Average NO2 Concentrations Research Articles

Spatiotemporal Distribution Characteristics of Air Pollution and Health Risks in Key Cities of China

Based on the monitoring data of five pollutants in 168 key cities under air pollution prevention and control in China from 2015 to 2020, using the MAKESENS model and the aggregate risk index(ARI), this study quantitatively analyzed the spatial and temporal distribution characteristics of air pollution and health risks in China and the six urban agglomerations. The results showed that:① PM2.5 pollution was the most serious pollution in Chinese key cities. Only 15% of the cities' six-year average concentrations of PM2.5 reached the National Secondary Standard, followed by that of NO2; 77% of the cities' six-year average concentrations of NO2 reached the National Secondary Standard. The urban agglomerations of Beijing-Tianjin-Hebei and Fenwei plain had the most serious air pollution, and the six-year average concentrations of PM2.5, SO2, CO, and NO2 were higher than those of other urban agglomerations. ② The concentrations of PM2.5, SO2, CO, and NO2 in key cities of China showed a decreasing trend, whereas the concentration of O3 in other urban agglomerations showed an increasing trend, except in the Chengdu-Chongqing urban agglomeration. The concentration of SO2 in the urban agglomerations of Beijing-Tianjin-Hebei and Fenwei plain changed the most significantly. ③ The health risk of air pollution in the key cities of China generally showed a decreasing trend, with a sharp decline from 2017 to 2018, and the population exposed to extremely high risks dropped from 160 million to 32.54 million. The urban agglomeration in the middle reaches of the Yangtze River had the most significant decline in health risks, whereas the key cities in China faced higher health risks in spring and winter seasons. ④ The Beijing-Tianjin-Hebei and Fenwei plain urban agglomerations had the highest health risks, and the urban agglomeration in the middle reaches of the Yangtze River had the lowest; O3 gradually replaced PM2.5 as the main pollutant affecting the health risk. These results can provide a reference for evaluating the effectiveness of urban air pollution control in China during the 13th Five-Year Plan period.

Abstract 14863: Omega-3 Fatty Acids Intake and Oxylipins Production in Response to Short-Term Ambient Air Pollution Exposure in Healthy Adults

Rationale: Exposure to air pollution is associated with adverse health effects through systemic inflammation and oxidative stress. One mechanism of beneficial effects of omega-3 polyunsaturated fatty acids (n-3 FA) is mediated via their inflammation resolution process by generating bioactive lipid mediators known as oxylipins. Objective: This study examined the association between n-3 FA-derived bioactive oxylipins and short-term exposure to ambient air pollution in healthy adults. Methods: Fifteen healthy adults were enrolled into either high or low n-3 groups based on n-3 FA intake and the participants underwent 4-5 blood collections for lipidomic profile of 55 oxylipins. Associations between ambient ozone, nitrogen dioxide (NO 2 ), and fine particulate matter (PM 2.5 ) levels and plasma oxylipins were assessed using mixed-effects models stratified by fatty acids levels. Results: Average concentrations of ozone (40.8±11.1 ppb), NO 2 (5.3±3.8 ppb), and PM 2.5 (10.2±4.1 μg/m 3 ) were below national ambient air quality standards during the study period. Compared to the low n-3 group exposed to ozone and PM 2.5 , high n-3 group had significant reduction in arachidonic acids (AA) derived pro-inflammatory oxylipins produced by lipoxygenase (LOX). For instance, 12 HETE was negatively associated with ozone levels [for an IQR increase in ozone, -58.1% (95% CI:-96.8, -19.4) vs. 14.5% (95% CI:-33, 62)] and PM 2.5 concentrations [for an IQR increase in PM 2.5 , -29.6% (95% CI:-49.1, -10.1) vs. 28.5% (95% CI:-3.8, 60.9)] at lag4 in the high n-3 group while the association was null in the low n-3 group. In contrast, high n-3 group exposed to ozone and PM 2.5 had significant increases in EPA and DHA derived pro-resolving oxylipins produced by LOX and cytochrome p450 (CYP) and soluble epoxide hydrolase (sEH) compared to the low n-3 group. Conclusions: We observed negative associations between short-term ambient air pollutants and pro-inflammatory oxylipins in the high n-3 groups, while the associations between short-term ambient air pollutants and pro-resolving oxylipins were positive in the high n-3 groups, suggesting that n-3 derived lipid mediators may mediate the inflammation resolution process in response to low levels of ambient air pollution in healthy adults.

