Nitrogen Dioxide Concentrations Research Articles

Периоперационное кондиционирование оксидом азота для предотвращения острого почечного повреждения при кардиохирургических вмешательствах у пациентов с хронической болезнью почек: промежуточные результаты рандомизированного контролируемого исследования DEF

INTRODUCTION: Acute kidney injury (AKI) is a common and serious complication after cardiac surgery performed under cardiopulmonary bypass (CPB). Patients with chronic kidney disease (CKD) are particularly vulnerable to cardiac surgery-associated AKI. Nitric oxide (NO) has great potential for implementing multi-organ protection in cardiac surgery. OBJECTIVES: To test the hypothesis that perioperative nitric oxide conditioning has a good safety profile and reduces the incidence of acute kidney injury during cardiac surgery under cardiopulmonary bypass in patients with chronic kidney disease. MATERIAL AND METHODS: An interim analysis of the results of the single-center prospective randomized controlled trial DEFENDER was conducted. Currently, the study included 96 patients with CKD who underwent cardiac surgery under CPB. Patients was randomized into 2 equal groups consisting of 48 people each. In the experimental group, during the operation and 6 hours after it, 80 ppm NO was delivered through the ventilator and CPB circuits. In the control group, during the operation and 6 hours after it, a standard oxygen-air mixture without NO was delivered through the ventilator and CPB circuits. The end points of the study were: the difference between groups in the incidence of AKI, the incidence of postoperative complications, outcomes and the safety profile of NO therapy. RESULTS: In the experimental group, the incidence of AKI was significantly lower compared to the control group (16,7 и 35,4 %, p = 0.036). In the experimental group, nitrogen dioxide concentration in the gas-air mixture and methemoglobin level were not above the reference range. The groups did not differ in the frequency of blood transfusions, the amount of postoperative bleeding, or the number of platelets on the first day after surgery. CONCLUSIONS: Perioperative nitric oxide conditioning has a good safety profile and reduces the incidence of acute kidney injury during cardiac surgery with CPB in patients with chronic kidney disease.

AIR QUALITY IN YEREVAN IN THE CONTEXT OF CLIMATE CHANGE

Over the past five years, the atmospheric air quality in Yerevan has continued to deteriorate, primarily attributed to a significant increase in airborne dust, particularly during the hot summer months that coincide with the peak tourist season. This phenomenon reflects a complex interplay among atmospheric emissions, air quality, emission source altitudes, changes in chemical composition, solar radiation, weather patterns, and topographic conditions. Sources of dust pollution in Yerevan include industrial activities, vehicular emissions, road dust, and construction activities. Data from various administrative districts indicate that, over the past five years, concentrations of dust, nitrogen dioxide, and sulfur dioxide frequently exceed established standards. Additionally, there are unregulated static sources of dust pollution within the city. This study conducts a comparative analysis of the primary pollutants in the context of climate change and urbanization in Yerevan over the last five years. It also assesses green areas and evaluates the effectiveness of greening initiatives, while considering compliance with national legislation in the Republic of Armenia.

Determining the Effectiveness of Interventions for the Reduction of Child Exposure to Traffic-Related Air Pollution at Schools in England

Traffic-related air pollution (TRAP) is a significant risk to human health and is particularly damaging to children as a vulnerable group. TRAP exposure near schools and on the school commute is linked to a growing number of adverse health effects, including respiratory and cardiovascular disease and can lead to (and exacerbate existing) respiratory conditions. The current study aimed to assess the effectiveness of interventions for the reduction of potential child exposure to TRAP at the school gates and on the school commute. This study employed dispersion modelling to assess the effects of interventions for reducing TRAP concentrations in the vicinity of five schools in England. The results revealed that all interventions led to reductions in nitrogen dioxide (NO2) concentrations. Improved travel routes were the most effective intervention for reducing concentrations along travel routes, while the introduction of low-emission zones (LEZs) proved most effective in reducing NO2 concentrations at schools, with greater effectiveness observed at shorter distances. Active travel also demonstrated effectiveness, particularly in areas with heavy traffic. When considering all receptors, LEZ implementation, active travel, and rideshare interventions exhibited effectiveness, with greater distance providing greater reductions in NO2 concentrations. Anti-idling was found to be more effective in sparsely populated areas. Combined with improved travel routes, anti-idling showed the greatest percentage difference in concentrations, followed by active travel, and rideshare.

