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The utilization of microalgae to treat carbon dioxide (CO2)-rich industrial off-gas has been suggested as both beneficial for emissions reduction and economically favorable for the production of microalgal products. Common sources of off-gases include coal combustion (2–15% CO2), cement production (8–15% CO2), coke production (18–23% CO2), and ore smelting (6–7% CO2). However, industrial off-gas also commonly contains other acid gas components [typically nitrogen oxides (NOX) and sulfur dioxide (SO2)] and metals that could inhibit microalgae growth and productivity. To utilize industrial off-gas effectively in microalgae cultivation systems, a number of solutions have been proposed to overcome potential inhibitions. These include bioprospecting to identify suitable strains, genetic modification to improve specific cellular characteristics, chemical additions, and bioreactor designs and operating procedures. In this review, results from microalgae experiments related to utilizing off-gas are presented, and the outcomes of different conditions discussed along with potential solutions to resolve limitations associated with the application of off-gas. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO2) represents a deleterious effect on acute myocardial infarction (AMI), but few relevant studies have been conducted in China. We aim to evaluate the acute effects of NO2 exposure on hospitalization for AMI in Lanzhou, China. In this study, we applied a distributional lag nonlinear model (DLNM) to assess the association between NO2 exposure and AMI hospitalization. We explored the sensitivity of various groups through stratified analysis by gender, age, and season. The daily average concentration of NO2 is 47.50 ± 17.38 µg/m3. We observed a significant exposure-response relationship between NO2 concentration and AMI hospitalization. The single pollutant model analysis shows that NO2 is positively correlated with AMI hospitalization at lag1, lag01, lag02, and lag03. The greatest lag effect estimate occurs at lag01, where a 10 µg/m3 increase in NO2 concentrations is significantly associated with a relative risk (RR) of hospitalization due to AMI of 1.027 [95% confidence interval (CI): 1.013, 1.042]. The results of the stratified analysis by gender, age, and season indicate that males, those aged ≥65 years, and the cold season are more sensitive to the deleterious effects caused by NO2 exposure. Short-term exposure to NO2 can enhance the risk of AMI hospitalization in urban Lanzhou. Implications: Exposure to particulate matter can lead to an increased incidence of AMI. Our study once again shows that NO2 exposure increases the risk of AMI hospital admission. AMI is a common and expensive fatal condition. Reducing NO2 exposure will benefit cardiovascular health and save on healthcare costs. [ABSTRACT FROM AUTHOR]

Epidemiological studies on air pollution, diabetes, and hypertension conflict. This study examined air pollution, diabetes, and hypertension in adults in 11 metropolitan areas of Iran (2012-2016). Local environment departments and the Tehran Air Quality Control Company provided air quality data. The VIZIT website and Stepwise Approach to Chronic Disease Risk Factor Surveillance study delivered chronic disease data. Multiple logistic regression and generalized estimating equations evaluated air pollution-related diabetes and hypertension. In Isfahan, Ahvaz, and Tehran, PM2.5 was linked to diabetes. In all cities except Urmia, Yasuj, and Yazd, PM2.5 was statistically related to hypertension. O3 was connected to hypertension in Ahvaz, Tehran, and Shiraz, whereas NO2 was not. BMI and gender predict hypertension and diabetes. Diabetes, SBP, and total cholesterol were correlated. Iran's largest cities' poor air quality may promote diabetes and hypertension. PM2.5 impacts many cities' outcomes. Therefore, politicians and specialists have to control air pollution. [ABSTRACT FROM AUTHOR]

This study aimed to determine if air pollution affected the risk of periodontitis outpatient visits. We collected the records of 56,456 periodontitis outpatient visits in Hefei, China, from January 1, 2014 to December 31, 2021. The relationship between air pollution and periodontitis outpatient visits was evaluated using distributed lag nonlinear and generalized linear models. Additional analyses were performed, stratifying the data by age, season, and sex. Subgroup analyses showed a significantly higher risk of periodontitis outpatient visits due to NO2 exposure during the warm season compared with the cold season. Moreover, O3 exposure was associated with a lower risk of periodontitis outpatient visits in the cold season. The findings suggest that NO2 exposure is associated with an increased risk of periodontitis outpatient visits, whereas O3 exposure is associated with a decreased risk of periodontitis outpatient visits. Season is found to be an effect modifier in these associations. [ABSTRACT FROM AUTHOR]

Here is described an instrument for ammonia determination utilizing near-infrared laser absorption suitable for high-temperature applications. The laser wavelength is scanned across the ammonia absorption line at 1.512 µm and wavelength-modulation spectroscopy is simultaneously performed to provide robust and accurate measurements. The thermal effects and beam-steering effects are highlighted in the design. An aluminum baffle is employed to alleviate the adverse impact of elevated temperature on the electronic components and evaluated by an infrared thermographic camera. The beam-steering effects were quantitatively assessed through a combination of two-dimensional computational fluid dynamics and ray tracing analysis. Reference standards from 1 to 20 ppm ammonia were used to verify the system performance. The determined ammonia concentrations exhibit good consistency with the reference values, as demonstrated by a coefficient of determination (R2) of 0.999. Furthermore, a detection limit of 0.02 ppm was achieved using an integration time of 60 s. Pprecision of 0.11 ppm was achieved using 1 s time resolution. [ABSTRACT FROM AUTHOR]

Epidemiologic studies have suggested a possible association between air pollution and chronic obstructive pulmonary disease (COPD), but it is controversial and difficult to draw causal inferences. Five methods were adopted to evaluate the causal relationship between air pollution and COPD in European and East Asian populations by using MR Analysis. A statistically significant causal relationship between PM2.5 and COPD was observed in the European population (OR: 2.34; 95% CI: 1.06–5.05; p = 0.033). Statistical significance remained after adjustment for confounding factors (adjusted OR: 2.28; 95% CI: 1.01–5.20; p = 0.048). In East Asian populations, PM2.5 absorbance, a proxy for black carbon, was statistically associated with COPD (OR: 1.41; 95% CI: 1.09–1.81; p = 0.007). We did not adjust for confounders in East Asian populations, as the association was independent of known confounders (e.g. smoking, respiratory tract infections, etc.). In conclusion, increased concentrations of PM2.5 and PM2.5 absorbance were associated with an increased risk of COPD. [ABSTRACT FROM AUTHOR]

In this experimental work, the effects of copper oxide (CuO) nanoparticles on emissions and performance of 4.4 kW diesel engine powered by palm biodiesel were studied. Palm biodiesel of 20% by volume was blended with diesel fuel (B20). Each test fuel blend was doped with CuO nanoparticles with concentrations of 25, 50, and 75 ppm. Experimentations were carried out for 0%, 25%, 50%, 75%, and 100% engine loads at a constant speed of 1500 rpm. Different parameters, such as brake thermal efficiency (BTE), brake-specific energy consumption (BSEC), carbon monoxide (CO), carbon dioxide (CO2), hydrocarbons (HC), nitrogen oxides (NOx), and smoke opacity were analysed. From the results, it is observed that by using CuO nanoparticles along with B20, BTE (1.18%-7.69%) were significantly increased and BSFC (4.12%-6.76) were lowered. Besides, by using CuO nanoparticles, there were also substantial reductions in CO (2.21%-8.86%). Furthermore, there is an insignificant increase in HC (0.3%-9.78%), CO2 (2.38%-5.97%), and NOx (1.75%-5.27%) emissions when compared to B20 blend. However, when compared to diesel fuel all the emissions were low for all biodiesel blends except NOx emission. Overall, it is concluded that CuO could be considered as a appropriate petroleum additive for palm biodiesel blends. [ABSTRACT FROM AUTHOR]