Nitrogen dioxide (NO2) levels and health problems in street sellers around Universitas Negeri Gorontalo (UNG)

Air is the most critical factor for human survival, which must and must always be maintained for quality. If the air quality changes from normal, the air has been polluted. Transportation activities are one of the contributing factors to air pollution. UNG is one of the largest campuses in Gorontalo Province, which involves students in increasing the number of residents outside the area who have an impact on campus activities and an increase in the number of vehicles. In the UNG area, street vendors sell from 6 in the morning to midnight. This makes street vendors a group at risk of experiencing health problems due to exposure to NO2 from vehicle exhaust emissions. This type of research is observational with a descriptive study design. This research was conducted on Jalan Jendral Sudirman, around the UNG campus. The population in this study were all street vendors selling around the UNG campus, totaling 58 traders. The sampling technique uses the Total Sampling technique; the entire population is used as a sample. The results showed that the average concentration of NO2 around the UNG campus did not exceed the quality standards set by Government Regulation No. 22 of 2021, namely 0.2 mg/m3, and the most common health complaints experienced by respondents were coughing 43 people (74.1%), body aches and headaches 36 people (62.1%), runny nose 32 people (55.2%), sore throat 12 people (20.7%). Moreover, the least experienced was eye irritation in 2 people (3.4%). It is suggested that there should be monitoring of pollutant concentrations, and it is hoped that street vendors will use masks when selling and reduce selling time.

Middle-term nitrogen dioxide exposure and electrocardiogram abnormalities: A nationwide longitudinal study

BackgroundRecently, professionals, such as those from the World Health Organization, have recommended a rigorous standard for nitrogen dioxide (NO2), a typical urban air pollutant affected by regular traffic emissions, based on its short-term and long-term cardiorespiratory effects. However, the association between middle-term NO2 exposure and cardiovascular disorders remains unknown. ObjectivesThis study was conducted to examine the relationship between NO2 exposure and its middle-term cardiovascular risks indicated by electrocardiogram (ECG) abnormalities. MethodWe included 61,094 subjects (132,249 visits) with repeated ECG observations based on longitudinal data from the China National Stroke Screening Survey (CNSSS). The NO2 exposure concentration was derived from a predictive model, measured as the monthly average concentration in the 6 months of preceding the ECG measurement. We used the generalized estimation equation to assess the association between NO2 exposure and ECG abnormalities. ResultFor each 10 µg/m3 increase in monthly average NO2 concentration, the odds ratio of ECG abnormalities was 1.10 (95% confidence interval [CI] 1.09–1.12) after multiple adjustments. Stratified regression analyses of urban and rural residents showed associations between middle-term NO2 exposure and ECG abnormalities in urban (OR 1.09 [95% CI 1.08–1.11]) and rural residents (OR 1.14 [95% CI 1.10–1.19]). The association was robust within different subpopulations. Associations generally remained statistically significant (OR 1.03 [95% CI 1.02–1.05]) after extra adjustment for PM2.5. Exposure-response relationship analysis revealed a nearly linear relationship between NO2 exposure and the risk for ECG abnormalities. ConclusionUsing the variation in ECG signals as a potentially reversible indicator for subclinical risk in cardiovascular systems, our study provides additional evidence on the increased risk posed by middle-term NO2 exposure. Our study showed that policies controlling for NO2 concentrations are beneficial to prevent cardiovascular diseases among Chinese adults.

Numerical investigation on NOx formation of staged oxy-fuel combustion in a 35 MW large pilot boiler

In this study, high-fidelity simulations are conducted on a 35 MW pulverized coal oxy-fuel boiler to investigate NOx formation characteristics under staged oxy-fuel combustion, including both fuel-staged and oxygen-fuel two-way staged modes. Detailed volatile components are considered by using the chemical percolation devolatilization model. A skeletal reaction mechanisms consisting of 35 species developed for fuel-NOx formation under oxy-fuel conditions are employed for the gas phase combustion and NOx modeling. The radiative property models are also optimized for oxy-fuel combustion. The results show that in the fuel-staged mode, a reduction atmosphere is established in the reburning zone to reduce the NOx concentration in the flue gas. A reduction of 5.6% in the average NO concentration at the furnace outlet is observed relative to the baseline oxy-fuel case. Moreover, the application of oxygen-fuel two-way staged combustion leads to a further reduction in NOx formation. The average NO concentration at the furnace outlet is decreased by 17% compared to the baseline oxy-fuel case. Pathway analysis indicates a reduction in the NO formation pathway involving HCN → NCO → NO, while the NO reduction pathway of NO → HCN is enhanced.

