Location-Specific Control of Precursor Emissions to Mitigate Photochemical Air Pollution.

The effects of precursor emission controls on air quality can vary greatly depending on where emission reductions occur. We use the adjoint of the Community Multiscale Air Quality (CMAQ) model to evaluate impacts of spatially targeted NOx emission reductions on odd oxygen (Ox = O3 + NO2). The air quality responses studied here include one population-weighted regionwide and three city-level receptors in Central California. We map high-priority locations for NOx control and their changes over decadal time scales. The desirability of NOx-focused emission control programs has increased between 2000 and 2022. We find for present-day conditions that reducing NOx emissions by 28% from targeted high-priority locations can achieve 60% of the air quality benefits of uniform NOx reductions at all locations. High-priority source locations are found to differ for individual city-level versus regionwide receptors of interest. While high-impact emission hotspots for improving city-level metrics are found within the city itself or closely adjacent, the spatial pattern of emission hotspots for improving regionwide air quality is more complex and requires comprehensive consideration of upwind sources. Results of this study can help to inform strategic decision-making at local and regional levels about where to prioritize emission control efforts.

Association between short-term exposure to environmental air pollution and atopic dermatitis flare in patients treated with dupilumab.

Background: The magnitude of short/medium-term air pollution exposure on atopic dermatitis (AD) flare has not been fully investigated. The aim of the study was to investigate the association of short/medium-term exposure to airborne pollution on AD flares in patients treated with dupilumab. Methods: Observational case-crossover study. Patients with moderate-to-severe AD under treatment with dupilumab were included. The exposure of interest was the mean concentrations of coarse and fine particulate matter (PM10, PM2.5), nitrogen dioxide, and oxides (NO2, NOx). Different intervals were considered at 1 to 60 days before the AD flare and control visit, defined as the visit with the highest Eczema Area and Severity Index scores >8 and ≤7, respectively. A conditional logistic regression analysis adjusted for systemic treatments was employed to estimate the incremental odds (%) of flare every 10 µg/m3 pollutant concentration. Results: Data on 169 of 528 patients with AD having 1130 follow-up visits and 5840 air pollutant concentration measurements were retrieved. The mean age was 41.4 ± 20.3 years; 94 (55%) men. The incremental odds curve indicated a significant positive trend of AD flare for all pollutants in all time windows. At 60 days, every 10 µg/m3 PM10, PM2.5, NOx, and NO2 increase concentration was associated with 82%, 67%, 28%, and 113% odds of flare, respectively. Conclusions: In patients treated with dupilumab, acute air pollution exposure is associated with an increased risk for AD flare with a dose-response relationship.

Role of oxides of nitrogen in the ozone-cardiorespiratory visit association.

Ozone (O3)-induced health effects vary in terms of severity, from deterioration of lung function and hospitalization to death. Several studies have reported a linear increase in health risks after O3 exposure. However, current evidence suggests a non-linear U- and J-shaped concentration-response (C-R) function. The potential increasing risks with decreasing O3 concentrations may seem counterintuitive from the traditional standpoint that decreasing exposure should lead to decreasing health risks. Tus, the question of whether the increasing risks with decreasing concentrations are truly O3-induced or might be from other C-R mechanisms. If these potential risks were not accounted for, this may have contributed to the risks observed at the low ozone concentration range. In this study, we examined the short-term effects of photochemical oxidant (Ox, parts per billiion) on outpatient cardiorespiratory visits in 21 Japanese cities after adjusting for other air pollutant-specific C-R functions. Daily cardiorespiratory visits from January 1, 2014 to December 31, 2016 were obtained from the Japanese Medical Data Center Co. Ltd. Similar period of meteorological and air pollution variables were obtained from relevant data sources. We utilized a time-stratified case crossover design coupled with the generalized additive mixed model (TSCC-GAMM) to estimate the association between Ox and cardiorespiratory outpatient visits, after adjusting for several covariates. A total of 2,588,930 visits were recorded across the study period, with a mean of 111.87 and a standard deviation of 138.75. The results revealed that crude Ox-cardiorespiratory visits exhibited a U-shaped pattern. However, adjustment of the oxides of nitrogen, particularly nitrogen monoxide (NO), attenuated the lower risk curve and subsequently altered the shape of the C-R function, with a substantial reduction observed during winter. NO- and nitrogen dioxide (NO2)-adjusted Ox-cardiorespiratory associations increased nearly linearly, without an apparent threshold. Current evidence suggests the importance of adjusting the oxides of nitrogen in estimating the Ox C-R risk functions.