Asphaltene stabilizers are the main means to inhibit the flocculation and sedimentation of asphaltenes in crude oil exploitation, transportation, and refining operations. In this work, the interactions between asphaltenes and 2-dodecyl benzene sulfonic acid, 4-dodecyl benzene sulfonic acid, 4-dodecyl aniline, 4-dodecyl phenol, polyisobutylene succinic imide benzene boric acid and polyisobutylene succinic imide benzene sulfonic acid were studied by XPS, XRD, DLS, TEM and SEM methods. The aggregation behavior of asphaltenes in the absence and presence of stabilizers was characterized by analyzing asphaltene's particle size, surface composition, and aggregate microstructure. It was observed that the interactions between asphaltene and stabilizers decreased asphaltene aggregate size in solution, and that the polymeric stabilizer with an acidic group was superior to the small-molecule stabilizer with an acidic group, but both better than chemicals with basic groups. It was found that stabilizer adsorption on asphaltenes affected the O, N, S contents of asphaltene surface and prompted formation of protonated pyridinic N+ and nitrogen-oxide -R-N+-O-, which further revealed that an acid-base reaction was the most effective at stabilizing asphaltene-stabilizer complexes, followed by π-π interactions and hydrogen bonds. We also found that the synergistic effects of π-π and acid-base reactions stimulated the transformation of 2-dodecyl benzene sulfonic acid adsorbed on asphaltene from the vertical state at low concentrations to the tiled arrangement at high concentrations. XRD results showed that adsorption of stabilizers on asphaltene increased the distance of asphaltene aromatic sheets and decreased the aggregation number of asphaltene to below the critical aggregation number of asphaltene tactoids. [ABSTRACT FROM AUTHOR]

There are significant gaps in air quality monitoring across many low- and middle-income countries, which can be filled by bioindicators like lichen. This study examined the links between lichen and air quality across urban environments in Nigeria. Lichen surveys and air quality monitoring were carried out across four major cities focusing on NO2, SO2, PM2.5, and PM10. Association rule mining was used to identify robust rules defining the association between lichen and air quality categories. For the maximal frequent set with Lichen in the antecedent, 9 and 5 rules were identified by A priori and Eclat, respectively. These indicated that three genera: Diorygma, Pyxine, and Physcia are the most commonly associated lichen with poor air quality particularly NO2 and SO2. This showed that these lichens are viable indicators of long-term air quality due to their consistent occurrence across the rules from different algorithms. [ABSTRACT FROM AUTHOR]

Carlsbad Caverns National Park (CAVE) is located in southeastern New Mexico and is adjacent to the Permian Basin, one of the most productive oil and natural gas (O&G) production regions in the United States. Since 2018, ozone (O3) at CAVE has frequently exceeded the 70 ppbv 8-hour National Ambient Air Quality Standard. We examine the influence of regional emissions on O3 formation using observations of O3, nitrogen oxides (NOx = NO + NO2), a suite of volatile organic compounds (VOCs), peroxyacetyl nitrate (PAN), and peroxypropionyl nitrate (PPN). Elevated O3 and its precursors are observed when the wind is from the southeast, the direction of the Permian Basin. We identify 13 days during the July 25 to September 5, 2019 study period when the maximum daily 8-hour average (MDA8) O3 exceeded 65 ppbv; MDA8 O3 exceeded 70 ppbv on 5 of these days. The results of a positive matrix factorization (PMF) analysis are used to identify and attribute source contributions of VOCs and NOx. On days when the winds are from the southeast, there are larger contributions from factors associated with primary O&G emissions; and, on high O3 days, there is more contribution from factors associated with secondary photochemical processing of O&G emissions. The observed ratio of VOCs to NOx is consistently high throughout the study period, consistent with NOx-limited O3 production. Finally, all high O3 days coincide with elevated acyl peroxy nitrate abundances with PPN to PAN ratios > 0.15 ppbv ppbv-1 indicating that anthropogenic VOC precursors, and often alkanes specifically, dominate the photochemistry. Implications: The results above strongly indicate NOx-sensitive photochemistry at Carlsbad Caverns National Park indicating that reductions in NOx emissions should drive reductions in O3. However, the NOx-sensitivity is largely driven by emissions of NOx into a VOC-rich environment, and a high PPN:PAN ratio and its relationship to O3 indicate substantial influence from alkanes in the regional photochemistry. Thus, simultaneous reductions in emissions of NOx and non-methane VOCs from the oil and gas sector should be considered for reducing O3 at Carlsbad Caverns National Park. Reductions in non-methane VOCs will have the added benefit of reducing formation of other secondary pollutants and air toxics. [ABSTRACT FROM AUTHOR]

Carlsbad Caverns National Park (CAVE), located in southeastern New Mexico, experiences elevated ground-level ozone (O3) exceeding the National Ambient Air Quality Standard (NAAQS) of 70 ppbv. It is situated adjacent to the Permian Basin, one of the largest oil and gas (O&G) producing regions in the US. In 2019, the Carlsbad Caverns Air Quality Study (CarCavAQS) was conducted to examine impacts of different sources on ozone precursors, including nitrogen oxides (NOx) and volatile organic compounds (VOCs). Here, we use positive matrix factorization (PMF) analysis of speciated VOCs to characterize VOC sources at CAVE during the study. Seven factors were identified. Three factors composed largely of alkanes and aromatics with different lifetimes were attributed to O&G development and production activities. VOCs in these factors were typical of those emitted by O&G operations. Associated residence time analyses (RTA) indicated their contributions increased in the park during periods of transport from the Permian Basin. These O&G factors were the largest contributor to VOC reactivity with hydroxyl radicals (62%). Two PMF factors were rich in photochemically generated secondary VOCs; one factor contained species with shorter atmospheric lifetimes and one with species with longer lifetimes. RTA of the secondary factors suggested impacts of O&G emissions from regions farther upwind, such as Eagle Ford Shale and Barnett Shale formations. The last two factors were attributed to alkenes likely emitted from vehicles or other combustion sources in the Permian Basin and regional background VOCs, respectively. Implications: Carlsbad Caverns National Park experiences ground-level ozone exceeding the National Ambient Air Quality Standard. Volatile organic compounds are critical precursors to ozone formation. Measurements in the Park identify oil and gas production and development activities as the major contributors to volatile organic compounds. Emissions from the adjacent Permian Basin contributed to increases in primary species that enhanced local ozone formation. Observations of photochemically generated compounds indicate that ozone was also transported from shale formations and basins farther upwind. Therefore, emission reductions of volatile organic compounds from oil and gas activities are important for mitigating elevated O3 in the region. [ABSTRACT FROM AUTHOR]

Numerous studies have evaluated the effects of lockdowns during the COVID-19 pandemic, but most of them have concerned large cities and regions. This study aimed to evaluate the dynamics of air pollutants during and after the implementation of a short lockdown in the medium-sized city of Pelotas, Brazil, using hourly measurements of pollutants. The evaluation period included in this study was between August 9th and 12th, 2020. A machine learning model was used to investigate the expected behavior against what was observed during the study period. All pollutants presented a gradual reduction until a dynamic plateau established 48 hours after the start of the lockdown: NO2 (↓4%), O3 (↓34%), SO2 (↓24%), CO (↓48%), PM10 (↓82%) and PM2.5 (↓82%). At the end of the restriction measures, the PM10 and PM2.5 levels continued to decline beyond expectations. Our findings show that these measures can positively affect the air quality in medium-sized cities. [ABSTRACT FROM AUTHOR]