Applying similar modeling to study vehicle exhaust transport in a confined mining space

To scientifically and effectively manage exhaust pollution in underground confined spaces and reduce hazards from personnel exhaust exposure, a systematic study of the distribution characteristics of diesel locomotive exhaust emissions in mines is needed. Aiming at large underground coal mining operations, an experimental platform for the physical simulation of vehicle exhaust transport in restricted spaces is designed and created. The Hongliulin Coal Mine in Shaanxi Province, China, is used as a prototype, and the platform consists of a coal mining face system, ventilation system, exhaust emission system, monitoring and surveillance system, and control platform. The experimental platform with carbon dioxide simulation of diesel exhaust pollution, in the role of different wind speed, the concentration of carbon dioxide is a downward trend, the wind speed is in the low wind speed on the 0.2 m of the concentration difference of 25.75%; the experimental platform exhaust transport process presents a clear “three-zone” change rule; experimental platform carbon dioxide concentration and the field nitrogen dioxide concentration change trend is consistent. The platform functions and features can provide guidance for mine exhaust management and exhaust exposure hazard prevention and control.

Effect of Air Pollutants and Environmental Noise on the Childhood Asthma Prevalence in Tehran, Iran

The purpose of this study is to investigate the effect of air pollutants and noise on the prevalence of childhood asthma in Tehran, Iran. The standardized questionnaire was completed by one of the parents of children aged 6–7 years or by adolescents aged 13–14 years. The asthma prevalence in ages 6-7 and 13–14 was found to be 8.8% and 17.44%, respectively. A significant positive association was observed between “ever wheezing” and monoxide carbon (CO) concentration (OR=1.84, 1.05-3.25 in 13–14 years), the occurrence of 4 to 12 wheezing attacks and sulfur dioxide (SO2) concentration (Odds Ratio [OR]=1.39, 1.04-1.91) and particulate matter less than 2.5 micron (PM2.5) concentration (OR=1.38, 1.05-1.98 and OR=1.13, 0.98-1.39 in 6-7 and 13–14 years, respectively), as well as one night per week of sleep disturbances and nitrogen dioxide (NO2) concentration (OR=1.09, 1.03-1.16 in 6–7 years, respectively). It was also found that there was a significant interaction between the noise level and particulate matter less than 10 microns (PM10) level. Based on the findings, exposure to certain outdoor air pollutants and noise can affect the prevalence of asthma symptoms in residents of Tehran. The simultaneous presence of air pollutants and noise has an aggravating effect on the prevalence of asthma symptoms. Therefore, controlling sources of pollutants for reducing asthma symptoms is suggested.

Identification of optimal locations for green space initiatives through GIS-based multi-criteria analysis and the analytical hierarchy process

Urban green spaces play a vital role in enhancing the well-being of communities and mitigating environmental challenges such as air pollution and global warming. Despite their importance, effective models to allocate these green spaces are often overlooked, particularly in developing countries. This study utilises GIS-based Multi-Criteria Analysis and the Analytical Hierarchy Process to recommend optimal locations for green space interventions in Lilongwe City, Malawi, based on nine factors: population density, proximity to roads, slope, Digital Elevation Model (DEM), Normalized Difference Vegetative Index (NDVI), land cover, existing green space, proximity to water bodies, and nitrogen dioxide concentration. The results show that 0.57% (23,776 hectares) of Lilongwe city is highly suitable while 14.50% (604,596 hectares) is unsuitable for green space interventions, where population density was the most determining factor. The suitability varied across the city, with highly suitable areas predominantly located in the southern part. The study highlights the importance of informed decision-making in urban green space planning, setting a standard for equitable access to green spaces and sustainable urban development.