Lung Effects of Household Air Pollution.

Biomass fuel smoke, secondhand smoke, and oxides of nitrogen are common causes of household air pollution (HAP). Almost 2.4 billion people worldwide use solid fuels for cooking and heating, mostly in low- and middle-income countries. Wood combustion for household heating is also common in many areas of high-income countries, and minorities are particularly vulnerable. HAP in low- and middle-income countries is associated with asthma, acute respiratory tract infections in adults and children, chronic obstructive pulmonary disease, lung cancer, tuberculosis, and respiratory mortality. Although wood smoke exposure levels in high-income countries are typically lower than in lower-income countries, it is similarly associated with accelerated lung function decline, higher prevalence of airflow obstruction and chronic bronchitis, and higher all-cause and respiratory cause-specific mortality. Household air cleaners with high-efficiency particle filters have mixed effects on asthma and chronic obstructive pulmonary disease outcomes. Biomass fuel interventions in low-income countries include adding chimneys to cookstoves, improving biomass fuel combustion stoves, and switching fuel to liquid petroleum gas. Still, the impact on health outcomes is inconsistent. In high-income countries, strategies for reducing biomass fuel-related HAP are centered on community-level woodstove changeout programs, although the results are again inconsistent. In addition, initiatives to encourage home smoking bans have mixed success in households with children. Environmental solutions to reduce HAP have varying success in reducing pollutants and health problems. Improved understanding of indoor air quality factors and actions that prevent degradation or improve polluted indoor air may lead to enhanced environmental health policies, but health outcomes must be rigorously examined.

Do heavy-duty and passenger vehicle emissions standards reduce per capita emissions of oxides of nitrogen? Evidence from Europe.

Oxides of nitrogen are among the most dangerous emissions to human health and to the environment. In European nations, road transportation contributes to approximately 40% of emissions of oxides of nitrogen with the dominant share coming from passenger and freight transport. To help mitigate emissions of oxides of nitrogen, the European Union (EU) has implemented vehicular emissions standards. This paper studies the effect of EU vehicular emissions standards on per capita emissions of oxides of nitrogen in European nations during the period 2000 to 2017, both for on-road vehicular emissions and at the economy level. To do this, pollution is modelled as a byproduct of economic production. After controlling for economic growth, historical per capita levels of emissions of oxides of nitrogen, and a series of geographic and technological factors, it is determined that the vehicular emissions standards put in place by the EU decrease per capita levels of emissions of oxides of nitrogen. More precisely, reducing the heavy duty emissions standard by 1 g/kWh leads to as much as a 7% reduction in per capita on-road emissions of oxides of nitrogen. Reducing the passenger vehicle emissions standards for both diesel and gasoline engines enhances this effect, resulting in an even greater reduction in per capita emissions of oxides of nitrogen. These results further suggest that any rebound effect taking place is outweighed by the reduction in emissions of oxides of nitrogen from lowering emissions standards.

Numerical study of different shape design of piston bowl for diesel engine combustion in a light duty single-cylinder engine.

Diesel engine is the prime mover on land transportation industry and used in a variety of power generation applications due to their higher fuel efficiency. However, the engine research community faces a major hurdle rigorous restriction introduced in the Glob to reduce pollutant emissions from internal combustion engines. Different piston bowl shape designs allows more precise mixing before combustion to enhance in the optimization using computational calculations to reduce emissions. The investigation was to reduce the NOx and PM emissions using combustion simulation comparing with each piston of a single-cylinder engine at a CR of 24, 4-stroke, and water-cooled Engine. The four piston bowl shapes of DSEVL2 BMW M47T, Shallow Hesselman, Lombardini 15LD350, and DOOSANP158FE were analyzed by the Diesel-RK combustion simulation. After successful validating; the simulation model shows that the peak cylinder pressure of Piston-2 is 131bar and the peak cylinder pressure of Piston-4 is 113bar. The Maximum Cylinder Temperature of the Piston-2 is 2048.2k, and the lowest value of Cylinder Temperature of the Piston-4 is 1680.9k the cylinder temperature of Piston-2 is 18% higher than Cylinder Temperature of Piston-4. The simulation result indicates that the temperature is within the acceptable limit in between 1400-2000k except for the piston temperature of 2048.2k. The PHRR of the Piston-3 is 0.082 with great variation in between maximum and minimum due to the presence of pre-and post-injection, the HRR-P4 is 0.035 J/°CA with the single injections. The HRR of the Piston-3 is the highest while HRR of the Piston-4 lowest with 39%. The NOx in the exhaust gas is 25.62 in the NOx piston-1; 16 in NOx of Piston-2, 18.2 in NOx-P3, and NOx-P4 is 12.74 g/kWh respectively. The NOx of the NOx-P2 is lower than first and second piston due to the lower fuel fraction of NWF dilution outer the sleeve, low fuel fraction in core of the free spray, low fuel fraction in fronts of the free spray, low fuel fraction in the core of the fuel free spray. The Particulate Matter emission in PM-P1 is 0.35, and PM-P2 is 0.43 â€‹g/kWh which is higher than all the other. Although there is a substantial decrease in PM, a penalty in NOx is observed for PM-P1 but PM of the P2 is higher after the peak result of emission.