Influence of nitric oxide delivery on kidney damage in experimental model of cardiopulmonary bypass with circulatory arrest

Aim. To evaluate the efficiency and safety of nitric oxide delivery for kidney protection in the simulation of cardiopulmonary bypass and circulatory arrest in the experiment.Materials and Methods. We performed an experimental modeling of cardiopulmonary bypass with circulatory arrest in 20 sheep of the Altai breed weighing 30-32 kg. Circulatory arrest was performed at moderate hypothermia (30-32°C) for 15 minutes and was followed by reperfusion and warming up to 37°C. Animals were divided into 2 equal groups: 10 sheep which received nitric oxide (NO) through the inhalations supply and cardiopulmonary bypass machine at a dose of 80 ppm, and 10 control sheep. We further collected biological fluids and tissue specimens for subsequent assessment of the safety of NO use and its nephropro-tective properties.Results. The proposed method of NO therapy during the cardiopulmonary bypass with circulatory arrest was safe and did not lead to an increase in toxic metabolites. In sheep which received NO therapy, the average concentration of NO2 throughout the entire period of the experiment was 1.2 ± 0.19 ppm (with a maximum allowable concentration of 3.0 ppm), and the concentration of methemoglobin (MetHb) was 2.3 ± 0.34% (with a maximum allowable level of 5.0%). Neutrophilic gelatinase-associated lipocalin (NGAL) was significantly lower in sheep which received NO therapy (0.67 ± 0.255 ng/mL versus 2.23 ± 0.881 ng/mL in the control group, p = 0.0001). Acute kidney injury was mitigated in sheep which received NO therapy.Conclusion. Experimental delivery of NO at a dose of 80 ppm during the cardiopulmonary bypass and circulatory arrest is safe and is associated with reduced acute kidney injury.

Air Pollutants Emission during Co-Combustion of Animal Manure and Wood Pellets in 15 kW Boiler

One of the aims of the environmental and energy policy of the European Union is to reduce the emission of air pollutants, primarily from heat and electricity production, e.g., using renewable energy sources. An example of such a fuel is agricultural biomass including animal manure, which can be used to produce energy in many ways, inter alia direct combustion. The aim of the study was to measure the concentration of NO, NOx, CO, dust and boiler efficiency during the combustion and co-combustion of wood and manure pellets. The research was conducted in the laboratory of the Poznań University of Technology using a 15 kW domestic boiler at maximum power. Manure pellets had higher moisture—9.2%, lower high heating value—17.25 MJ·kg−1, lower low heating value—16.45 MJ·kg−1, and higher ash content—11.23% than wood pellets. The average concentrations of CO, NO, NOx and dust for 100% wood pellets were 198 ± 27 mg·m−3, 129 ± 5 mg·m−3, 198 ± 8 mg·m−3 and 8.7 ± 0.5 mg·m−3, respectively. For this, the fuel boiler power was 13.6 kW (air–fuel ratio 1.48), and it was close to the maximal nominal power. Increasing the share of manure pellets in the burning mixture worsened the stability of the combustion process, and the occurrence of incomplete combustion was observed, which resulted in an increased concentration of CO and dust. Additionally, NO and NOx concentrations also increased. The average boiler power during the combustion of 100% manure pellets was 7.8 kW (air–fuel ratio 2.2), and the average concentrations of CO, NO, NOx and dust were 1548 ± 555 mg·m−3, 355 ± 53 mg·m−3, 554 ± 88 mg·m−3 and 482 ± 63 mg·m−3, respectively.

Associations between Dengue Incidence, Ecological Factors, and Anthropogenic Factors in Singapore.

