A scalar-on-quantile-function approach for estimating short-term health effects of environmental exposures.

Environmental epidemiologic studies routinely utilize aggregate health outcomes to estimate effects of short-term (eg, daily) exposures that are available at increasingly fine spatial resolutions. However, areal averages are typically used to derive population-level exposure, which cannot capture the spatial variation and individual heterogeneity in exposures that may occur within the spatial and temporal unit of interest (eg, within a day or ZIP code). We propose a general modeling approach to incorporate within-unit exposure heterogeneity in health analyses via exposure quantile functions. Furthermore, by viewing the exposure quantile function as a functional covariate, our approach provides additional flexibility in characterizing associations at different quantile levels. We apply the proposed approach to an analysis of air pollution and emergency department (ED) visits in Atlanta over 4 years. The analysis utilizes daily ZIP code-level distributions of personal exposures to 4 traffic-related ambient air pollutants simulated from the Stochastic Human Exposure and Dose Simulator. Our analyses find that effects of carbon monoxide on respiratory and cardiovascular disease ED visits are more pronounced with changes in lower quantiles of the population's exposure. Software for implement is provided in the R package nbRegQF.

Emission performance evaluation of urban passenger car fleet through field investigation data in a megacity.

Continued improvements in living standards and the economic well-being in the megacities have led to a huge surge in vehicular density. The worst environmental outcome of the same has been persistent unsafe urban air quality, thanks to vehicular emission. Further, the existing inspection and maintenance programs, conceived to check such emission remain largely ineffective, particularly in developing countries. This is due to the absence of a thorough assessment of the vehicle's compliance with the in-use emission norms generated through reliable field investigation data. To address this gap, the present comprehensive study collected real-time tailpipe emission data from 2040 cars in Delhi, India. Exhaust emission parameters, namely, CO (carbon monoxide), HC (hydrocarbon), and SE (smoke emission), were recorded from both petrol and diesel-driven cars of private ownership, in collaboration with the emission compliance test centers. The performance of cars was assessed in terms of their compliance with the in-use BS (Bharat Stage) emission norms. The one-of-its-kind study reported the petrol cars to be highly compliant toward the BS IV norm while faring even better toward BS II for both CO and HC emissions (80-90%). The conformance to the HC norm was found to be typically better than that for CO (85-90% versus 75-80%). For the diesel-driven cars, BS III compliance levels were reported relatively better compared to BS IV (90% in the case of the former against 80% in the latter's case). Further, the study puts forward a clear indication that the in-use emission norm and maintenance status of cars have a direct and negative relationship with tailpipe emission parameters. Cars of both overseas and domestic origin have almost equal degrees of compliance with the emission norms (over 80% in any case). The study recommends the incorporation of these two critical vehicular variables, i.e., maintenance status and in-use emission standard in the emission certification policy.

Effects of the turbocharged Miller cycle strategy on the performance improvement and emission characteristics of diesel engines.

The turbocharged Miller cycle strategy is studied to improve the power density of diesel engines and reduce emissions. A thermodynamic model and a 1D simulation model of turbocharged diesel engine are established. Results show that the introduction of the Miller cycle reduces the thermal efficiency under naturally aspirated conditions because of the low effective compression ratio, whereas it increases the thermal efficiency under a turbocharged condition owing to the energy recovered by the turbocharger. Under restricted combustion pressure and fixed intake mass, the thermal efficiency first increases and then decreases with increasing Miller cycle ratio, and the peaks occur at approximately 30%-50%. The gain of isochoric combustion ratio overlaps the loss of effective compression ratio due to the Miller cycle on the lower side, whereas it reverses on the higher side. With maximum and equal intake mass, the maximum power initially increases and subsequently decreases with increasing Miller cycle ratio, reaching a peak at 40%. Under a fixed isochoric combustion ratio, the thermal efficiency first increases and then decreases with increasing intake mass, and the optimum intake mass corresponding to the highest thermal efficiency decreases with increasing Miller cycle ratio. The lower the restricted combustion pressure is, the higher the gain in power and thermal efficiency by the Miller cycle strategy. Based on the calculation of the 1D model validated using a practical engine, the power can be increased from 41.6 kW/L to 100 kW/L while the brake thermal efficiency can be increased from 34.98% into 38.55% by increasing the Miller cycle ratio from 19% to 30% and the combustion pressure from 17.7 MPa to 35 MPa. With the application of the supercharged Miller cycle, when the Miller cycle ratio is 30% and the power intensity is increased from 60 kW/L to 100 kW/L, NOx decreases by 32.4%, CO decreases by 28%, showing a tendency to decrease and then stabilize, and HC increases by 5.3%. When the power is 80 kW/L and the Miller cycle ratio is increased from 10% to 30%, NOx decreases by 8.6%, CO decreases by 2%, and HC increases by 0.04%.