Responses of Photochemical Air Pollution in California's San Joaquin Valley to Spatially and Temporally Resolved Changes in Precursor Emissions.

Ground-level ozone adversely affects human health and ecosystems. The effectiveness of control programs depends on which precursor(s) are controlled, by how much, and where and when emission reductions occur. We use the adjoint of the Community Multiscale Air Quality model to investigate odd oxygen (Ox ≡ O3 + NO2) sensitivities in California's San Joaquin Valley (SJV) to precursor emissions from local and upwind sources. Sensitivities are mapped and disaggregated by hour and day. Taken together, impacts of precursor emissions in the San Francisco Bay area and Sacramento Valley are similar in magnitude to impacts of local SJV emissions. Same-day emission sensitivities are mostly attributable to local sources, with the most influential anthropogenic emissions of VOCs (volatile organic compounds) and NOx (nitrogen oxides) occurring in the morning (9-11 am) and early afternoon hours (1-3 pm), respectively. For the northernmost SJV receptor, the influence from Sacramento Valley emissions peaks 5-6 h later than Bay area emissions; this difference diminishes for SJV receptors located further downwind. Results show a shift toward more NOx-sensitive conditions in the afternoon with all but the southernmost receptor shifting from VOC- to NOx-sensitive conditions. We also evaluate opportunities to control pollution through shifts in precursor emission location and timing.

Sampling Low Air Pollution Concentrations at a Neighborhood Scale in a Desert U.S. Metropolis with Volatile Weather Patterns.

BACKGROUND: Neighborhood-scale air pollution sampling methods have been used in a range of settings but not in low air pollution airsheds with extreme weather events such as volatile precipitation patterns and extreme summer heat and aridity-all of which will become increasingly common with climate change. The desert U.S. metropolis of Tucson, AZ, has historically low air pollution and a climate marked by volatile weather, presenting a unique opportunity. METHODS: We adapted neighborhood-scale air pollution sampling methods to measure ambient NO2, NOx, and PM2.5 and PM10 in Tucson, AZ. RESULTS: The air pollution concentrations in this location were well below regulatory guidelines and those of other locations using the same methods. While NO2 and NOx were reliably measured, PM2.5 measurements were moderately correlated with those from a collocated reference monitor (r = 0.41, p = 0.13), potentially because of a combination of differences in inlet heights, oversampling of acutely high PM2.5 events, and/or pump operation beyond temperature specifications. CONCLUSION: As the climate changes, sampling methods should be reevaluated for accuracy and precision, especially those that do not operate continuously. This is even more critical for low-pollution airsheds, as studies on low air pollution concentrations will help determine how such ambient exposures relate to health outcomes.

Estimating 2013-2019 NO2 exposure with high spatiotemporal resolution in China using an ensemble model.

Air pollution has become a major issue in China, especially for traffic-related pollutants such as nitrogen dioxide (NO2). Current studies in China at the national scale were less focused on NO2 exposure and consequent health effects than fine particulate exposure, mainly due to a lack of high-quality exposure models for accurate NO2 predictions over a long period. We developed an advanced modeling framework that incorporated multisource, high-quality predictor data (e.g., satellite observations [Ozone Monitoring Instrument NO2, TROPOspheric Monitoring Instrument NO2, and Multi-Angle Implementation of Atmospheric Correction aerosol optical depth], chemical transport model simulations, high-resolution geographical variables) and three independent machine learning algorithms into an ensemble model. The model contains three stages: (1) filling missing satellite data; (2) building an ensemble model and predicting daily NO2 concentrations from 2013 to 2019 across China at 1×1 km2 resolution; (3) downscaling the predictions to finer resolution (100 m) at the urban scale. Our model achieves a high performance in terms of cross-validation to assess the agreement of the overall (R2 = 0.72) and the spatial (R2 = 0.85) variations of the NO2 predictions over the observations. The model performance remains moderately good when the predictions are extrapolated to the previous years without any monitoring data (CV R2 > 0.68) or regions far away from monitors (CV R2 > 0.63). We identified a clear decreasing trend of NO2 exposure from 2013 to 2019 across the country with the largest reduction in suburban and rural areas. Our downscaled model further improved the prediction ability by 4%-14% in some megacities and captured substantial NO2 variations within 1-km grids in the urban areas, especially near major roads. Our model provides flexibility at both temporal and spatial scales and can be applied to exposure assessment and epidemiological studies with various study domains (e.g., national or citywide) and settings (e.g., long-term and short-term).