Diesel engine exhaust (DE) consists of a complex mixture of gases and aerosols, originating from sources such as engines, turbines, and power generators. It is composed of a wide range of toxic compounds ranging from constituents that are irritating to those that are carcinogenic. The purposes of this work were to characterize DE originating from different engine types on a ship operating offshore and to quantify the potential exposure of workers on the ship's helicopter deck to select DE compounds. Sampling was conducted on a Norwegian Nansen-class frigate that included helicopter operations. Frigate engines and generators were fueled by marine diesel oil, while the helicopter engine was fueled by high flash point kerosene-type aviation fuel. Exhaust samples were collected directly from the stack of the diesel engine and one of the diesel generator exhaust stacks, inside a gas turbine exhaust stack, and at the exhaust outlet of the helicopter. To characterize the different exhaust sources, non-targeted screening of volatile and semi-volatile organic compounds was performed for multiple chemical classes. Some of the compounds detected at the sources are known irritants, such as phthalic anhydride, 2,5-dyphenyl-p-benzoquinone, styrene, cinnoline, and phenyl maleic anhydride. The exhaust from the diesel engine and diesel generator was found to contain the highest amounts of particulate matter and gaseous compounds, while the gas turbine had the lowest emissions. Personal exposure samples were collected outdoors in the breathing zone of a helicopter deck operator over nine working shifts, simultaneously with stationary measurements on the helicopter deck. Elemental carbon, nitrogen dioxide, and several volatile organic compounds are known to be present in DE, such as formaldehyde, acrolein, and phenol were specifically targeted. Measured DE exposures of the crew on the helicopter deck were variable, but less than the current European occupational exposure limits for all compounds, except elemental carbon, in which concentration varied between 0.5 and 37 µg/m3 over nine work shifts. These findings are among the first published for this type of working environment. [ABSTRACT FROM AUTHOR]

Two features in time series data: the existence of time trends and the degree of persistence, are examined in this work on the nitrogen oxides emissions from 37 OECD countries. Updated techniques in time series are used that allow for fractional degrees of differentiation in the data. Thus, if the number of differences required is one, nitrogen oxides emissions are not mean reverting in the sense that if there is an exogenous shock (resulting from a technological advancement to change nitrogen oxides emissions), the effect of such shock on nitrogen oxides emissions will be permanent. Time trends are observed in half of the series. For these countries the trend coefficient is found to be positive in all cases. This is an indication that continuous technological progress is needed in taming NOx emissions. In addition to developing their own local technologies, less technologically endowed OECD countries should engage in collaboration with the more technologically endowed countries in order to facilitate increase in trans-border transfer of technology. The technologically advanced countries should also strive to continue to introduce better technologies in a bid to reduce NOx emissions. Most of the results show evidence for persistence of nitrogen oxides emissions. [ABSTRACT FROM AUTHOR]

This study investigated the correlation between the concentration of air pollutants in two metropolitan cities, Seoul and Incheon, located in South Korea with different urban characteristics and the number of patients with circulatory diseases among residents exposed to air pollution. The residential area was selected as Eunpyeong-gu of Seoul Metropolitan City and the industrial area as Jung-gu of Incheon Metropolitan City. The evaluation period is between 2015 and 2016. The relevant data provide by the Korea governmental agency were analysed to derive the purpose of this study. It was confirmed that PM10, PM2.5, nitrogen dioxide, carbon monoxide, and sulfur dioxide among air pollutants had an increasing impact on the incidence rate of circulatory diseases. The PM2.5 was positively correlated with the incidence rate of all circulatory diseases in residential area (p < 0.05). The carbon monoxide showed a positive correlation with circulatory system diseases except for hypertension in residential area. (p < 0.05). The sulfur dioxide was positively correlated with all circulatory diseases in both residential and industrial area (p < 0.05). Based on the results obtained from this study, it was found that there are different types of air pollutants that affect circulatory diseases in residential and industrial areas. [ABSTRACT FROM AUTHOR]

Flue gases emitted from the industries and other emission sources are considered the main atmospheric issues. The main Flue gases emitted are sulfur oxides SOX and Nitrogen oxides NOX. The study was about methods of removing SOX and NOX from emitted gases and the possibility of deriving useful byproducts. The process for removing was investigated using different absorbers, process conditions, and phosphorus allotropes. The yellow phosphorus (P4) was applied for removal accompanied by Potash. The simultaneous removal achieved higher removing efficiency for SOX than NOX. Yellow phosphorus emulsion proved to be one of the effective SOX and NOX removal techniques. Byproducts produced from SOX and NOX proved to contain the complete fertiliser Nitrogen Phosphorus Potassium NPK. The obtained results showed that several useful byproducts can be derived from SOX and NOX removal process. [ABSTRACT FROM AUTHOR]

Sulfur dioxide (SO2) and nitrogen oxides (NOx) in flue gas are a hazardous atmospheric pollutant associated with coal combustion and non-ferrous metal production. Here we report that laboratory pilot unit for scrubbing of industrial flue gas containing 80 ± 2 ppm SO2 followed by melt regeneration with either CO or natural gas, verified that only 1.5–2.0 ppm SO2 remained in the flue gas. The tests with the semi-industrial scale unit (271.26 kg of the eutectic carbonate melt and flue gas containing 0.15% SO2, 13 ppm NO, 52 ppm NO2) were received. In all tests, sulfur extraction from flue gas to the carbonate melt was >90–95% and nitrogen oxides extraction from flue gas to the carbonate melt was 60%. Sulfur and nitrogen oxides extraction from carbonate–sulfate–nitrite melt during regeneration stage was >99%. Carbonate melt-based SO2 scrubbing therefore represents a practical and economical method for limiting sulfur and NOx emission to the atmosphere from both coal-firing power stations and non-ferrous metallurgical processing plants. [ABSTRACT FROM AUTHOR]

With mushrooming growth of coal-based industry, the discharged tail gas containing nitrogen oxides had given significant effect on air quality and people's health in China. Therefore, more stringent NOx emission standards were proposed. Among many technologies, wet scrubbing technology may be an effective way to solve the above problem, but it was limited by absorption of nitrogen oxides. Therefore, rotating packed bed (RPB) was used to intensify the absorption process of nitrogen oxides by ferrous chelate solution. To speed up its industrialization, a theoretical model was proposed by considering chemical reactions, gas and liquid mass transfer rate, liquid holdup and gas–liquid effective interfacial area. The effects of high gravity factor, gas velocity, gas–liquid ratio, temperature and concentration of ferrous chelate solution on NOx removal efficiency were conducted by model and also compared with experimental results. With high absorption efficiency and small equipment size in RPB, it had a great potential to apply in the absorption other harmful matters. [ABSTRACT FROM AUTHOR]

Dinosaur National Monument (DINO) is located near the northeastern edge of the Uinta Basin and often experiences elevated levels of wintertime ground-level ozone. Previous studies have shown that high ozone mixing ratios in the Uinta Basin are driven by elevated levels of volatile organic compounds (VOCs) and nitrogen oxides (NOx) from regional oil and gas development coupled with temperature inversions and enhanced photochemistry from persistent snow cover. Here, we show that persistent snow cover and temperature inversions, along with abundant ammonia, also lead to wintertime haze in this region. A study was conducted at DINO from November 2018 through May 2020 where ozone, speciated fine and coarse aerosols, inorganic gases, and VOCs were measured. Three National Ambient Air Quality Standards (NAAQS) ozone exceedances were observed in the first winter, and no exceedances were observed in the second winter. In contrast, elevated levels of particulate matter were observed both winters, with 24-h averaged particle light extinction exceeding 100 Mm−1. These haze events were dominated by ammonium nitrate, and particulate organics were highly correlated with ammonium nitrate. Ammonium nitrate formation was limited by nitric acid in winter. As such, reductions in regional NOx emissions should reduce haze levels and improve visibility at DINO in winter. Long-term measurements of particulate matter from nearby Vernal, Utah, suggest that visibility impairment is a persistent issue in the Uinta Basin in winter. From April through October 2019, relatively clean conditions occurred, with average particle extinction of ~10 Mm−1. During this period, ammonium nitrate concentrations were lower by more than an order of magnitude, and contributions from coarse mass and soil to haze levels increased. VOC markers indicated that the high levels of observed pollutants in winter were likely from local sources related to oil and gas extraction activities. Implications: Elevated ground-level ozone and haze levels were observed at Dinosaur National Monument in winter. Haze episodes were dominated by ammonium nitrate, with 24-h averaged particle light extinction exceeding 100 Mm−1, reducing visual range near the surface to ~35 km. Despite elevated ammonium nitrate concentrations, additional gas-phase ammonia was available, such that any increase in NOx emissions in the region is likely to lead to even greater haze levels. [ABSTRACT FROM AUTHOR]