Environmental pollutants PM2.5, PM10, carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3) impair human cognitive functions.

OBJECTIVE: Environmental pollution is an emerging global public health problem across the world and causes serious threats to ecosystems, human health, and the planet. This study is designed to explore the impact of environmental pollution particulate matter PM2.5, PM10, carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3) on cognitive functions in students from schools located in or away from air-polluted areas. SUBJECTS AND METHODS: In this study, two schools were selected: one was located near a traffic-polluted area (school #1), and the second was in an area away from the traffic-polluted area (school #2). In this study, a total of 300 students were recruited: 150 (75 male and 75 female) students from school #1 located in a traffic-polluted area, and 150 students (75 male and 75 female) from school #2 located away from a traffic polluted area. The overall average age of students was 13.53±1.20 years. The students were selected based on age, gender, health status, height, weight, BMI, ethnicity, and homogenous socio-economic and educational status. The pollutants PM2.5, PM10, CO, NO2, O3, and SO2 were recorded in the surrounding environment. The overall mean concentration of environmental pollutants in school #1 was 35.00±0.65 and in school #2 was 29.95±0.32. The levels of airborne particles were measured, and the cognitive functions were recorded using the Cambridge Neuropsychological Test Automated Battery (CANTAB). The students performed the cognitive functions tasks, including the attention switching task (AST), choice reaction time (CRT), and motor screening task (MOT). RESULTS: The results revealed that the AST-Mean 928.34±182.23 vs. 483.79±146.73 (p=0.001), AST-mean congruent 889.12±197.12 vs. 473.30±120.11 (p=0.001), AST-mean in-congruent 988.98±201.27  vs. 483.87±144.57 (p=0.001), CRT-Mean 721.36±251.72  vs. 418.17±89.71 (p=0.001), and MOT-Mean 995.07±394.37 vs. 526.03±57.83 (p=0.001) were significantly delayed among the students who studied in school located in the traffic polluted area compared to students who studied in school which was located away from the traffic-polluted area. CONCLUSIONS: Environmental pollution was significantly higher in motor vehicle-congested areas. Cognitive functions were impaired among the students who were studying in a school located in a polluted area. The results further revealed that the students studying in schools located in environmentally polluted areas have attention, thinking, and decision-making abilities related to cognitive function impairment.

Trans-boundary spatio-temporal analysis of Sentinel 5P tropospheric nitrogen dioxide and total carbon monoxide columns over Punjab and Haryana Regions with COVID-19 lockdown impact.

This study conducts a spatio-temporal analysis of tropospheric nitrogen dioxide (NO2) and total carbon monoxide (CO) concentrations in the Punjab and Haryana regions of India and Pakistan, using datasets from the Sentinel 5-Precursor (S5P) satellite. These regions, marked by diverse economic growth factors including population expansion, power generation, transportation, and agricultural practices, face similar challenges in atmospheric pollution, particularly evident in major urban centers like Delhi and Lahore, identified as pollution hotspots. The study also spotlights pollution associated with power plants. In urban areas, tropospheric NO2 levels are predominantly elevated due to vehicular emissions, whereas residential activities mainly contribute to CO pollution. However, precisely attributing urban CO sources is complex due to its longer atmospheric residence time and intricate circulation patterns. Notably, the burning of rice crop residue in November significantly exacerbates winter pollution episodes and smog, showing a more pronounced correlation with total CO than with tropospheric NO2 levels. The temporal analysis indicates that the months from October to December witness peak pollution, contrasted with the relatively cleaner period during the monsoon months of July to September. The severe pollution in the OND quarter is attributed to factors such as variations in boundary layer height and depletion of OH radicals. Furthermore, the study highlights the positive impact of the COVID-19 lockdown on air quality, with a significant decrease in NO2 concentrations during April, 2020 (Delhi: 59%, Lahore: 58%). However, the reduction in total CO columns was less significant. The study also correlates lockdown stringency with tropospheric NO2 columns (R2: 0.37 for Delhi, 0.25 for Lahore, 0.22 for Rawalpindi/Islamabad), acknowledging the influence of various meteorological and atmospheric variables. The research highlights the significant impact of crop residue burning on winter pollution levels, particularly on total CO concentrations. The study also shows the notable effect of the COVID-19 lockdown on air quality, significantly reducing NO2 levels. Additionally, it explores the correlation between lockdown stringency and tropospheric NO2 columns, considering various meteorological factors.