Ambient smoke exposure and indoor air quality in eastern Massachusetts during the 2023 wildfire season

ABSTRACT Widespread North American wildfires in 2023 led to exposure to ambient wildfire smoke outside of traditionally wildfire-prone regions. The objective was to evaluate levels of indoor air pollutants in relation to ambient wildfire smoke exposure in eastern Massachusetts. Using a real-time multipollutant sensor system in five Boston area households, this study assessed indoor fine particulate matter (PM2.5), nitrogen dioxide (NO2), and total volatile organic compound concentrations (TVOC) two days before and during days of hazardous wildfire smoke exposure (smoke days). The relationship between ambient PM2.5 from regulatory monitors and indoor PM2.5 before and during smoke days was investigated by mixed effects linear regression. During smoke days and the preceding non-smoke days, median indoor PM2.5 was 9.9 µg/m3 and 3.5 µg/m3 (p < 0.001), respectively; median NO2 was 20.5 ppb and 18.4 ppb (p = 0.11); median TVOC was 6,715 µg/m3 and 5,361 µg/m3 (p = 0.35). A 1% increase in ambient PM2.5 was associated with a 0.93% increase in indoor PM2.5 on smoke days (95% CI, 0.54%–1.32%) and a 0.34% increase on non-smoke days (95% CI, 0.17%–0.66%), though interaction testing of smoke day status was not statistically significant (p = 0.14). In Northeastern US homes, indoor PM2.5 increased significantly during ambient wildfire smoke exposure, which may reflect increased infiltration and increased indoor particle-generating activities during smoke days. Implications: This study reports on household exposure to wildfire smoke in eastern Massachusetts, finding that indoor PM2.5 more than doubled compared to preceding non-smoke days, while indoor NO2 and TVOC did not significantly rise. Though the generalizability of this study is limited by the small number of homes studied, the findings suggest that more investigation is needed to understand indoor air pollution during future wildfire smoke exposure in regions not traditionally wildfire-prone and to inform mitigation efforts.

Munich’s selective diesel vehicle ban and its impact on nitrogen dioxide concentrations: A quasi-experimental study

BackgroundThe current limit on NO2 concentrations of 40 μg/m3, set by the European Union, has been regularly exceeded in Munich, Germany. This limit will likely be reduced towards the WHO recommended target of 10 μg/m3. Against this backdrop, the city implemented a selective diesel vehicle ban within the existing low-emission zone in February 2023, targeting Euro 4 and older diesel vehicles. Our study investigated the effect of Munich’s selective diesel vehicle ban on NO2 concentrations, focusing on the half-year period following its implementation. MethodsOur study utilized a synthetic control approach (primary analysis) and a controlled interrupted time series approach (secondary analysis). These quasi-experimental methodologies create a ‘counterfactual’ no-intervention scenario, enabling comparison between observed and counterfactual scenarios to estimate an intervention effect. We employed historical controls, using routine data from multiple monitoring stations located within and outside the low-emission zone for 2014 to 2022, and considered possible confounders. ResultsNO2 concentrations within Munich’s low-emission zone showed overall declining trends from August 2014 to July 2023. Effects of the selective diesel vehicle ban were small and wide confidence intervals indicate large uncertainty in the magnitude and direction of the effect. At Landshuter Allee, the average intervention effect was −2.67 μg/m3 (95 %-CI = [-12.72; 7.38]), at Stachus it was −2.74 μg/m3 (95 %-CI = [-9.91; 4.42]), and at Lothstrasse it was −1.03 μg/m3 (95 %-CI = [-7.75; 5.69]). The secondary analysis confirmed these findings, reinforcing uncertainty about the effect of the intervention. ConclusionOur study suggests that Munich’s selective diesel vehicle ban had a limited effect on lowering NO2 concentrations. Possible explanations include the ban’s focus on Euro 4 and older diesel vehicles, many exemptions to the selective ban, and unclear enforcement. This highlights that comprehensive approaches and ongoing, well-designed monitoring and evaluation are crucial for addressing urban air pollution and protecting public health.