Experimental research has been conducted to study the influence of aqueous nanofluids such as aqueous zinc oxide nanofluid (ZN), aqueous aluminium oxide nanofluid (AN), aqueous cerium oxide nanofluid (CN) on performance and the emission behavior of a compression-ignition engine powered by blends of nanofluids. In this research, the dosage levels of aqueous nanofluid vary with diesel. For each nanofluid, four dosage levels, namely 3%, 4%, 5%, and 6% by weight, are identified and twelve blends are prepared. The effects of aqueous nanofluids on various chemical and physical properties of diesel are studied. Load tests on the engine with blends and diesel are carried out. The combustion characteristics, performance, and exhaust emissions of the blends are studied and compared to pure diesel. The results obtained indicate that the blends with 5% of CN, 5% of AN, and 5% of ZN showed better results among their other blends and the blend with 5% of CN showed the best performances compared to all blends and diesel. Compared to diesel, the 5% CN blend produced 6.28% more brake thermal efficiency and a reduction of 36.36% in hydrocarbons, 17.24% in carbon monoxide, 18.75% in nitrogen oxides and 30% in smoke emissions at maximum rated load. [ABSTRACT FROM AUTHOR]

Background: Severe nitrogen oxide poisoning can lead to life-threatening pulmonary injury. Methods: we report two cases of severe nitrogen-oxide-induced hypoxia treated with veno-venous extracorporeal membrane oxygenation (ECMO). After exposure, the conditions of both patients continued to deteriorate despite maximal mechanical ventilation with a fraction of inspired oxygen of 100%; therefore, we started veno-venous ECMO. The times from presentation to the initiation of ECMO in the two patients were 1 and 2 days. The hypoxemia and respiratory failure improved quickly after ECMO support. Results: The patients were discharged without complications. The durations of ECMO for the two patients were 5 and 6 days. Conclusion: This report describes how early ECMO support was used to treat potentially fatal pulmonary injury after exposure to nitrogen oxide. The duration of the ECMO run is a critical determinant of patient survival. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine the relationship between weekly specific maternal air pollution exposures and low birth weight. We fitted a distributed lag nonlinear model (DLNM) to analyze the nonlinear exposure-response association and delayed effects of air pollutants on the risk for low birth weight. The model assumed that all live births have 40 gestational weeks.The 1st week lag was the 40th gestational week, and 40th lag week was the 1st gestational week.The study included 71,809 live births (from July 1, 2016, to June 30, 2019), of which 2,391 (3.33%) exhibited low birth weight. The results demonstrated that exposure of pregnant women to PM10 at lag 22-30 weeks was significantly associated with low birth weight risk, with the greatest impact at the lag 30 week. Exposure to SO2 at lag 29-37 weeks was significantly associated with low birth weight risk. The sensitive exposure window for NO2 began at lag 25-37 weeks of pregnancy. The lag 6-10 weeks constituted the susceptible exposure window for O3. Therefore we concluded that maternal exposures to PM10, SO2, NO2, and O3 were associated with increased risk for low birth weight. [ABSTRACT FROM AUTHOR]

This study aimed to assess the relationship between nitrogen dioxide (NO2) exposure and the risk of eye and adnexa diseases (EADs) among children in Shenzhen, China. Information about the daily number of outpatients with EADs and the concentration of air pollutants and meteorological data were collected. A generalized additive model was used to assess the effect of NO2 exposure on the risk of EADs during outpatient visits. An increase in NO2 level by 10 μg/m3 was related to an increase in the daily number of outpatients by 5.43% (95% confidence interval [CI]: 2.25%, 8.70%) at lag0, by 4.35% (95% CI: 1.15%, 7.66%) at lag1, and by 3.21% (95% CI: 0.05%, 6.47%) at lag3. In addition, the relationship between NO2 exposure and the risk of dacryoadenitis was the strongest, with an estimated value of 15.0% (95% CI: 7.99%, 22.5%) at lag0. Moreover, the association between NO2 exposure and the risk of EADs among children in Shenzhen was confirmed in this study. Therefore, the government should introduce stringent environmental policies to control air pollution and protect human health, particularly that of the vulnerable population. [ABSTRACT FROM AUTHOR]

The implementation of pollutant emission control has made initial achievements in the plant power, iron, and steel industries in China. To further improve air quality, it is of great significance to carry out research on zero-impact emissions of the petrochemical industry. Based on the existing concept and practice of zero emissions, this study proposes the concept of zero-impact emissions, taking emission concentration as the constraint. A typical petrochemical enterprise (namely Enterprise A) in Shanghai Chemical Industry Park as the research object, and used the CALPUFF model to simulate the target pollutant emissions (i.e. sulfur dioxide (SO2), nitrogen oxide (NOx), particulate matter (PM), and volatile organic compounds (VOCs)). The current emission standard, spatial distributions, and emission heights of chimneys in Enterprise A was considered as the baseline emission scenario and taking the zero-impact emission as a target for simulation. The results show that the current emission standards of NOx and VOCs (benzene) exceeded the zero-impact emission limits, and needed to be reduced by 22% and 87.5%, respectively. Moreover, the areas that exceeded the zero-impact concentration limits were located northwest of the chimneys and Hangzhou Bay. In terms of seasonal effects, the wind conditions in spring were more adverse for the enterprise to achieve zero-impact emissions. Based on the simulation, the zero-impact emission limits of SO2, NOx, PM, and VOCs (benzene) for Enterprise A were 50 mg/m³, 78 mg/m³, 10 mg/m³, and 0.32 mg/m³, respectively.Implications: Through case study, this paper solves the environmental management issue which is of universal significance for chemical industry park. The concept of zero-impact emissions and the determination method of zero-impact concentration limits proposed in this study could be used as references for related research on cutting emissions. Although the conclusion of this study about the emission limits is not suitable for other enterprises to apply directly, the calculation method of zero-impact emission limit can be used by other enterprises. Furthermore, the zero-impact emission limits on park scale can be determined after comprehensive evaluation based on the calculation results of multiple enterprises. [ABSTRACT FROM AUTHOR]

Sampling and analysis of filterable particulate matter (FPM), FPM2.5, condensable particulate matter (CPM), polycyclic aromatic hydrocarbons (PAHs), sulfur oxides (SOx), and nitrogen oxides (NOx) emitted from a coal-fired boiler equipped with selective catalytic reduction (SCR)+ electrostatic precipitator (ESP) + wet flue gas desulfurization (WFGD) + wet electrostatic precipitator (WESP) as air pollution control devices (APCDs) are conducted. The results show that NOx concentration emitted from the coal-fired boiler is 56 ± 2.17 ppm (with the NOx removal efficiency of 47.2%), which does not meet the best available control technology (BACT) emission standard (≤ 30 ppm). On the other hand, the WFGD adopted has a good removal efficiency for SOx and HCl. Both SOx and HCl emission concentrations are < 1 ppm, and removal efficiencies are > 99%. The FPM and FPM2.5 emitted from the coal-fired boiler are 0.9 ± 0.06 mg/Nm³ and < 0.09 ± 0.006 mg/Nm³, respectively. The overall removal efficiency of FPM achieved with ESP+WFGD+WESP+MGGH is 99.98%. However, high concentration of CPM (37.4 ± 6.3 mg/Nm³) is measured, which is significantly higher than FPM and FPM2.5. The concentrations of 27 PAHs at the WESP inlet and stack are measured as 667 ng/Nm³ and 547 ng/Nm³, respectively while the removal efficiencies of gas- and solid-phase PAHs are 9% and 58%, respectively. The results show that APCDs adopted are not effective in removing PAHs (only 18%), and gas-phase PAHs contribute the most in the total PAH emission. In addition, the benzo(a)pyrene equivalent (BaPeq) concentration emitted from the stack is 28.8 ng-BaPeq/Nm³, and most of it is contributed by 4–6 ring PAHs with high toxic equivalent factors (TEFs). Furthermore, the emission factors of air pollutant emitted from coal-fired boilers equipped with different combinations of APCDs are compiled and compared. The results show that except for CPM and NOx, the emission factors of air pollutant calculated for this coal-fired boiler are lower if compared with other studies.Implications: Primary particles discharged from coal-fired processes include filterable particulate matter (FPM) and condensable particulate matter (CPM). PM2.5 emissions would be greatly underestimated if CPM is ignored. Polycyclic aromatic hydrocarbons (PAHs) are semi-volatile organic compounds (SVOCs) formed by two or more fused benzene rings. PAHs have attracted much public attention because of toxicity and carcinogenicity. This study selects one coal-fired boiler with the best available control technology (BACT) to simultaneously measure the concentrations of PM, PAHs, and gaseous pollutants at the inlet and outlet of air pollution control devices (APCDs) to understand the efficacy of APCDs adopted and pollutant emission intensity. [ABSTRACT FROM AUTHOR]

