles de PCR &lt; 12 mg/L y nitritos/nitratos &lt; 35,5 µmol/L se identificó como un factor protector (HR 0,21, IC 95% 0,06-0,71).&#x0D; Conclusión: Este estudio sugiere que la determinación de nitritos/nitratos en conjunto con los niveles de PCR puede ser de utilidad para estratificar el riesgo de nuevos eventos en pacientes con infarto cerebral agudo.

The effects of voluntary exercise on histological and stereological changes of sciatic nerve, nitric oxide levels, and peripheral neuropathy caused by high-fat diet-induced type 2 diabetes in male rats

This research was conducted to investigate the possible beneficial impacts of voluntary exercise on sciatic tissue, nitric oxide levels, stereological changes, and peripheral neuropathy caused by "high-fat-diet (HFD)"-induced "type 2 diabetes mellitus (T2DM)" in male rats. Rats were put into four experimental groups at random: "healthy control (C), voluntary exercise (VE), diabetic (D), and diabetic rats treated by voluntary exercise (VED)"; each group contain eight animals. Animals in VE and VED groups performed "voluntary exercise (VE)" for ten weeks. Animals in D and VED groups became diabetic after receiving a HFD for four weeks and an intraperitoneal injection (IP) of "streptozotocin (STZ)" (35 mg/kg). In order to evaluate mechanical and thermal algesia, hot plate, tail withdrawal, and von Frey tests were carried out. At the end of this study, serum NOx levels were assessed, and histological and stereological analyses were conducted. Mechanical nociceptive thresholds indicated considerable reduction (p < 0.001) which was followed by a remarkable enhance (p < 0.001) in thermal nociceptive threshold of D group. Tissue changes were also seen in sciatic nerve of D group. Voluntary exercise modified thermal and mechanical sensitivity in diabetic rats. It also improved the damaged sciatic nerve in diabetic animals.

Impacts of High Fructose Diet and Chronic Exercise on Nitric Oxide Synthase and Oxidative Stress in Rat Kidney.

Chronic exercise (Ex) exerts antihypertensive and renoprotective effects in rats fed a high fructose diet (HFr). To elucidate the mechanisms, the impacts of an HFr and Ex on the nitric oxide (NO) system and oxidative stress in the kidney were examined. Rats were fed a control diet or an HFr, and a part of the HFr-fed rats underwent treadmill running for 12 weeks. The HFr did not affect nitrate/nitrite (NOx) levels in plasma and urine, and Ex increased the NOx levels. The HFr increased thiobarbituric acid reactive substance (TBARS) levels in plasma and urine, and Ex decreased the HFr-increased TBARS levels in plasma. The HFr increased the neuronal and endothelial NO synthase (nNOS and eNOS) expressions, and Ex enhanced the HFr-increased eNOS expression. The HFr inhibited the eNOS phosphorylation at serine 1177, and Ex restored the HFr-inhibited eNOS phosphorylation. The HFr increased xanthine oxidase and NADPH oxidase activities, and Ex restored the HFr-increased xanthine oxidase activity but enhanced the HFr-increased NADPH oxidase activity. The HFr increased the nitrotyrosine levels, and Ex attenuated the HFr-increased levels. These results indicate that although Ex enhances the HFr-increased eNOS expression and NADPH oxidase activity, an HFr inhibits renal eNOS phosphorylation and NO bioavailability, whereas Ex ameliorates them.

New Particle Formation Occurrence in the Urban Atmosphere of Beijing During 2013–2020

AbstractNew particle formation (NPF) has strong influences on air quality and global climate. However, it was still ambiguous under which atmospheric condition NPF can occur, due to lack of long‐term observation data analysis. The long‐term measurement of NPF was conducted from 2013 to 2020 at PeKing University Urban Atmosphere Environment MonitoRing Station in Beijing, during which strong pollution control measures were conducted. However, the NPF frequency (NPF‐freq) remained stable within 40.4%–48.9% in an average of 42.5%. The occurrence of NPF events was characterized by lower levels of NOx, condensational sink, relative humidity, and higher levels of wind speed and north wind proportion. SO2 may act as one limiting factor only in summer. An H2SO4‐base nucleation indicator, I275K was calculated. It was found that I275K &gt; 243 can separate the NPF and non‐NPF days quite well during the 8 years, with bias at 17%. Accordingly, it was also revealed that the simultaneous control of SO2 and PM2.5 (serving as condensation sink) in Beijing happened to cause the stable level of I275K, as well as the NPF frequency during 2013–2020. The results implicated that along with the reduction of primary emission, the secondary NPF process may become more important in aerosol evolution by its stable frequency, and the precise control of gaseous precursors is required for particle pollution mitigation in the future.