Assessment of the risk to the health of the population living in the zone influenced by atmospheric emissions from the engineering industry

Introduction. During operation, machine-building enterprises emit pollutants that can negatively affect the health of the population. The study aims to determine the impact of emissions from a machine–building plant, as well as background atmospheric pollution, on the health risk of the population of Novokuznetsk. Materials and methods. The work used data from the volume of maximum permissible emissions of a machine-building plant. The researchers calculated the maximum and average concentrations of pollutants using the "ECOcenter – Standard" program at 36 exposure points selected on the city map. Experts determined the maximum permissible concentrations of pollutants in the atmosphere in accordance with SanPiN 1.2.3685-21. The authors calculated the risks to public health in accordance with the Guidelines R 2.1.10.1920-04. The classification of risk levels was carried out on the basis of MP 2.1.10.0156-19. 2.1.10. Scientists also made a risk assessment considering background atmospheric pollution. Results. Specialists carried out a risk assessment from exposure to nitrogen dioxide, carbon monoxide, sulfur dioxide, carbon (soot), inorganic dust, hexavalent chromium. The maximum and average concentrations of pollutants, as well as the maximum concentrations calculated taking into account background pollution, did not exceed the maximum permissible level. The average concentrations of nitrogen dioxide and hexavalent chromium, taking into account the background, exceeded the hygienic standard. The values of the hazard indices for acute and chronic exposures without taking into account the background, as well as for acute exposures taking into account the background, corresponded to the minimum (target) risk level. The values of the hazard indices for chronic inhalation effects, considering the background, corresponded to the alarming risk level at five points, amounting to 3.084–3.800. With chronic exposure, taking into account the background, an alarming level of risk was revealed for the effect on the respiratory organs (at four points the hazard index was 3.117 to 3.616) and blood (at three points the hazard index was in the range from 3.090 to 3.433). The total individual carcinogenic risk, excluding background, did not exceed the permissible level, ranging from 1.08×10–8 to 2.43×10–7 at different points, taking into account the background, amounted to 1.79×10–4–2.26×10–4, which corresponds to an alarming level. Hexavalent chromium makes the main contribution to the formation of carcinogenic risk. Limitations. Calculated concentrations of pollutants were used to assess the risks. Conclusion. The risks from exposure to atmospheric emissions from the machine-building plant correspond to the minimum (target) level. Background concentrations of toxic substances in chronic inhalation exposures determine an alarming level of non-carcinogenic risk at five points, as well as an alarming level of carcinogenic risk at all points of exposure. Ethics. This study did not require the conclusion of the Ethics Committee.

Impact of net zero policy scenarios on air pollution inequalities in England and Wales

BackgroundThe UK is committed to achieve net zero greenhouse gas emissions by 2050. The suite of policies needed to reach net zero will lead to improvements in air quality and, consequently, could lessen air pollution inequalities. We assessed air pollution inequalities across different sociodemographic groups in England and Wales and explored how these might be differentially impacted by future air pollution projections in 2030 and 2040 under net zero policies. MethodsWe employed a geodemographic classification approach to categorise neighbourhoods into five distinct clusters based on 2021 UK Census sociodemographic variables. We modelled fine particulate matter (PM2.5) and nitrogen dioxide (NO2) concentrations for the year 2019, and predicted concentrations in 2030 and 2040. We compared a business-as-usual (BAU) scenario and two policy pathways to achieve net zero currently considered by the UK government. We aggregated air pollution concentrations to the neighbourhood level and assessed differential neighbourhood-level concentrations across the geodemographic groups using descriptive statistics and box plots. ResultsThe Urban Central Professionals group experienced 14 µg/m3 higher average NO2 concentrations compared with the Rural Elderly group in 2019. Despite substantial improvements to air quality in 2030 and 2040 of up to 6.3 µg/m3 for NO2 based on BAU, and further reductions of up to 2.4 µg/m3 NO2 under net zero policies, the overall pattern of inequality persists, but is predicted to be less pronounced. ConclusionsOur findings demonstrate the effectiveness of targeted policies and innovations in reducing both air quality and greenhouse gas emissions and in bridging the environmental inequality gap. Our findings are essential to develop targeted communication campaigns to secure acceptance and willingness across the sociodemographic spectrum to support the significant behavioural changes needed to achieve net zero, by highlighting the wider co-benefits to the environment and health of such policies.

Air Quality Geospatial Analysis in Vulnerable Areas. Case Study of Valencia (Spain).