Investigating the impact of n-heptane (C7H16) and nanoparticles (TiO2) on diesel-microalgae biodiesel blend in CI diesel engines.

Recent global challenges encompass profound environmental pollution and the depletion of finite fuel resources. In this study, the biodiesel used in the mixture was derived from Azolla pinnata microalgae oil through a trans-esterification reaction chosen for its high oil concentration. During the initial phase of the experiment, varying volumes of biodiesel (5%, 10%, and 15%) and n-heptane (5%, 10%, and 15%) were introduced to diesel to form a ternary fuel blend. The experimental outcome shows that an n-heptane and biodiesel mixture of 10% by volume would produce the best results. Next, experiments were carried out by incorporating 10, 40, and 80 ppm titanium oxide (TiO2) nanoparticles (NPs) in a recommended ternary fuel blend. The experimental investigation showed that D80A10H10TNP40 (diesel 80% + biodiesel 10% + n-heptane 10% + TiO2 40 ppm) caused a 7.21% increase in brake thermal efficiency (BTE) with a decrease in brake specific fuel consumption (BSFC) and brake specific energy consumption (BSEC) by 9.58% and 10%, respectively, compared to (diesel 80% + biodiesel 20%) D80A20. D80A10H10TNP40 exhibits lower emissions, with a significant reduction of 11.29% and 20.96% in carbon monoxide (CO) and unburnt hydrocarbons (UBHC), respectively. Nitrogen oxide (NOX) and smoke emissions were reduced by 3.3% and 11.13%, respectively, compared to D80A10H10. Furthermore, D80A10H10TNP40 demonstrated enhanced combustion properties, comprising a significant rise of 4.39% in-cylinder pressure (CP), 35.29% in heat release rate (HRR), and 25.05% in the rate of pressure rise (RPR). The findings of this investigation indicate that D80A10H10TNP40 exhibits enhanced efficiency, emission, and combustion properties compared to the D80A20 fuel.

Spatial and temporal analysis of influential factors on motor vehicle carbon monoxide emissions in China considering emissions trading scheme.

The number of cars is increasing every year and the environmental aspects of transport are becoming a hot topic. The spatial and temporal patterns of motor vehicle carbon monoxide (CO) emissions are still unclear due to the unbalanced economic development and heterogeneous geographic conditions of China. With the objective of realizing a reduction in motor vehicle CO emissions, his study explores the transport carbon emission reduction pathways of China from motor vehicle CO emission. Firstly, the entropy method is adopted to comprehensively evaluate the CO emissions from motor vehicles in each province; secondly, the development of a Geographically and Temporally Weighted Regression (GTWR) model facilitates the examination of the spatiotemporal dynamics pertaining to the influencing factors of motor vehicle CO emissions within each province.; finally, the characteristics of motor vehicle CO emissions in ETS pilot areas and non-ETS pilot areas are compared. The results show that: (1) After the completion of the six ETS pilot areas in 2011, the CO emission from motor vehicles is reduced by 18% compared with 2010.(2)The entropy method shows that the largest CO emissions from motor vehicles are from Beijing, Shanghai, Guangdong and other provinces with high economic levels.(3) The results of the GTWR model show that the positive effects of economic level, population size, road mileage intensity and motor vehicle intensity on motor vehicle CO emissions are decreasing year by year. The negative effect of metro line intensity on CO emission decreases year by year. This study can help decision makers to identify the high emission areas, understand the influencing factors, and formulate emission reduction measures to achieve the purpose of carbon emission reduction in transport.

Analysis of nighttime aerosols and relation to covariates over a highly polluted sub-Saharan site using Mann-Kendall and wavelet coherence approach.