Singapore experiences endemic dengue. Vector control remains the primary means to reduce transmission due to the lack of available therapeutics. Resource limitations mean that vector-control tools need to be optimized, which can be achieved by studying risk factors related to disease transmission. We developed a statistical modelling framework which can account for a high-resolution and high-dimensional set of covariates to delineate spatio-temporal characteristics that are associated with dengue transmission from 2014 to 2020 in Singapore. We applied the proposed framework to two distinct datasets, stratified based on the primary type of housing within each spatial unit. Generalized additive models reveal non-linear exposure responses between a large range of ecological and anthropogenic factors as well as dengue incidence rates. At values below their mean, lesser mean total daily rainfall (Incidence rate ratio (IRR): 3.75, 95% CI: 1.00-14.05, Mean: 4.40 mm), decreased mean windspeed (IRR: 3.65, 95% CI: 1.87-7.10, Mean: 4.53 km/h), and lower building heights (IRR: 2.62, 95% CI: 1.44-4.77, Mean: 6.5 m) displayed positive associations, while higher than average annual NO2 concentrations (IRR: 0.35, 95% CI: 0.18-0.66, Mean: 13.8 ppb) were estimated to be negatively associated with dengue incidence rates. Our study provides an understanding of associations between ecological and anthropogenic characteristics with dengue transmission. These findings help us understand high-risk areas of dengue transmission, and allows for land-use planning and formulation of vector control policies.

SPATIO-TEMPORAL VARIABILITY OF AIR QUALITY AND RELATIONSHIP WITH METEOROLOGICAL PARAMETERS IN CAPE TOWN, SOUTH AFRICA

Abstract. African cities are growing fast, and this rapid urbanisation has tremendously increased air pollution and greenhouse gas emissions. Despite this disturbing reality, the deleterious impacts of air pollution on livelihoods and the environment are often overlooked. Recently, the link between air quality and meteorological parameters has received attention from researchers and understanding this relationship could significantly improve our understanding of the spatial and temporal dynamics of air quality. This study focuses on analysing the spatiotemporal variation of three key air quality parameters, namely nitrogen dioxide (NO2), sulphur dioxide (SO2), and particulate matter (PM10), in Cape Town between 2020 and 2021. The study also aims to assess the relationship between air quality and meteorological parameters during this period, and the compliance with national and international air quality guidelines. Air quality data were collected from five monitoring stations in the City of Cape Town. A preliminary analysis of the data reveals high increases in the concentration of air pollutants from 2020 to 2021. For instance, the average monthly concentration of NO2 and SO2 at Bellville South station more than doubled during this period (from 6.7–14.8 µg/m3 and 3.4–8.1 µg/m3, respectively). This is worrisome as the air quality index (AQI) exceeded the safe limits at several sites. There is a need for urgent action by national and city governments in Africa to invest in air quality monitoring systems to enhance the well-being of citizens and promote the long-term sustainability of cities and infrastructure.

Effects of Mobility Restrictions on Air Pollution in the Madrid Region during the COVID-19 Pandemic and Post-Pandemic Periods

Air quality is one of the problems cities face today. The COVID-19 pandemic provided a unique opportunity to study the influence of traffic reduction on air quality during 2020, 2021, and 2022. The aim of this paper is to analyze the impacts and relationship between mobility restrictions in six COVID-19 wave periods and air pollution and evolution in the post-pandemic period differentiating Madrid city from its metropolitan area. We tested whether the changes produced for NO2, NOx, PM2.5, PM10, and O3 in the urban traffic and suburban traffic air quality stations data in comparison to the 2019 reference period were significant. The findings of this study show that the periods with the greatest reduction in pollutant concentrations were the first and third COVID-19 waves, when mobility restrictions were most stringent: there was strict confinement for the first wave (i.e., 47% reduction in daily average NO2 concentration), while severe weather forced a reduction in traffic in the region in the third wave period (i.e., 41% reduction in daily average NOx concentration). With the return to normal activity in the last period, pollutant concentrations began to exceed pre-pandemic levels. At the urban level, the reductions were more noticeable in relation to NO2 and NOx, while at the suburban level, changes were less prominent, except for the O3. The results are particularly inspiring for designing future mobility strategies for improving air quality in urban and metropolitan areas.

Comparison of the Air Quality within the Northern Region of India both During and After the Lockdown

The World Health Organization (WHO) declared COVID-19 a global pandemic due to the novel infectious coronavirus disease found in late 2019. Some positive impacts have been seen on the natural environment during the outbreak of COVID-19. In this study, we have tried to analyse the impact of lockdown on air quality at four major northern states of India (Delhi, Uttar Pradesh, Rajasthan, and Haryana) located in the National Capital Region (NCR). This study compared the variation in air pollutants during the first lockdown phase (25th March to 15th April) 2020 and after the lockdown phase (25th March to 15th April) 2022, including PM10, PM2.5, NO2, and SO2. The average concentration of PM10, PM2.5, NO2, and SO2 reduced by 70.43%, 64.7%, 66.37%, and 36.89% over National Capital Region (NCR) during the lockdown phase. A good pollution control plan can lead to significant improvements in air quality in the future, which should provide confidence to policymakers involved in developing air quality policies.