The escalating concern over poor air quality, particularly nitrogen dioxide (NO2), poses a critical public health challenge, especially for vulnerable populations, such as children, older adults, and those with chronic diseases. This study aimed to analyze air quality in areas with vulnerable populations through a geospatial analysis of NO2 concentration measured by the passive dosimetry method in 2022. The results reveal high vulnerability caused by areas with over-centralized facilities and high concentrations of nitrogen dioxide, often coinciding with busy avenues. The study emphasizes the urgent need to address air quality disparities, providing crucial insights for public decision-makers to allocate resources effectively and reduce environmental inequalities in the city, ultimately safeguarding the health of at-risk communities.

Well-planned greenery improves air urban quality - Modelling the effect of altered airflow and pollutant deposition

Urban air quality is influenced by vegetation through alterations in airflow and pollutant deposition processes. We investigated these interactions by integrating the Vegetation Impact Dynamic Assessment model (VIDA) with the Large-Eddy Simulation model PALM. Our analysis focus on nitrogen dioxide (NO₂) and particulate matter (PM) concentrations at the local scale, considering three tree genera. Our findings reveal the necessity of accounting for both gaseous pollutants and particles separately due to their differing mechanisms of deposition onto leaves. The coupled PALM-VIDA model demonstrates a significant reduction in PM levels across the modelling domain and within street canyons when deposition to vegetation is incorporated. Reduction in NO₂ through deposition to vegetation is lower but human NO2 exposure can still be decreased if tree species selection and placement leads to desirable effects on air flow. Sparse tree arrangements or species with sparse crowns facilitate ventilation and are often better at reducing NO₂ concentrations in street canyons compared to denser vegetation with higher deposition but negative effects on ventilation. Our study informs urban planning and green infrastructure design, underscoring the multifaceted role of urban greenery in air pollution mitigation strategies. Its main conclusion is that both deposition processes and the influence of air mixing and ventilation need to be considered to accurately assess the effects of urban trees on local air quality. Ill-considered placement and species selection may cause a net increase in pollutants underneath the trees. However, careful planning can address this risk and instead improve overall air quality.

Spatial Analysis of Air Pollutants in an Industrial City Using GIS-Based Techniques: A Case Study of Pavlodar, Kazakhstan

The given research employs high-resolution air quality monitoring and contemporary statistical methods to address gaps in understanding the urban air pollution in Pavlodar, a city with a significant industrial presence and promising touristic potential. Using mobile air quality sensors for detailed spatial data collection, the research aims to quantify concentrations of particulate matter (PM2.5, PM10), carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ground-level ozone (O3); assess their distribution; and identify key influencing factors. In this study, we employed Geographic Information Systems (GISs) for spatial analysis, integrating multi-level B-spline interpolation to model spatial variability. Correlation analysis and structural equation modeling were utilized to explore the relationships between variables, while regression analysis was conducted to quantify these relationships. These techniques were crucial for accurately mapping and interpreting spatial patterns and their underlying factors. The study identifies PM2.5 and NO2 as the primary contributors to air pollution in Pavlodar, with NO2 exceeding the 24 h threshold in 87.38% of locations and PM2.5 showing the highest individual air quality index (AQI) in 75.7% of cases. Correlation analysis reveals a positive association between PM2.5 and AQI and a negative correlation between NO2 and AQI, likely due to the dominant influence of PM2.5 in AQI calculations. Structural equation modeling (SEM) further underscores PM2.5 as the most significant impactor on AQI, while NO2 shows no significant direct impact. Humidity is positively correlated with AQI, though this relationship is context-specific to seasonal patterns observed in May. The sectoral analysis of landscape indices reveals weak correlations between the green space ratio (GSR) and air quality, indicating that while vegetation reduces pollutants, its impact is minimal due to urban planting density. The road ratio (RR) lacks sufficient statistical evidence to draw conclusions about its effect on air quality, possibly due to the methodology used. Spatial variability in pollutant concentrations is evident, with increasing PM2.5, PM10, and AQI towards the east-northeast, likely influenced by industrial activities and prevailing wind patterns. In contrast, NO2 pollution does not show a clear geographic pattern, indicating vehicular emissions as its primary source. Spatial interpolation highlights pollution hotspots near industrial zones, posing health risks to vulnerable populations. While the city’s overall AQI is considered “moderate”, the study highlights the necessity of implementing measures to improve air quality in Pavlodar. This will not only enhance the city’s attractiveness to tourists but also support its sustainable development as an industrial center.