High emissions of aerosols and trace gases during nighttime can cause serious air quality, climate, and health issues, particularly in extremely polluted cities. In this paper, an effort has been made to examine the variations in aerosols and trace gases over a sub-Saharan city of Ilorin (Nigeria) during nighttime. We have used Aerosol Robotic Network data of aerosol optical depth (AOD) at 500 nm, Angstrom exponent (AE) (440/870), and precipitable water (WVC). Both AE and WVC showed a decreasing trend of -0.0012% and -0.0010% per year, respectively. We also analyzed nighttime data of carbon monoxide (CO), methane (CH4 ), and ozone (O3 ) from Atmospheric Infrared Sounder and aerosol subtypes from CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation). AOD, AE, and WVC average values are found to be 0.64 ± 0.33, 0.74 ± 0.24, and 3.40 ± 0.97, respectively. As a result of northeasterly winds carrying Saharan dust during the dry season, the greatest value of AOD (1.29) was observed in February. Desert dust aerosols (37.63%) were the most prevalent type, followed by mixed aerosols (44.15%). Winds at a height of 1500 m above ground level were likely transporting Saharan dust to Ilorin. CALIPSO images revealed that Ilorin's atmosphere contained dust, polluted continental, clean maritime, and polluted dust on high AOD days. The National Oceanic and Atmospheric Administration's vertical sounding profiles showed that the presence of high AOD values was caused by the inversion layer trapping aerosol pollution. Average nighttime concentrations of CO, O3 , and CH4 were measured to be 127 ± 18, 29.7 ± 2.1, and 1822.6 ± 12.7 ppbv, respectively. The wavelet coherence spectra exhibited significant quasi-biannual and quasi-annual oscillations at statistically significant levels.

For Submission to the Journal of Community Health: Carbon Monoxide Awareness and Detector Use in the State of Wisconsin.

Carbon monoxide (CO) is a leading cause of poisoning. CO detectors are a known-effective prevention strategy, however, little is known about use of detectors or knowledge of risk. This study assessed awareness of CO poisoning risk, detector laws, and detector use among a statewide sample. Data collected from the Survey of the Health of Wisconsin (SHOW) included a CO Monitoring module added to the in-home interview for 466 participants representing unique households across Wisconsin in 2018-2019. Univariate and multivariable logistic regression models examined associations between demographic characteristics, awareness of CO laws and detector use. Less than half of households had a verified CO detector. Under 46% were aware of the detector law. Those aware had 2.82 greater odds of having a detector in the home compared to those unaware of the law. Lack of CO law awareness may lead to less frequent detector use and result in higher risk of CO poisoning. This highlights the need for CO risk and detector education to decrease poisonings.

Is carbon monoxide testing in pregnancy an acceptable and effective smoking cessation initiative? An integrative systematic review of evidence.

PROBLEM: Over 25000 Australian women smoke during pregnancy each year, with risks to mother and baby including miscarriage, pre-eclampsia, placental issues, premature birth, and stillbirth. BACKGROUND: Carbon Monoxide testing has been introduced in antenatal care settings to help identify smokers and motivate them to quit. AIM: This integrative systematic review aims to take a holistic look at Carbon Monoxide (CO) testing to understand how effective and acceptable this practice is in antenatal care. METHODS: PubMed, Scopus and CINAHL were searched for literature relating to pregnant women where CO testing has been used to identify smoking as part of a smoking cessation initiative. The search results were then screened and reviewed independently by two authors. A total of 15 studies were deemed relevant and proceeded to quality appraisal using the Crowe Critical Appraisal Tool. A Narrative Synthesis method was used to present the findings. DISCUSSION: Synthesis resulted in four themes: smoking identification and referral to cessation support, smoking cessation, midwifery usability of CO testing and women's perception of CO testing. Whilst carbon monoxide testing increased the identification and referral to cessation support for pregnant smokers, it did not make an overall difference to smoking cessation rates. Midwives frequently report having too little time to conduct carbon monoxide testing. Findings suggest that women accept the test, but their opinions are under-represented in the existing evidence. Midwives and women report concern for the midwife/woman relationship if testing is not conducted well. CONCLUSION: Whilst carbon monoxide testing can identify smoking, it does not appear to motivate pregnant smokers to quit.