Fine particulate matter (PM2.5) is one of the main pollutants in the atmosphere and poses a huge threat to public health. Secondary aerosol pollutants that are formed by precursor pollutants in the atmosphere represent a large proportion of PM2.5; furthermore, photochemical reactions play an important role in their transformation processes. This review systematically presents the chemical and toxicological transformations of secondary organic aerosol (SOA), secondary inorganic aerosol (SIA), and metal species in PM2.5 under photochemical conditions. Specifically, major SOAs and SIAs are observed to be formed from volatile organic compounds (VOCs) and sulfur/nitrogen oxides through photochemical reactions, while metal species in PM2.5 participate in a series of photochemical reactions. Additionally, we compare the toxicities of precursor pollutants with their secondary pollutants after photochemical reactions. In general, major SOAs are found to be more toxic than their precursors, while major SIAs are less toxic than their precursors. As different metal species have different toxicities, changes in their toxicities after photoreaction depend on the specific metal and the photochemical reaction. By demonstrating that photochemical reactions can affect the toxicities of PM2.5 components, this review provides a promising perspective toward reducing air pollution and its health risks by investigating the related photochemical reactions. [ABSTRACT FROM AUTHOR]

Civil dispersed coal combustion has become an important source of Nitrogen oxides (NOx), which has caused serious pollution to the ecological environment. In order to control NOx emission in the combustion process of civil coal, coal-based solid clean fuel should be used instead of dispersed combustion of coal, so as to achieve the purpose of reducing NOx emission. The pyrolysis and combustion tests of different iron additives loaded coals were performed. The raw and pyrolytic chars were prepared and characterized by X-ray photoelectron spectroscopy (XPS), nitrogen adsorption, scanning electron microscope (SEM) and X-ray diffraction (XRD). The results indicate that iron additives introduced into raw coal in one step have coupling effect on NOx emission control during pyrolysis and combustion. The addition of iron can lead to more Fe2O3, Fe3O4 and α-Fe in coke and promote coke cracking. Supporting iron catalysts could make coke structure more porous, which increases the contact area of gas. These all make the conversion of N2 increase from 16.71% to 29.64% during pyrolysis. The existence of iron catalyst can also promote the proportion of pyridinic N (N-6) and quaternary nitrogen (N-Q) relatively increase. At the same time, the existence of iron catalyst is beneficial to catalytic reduction of NOx by C and CO. The emissions of NOx during combustion can be reduced by 34.01%. The iron catalyst introduced in one step has a coupling effect on NOx control in coal pyrolysis-combustion process, which realizes a two-step nitrogen reduction effect in combustion. It provides theoretical basis for ultra-low NOx emission in clean fuel combustion. [ABSTRACT FROM AUTHOR]

It is not a deniable fact that the incessant reduction of fossil fuel is terrible for most of us. It becomes vital to have access to other substitute resources. Biodiesel is known as a green fuel produced through a 'transesterification' process whereby oil (triglycerides) and methanol are used along with the support of homogeneous as well as heterogeneous catalysts. The usage of homogeneous catalysts results into obstacles such as; soap formation reaction, difficulties in separation of catalysts from the mixture as well as assured higher expense. To overcome these hurdles, various basic or acidic heterogeneous catalysts have been applied for biodiesel synthesis. But such catalysts have drawbacks like; mass transfer resistance, time consumption, fast deactivation, inefficiency of the catalytic process and most importantly a fact that cannot be neglected, they are hazardous for the environment. Nevertheless, these issues can be mitigated by employing nano-sized particles of metal oxides as catalysts. The synthesized nanoparticles with high specific surface area, catalytic activity and selectivity can solve most of such complications arising in the transesterification reaction. Nanoparticles can play an important role in enhancing the product quality and achieving optimal operating condition for such process. In this paper, efforts have been thru by the authors to provide an insight regarding the synthesis of biodiesel with the help of nanocatalysts that has been so far observed, analyzed and applied. Abbreviations: ASTM: American Society for Testing and Materials; BaO: Barium oxide; CaO: Calcium oxide; FAME: Fatty Acid Methyl Ester; FFA: Free Fatty Acid; H2SO4: Sulfuric Acid; HC: Hydrocarbons; HCl: hydrochloric acid; KL: Kraft Lignin; KOH: Potassium Hydroxide; LiO2: Lithium Oxide; MgO: Magnesium oxide; NaOH: Sodium Hydroxide; NOx: Nitrogen oxide; PAH: Polycyclic Aromatic Hydrocarbons; SDBS: Sodium Dodecyl Benzene Sulfonate; SrO: Strontium oxide; SWCNH: Single-Walled Carbon Nanohorn; TiO2: Titanium dioxide/Titania; UCO: Used Cooking Oil; ZrO2: Zirconium dioxide; ZnO: Zinc oxide. [ABSTRACT FROM AUTHOR]

Natural gas (NG) has many advantages of clean fuels and can replace gasoline in spark ignition (SI) engines. However, it comes with disadvantages such as low energy density. Hydrogen blended NG can improve the fuel characteristics. Ignition timing also plays an important role in engine performance, especially at lean limits. Experiments were conducted for performance and emissions with hydrogen-compressed natural gas (HCNG) blends in a spark ignition (SI) engine with fixed ignition timing. HCNG blends with 0–15% hydrogen were tested with maximum brake torque (MBT) spark timing 30° before top dead center (BTDC) ignition. Significant reduction of carbon monoxide (CO), carbon dioxide (CO2) and hydrocarbons (HC) along with improved break thermal efficiency was observed with higher hydrogen fraction. There was no significant benefit in indicated thermal efficiency or NOx reduction by using MBT ignition. Hence, the expensive retrofitting of using variable spark timing apparatus can be avoided for on-road vehicles. [ABSTRACT FROM AUTHOR]

Recent studies have reached mixed conclusions regarding the association between exposure to air pollutants and attention-deficit hyperactivity disorder (ADHD). We performed systematic review and meta-analysis to determine whether air pollutants were risk factors for the development of ADHD in children. We systematically searched databases for all relevant studies up to 2 July 2019. Together, the studies indicated that exposure to PAHs (risk ratio (RR): 0.98, 95% confidence interval (CI): 0.82–1.17), NOx (RR: 1.04, 95% CI: 0.94–1.15), and PM (RR: 1.11, 95% CI: 0.93–1.33) did not have any material relationship with an increased risk of ADHD. Heterogeneity of study data was low (I2: 2.7%, P = 0.409) for studies examining PAHs, but was substantial for NOx and PM (I2: 68.4%, P = 0.007 and I2: 60.1%, P = 0.014, respectively). However, these results should be interpreted with caution since the number of epidemiological studies investigating this issue were limited. [ABSTRACT FROM AUTHOR]