Densification versus urban sprawl. Modeling the impact of two urban growth scenarios on air quality

This study analyzes the impact of urban form on air pollution for two urban growth scenarios in 2040 for Quito, Ecuador: Urban sprawl (low-density outward expansion) and densification (the population increase occurs within the 2017 city boundaries). We estimate concentrations of carbon monoxide (CO), nitrogen oxides (NOx), nitrogen dioxide (NO2), ozone (O3), and particulate matter with an aerodynamic diameter equal to or less than 2.5 μm (PM2.5). Two downscaled global emission pathways (ECLIPSE) that present a lower/upper range are applied: 1) Current legislation emissions, CLE, and 2) Maximum technically feasible reductions, MTFR. The population is expected to increase by 50%, from 3 million in 2017 to 4.5 million in 2040. The sprawl scenario considerably increases the urban area by 52%. However, these new areas hold only 9% of the population. Both pathways present considerably lower emissions for 2040 than in 2017. Emissions for all sectors, except transportation, are the same for both scenarios. Transport emissions for the densification scenario are 32% lower than for urban sprawl.Due to reduced emissions, the 2040 scenarios result in lower CO, NOx, and PM2.5 concentrations for both pathways compared to 2017. This drop is more marked for the MTFR pathway compared to CLE. Contrary to our expectations, the two scenarios result in similar annual concentrations at the metropolitan level. Even when emission variations are considerable, differences between the scenarios are relatively small, particularly for CO, O3, and PM2.5, due to high regional contributions. However, the spatial distribution of concentrations within urban areas differs significantly; thus, the sprawl scenario results in a larger surface with higher CO, NOx, NO2, and PM2.5 levels and the opposite for O3. Still, due to the population distribution, the densification scenario exposes more residents to higher CO, O3, and PM2.5 values, and the sprawl scenario exposes more inhabitants to higher concentrations of NO2 and NOx.We find an improvement in air quality for both scenarios in 2040 compared to 2017. The annual average NO2 concentrations exceed local regulations in a small urban area only for the CLE pathway. In contrast, for PM2.5, the area and population exposed to levels that exceed the local regulation are higher than that for NO2 and more significant for the densification than the sprawl scenario and for the CLE than the MTFR pathway.

Studies on the variation in concentrations of respirable suspended particulate matter (PM10), NO2 and SO2 in and around Nagpur

The objective of this study is to assess the long-term variation in concentrations of Respirable suspended particulate matter (PM10), sulphur dioxide (SO2) and nitrogen dioxide (NO2) in the ambient air of Nagpur (India) during 2011-2018. The pollution data during the above period at three locations, viz., residential (Station-I), industrial (Station-II), and commercial location (Station-III) has been analyzed. The highest daily average concentration of PM10 at residential, industrial, and commercial locations was found 154 microgm/m3, 199 microgm/m3, and 153 microgm/m3, whereas, the average annual concentration at these locations was found 101.87 microgm/m3, 115.37 microgm/m3 and 98.75 microgm/m3, respectively during the above period. The highest daily average concentration of SO2 was found at 18 microgm/m3, 22 microgm/m3 and 19 microgm/m3 and the average annual concentration was 13.25 microgm/m3, 13.5 microgm/m3, 13 microgm/m3 at respective locations. And the highest daily average concentration of NO2 was found 77 microgm/m3, 60 microgm/m3, 60 microgm/m3 and the annual average concentration was 44.125 microgm/m3, 41.825 microgm/m3 and 40.25 microgm/m3 at the respective locations. The exceedance factors for PM10 varied from 'moderate to high' at the residential and commercial locations and from 'high to moderate' at the industrial location. Planetary boundary layer height (PBLH) and ventilation coefficient (VC) were also estimated over the region for 2011-2018. The maximum PBLH and VC observed during the study period was in the summer season, and the minimum was in the post-monsoon season. Annual and Seasonal Air quality index analysis shows that the level of pollution was in the range of SATIFACTORY to MODERATE. A study of seasonal analysis of PM10, SO2 and NO2 showed that the higher concentrations were found in winter relative to summer with the least concentration occurring during the monsoon season. A regression analysis was performed to check PM10's interdependence with other contaminants. A positive association was found between PM10 and SO2 for all seasons. A negative association was found between PM10 and NO2 in summer for all the stations and winter at Station-I and Station-III. Similarly, the correlation between PM10 and meteorological parameters such as wind speed and temperature was found to be negative whereas it was positive for relative humidity.