Biodiesel synthesis from chicken feather meal using S/AlMCM-41 catalyst and engine performance analysis.

In this study, Sulphated/AlMCM-41 (S/AlMCM-41) catalysts were synthesized and used to produce biodiesel from CFMO. Different percentages of S/AlMCM-41 catalysts were prepared and characterized by X-ray diffraction, BET studies, TPD, and SEM-EDS analysis. Sulphur incorporation to the MCM framework though reduced the surface area, and pore volume of the catalyst, sufficient acidity were produced in the catalyst surface. The existence of functional groups and the composition of the biodiesel obtained was analysed by FTIR and GC-MS. S/AlMCM-41 (80%) catalyst presented a high catalytic activity with maximum biodiesel conversion % when compared to other variants. The bio-ester produced from CFMO with S/AlMCM-41 (80%) catalyst possessed the higher calorific value of 50 MJ/kg and flashpoint of 153 °C and other properties analogous to the standard biodiesel. The engine performance was examined for biodiesel blends with neat diesel, where biodiesel blends performed better than neat diesel. The exhaust gas emission studies also highlighted that the obtained biodiesel showed emission characteristics similar to the standard biodiesel, whereas marginally higher emission for CO and CO2 of about 2.2 and 7.9% was reported.

Real-world tailpipe emissions from autorickshaws (3-wheelers) under heterogeneous traffic conditions.

The current study aimed to measure real-world emissions of three-wheeled autorickshaws powered by CNG and parameters (such as speed, acceleration, air-fuel (A/F) ratio, and rpm) influencing 3-wheeler emission rates. Test vehicles manufactured under Bharat Standards BS-III and BS-IV were monitored for exhaust emissions in Delhi city using a portable exhaust emission measurement system (AVL Ditest Gas 1000). The average emission rates of CO, HC, and NO gases for on-road autorickshaws were found to be 0.015 ± 0.017, 0.003 ± 0.0017, and 0.007 ± 0.005 g/s, respectively. Further, the highest emission factor values of 3.98 g/km and 3.93 g/km were estimated for CO and HC+NO gases, respectively. These values were found to be 1.4-3.2 times higher than the respective BS emission norms (BS III-CO =1.25 g/km, HC+NO = 1.25 g/km; BS-IV-CO = 0.94 g/km and HC+NO = 0.94 g/km). In this study, it was observed that the driving pattern and emissions were affected by traffic characteristics, driver behavior (constant acceleration and deceleration), and vehicle characteristics. The air-fuel ratio (A/F) was found to correlate highly with emission rates, followed by acceleration/deceleration and speed. Further analysis found that more than 70% of the aggregated emissions were due to acceleration and deceleration, which contributed to nearly 70% of the travel time. This was followed by the breakdown of speed and emissions into different bins, which found that 20-30 kmph has a higher emission rate and 40-50 kmph bin has a lower emission rate.

The burden of disease attributable to indoor air pollutants in China from 2000 to 2017.