Fine particulate matter (PM2.5) is one of the main pollutants in the atmosphere and poses a huge threat to public health. Secondary aerosol pollutants that are formed by precursor pollutants in the atmosphere represent a large proportion of PM2.5; furthermore, photochemical reactions play an important role in their transformation processes. This review systematically presents the chemical and toxicological transformations of secondary organic aerosol (SOA), secondary inorganic aerosol (SIA), and metal species in PM2.5 under photochemical conditions. Specifically, major SOAs and SIAs are observed to be formed from volatile organic compounds (VOCs) and sulfur/nitrogen oxides through photochemical reactions, while metal species in PM2.5 participate in a series of photochemical reactions. Additionally, we compare the toxicities of precursor pollutants with their secondary pollutants after photochemical reactions. In general, major SOAs are found to be more toxic than their precursors, while major SIAs are less toxic than their precursors. As different metal species have different toxicities, changes in their toxicities after photoreaction depend on the specific metal and the photochemical reaction. By demonstrating that photochemical reactions can affect the toxicities of PM2.5 components, this review provides a promising perspective toward reducing air pollution and its health risks by investigating the related photochemical reactions. [ABSTRACT FROM AUTHOR]

Carbon taxation affects carbon dioxide (CO2) emissions through the price of fossil fuels, and hence can also affect emissions of air pollutants. Based on this fact, this study aims at exploring the impact of the carbon tax in Japan on various pollutants' emissions, using a regression-based approach. The main contribution of this study is to assess the impact of a tax that is mainly directed at cutting CO2, on other gases, namely sulphur dioxide (SO2), suspended particulate matter (SPM), carbon monoxide (CO) and nitrogen oxide (NOX), as well as analyzing the impact of this tax on different sectors of the Japanese economy. Our results imply that the introduction of the carbon tax in Japan effectively reduced non-CO2 greenhouse gases (GHGs) and pollutants, even when controlling for demographic and economic variables. The results of this study can be explained by a partial decoupling of fossil fuel consumption and GHG emissions, possibly through investment in anti-pollution measures. [ABSTRACT FROM AUTHOR]

We identified two climatological parameters that are key to modeling the behavior of tropospheric ozone (O3) produced in the urban area of a heavily polluted city in the Colombian Andes. These parameters are the relative humidity (RH) and total radiation intensity (I). In topographically constrained areas, the production of tropospheric O3, as a by-product during photo-oxidation of carbon monoxide (CO) and nitrogen oxides (NO and NO2) has received much attention over the last decades. Models used to describe O3 dynamics are based on computationally demanding techniques that require lots of input data, however. This study proposes a simple approach for describing O3. To that end, it evaluates fifteen empirical models based on the combination of four linear regressions: O3 against RH, temperature (T), wind speed (U), and I. Each model is driven by the analyzed climatological parameters over the period from 2012 to 2018 and further run using either daily or monthly averaged data. The best fitting model for monthly averaged data outperformed that for daily averaged data in both mathematical simplicity and accuracy; however, the differences between these models remained <0.4 percent. The results suggest that the O3 produced increases with I and decreases with RH. [ABSTRACT FROM AUTHOR]

Bismuth(III) nitrate (Bi(NO3)3) has pharmaceutical applications and is usually produced from elemental bismuth dissolution in nitric acid (HNO3). However, if bismuthinite (Bi2S3), which is one of the main minerals of bismuth, is used to produce elemental bismuth, sulfur dioxide (SO2), carbon monoxide (CO), and nitrogen oxides (NOx) are produced, which are three of the air pollutants considered the most serious threats to human health and welfare. This communication takes a thermodynamic approach to examine and then suggests an environmentally friendlier procedure to produce Bi(NO3)3: the direct dissolution of Bi2S3 in 1 M HNO3 at room temperature (25 °C). [ABSTRACT FROM AUTHOR]

Nitrogen oxides conversion rate, ammonia slip, and urea crystallization are major problems in the application of the selective catalytic reduction systems of diesel engine. Based on the bench test, the selective catalytic reduction system model was proposed with the code AVL Fire to investigate these problems. The research results indicate that the increasing ammonia/nitrogen oxides feed ratio contributes to reduce the emission of nitrogen oxides. However, the excessive supply of urea-water solution causes the increase of ammonia slip and liquid film. Nitrogen oxides conversion rate reaches a higher level when the exhaust temperature is 450°C. The performance of the system goes worse as the exhaust flow rate increases. The location of the mixer has a huge impact on the flow streamline. The formation of the liquid film and the interaction between the pipe and the droplets depend on the flow streamline. The mixer location is optimized to reduce the quantity of ammonia slip and liquid film based on the numerical study. [ABSTRACT FROM AUTHOR]

The stability and performance of nitrate ester-based energetic materials may be compromised by their degradation, which is primarily promoted by the NOx. To overcome this issue, the typical approach is the addition of stabilizers to the original formulation of the energetic materials. However, this is not always suitable, particularly if pure materials are needed. Thus, this work presents a new method consisting of capturing the released NOx on activated carbons impregnated with TiO2 nanoparticles. The principle is to perform the oxidation of NOx to HNO3 by photocatalysis in presence of TiO2. Consequently, four different activated carbons are prepared by chemical activation with ZnCl2 and H3PO4 to achieve diverse textural and functional properties. They are subjected to impregnation with 1 wt. % of TiO2. Hence, they are thoroughly characterized by means of nitrogen sorption isotherms, Fourier transform infrared spectroscopy and X-ray fluorescence. Afterwards, their efficiency under different light conditions is assessed through the capture of NOx evolved from the accelerated degradation of nitrocellulose quantified by Bergmann-Junk test. The quantity of captured NOx is determined by ion chromatography. The results show that a combination of a micro and mesoporous material with low surface functions is the optimal criterion to achieve the desired deposition rate of TiO2. This is obtained by the heat-treated activated carbon synthetized using H3PO4. In addition, more than 60% of the released NOx are efficiently captured by the prepared materials under ultraviolet light, corresponding to 0.0723 mmol of NOx per gram of impregnated activated carbon. [ABSTRACT FROM AUTHOR]

To eliminate nitrogen oxides (NOx), composite carrier-supported catalysts (Mn-Ce/MWCNT-W) and traditional catalysts (Mn-Ce/MWCNT and W-Mn-Ce/MWCNT) were prepared using an ultrasonic impregnation method that preformed low-temperature ammonia-selective catalytic reduction (SCR) removal of NOx. The promotion effects of MWCNT-W composite carriers for low temperature SCR activities and SO2 tolerance of the catalysts were systematically investigated. Compared to traditional catalyst, Mn-Ce/MWCNT-W catalyst, with a 30% WOx/MWCNT mass ratio, demonstrated improved SCR activity and high N2-selectivity from 100°C to 200°C. A series of characterizations were carried out and it was found that there were more redox sites and the stronger the NH3 adsorption capacity over the composite carrier-supported catalysts than traditional catalysts. Also, with this composite carrier-supported catalyst, the improvement of SCR reaction was considered to be from the abundance of high valence state Mn and well dispersed active components. Notably, compared to traditional catalyst, the composite carrier-supported catalyst exhibited the stronger sulfur resistance. Thus, using MWCNT-W composite carriers to prepare Mn-Ce/MWCNT-W catalysts resulted in excellent NOx conversion and SO2 resistance at low temperatures. Implications: LT NH3-SCR of NOx is an effective way to remove NOx from stationary sources. The physicochemical properties of the support not only affect a catalyst's LT SCR activity but also affect the catalyst's anti-poisoning performance. The modified carriers could promote active component dispersion, which is conducive to SCR reaction. However, for LT SCR reactions, few reports have addressed the design and preparation of composite carrier-supported catalysts. The goal of this study was to design and synthesize Mn-Ce/MWCNT-W catalysts and to observe the influence of composite support in Mn-based catalysts on LT SCR activity and sulfur resistance. [ABSTRACT FROM AUTHOR]