Evaluating background and local contributions and identifying traffic-related pollutant hotspots: insights from Google Air View mobile monitoring in Dublin, Ireland

Mobile monitoring provides high-resolution observation on temporal and spatial scales compared to traditional fixed-site measurement. This study demonstrates the use of high spatio-temporal resolution of air pollution data collected by Google Air View vehicles to identify hotspots and assess compliance with WHO Air Quality Guidelines (AQGs) in Dublin City. The mobile monitoring was conducted during weekdays, typically from 7:00 to 19:00, between 6 May 2021 and 6 May 2022. One-second data were aggregated to 377,113 8 s road segments, and 8 s rolling medians were aggregated to hourly and daily levels for further analysis. We assessed the temporal variability of fine particulate matter (PM2.5), nitrogen monoxide (NO), nitrogen dioxide (NO2), ozone (O3), carbon monoxide (CO), and carbon dioxide (CO2) concentrations at hyperlocal levels. The average daytime median concentrations of NO2 (28.4 ± 15.7 µg/m3) and PM2.5 (7.6 ± 4.7 µg/m3) exceeded the WHO twenty-four hours (24 h) Air Quality Guidelines in 49.4% and 9% of the 1-year sampling time, respectively. For the diurnal variation of measured pollutants, the morning (8:00) and early evening (18:00) showed higher concentrations for NO2 and PM2.5, mostly happening in the winter season, while the afternoon is the least polluted time except for O3. The low-percentile approach along with 1-h and daytime minima method allowed for decomposing pollutant time series into the background and local contributions. Background contributions for NO2 and PM2.5 changed along with the seasonal variation. Local contributions for PM2.5 changed slightly; however, NO2 showed significant diurnal and seasonal variability related to traffic emissions. Short-lived event enhancement (1 min to 1 h) accounts for 36.0–40.6% and 20.8–42.2% of the total concentration for NO2 and PM2.5. The highly polluted days account for 56.3% of total NO2, highlighting local traffic is the dominant contributor to short-term NO2 concentrations. The longer-lived events (> 8 h) enhancement accounts for 25% of the monitored concentrations. Additionally, conducting optimal hotspot analysis enables mapping the spatial distribution of “hot” spots for PM2.5 and NO2 on highly polluted days. Overall, this investigation suggests both background and local emissions contribute to PM2.5 and NO2 pollution in urban areas and emphasize the urgent need for mitigating NO2 from traffic pollution in Dublin.

Assessing and anticipating environmental challenges in Lahore, Pakistan: future implications of air pollution on sustainable development and environmental governance.

Urban environment and air quality are changing primarily due to land use land cover (LULC) changes, economic activity, and urbanization. Air pollution has been increasingly acknowledged as a major issue for cities due to its extensive effects on health and well-being. As the second most populous city in the country, Lahorefaces alarming levels of air pollutants, whichinduced this study to focus on the pervasive issue of air pollution in Lahore. For this, the study collected air pollutants data from the Environmental Protection Department of Punjab and analyzed them using the ARIMA model. In the research results, both the observed data and predictive models uncovered concerning trends in pollutant concentrations, ultimatelyportraying a concerning picture for air quality management. Carbon monoxide (CO) levels show a consistent rise, surpassing Pakistan's environmental standards by 2025. Similarly, nitrogen dioxide (NO2) concentrations escalate, exceeding prescribed standards. Ground-level ozone (O3) also demonstrates a substantial increase, surpassing standards by 2025. Both PM2.5 and PM10 exhibit marked upward trends, projected to exceed recommended limits, particularly PM10 throughout the study year. The Air Quality Index exhibits an observable upward trend, fluctuating between 70 and 442 from 2015 to 2020. Similarly, a positive correlation was found between population growth and land use conversion into residential areas. Projections suggest a continuous increase, potentially hitting a severe level of 500 during winter by 2025. These findings point to an impending air pollution crisis, demanding urgent action to address the hazardous situation in the city. The study recommends that urban air pollution should be reduced, and the negative health effects of air pollution should be minimized using vegetation barriers, screens, and greening initiatives. Strict regulations and monitoring initiatives need to be put in place in big cities to monitor pollution and vegetation.