BACKGROUND: High-level exposure to indoor air pollutants (IAPs) and their corresponding adverse health effects have become a public concern in China in the past 10 years. However, neither national nor provincial level burden of disease attributable to multiple IAPs has been reported for China. This is the first study to estimate and rank the annual burden of disease and the financial costs attributable to targeted residential IAPs at the national and provincial level in China from 2000 to 2017. METHODS: We first did a systematic review and meta-analysis of 117 articles from 37 231 articles identified in major databases, and obtained exposure-response relationships for the candidate IAPs. The exposure levels to these IAPs were then collected by another systematic review of 1864 articles selected from 52 351 articles. After the systematic review, ten IAPs with significant and robust exposure-response relationships and sufficient exposure data were finally targeted: PM2·5, nitrogen dioxide, sulphur dioxide, ozone, carbon monoxide, radon, formaldehyde, benzene, toluene, and p-dichlorobenzene. The annual exposure levels in residences were then evaluated in all 31 provinces in mainland China continuously from 2000 to 2017, using the spatiotemporal Gaussian process regression model to analyse indoor originating IAPs, and the infiltration factor method to analyse outdoor originating IAPs. The disability-adjusted life-years (DALYs) attributable to the targeted IAPs were estimated at both national and provincial levels in China, using the population attributable fraction method. Financial costs were estimated by an adapted human capital approach. FINDINGS: From 2000 to 2017, annual DALYs attributable to the ten IAPs in mainland China decreased from 4620 (95% CI 4070-5040) to 3700 (3210-4090) per 100 000. Nevertheless, in 2017, IAPs still ranked third among all risk factors, and their DALYs and financial costs accounted for 14·1% (95% CI 12·3-15·6) of total DALYs and 3·45% (3·01-3·82) of the gross domestic product. Specifically, the rank of ten targeted IAPs in order of their contribution to DALYs in 2017 was PM2·5, carbon monoxide, radon, benzene, nitrogen dioxide, ozone, sulphur dioxide, formaldehyde, toluene, and p-dichlorobenzene. The DALYs attributable to IAPs were 9·50% higher than those attributable to outdoor air pollution in 2017. For the leading IAP, PM2·5, the DALYs attributable to indoor origins are 18·3% higher than those of outdoor origins. INTERPRETATION: DALYs attributed to IAPs in China have decreased by 20·0% over the past two decades. Even so, they are still much higher than those in the USA and European countries. This study can provide a basis for determining which IAPs to target in various indoor air quality standards and for estimating the health and economic benefits of various indoor air quality control approaches, which will help to reduce the adverse health effects of IAPs in China. FUNDING: The National Key Research and Development Program of China and the National Natural Science Foundation of China.

Effects of n-pentanol/biodiesel blend fuels on combustion and conventional and unconventional emission characteristics of diesel engine.

The use of n-pentanol/biodiesel as a diesel engine fuel is one of the important ways to reduce fossil fuel consumption and lower diesel engine emissions. The objective of this work was to investigate the mechanism of the effect of different n-pentanol blending ratios (0%, 10%, 20%, and 30%) on the combustion and emission performance of a common rail diesel engine. Tests were conducted on a four-cylinder supercharged intercooled diesel engine at 1540 r/min with brake mean effective pressures of 0.289, 0.578, and 0.867 MPa. The results showed that with the increase of the n-pentanol blending ratio, the ignition delay was prolonged, the combustion duration was shortened, and the heat release center was shifted forward. The combustion process at medium and high loads was improved. When the blending ratio of n-pentanol reached 20%, the blended fuel showed better combustion characteristics at all three loads, and the peak in-cylinder pressure of the blended fuel increased by 13.74%, 1.95%, and 5.26% at the three loads, respectively, compared with that of pure biodiesel. With the increase of the n-pentanol blending ratio, HC, CH2O, CH4, and CH3CHO emissions increased at all three loads. Soot emission was reduced by 25.86%, 19.71%, and 31.59% at three loads when the n-pentanol blending ratio was 30%. C2H4 emissions increased with the increase of n-pentanol blending ratio at the low-load condition and showed a decreasing tendency at the medium and high loads. At high load conditions, NOx emissions increased with increasing n-pentanol blending ratio, and CO emissions decreased with increasing n-pentanol blending ratio.

Carbon Monoxide Levels Produced by Propane/Isobutane Canister Stoves inside a Tent.

INTRODUCTION: Improper use of camp stoves in enclosed spaces has resulted in fatalities from carbon monoxide (CO) poisoning. Prior research has focused on the CO output of stoves burning white gas, unleaded gas, or kerosene. Stoves burning an isobutane/propane fuel have not been investigated and are the focus of this study. METHODS: Three stoves utilizing isobutane/propane fuel were used to heat a pot of water inside a 3-season tent under controlled settings. Multiple runs with each stove were performed, and CO measurements, in parts per million (ppm), were recorded at 1-min intervals for a total of 15 min using a RAE Systems gas monitor. Data are reported as mean with SD. Repeated measures analysis of variance was utilized to examine changes over time. Statistical significance was set at P<0.05. RESULTS: There was a statistically significant main effect of time and CO level, F (14, 168)=7.6, P<0.001. There was a statistically significant difference between-subjects effect of stove group F (2, 12)=8.6, P=0.005, indicating that CO levels were different depending on the stove. Tukey's post-hoc analyses revealed that stove A had the highest CO levels. The average level of stove A was statistically significantly higher than that of stove B and stove C, with a mean CO level difference of 79 ppm (95% CI, 3-156), P=0.043 and 117 ppm (95% CI, 40-194), P=0.004, respectively. CONCLUSIONS: Stoves utilizing isobutane/propane fuel can produce unsafe CO levels and should not be used in enclosed spaces.