To eliminate nitrogen oxides (NOx), composite carrier-supported catalysts (Mn-Ce/MWCNT-W) and traditional catalysts (Mn-Ce/MWCNT and W-Mn-Ce/MWCNT) were prepared using an ultrasonic impregnation method that preformed low-temperature ammonia-selective catalytic reduction (SCR) removal of NOx. The promotion effects of MWCNT-W composite carriers for low temperature SCR activities and SO2 tolerance of the catalysts were systematically investigated. Compared to traditional catalyst, Mn-Ce/MWCNT-W catalyst, with a 30% WOx/MWCNT mass ratio, demonstrated improved SCR activity and high N2-selectivity from 100°C to 200°C. A series of characterizations were carried out and it was found that there were more redox sites and the stronger the NH3 adsorption capacity over the composite carrier-supported catalysts than traditional catalysts. Also, with this composite carrier-supported catalyst, the improvement of SCR reaction was considered to be from the abundance of high valence state Mn and well dispersed active components. Notably, compared to traditional catalyst, the composite carrier-supported catalyst exhibited the stronger sulfur resistance. Thus, using MWCNT-W composite carriers to prepare Mn-Ce/MWCNT-W catalysts resulted in excellent NOx conversion and SO2 resistance at low temperatures. Implications: LT NH3-SCR of NOx is an effective way to remove NOx from stationary sources. The physicochemical properties of the support not only affect a catalyst's LT SCR activity but also affect the catalyst's anti-poisoning performance. The modified carriers could promote active component dispersion, which is conducive to SCR reaction. However, for LT SCR reactions, few reports have addressed the design and preparation of composite carrier-supported catalysts. The goal of this study was to design and synthesize Mn-Ce/MWCNT-W catalysts and to observe the influence of composite support in Mn-based catalysts on LT SCR activity and sulfur resistance. [ABSTRACT FROM AUTHOR]

Traffic authorities have taken various measures to mitigate vehicular-source pollution emissions, among which setting speed limits has been proved to be effective. However, most of the existing macroscopic research proposes idealized mathematical models to design optimal speed limit from the perspective of network equilibrium, and the simplified pollution emission functions cannot accurately reflect the emission mechanism. In order to improve the accuracy of emission calculation and obtain more reliable speed limit schemes in a large-scale network, an integrated traffic simulation approach was proposed herein to derive environment-friendly road speed limit schemes. First, this article built an integrated simulation framework to portray traffic operations and emissions comprehensively. Subsequently, a toy network was employed to demonstrate how to obtain environment-friendly speed limit schemes using this framework. Then this article utilized it to determine the corresponding optimal speed limit schemes on the Second Ring road network in Beijing under different scenarios. The results indicated that traffic authorities should impose adaptive rather than fixed speed limits according to traffic period and emission reduction priority. Moreover, imposing the derived speed limit schemes, the amounts of total emissions, hydrocarbons, carbon monoxide, nitrogen oxides, carbon dioxide, and fine particulate matter decreased by 2.24%, 0.72%, 0.13%, 1.61%, 2.32%, and 5.35% during peak hour, and by 8.31%, 0.60%, 1.92%, 7.16%, 8.60%, and 8.72% during off-peak hour, respectively. Implications: In order to alleviate traffic pollutions emission issues more effectively from the traffic management perspective, we put forward an integrated traffic simulation approach to derive the environmental friendly road speed limit schemes. We combined MOVES and PARAMICES to build the integrated traffic simulation framework to portray road traffic operations and emissions elaborately. To verify the effectiveness of our method on real large road network, we used this method to find out the corresponding optimal speed limit schemes within the combination scheme set on Second Ring road network in Beijing under different traffic demand scenarios. Comparing with the current speed limit scheme, our derived speed limit scheme contributed to lowering emission. The amounts of total pollution emissions, hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), carbon dioxide (CO2), and fine particulate matter (PM2.5) decreased by 2.24%, 0.72%, 0.13%, 1.61%, 2.32%, and 5.35% during peak hours, and by 8.31%, 0.60%, 1.92%, 7.16%, 8.60%, and 8.72% during off-peak hours, respectively. [ABSTRACT FROM AUTHOR]

The study investigated the reactive dissolution of gas phase nitrogen-oxides and ozone in water. Mixtures with variable composition of nitrogen oxides were produced by mixing nitric oxide (NO) with ozone. Pure NO in Ar carrier gas resulted in the production of NO2− but its production rate was limited by low NO solubility. The presence of NO2 in the gas increased the production of NO2− while NO3− was also produced. The presence of N2O5 in the gas abruptly increased the production of NO3− due to higher solubility of N2O5. In the present configuration, about 8% of NO2 was dissolved in the water while for N2O5 the fraction was 78%. [ABSTRACT FROM AUTHOR]

We conducted a probabilistic risk assessment for seven nitrosamines (i.e., N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosodibuthylmine (NDBA), N-nitrosopyrrolidine (NPYR), N-nitrosopiperidine (NPIP), N-nitrosomorpholone (NMOR) and N-nitrosomethylethylamine (NMEA)) to assess the cancer risk posed by dietary intake of nitrosamines for Korean people. The estimated cancer risks were the highest in the order of NDMA, NDEA, NDBA, NPYR, NPIP, NMOR and NMEA. The cancer risks of NPYR, NPIP, NMOR and NMEA was estimated to be lower than de minimis risk (i.e., a cancer risk of 10−6), and thus, can be ignored. The derived cancer risks of NDEA and NDBA exceeded de minimis risk, but did not exceed de manifestis risk (i.e., a cancer risk of 10−4), meaning that no imminent action is required for either chemical. However, because the high-end cancer risk (i.e., > 90th percentile) by NDMA intake exceeded de manifestis risk owing to its strong carcinogenicity and high daily intake rate, action to reduce the cancer risk from dietary intake of NDMA is strongly warranted. Because NDMA formation in foods is an unavoidable chemical reaction between NDMA precursors (i.e., nitrogen oxides and organic amines), we recommend focusing on reducing the contents of NDMA precursors in foods as a best management practice. [ABSTRACT FROM AUTHOR]

This study focuses on effects of fine particulate matter (PM2.5) on chronic disease under different levels of temperature. We obtained type 2 diabetes, cerebral stroke and coronary heart disease hospital admissions (HAs) from five hospitals in urban Tianjin as well as the concentrations of PM2.5, nitrogen dioxide (NO2) and sulphur dioxide (SO2). We used distributed lag nonlinear models to explore nonlinear and lag effects of PM2.5. In single-pollutant models, PM2.5 was positively associated with type 2 diabetes, cerebral stroke and coronary heart disease HAs, with strongest effects at lag1, lag0 and lag06, respectively. The corresponding relative risk rates (RR%) were 1.836%, 2.083% and 6.428%. In co-pollutant models, the correlation between PM2.5 and HAs on high-temperature days was generally stronger than that on low-temperature days. This study indicated that PM2.5 can increase HA rates for these chronic diseases, and effects of PM2.5 on high-temperature days were stronger than that on low-temperature days. [ABSTRACT FROM AUTHOR]

To evaluate the association between ambient air pollution and hyperuricemia, we prospectively followed 1748 traffic police officers without hyperuricemia at baseline (2009–2014) from 11 districts in Guangzhou, China. We calculated six-year average PM10, SO2 and NO2 concentrations using data collected from air monitoring stations. The hazard ratios for hyperuricemia per 10 µg/m3 increase in air pollutants were 1.46 (95% CI: 1.28–1.68) for PM10, 1.23 (95% CI: 1.00–1.51) for SO2, and 1.43 (95% CI: 1.26–1.61) for NO2. We also identified changes in the ratio of serum uric acid to serum creatinine concentrations (ua/cre) per 10 µg/m3 increase in air pollutants as 11.54% (95% CI: 8.14%-14.93%) higher for PM10, 5.09% (95% CI: 2.76%-7.42%) higher for SO2, and 5.13% (95% CI: 2.35%-7.92%) higher for NO2, respectively. Long-term exposure to ambient air pollution was associated with a higher incidence of hyperuricemia and an increase in ua/cre among traffic police officers. [ABSTRACT FROM AUTHOR]