Investigating major sources of air pollution and improving spatiotemporal forecast accuracy using supervised machine learning and a proxy

Because weather can’t be controlled, air pollution can only be managed by planning and controlling the sources. Therefore, mathematical models that do not relate the source to the air quality do not offer guidance on how to regulate the air quality. This is often due to a lack of information about sources or a limited budget to measure emissions from sources that are expected to have a major contribution. A proxy for emission rate was used in modeling to improve the prediction of pollutant concentration and to investigate major sources. The daily average air concentration of NO2 and SO2 were predicted at five different locations using supervised machine learning methods, including random forests and support vector machines regression. Three models were constructed using different combinations of features. In model I, only features relating to the weather were used. Model II used only features of the types and quantities of fossil fuels consumed by power plants, which serve as a proxy for emission rates. In model III, all features from models I and II were used. Model III was found to be the most accurate. The average improvement in R2 for NO2 and SO2 regressions for all sites and using both methods were between 61% and 33%, respectively. This improvement in the prediction indicates that power plants are major sources and contribute significantly to the ambient level of SO2 and NO2 levels. The relative importance of all fuel consumption features was found to be comparable to the value of all weather features. The relative importance values of the fuel consumption features show an opportunity to improve air quality by burning a quantity of fuel in a power plant that has a smaller relative importance value instead. However, whether the receptors are located in rural or urban areas must be considered to maximize the net benefits.

An Analytical Study on Air Quality of Some Historical and Cultural Cities in Uttar Pradesh (India) with Special Reference to the Environment and Human Health

Abstract: The rapid urbanization, different construction works and deforestation recently increased in some famous historical, cultural and religious cities in Uttar Pradesh due to higher population pressure. Thousands of pilgrims visit these cities every year by motor and other vehicles. The motor vehicle exhaust also plays a vital role to enhance the toxic gases and aerosol in the environment. Many toxic particles, molecules, toxic gasses, chemicals, dust particles, vehicle exhausts and microorganisms also help to increase deterioration in air quality. Some factors like particulate matter, sulphur di oxide, nitrogen oxide, carbon mono oxide, carbon di oxide in higher concentrations directly affect and change the air texture as well as air quality. Higher concentrations of these substances are very injurious to the environment as well as living being including human. In present investigation a comparative study is done in between the residential and industrial/commercial area of five famous historical, cultural religious cities of Uttar Pradesh i.e. Varanasi, Prayagraj, Mathura, Gorakhpur and Ayodhya. Four air quality parameters i.e., air quality index (AQI), SO2, NO2 and PM10 average annual concentrations have been taken for this analytical study. AQI (Air quality index) was found 2 to 4 times higher in residential area while 3-6 times higher in industrial/commercial area in comparison to normal AQI value (0-50) in all studied cities/area. The highest average annual AQI value was recorded (166.40 microgram/m3) in Saket Nagar residential of Varanasi while 313.36 recorded in Geeda industrial area of Gorakhpur. The annual average of sulphur dioxide (SO2) concentration found 26.46 (microgram/m3) and 26.12 (microgram/m3) in residential area Varanasi and Prayagraj respectively which is slightly higher than the standard value (20microgram/m3). SO2 concentration recorded higher almost in industrial area of all cities. It was found highest in Geeda industrial area of Gorakhpur (49.70 microgram/m3) in comparison to normal annual value (20 microgram/m3). The annual average NO2 concentration in residential area almost found below or equal to normal value but it was recorded more than 3 times (33.44 microgram/m3) in Geeda industrial area of Gorakhpur. The particulate matter (PM10) concentration recorded very high in all residential as well as industrial/commercial area of all studied cities. The highest PM10 concentration 198.47(microgram/m3) found in Saket Nagar residential area of Varanasi city which is about 20 times higher than the normal value (10 microgram/m3). The highest average annual concentration of PM10 recorded 355.06 (microgram/m3) in Geeda industrial area of Gorakhpur which is about 36 times higher than normal annual value. The increasing concentration of the studied factors adversely affecting the environment as well as human health in these cities. The long term or short-term exposure of these pollutants is responsible for increasing various pulmonary disease in these cities.