Evaluating the impact of varying expired carbon monoxide thresholds on smoking relapse identification: insights from the E3 trial on e-cigarette efficacy for smoking cessation.

OBJECTIVES: Expired carbon monoxide (ECO) is often used in smoking cessation trials to biochemically validate self-reported smoking status. The optimal ECO threshold to distinguish individuals who smoke from those who do not is debated. DESIGN: The data from the 'Evaluating the Efficacy of E-Cigarette use for Smoking Cessation (E3) Trial' were used; the E3 trial was a randomised controlled trial that examined e-cigarettes efficacy for smoking cessation. SETTINGS: Participants were recruited from 17 Canadian sites across 4 provinces. PARTICIPANTS: This substudy included data from participants who returned for at least one of the clinical visits at week 4 (291), 12 (257) or 24 (218) and provided both self-reported smoking status and ECO measures. Analyses were based on 766 paired measures (ie, self-reported smoking status with corresponding ECO). RESULTS: The ability of ECO measurements to discriminate between adults who reported smoking and those who reported abstinence varied with the threshold used. ECO thresholds of 6, 7, 8 and 9 parts per million (ppm) yielded the greatest area under the receiver operating characteristic curve (0.84). These thresholds produced sensitivities of 84%, 82%, 78% and 76% and specificities of 84%, 87%, 90% and 91%, respectively. However, at a threshold of 6 ppm, intersecting sensitivity (84%) and specificity (84%) were maximised with respect to each other. Biochemical validation had the highest agreement with self-report at an ECO threshold of 6 ppm (κ=0.57; 95% CI, 0.51 to 0.64). CONCLUSION: The classification of participants' smoking status depends on the ECO threshold used for biochemical validation. We recommend that future smoking cessation trial investigators analyse and report the impact that varying ECO thresholds has on trial results. TRIAL REGISTRATION NUMBER: NCT02417467.

Enhancing emission control and analyzing the performance and combustion attributes of vehicular engines with spirulina microalgae diesel Ce2O3 nanoparticles blends.

The current research investigates the utilization of spirulina microalgae biodiesel blends in a naturally aspirated constant speed compression ignition engine with Ce2O3 nanoparticles at the concentration of 50 ppm under diverse engine loading conditions. Blends of microalgae dispersed with neat diesel at the volume of 20% and 40%. A series of tests were conducted to evaluate the combined effects of microalgae and nanoparticles on engine performance, combustion efficiency, and emission characteristics. The study revealed that increasing the microalgae concentration in the diesel fuel resulted in reduced brake thermal efficiency due to less effective atomization and lower calorific value. Surprisingly, the 20% biodiesel blend with nanoparticles exhibited the highest brake thermal efficiency across various engine loads, while the 40% blend showed higher brake specific fuel consumption compared to both the 20% blend and neat diesel, primarily because of its lower heating value necessitating increased fuel consumption. Furthermore, the biodiesel blends led to lower in-cylinder pressure than pure diesel, mainly attributable to suboptimal atomization. In terms of emissions, the utilization of microalgae-based fuel led to a significant reduction in NOx, CO, and smoke emissions, attributed to the lower cylinder temperatures associated with these blends. In conclusion, this study underscores the potential of spirulina microalgae, particularly when combined with nanoparticles at an optimal concentration, as a promising and environmentally friendly alternative for compression ignition engines.

Investigation of bioethanol production from jatropha deoiled cake and its blending effects for environmental sustainability.

This paper describes the process of extracting ethanol from Jatropha curcas and its various blending effects on spark-ignited engine performance for environmental sustainability. Alternatives to conventional fuel sources have to be found because of the depletion of fossil fuels and stringent regulations. Every day, the growing population and improved transportation increase the energy demand. Bioethanol is an effective substitute for gasoline and SI engine diesel. Worldwide, passenger cars typically blend 10% bioethanol with gasoline. Some nations, like India, have stated plans to blend 20% bioethanol with gasoline starting shortly. From leftover jatropha deoiled cake (JDC), bioethanol was produced utilizing the fermentation and vacuum distillation methods. Four different blends were prepared on a volumetric basis at different engine speeds at a constant compression ratio of 10:1 and the wide-open throttle was tested for various performances and emissions. Bioethanol enrichments reduce CO and CO2 emissions but increase nitrogen oxide emissions. JDCE 15 was found to have the best engine performance out of all the fuel blends tested. This study suggests that, if NOx emission reduction measures are carried out, JDC can be used as a source for the manufacturing of second-generation bioethanol.