In oxidations by nitric acid (HNO3), such as the dissolution of gold (Au) in aqua regia, mixtures of nitrogen monoxide (NO) and nitrogen dioxide (NO2) are produced. In this article, the exact processes through which these two nitrogen oxides are produced were discussed. It was shown that in the processes of dissolution in HNO3 or aqua regia, NO2 is never a direct product of oxidations by HNO3. It was also explained that in such processes, NO2 is always produced from HNO3 and NO reacting. Further, the effect of the concentration of HNO3 was discussed in light of thermodynamic calculations. [ABSTRACT FROM AUTHOR]

In oxidations by nitric acid (HNO3), such as the dissolution of gold (Au) in aqua regia, mixtures of nitrogen monoxide (NO) and nitrogen dioxide (NO2) are produced. In this article, the exact processes through which these two nitrogen oxides are produced were discussed. It was shown that in the processes of dissolution in HNO3 or aqua regia, NO2 is never a direct product of oxidations by HNO3. It was also explained that in such processes, NO2 is always produced from HNO3 and NO reacting. Further, the effect of the concentration of HNO3 was discussed in light of thermodynamic calculations. [ABSTRACT FROM AUTHOR]

This work analyzes the emission characteristics of cashew nut shell biodiesel-fueled diesel engine with zinc oxide nanoparticle at various particle sizes (10 nm and 20 nm). Zinc oxide (ZnO) at a particle size of 10 nm and 20 nm were blended with cashew nut shell biodiesel using ultrasonicator, and the physicochemical properties were measured. Results revealed that cashew nut shell biodiesel promotes a lower level of hydrocarbon (HC), carbon monoxide (CO), and smoke emissions with a significant increase in carbon dioxide (CO2) and nitrogen oxide (NOx) emissions. By adding 10 nm, the particle size of ZnO nanoparticle in cashew nut shell biodiesel reduces the CO, HC, smoke and NOx emission. The addition of ZnO nanoparticle at higher particle size in base fuel further reduces the CO, HC, smoke and NOx emissions. [ABSTRACT FROM AUTHOR]

Effects of the hyperbaric environment on the autonomic nervous system (ANS) in recreational divers are not firmly settled. Aim of this exploratory study was to (1) assess ANS changes during scuba diving via recordings of electrocardiograms (ECG) and to (2) study whether nitrox40 better improves sympathovagal balance over air. 13 experienced divers (~40yrs) performed two open-water dives each breathing either air or nitrox40 (25m/39min). 3-channel ECGs were recorded using a custom-made underwater Holter-monitor. The underwater Holter system proved to be safe. Air consumption exceeded nitrox40 consumption by 12% (n = 13; p < 0.05). Both air and nitrox40 dives reduced HR (10 vs 13%; p < 0.05). The overall HRV (pNN50: 82 vs 126%; p < 0.05) and its vagal proportion (RMSSD: 33 vs 50%; p < 0.05) increased during the dive. Moreover, low (LF: 61 vs 47%) and high (HF: 71 vs 140%) frequency power were increased (all p < 0.05), decreasing the ratio of LF to HF (22 vs 34%). : Conventional open-water dives distinctly affect the ANS in experienced recreational divers, with sympathetic activation less pronounced than vagal activation thereby improving the sympathovagal balance. Nitrox40 delivered two positive results: nitrox40 consumption was lower than air consumption, and nitrox40 better improved the sympathovagal balance over air. [ABSTRACT FROM AUTHOR]

Chronic aging-related diseases result in the greatest burden to the health care system, yet there is little agreement on optimal levels of vitamins or the functional significance of many other dietary molecules in disease prevention. This review presents accumulated information regarding the role of γ-tocopherol in the prevention of nitrogen oxide-mediated damage and its impact on aging-related diseases. γ-Tocopherol is ubiquitous in the diet and levels appear to be physiologically regulated such that levels rise in response to inflammation and deficiencies in certain key vitamins. The unique antioxidant properties of γ-tocopherol, whereby DNA-damaging nitrogen dioxide is rapidly converted to nitric oxide, suggest a mechanistic justification for a functional role in the prevention of DNA damage over time. Data from cell, animal, and human studies indicate that γ-tocopherol appears to have significant beneficial effects, protecting cells from inflammatory damage; however, interpretation of epidemiologic studies is complex due to the paradoxical rise in levels of γ-tocopherol in response to known etiologic risk factors. Current knowledge of its antioxidant mechanism of action, apparent physiological regulation, and impact on various enzymatic pathways suggests γ-tocopherol may have a functional role in maintaining human health. Its utility as a biomarker and the consequences of its deficiency deserve further study. [ABSTRACT FROM AUTHOR]

This paper describes nitrogen oxide (NOx) measurements from a reacting jet in crossflow (RJICF). The NOx production of the RJICF is controlled by jet stoichiometry, crossflow temperature and composition, and the mixing rates between the fluid streams. Mixing occurs both pre- and post-flame. Pre-flame mixing refers to mixing between the reactant jet and the crossflow prior to combustion and determines the stoichiometry of burning; it is controlled by degree of flame lifting, LO, and the shear layer vortices. Post-flame mixing refers to mixing of these secondary combustion products with the crossflow; it is controlled by the counter-rotating vortex pair. The literature has clearly shown a monotonic increase in RJICF NOx production with its bulk average temperature rise (ΔT) but also indicated significant dependencies on momentum flux ratio (J), jet stoichiometry (ϕjet), and other parameters. Moreover, these parameters are always coupled for a given geometry (e.g., LO varies with ϕjet), and the fundamental influence parameters require clarification. To address this, significant effort was spent in this work on differentiating these coupled effects. NOx measurements were obtained from premixed ethane/methane/air jets injected into a vitiated crossflow of lean combustion products, for ΔT values between 75 and 350 K. Data were obtained at two crossflow temperatures (1350 K and 1410 K), two jet geometries, J values from 6 to 40, and ϕjet from 0.8 to 8.0. Ethane/methane ratio was varied to influence flame lifting independent of other parameters. Jet geometry was varied to influence shear layer vortex growth rates and, hence, pre-flame mixing rates. Overall, these data are consistent with the idea that NOx emissions are largely controlled by the stoichiometry at which combustion actually occurs, referred to as ϕFlame. ϕFlame is influenced by ϕjet and pre-flame mixing of the jet and crossflow that, in turn, depend upon LO, nozzle geometry, and crossflow temperature. While this result is expected, it manifests itself in complex manners. For example, NOx levels were observed to be nearly independent of ϕjet for a range of conditions, due to the coupled dependence of ϕjet and LO. Similarly, NOx emissions are a factor of three lower in the nozzle jet geometry relative to a fully developed exit flow, due to enhanced pre-flame mixing. From a practical point of view, the key implication of these results is its suggestion for minimizing NOx production at a given ΔT – designing injection schemes that enhance flame lifting and shear layer vortex growth rates. Finally, there are indications in the data of additional post-flame mixing effects that require further work to clarify. [ABSTRACT FROM AUTHOR]

Accurate thermochemical mechanisms that can predict the formation of nitrogen oxides (NO x ) are important design tools for low-emissions engines. The lack of accurate direct measurements of reaction rates and the associated measurement scatter have resulted in recommended rate parameters for individual chemical reactions that have large uncertainty intervals. In an effort to quantify the impact of these parametric uncertainties on emissions predictions, forward uncertainty propagation is performed with five spectral methods. Sparse grids are identified as the optimal technique to rapidly construct accurate surrogate models. Subsequent polynomial expansions with sparse grids, performed in one-dimensional atmospheric laminar flames for only the 30 uncertain reactions that greatly affect NO formation, produce uncertainty intervals two orders of magnitude larger than nominal predictions. Primary uncertainty sources were identified with reaction pathway analyses to evaluate the contribution of individual formation routes and the uncertainties in prompt NO were found to propagate mostly from the CH chemistry. These results highlight the necessity of a comprehensive approach, using experimental measurements with uncertainty quantification and inference techniques, to reduce uncertainty and develop predictive NO x models. [ABSTRACT FROM AUTHOR]