Assessment of light-duty versus heavy-duty diesel on-road mobile source emissions using general additive models applied to traffic volume and air quality data and COVID-19 responses

ABSTRACT Following the outbreak of the COVID-19 pandemic, several papers have examined the effect of the pandemic response on urban air pollution worldwide. This study uses observed traffic volume and near-road air pollution data for black carbon (BC), oxides of nitrogen (NOx), and carbon monoxide (CO) to estimate the emissions contributions of light-duty and heavy-duty diesel vehicles in five cities in the continental United States. Analysis of mobile source impacts in the near-road environment has several health and environmental justice implications. Data from the initial COVID-19 response period, defined as March to May in 2020, were used with data from the same period over the previous two years to develop general additive models (GAMs) to quantify the emissions impact of each vehicle class. The model estimated that light-duty traffic contributes 4–69%, 14–65%, and 21–97% of BC, NOx, and CO near-road levels, respectively. Heavy-duty diesel traffic contributes an estimated 26–46%, 17–63%, and −7–18% of near-road levels of the three pollutants. The estimated mobile source impacts were used to calculate NOx to CO and BC to NOx emission ratios, which were between 0.21–0.32 μg m−3 NOx (μg m−3 CO)−1 and 0.013–0.018 μg m−3 BC (μg m−3 NOx)−1. These ratios can be used to assess existing emission inventories for use in determining air pollution standards. These results agree moderately well with recent National Emissions Inventory estimates and other empirically-derived estimates, showing similar trends among the pollutants. However, a limitation of this study was the recurring presence of an implausible air pollution impact estimate in 41% of the site-pollutant combinations, where a vehicle class was estimated to account for either a negative impact or an impact higher than the total estimated pollutant concentration. The variations seen in the GAM estimates are likely a result of location-specific factors, including fleet composition, external pollution sources, and traffic volumes. Implications: Drastic reductions in traffic and air pollution during the lockdowns of the COVID-19 pandemic present a unique opportunity to assess vehicle emissions. A General Additive Modeling approach is developed to relate traffic levels, observed air pollution, and meteorology to identify the amount vehicle types contribute to near-road levels of traffic-related air pollutants (TRAPs), which is important for future emission regulation and policy, given the significant health and environmental justice implications of vehicle-related pollution along major roadways. The model is used to evaluate emission inventories in the near-road environment, which can be used to refine existing estimates. By developing a locally data-driven method to readily characterize impacts and distinguish between heavy and light duty vehicle effects, local regulations can be used to target policies in major cities around the country, thus addressing local health disbenefits and disparities occurring as a result of exposure to near-road air pollution.

Comparison of emission NOx, CO, CO2 and smoke number of mixed waste plastic oil, n-Octanol and diesel with the blend ratio of (10%, 20% & 30%) in a single cylinder diesel engine

According to this study, the combined NOx and Smoke Opacity of waste plastic oil and N-Octanol are higher than diesel fuel. To find the optimal combination, waste plastic oil was blended with diesel. The best blend (10%, 20%, and 30%) was contrasted with a blend of diesel and N-Octanol. Five load variations have been tested using a stationary, single-cylinder Kirloskar engine with a bore and stroke of 85 and 110 mm. The G-power was estimated using the G-Power tool v-3.1.9.7, and the sample size was 60. According to the tested experiments, the best blend, D50W30O20, had a NOx level of 2098 ppm for pure diesel and 2145 ppm for waste plastic oil. For neat diesel, the smoke opacity was 32.1. For waste plastic oil, 57.6, and the optimum blend, D50WPO40O10, 41.3. The group’s significance level of 0.000 (p0.05) indicates a meaningful difference. Within the investigation parameters, D50WPO30O20 had a NOx rating 82% higher than diesel and 47% higher for the waste plastic oil blend. When compared to diesel, the smoke opacity of the waste plastic oil blend was 16% higher, and the smoke opacity of D50WPO20O30 was 9% higher.