High-sensitive and fast-responsive In2O3 thin film sensors for dual detection of NO2 and H2S gases at room temperature

In this work, the room-temperature dual gas sensing characteristics of indium oxide (In2O3) thin films towards NO2 and H2S have been studied. In2O3 thin films were synthesized by the thermal oxidation of indium metal films of various thicknesses in the range of 50–250 nm deposited by thermal evaporation method. Grazing incidence X-ray diffraction (GI-XRD) revealed the change in preferred orientation of In2O3 thin films corresponding to varying thickness, while field-emission electron microscopy studies showcased evolving surface morphologies from individual grains to granular network with respect to the increase in film thickness. Investigations were made on the ability of In2O3 thin films to detect various low concentrations of nitrogen dioxide (NO2) and hydrogen sulfide (H2S) gases at ambient temperature. In2O3 thin films synthesized using 100 nm thick In films exhibited good sensing response of around 58 and 68 % towards NO2 and H2S gases of 5 ppm respectively, at room temperature (27 °C) with the response time of 36 and 18 s. Remarkably, the lower experimental detection limit of these toxic gases could be extended up to 100 ppb. Using X-ray photoelectron spectroscopy, a large presence of surface oxygen is observed on the In2O3 thin film. The sensor has demonstrated remarkable sensing abilities, including strong selectivity, quick sensing response, and good repeatability.

SPATIOTEMPORAL OF NITROGEN DIOXIDE (NO2) CONCENTRATION IN THE URBAN ENVIRONMENT OF KLANG VALLEY, MALAYSIA

The high concentration of nitrogen dioxide (NO2) directly results in Klang Valley’s air quality deterioration, causing a public health risk. This study was conducted to analyse the daily-averaged and annual concentration of nitrogen dioxide (NO2) on a spatial-temporal scale at five continuous monitoring stations under the Department of Environment (DOE) in Klang Valley, namely, Klang, Shah Alam, Petaling Jaya, Kajang, and Cheras from 2000 to 2009 using Man-Kendall statistical analysis and interpolation technique in Geographic Information System (GIS). The result clearly showed that the Petaling Jaya station was identified as the most polluted compared to other stations, with an average concentration of more than 0.050 ppm every year and reaching the maximum concentration of 0.069 ppm where the mean was 0.030 in 2001. Based on the p-value derived from the Mann-Kendall statistical analysis, the Klang, Petaling Jaya, Shah Alam, and Cheras stations recorded a significant trend with p-values &lt; 0.05 at 0.0001 and 0.020, respectively. The annual concentration of NO2 in all the stations was in the range of 0.015 to 0.04 ppm from 2004 to 2009, compared to 0.005 to 0.01 ppm from 2000 to 2003. The highest annual-averaged NO2 concentration was reported at the Petaling Jaya station between 0.035 and 0.004 ppm for all years except 2007 and 2009 when concentrations were in the 0.03 to 0.035 ppm. Notably, the Petaling Jaya station had the highest annual NO2 concentration, which ranged from 0.025 to 0.04 ppm due to emissions from motor vehicles. The major pressure on road infrastructure was recognised, mainly a lack of space to accommodate the effect of the maximum density of motor vehicles and traffic, resulting in traffic congestion in the city centre.

International airport emissions and their impact on local air quality: chemical speciation of ambient aerosols at Madrid–Barajas Airport during the AVIATOR campaign