Ambient carbon monoxide and relative risk of daily hospital outpatient visits for respiratory diseases in Lanzhou, China.

At present, evidence of the associations between carbon monoxide (CO) and respiratory diseases (RD) in Northwest China is limited and controversial. The aim of this study is to evaluate the impact of ambient CO on outpatient visits for RD in Lanzhou, China. The daily amount of outpatient visits for total and cause-specific RD, air pollutant, and weather variables were collected in Lanzhou, China from 1st January 2013 to 31st December 2019. A generalized additive model and distributed lag nonlinear model were used to assess associations between CO and outpatient visits for RD. During the study period, a total of 1,623,361 RD outpatient visits were recorded. For each interquartile range (IQR) (0.77 mg/m3) increase in CO, the relative risk (RR) was 1.163 (95% CI: 1.138, 1.188) for total RD at lag07, 1.153 (95% CI: 1.128,1.179) for upper respiratory tract infection (URTI) at lag07, 1.379 (95% CI: 1.338,1.422) for pneumonia at lag07, 1.029 (95% CI: 0.997,1.062) for chronic obstructive pulmonary disease (COPD) lag04, 1.068 (95% CI: 1.028,1.110) for asthma lag03, and 1.212 (95% CI: 1.178,1.247) for bronchitis lag07, respectively. In the subgroup analyses, the impacts of CO were more pronounced on total RD, pneumonia, COPD, and bronchitis in males than females, while the opposite was true in URTI and asthma. The impact of CO on RD was the strongest for children under 15 years-of-age. We also found significantly stronger effects during cold seasons compared to warm seasons. In addition, we observed a roughly linear exposure-response curve between CO and RD with no threshold effect. This study in Lanzhou revealed a remarkable association between CO level and an elevated risk of total and cause-specific RD outpatient visits, especially for pneumonia.

Assessment and usability of Jatropha biodiesel blend with phenolic antioxidant to control NOx emissions of an unmodified diesel engine.

The excessive utilization of fossil fuels has worsened global warming and exacerbated the levels of air pollution in the environment, forcing us to consider alternative fuels for compression ignition engines. The current research aims to explore the possibilities of renewable fuels outperforming diesel fuel in terms of combustion, performance, and emission characteristics. Biodiesel is an environmentally friendly and renewable alternative fuel. The major drawback of biodiesel is the significant rise in nitrogen oxide (NOx) emissions. The main novelty and objective of this research is to investigate the performance and emission characteristics of variable compression ratio diesel engine using DPA antioxidant additive. For this investigation, diesel, Jatropha biodiesel (B30) and 100 ppm of phenolic antioxidant diphenylamine (DPA) blended with B30 have been used as fuel named B30+DPA100. From experimental outcomes, the inclusion of diphenylamine to B30 blend resulted in brake-specific fuel consumption (BSFC) and exhaust gas temperature (EGT) being reduced by 8.86% and 4.12%, respectively, compared to B30. Simultaneously, there was a 1.11% increase in brake thermal efficiency (BTHE). The B30+DPA100 fuel blend demonstrates effective control over NOx and other emissions. The emissions of NOx, carbon monoxide (CO), hydrocarbon (HC), and smoke from the B30+DPA100 blend have shown a reduction of 6.8%, 5.34%, 7.86%, and 15.67%, respectively, when compared to diesel. However, there has been an increase in carbon dioxide (CO2) by 7.8%. One notable advantage of the B30+DPA100 blend is the significant decrease in NOx emissions. Additionally, the cylinder pressure for B30+DPA100 has been lowered by 4.93% compared to B30. On the other hand, the net heat release rate (NHR) has experienced a 1.72% increase. The particle size of different elements present in the crankcase oil has been calculated by Zetasizer Nano. The analysis revealed varying particle sizes for different elements in the crankcase oil: aluminum (2.724 µm), chromium (2.78 µm), iron (2.423 µm), and lead (2.587 µm).