Impact of body mass index on the circulating levels of nitric oxide metabolites in clinicopathological features from women with breast cancer

AbstractTo investigate the clinical meaning of systemic nitric oxide metabolites (NOx) by comparing eutrophic and overweight/obese patients with breast cancer, considering clinical factors determinant of disease prognosis. A total of 61 women diagnosed with breast cancer were included in the study. NOx estimative was performed on plasma samples using the cadmium–copper‐Griess method. It was then categorized according to the age at diagnosis, body mass index, menopausal status, tumor histological features, molecular subtype lymph nodal invasion, and emboli presence, considering p ≤ 0.05 as significant. A significant augment was observed in NOx levels from overweight patients carrying Luminal B tumors concerning the Luminal B eutrophic ones. There was a considerable reduction in NOx levels in eutrophic postmenopausal patients compared to the overweight postmenopausal ones. Patients bearing tumor sizes between 2 and 5 cm in the eutrophic group had lower levels of NOx, concerning the overweight patients carrying tumors of the same size interval. Circulating NOx levels change significantly according to the trophic‐adipose status of breast cancer patients, and it is further affected by prognostic factors related to poor disease prognosis.

Analysis of CRDI diesel engine characteristics operated on dual fuel mode fueled with biodiesel-hydrogen enriched producer gas under the single and multi-injection scheme

The present work aims to investigate the consequences of pilot fuel (PF) multiple injections and hydrogen manifold injection (HMI) on the combustion and tailpipe gas characteristics of a common rail direct injection (CRDI) compression ignition (CI) engine operated on dual fuel (DF) mode. The CI engine can perform on a wide variety of fuels and under high pilot fuel (PF) pressure. Pilot fuel injection (PFI) is achieved at TDC, 5, 10, and 15ºCA before the top dead center (bTDC), and divided injection consists of injecting fuel in three different magnitudes on a time basis and PF is injected into the engine cylinder at a pressure of 600 bar. In this work, the hydrogen flow rate (HFR) was fixed at 8 lpm constant and producer gas was inducted without any restriction. The investigational engine setup has the ability to deliver a PF and hydrogen (H2) precisely in all operating circumstances using a separate electronic control unit (ECU). Results showed that diesel-hydrogen enriched producer gas (HPG) operation at maximum operating conditions provided amplified thermal efficiency by 4.01% with reduced emissions, except NOx levels, compared to biodiesel-HPG operation. Further, DiSOME with the multi-injection strategy of 60 + 20+20 and 50 + 25+25, lowered thermal efficiency by 4.8% and 9.12%, respectively compared to identical fuel combinations under a single injection scheme. However, reductions in NOx levels, cylinder pressure, and HRR were observed with a multi-injection scheme. It is concluded that multi-injection results in lower BTE, changes carbon-based emissions marginally, and decreases cylinder pressure and heat release rate than the traditional fuel injection method.

Effect of diethyl ether addition to waste cooking oil biodiesel on the combustion and emission characteristics of a swirl-stabilized premixed flame

Waste cooking oil biodiesel is a promising alternative to diesel and jet fuels. However, the challenge of using waste cooking oil biodiesel is its higher viscosity and lower volatility than diesel fuel, which hinder its spray and atomization from achieving diesel levels. These drawbacks can be enhanced by adding a less viscous fuel like diethyl ether. Thus, an experimental approach has been performed to investigate the effect of diethyl ether addition to waste cooking oil biodiesel in the lean pre-vaporized premixed system. Test fuels considered in this study are B20 (20% biodiesel + 80% Jet A-1), B20D10 (20% biodiesel + 10% diethyl ether + 70% Jet A-1), B20D30 (20% biodiesel + 30% diethyl ether + 50% Jet A-1) as well as pure Jet A-1. These blends are applied in the lean pre-vaporized premixed system with preheated air at 350 ℃ at a fixed equivalence ratio of 0.85 (lean condition). Results showed a 68, 38.4, 14.5, and 43.4% decrease in CO, NOx, CO2, and UHC emissions, respectively, for the B20D30 blend, compared with pure Jet A-1 fuel at the combustor exit, while the B20D10 blend indicated a 15.8, 8.9, 6.17, and 51.4% drop in CO, NOx, CO2, and UHC levels, correspondingly. Jet A-1 achieved a higher maximum temperature than those for other blends. The B20 blend revealed a relative variation in flame temperature distribution, while diethyl ether blends shared a similar temperature distribution compared with Jet A-1. Generally, B20D10 and B20D30 blends had the ability to reduce emission levels. Overall, it can be concluded that the recommended diethyl ether blending ratio is 30%, regarding emission levels and flame temperature profile.