Factors Affecting Nitrate Concentrations and Nitrogen and Oxygen Isotope Values of Effluents from Waste Water Treatment Plant

Urban domestic sewage is one of the important nitrate (NO-3) sources for surface water; however, their NO-3 concentrations and nitrogen and oxygen isotope values (δ15N-NO-3 and δ18O-NO-3) remain unclear, and the factors affecting NO-3 concentrations and δ15N-NO-3 and δ18O-NO-3 values of effluents in the waste water treatment plant (WWTP) are still unknown. Water samples in the Jiaozuo WWTP were collected to illustrate this question. Influents, clarified water in the secondary sedimentation tank (SST), and effluents of the WWTP were sampled every 8 h. The ammonia (NH+4) concentrations, NO-3 concentrations, and δ15N-NO-3 and δ18O-NO-3 values were analyzed to elucidate the nitrogen transfers through different treatment sections and illustrate the factors affecting the effluent NO-3 concentrations and isotope ratios. The results indicated that ① the mean NH+4 concentration was (22.86±2.16) mg·L-1 in the influent and decreased to (3.78±1.98) mg·L-1 in the SST and continuously reduced to (2.70±1.98) mg·L-1 in the effluent of the WWTP. The median NO-3 concentration was 0.62 mg·L-1 in the influent, and the average NO-3 concentration increased to (33.48±3.10) mg·L-1 in the SST and gradually increased to (37.20±4.34) mg·L-1 in the effluent of the WWTP. ② The mean values of δ15N-NO-3 and δ18O-NO-3 were (17.1±10.7)‰ and (19.2±2.2)‰ in the influent of the WWTP, the median values of δ15N-NO-3 and δ18O-NO-3 were 11.9‰ and 6.4‰ in the SST, and the average values were (12.6±1.9)‰ and (5.7±0.8)‰ in the effluent of the WWTP. ③ The NH+4 concentrations of influent had significant differences compared to those in the SST and the effluent (P<0.05). The reduction of NH+4 concentrations in the SST was due to the above nitrification during the aerobic treatment process, which transferred NH+4 to NO-3. The NH+4 concentrations in the SST had no significant differences with that in the effluent of the WWTP (P>0.05). ④ The NO-3 concentrations in the influent had significant differences with those in the SST and the effluent (P<0.05), and minor NO-3 concentrations but relatively high δ15N-NO-3 and δ18O-NO-3 values in the influent were probably due to denitrification during the pipe sewage transportation. The obviously increased NO-3 concentrations (P<0.05) but decreased δ18O-NO-3 values (P<0.05) in the SST and the effluent resulted from water oxygen incorporation during the nitrification. The above results confirmed the impacts of aerobic and anaerobic treatment processes on NO-3 concentrations and isotope ratios of effluent from the WWTP and provided scientific basis for the identification of sewage contributions to surface water nitrate via average δ15N-NO-3 and δ18O-NO-3 values.

Disparities in ambient nitrogen dioxide pollution in the United States

Average ambient concentrations of nitrogen dioxide (NO2), an important air pollutant, have declined in the United States since the enactment of the Clean Air Act. Despite evidence that NO2 disproportionately affects racial/ethnic minority groups, it remains unclear what drives the exposure disparities and how they have changed over time. Here, we provide evidence by integrating high-resolution (1 km × 1 km) ground-level NO2 estimates, sociodemographic information, and source-specific emission intensity and location for 217,740 block groups across the contiguous United States from 2000 to 2016. We show that racial/ethnic minorities are disproportionately exposed to higher levels of NO2 pollution compared with Whites across the United States and within major metropolitan areas. These inequities persisted over time and have worsened in many cases, despite a significant decrease in the national average NO2 concentration over the 17-y study period. Overall, traffic contributes the largest fraction of NO2 disparity. Contributions of other emission sources to exposure disparities vary by location. Our analyses offer insights into policies aimed at reducing air pollution exposure disparities among races/ethnicities and locations.

Use of symptom diary in primary students: association of nitrogen dioxide with prevalence of symptoms.