Abstract. Madrid–Barajas Airport (MAD) is the fourth-busiest airport in Europe. The aerosol chemical composition and the concentrations of other key pollutants were measured at the airport perimeter during October 2021 to assess the impact of airport emissions on local air quality. A high-fidelity ambient instrumentation system was deployed at Madrid–Barajas Airport to measure the following: concentrations of organic aerosols (with their composition), black carbon (eBC), carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NOx), sulfur dioxide (SO2), particulate matter (PM2.5, PM10), total hydrocarbon (THC), and total particle number. The average concentrations of eBC, NOx, SO2, PM2.5, PM10, CO, and THC at the airport for the entire campaign were 1.07 µg m−3, 22.7 µg m−3, 4.10 µg m−3, 9.35 µg m−3, 16.43 µg m−3, 0.23 mg m−3, and 2.30 mg m−3, respectively. The source apportionment analysis of the non-refractory organic aerosol (OA) using positive matrix factorisation (PMF) allowed us to discriminate between different sources of pollution, namely less oxidised oxygenated organic aerosol (LO-OOA), alkane organic aerosol (AlkOA), and more oxidised oxygenated organic aerosol (MO-OOA). The results showed that LO-OOA and MO-OOA account for more than 80 % of the total organic particle mass measured near the runway. Trace gases correlate better with the AlkOA factor than LO-OOA and MO-OOA, indicating that AlkOA is mainly related to primary combustion emissions. Bivariate polar plots were used for pollutant source identification. Significantly higher concentrations of the obtained factors were observed at low wind speeds (&lt;3 m s−1) from the southwest, where two of the runways and all terminals are located. Higher SO2/NOx and CO/eBC ratios were observed when the winds originated from the northeast, where the two northern runways are located. These elevated ratios are attributed to the aircraft activity being the major pollutant source in the northeast area.

The temporal-spatial association of respiratory manifestations and air pollution in children referred to the Emergency Department of Akbar Children’s Hospital, Mashhad, Iran

BackgroundAir pollution causes many respiratory disorders, especially in children and the elderly. These disorders include asthma exacerbations, bronchiolitis, and pneumonia. Research on the association between air pollution and respiratory disorders helps to reevaluate environmental policies in developing countries.MethodsThis descriptive cross-sectional study was conducted on 932 children with respiratory manifestations admitted from December 2017 to December 2019 at the Emergency Department of Akbar Children’s Hospital of Mashhad University of Medical Sciences, Mashhad, Iran. Air pollution indices such as concentration of sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and particulate matter (PM) smaller than 2.5 and 10 μm and other parameters, including the air quality index (AQI), air temperature, and humidity level from 2017 to 2019, were retrieved from Mashhad Environmental Pollution Monitoring Center. Demographic and clinical data of patients were collected from patients’ hospital documents. We used descriptive analytical methods such as central tendency, variability, and frequency distribution to report and analyze demographic and clinical data through tables and diagrams. The association between air pollution indices and respiratory manifestations was examined by the Spearman correlation test. The correlation between the AQI and total hospital admissions and asthma-related hospital admissions was also evaluated by the Spearman correlation test.ResultsHospital admissions due to respiratory manifestations were not associated with the AQI of each month (p-value = 0.794). The concentration of SO2 was correlated with respiratory-related hospital admissions (correlation coefficient = 0.487, p-value = 0.016) but not asthma attacks.ConclusionGenerally, our cross-sectional study showed no statistically considerable association between air pollution and hospital admissions due to respiratory manifestations and asthma attacks in children. Of the air pollution indices, only SO2 concentration was associated with respiratory-related hospital admissions but not asthma attacks.

Long-Term Nitrogen Dioxide Exposure as a Possible 5-Year Mortality Risk Factor in Diabetic Patients Treated Using Off-Pump Surgical Revascularization-A Retrospective Analysis.

Background: There is mounting evidence that diabetic-related cardiac metabolism abnormalities with oxidative stress and inflammatory mechanism activation align with the functional impairments that result in atherosclerotic lesion formation. Among the possible non-traditional coronary lesion risk factors, environmental exposure may be significant, especially in diabetic patients. Methods: A total of 140 diabetic patients (115 (82%) males and 25 (18%) females) with a mean age of 65 (60-71) underwent surgical revascularization due to multivessel coronary disease. The possible all-cause mortality risk factors, including demographical and clinical factors followed by chronic air pollution exposure, were identified. Results: All patients were operated on using the off-pump technique and followed for 5.6 (5-6.1) years. The multivariable model for 5-year mortality prediction presented the nitrogen dioxide chronic exposure (HR: 3.99, 95% CI: 1.16-13.71, p = 0.028) and completeness of revascularization (HR: 0.19, 95% CI: 0.04-0.86, p = 0.031) as significant all-cause mortality risk factors. Conclusions: Ambient air pollutants such as an excessive chronic nitrogen dioxide concentration (>15 µg/m3) may increase 5-year all-cause mortality in diabetic patients following surgical revascularization.