Air pollution is a global public health concern, and numerous studies have attempted to identify the health effects of air pollutants, including nitrogen dioxide (NO2). In China, there are few studies investigating the relationship between NO2 exposure and symptoms among children at an individual level. The aim of the study was to evaluate the acute effects of NO2 on prevalence of symptoms of primary students. An environmental and health questionnaire survey was administered to 4240 primary students in seven districts of Shanghai. Daily symptoms, as well as the daily air pollution and meteorological data from each community, were recorded during the corresponding period. A multivariable logistic regression model was utilized to analyze the relationship between the prevalence of symptoms and NO2 exposure in school-age children. A model with interaction items was adopted to estimate the interactive effects of NO2 and confounding factors on symptoms. The average NO2 level in central urban, industrial and rural areas were 62.07 ± 21.66, 54.86 ± 18.32 and 36.62 ± 21.23μgm-3, respectively. Our findings demonstrate that the occurrence of symptoms was significantly affected by NO2 exposure in the short-term. The largest associations were observed for a 10μgm-3 increase in 5-day moving average (lag04) NO2 concentration with prevalence of general symptoms (odds ratio [OR] = 1.15, 95% confidence interval [95% CI]: 1.07-1.22), throat symptoms (OR = 1.23, 95% CI: 1.13-1.35) and nasal symptoms (OR = 1.142, 95% CI: 1.02-1.27). Subgroup analysis showed that non-rural areas, boys, nearby environmental pollution source and history of present illness were all susceptible factors to the effects of NO2 exposure. Furthermore, there were interactive effects between NO2 exposure and area types on reported symptoms. NO2 can increase the risk of symptoms in primary students in the short-term, which could be significantly enhanced in central urban and industrial areas.

Assessment of Air Pollution in Different Areas (Urban, Suburban, and Rural) in Slovenia from 2017 to 2021

Air pollution can have a significant effect on human health. The present work is focused on the investigation of daily, monthly, and annual concentration levels of five typical air pollutants (SO2, NO2, NOX, PM10, and PM2.5) in the Republic of Slovenia (RS) from January 2017 to December 2021. The study was conducted at five different monitoring stations of the following kind: traffic (A), industrial (D), and background (B, C, E). The obtained results showed a decline in the average concentrations for all the studied air pollutants through the years, respectively. The daily average SO2 concentrations were the lowest in the year 2021 at location B, which is classified as background location, while the highest were detected in the year 2018 at location E, which is also classified as background location. The average daily concentrations of NO2 and NOX were the highest at location A in the year 2017, whereas the lowest were detected in the year 2010 and 2021. It is believed that those results are a consequence of measures set by the Slovenian government during the COVID-19 pandemic. The PM10 and PM2.5 daily average concentrations were the highest at location A in 2017, while the lowest were observed in the year 2019 at location C. Meteorological parameters (temperature, wind speed, and relative humidity) were studied in addition. In general, the high temperatures in ambient air are responsible for the intense concentrations of air pollutants. It was found in the study results for temperature, wind speed, and relative humidity that no significant difference was shown between studied years.

Non-premixed combustion and NOX emission characteristics in a micro gas turbine swirl combustor fueled by methane and ammonia at various heat loads

In comparison to methane (CH4), ammonia (NH3) is considered a potential carbon-free alternative fuel that can reduce greenhouse gas emissions. But a principal concern is the generation of elevated nitrogen oxide (NOX) emissions from NH3 flame. In this study, the detailed reaction mechanisms and thermodynamic data of CH4 oxidation and NH3 oxidation were performed using the steady and unsteady flamelet models. After validation of the turbulence model, the combustion and NOX emission characteristics of CH4/air and NH3/air non-premixed flames in a micro gas turbine swirl combustor under a series of identical heat loads were numerically investigated and compared. The present results show that the high-temperature zone of the NH3/air flame migrates more rapidly toward the outlet of the combustion chamber than that of the CH4/air flame as the heat load increases. The average NO, N2O, and NO2 emission concentrations at all heat loads from NH3/air flame are respectively 6.12, 161.05 (given the very low N2O emission concentration from CH4/air flame), and 2.89 times higher than those from CH4/air flame. There are correlation trends between some parameters (e.g. characteristic temperature and OH emissions) with the variation of the heat load, and the relevant parameters can be tracked to predict the emission trends after changing the heat load.