Long-term variability of trace gases over the Indian Western Himalayan Region.

The four-year continuous measurements of CO, NOx, NH3, SO2, and O3 were carried at a high altitude site (32.12°N, 76.56°E at 1347 m AMSL) of the Indian Western Himalayan area to study the mixing ratios of these gases for understanding the changing trends of these trace gases over the region. Each of these trace gases showed significant daily and monthly variabilities. The highest variability was recorded in the monthly mean values of O3 as it varied from 10 to 63 ppb during the study period. All the trace gases except CO showed maximum variability in the pre-monsoon seasons due to the strong advection and vertical circulation of air masses at the site. The seasonal mean maxima of CO were recorded during the monsoon season, while the mean maxima of NH3 were recorded during the post-monsoon seasons. The meteorological parameters have been found to influence the mixing ratios of trace gases. The least variability in the mean seasonal mixing ratios of SO2 during the study period indicated the constant point source of SO2 near the site. The trajectories analysis revealed that the area receives maximum air masses from the southeast to the west directions where a number of the coal-based thermal power plants, industries, cement plants, and agricultural fields are also located. The influence of valley-to-mountain circulations was also observed at the site, resulting in the transport of pollutant-rich air masses from local and distant sources to the site. A comparison of the mixing ratios of different trace gases obtained in the present study is also made with the values reported for other high altitude stations in the world.

Epigenome-wide analysis of long-term air pollution exposure and DNA methylation in monocytes: results from the Multi-Ethnic Study of Atherosclerosis.

Air pollution might affect atherosclerosis through DNA methylation changes in cells crucial to atherosclerosis, such as monocytes. We conducted an epigenome-wide study of DNA methylation in CD14+ monocytes and long-term ambient air pollution exposure in adults participating in the Multi-Ethnic Study of Atherosclerosis (MESA). We also assessed the association between differentially methylated signals and cis-gene expression. Using spatiotemporal models, one-year average concentrations of outdoor fine particulate matter (PM2.5) and oxides of nitrogen (NOX) were estimated at participants' homes. We assessed DNA methylation and gene expression using Illumina 450k and HumanHT-12 v4 Expression BeadChips, respectively (n = 1,207). We used bump hunting and site-specific approaches to identify differentially methylated signals (false discovery rate of 0.05) and used linear models to assess associations between differentially methylated signals and cis-gene expression. Four differentially methylated regions (DMRs) located on chromosomes 5, 6, 7, and 16 (within or near SDHAP3, ZFP57, HOXA5, and PRM1, respectively) were associated with PM2.5. The DMRs on chromosomes 5 and 6 also associated with NOX. The DMR on chromosome 5 had the smallest p-value for both PM2.5 (p = 1.4×10-6) and NOX (p = 7.7×10-6). Three differentially methylated CpGs were identified for PM2.5, and cg05926640 (near TOMM20) had the smallest p-value (p = 5.6×10-8). NOX significantly associated with cg11756214 within ZNF347 (p = 5.6×10-8). Several differentially methylated signals were also associated with cis-gene expression. The DMR located on chromosome 7 was associated with the expression of HOXA5, HOXA9, and HOXA10. The DMRs located on chromosomes 5 and 16 were associated with expression of MRPL36 and DEXI, respectively. The CpG cg05926640 was associated with expression of ARID4B, IRF2BP2, and TOMM20. We identified differential DNA methylation in monocytes associated with long-term air pollution exposure. Methylation signals associated with gene expression might help explain how air pollution contributes to cardiovascular disease.

Variability of ozone and oxides of nitrogen in the tropical city, Bengaluru, India.

Bengaluru, also considered India's Silicon Valley, has seen steady growth in population over the years. Bengaluru's rapid development has resulted in dwindling reservoirs, increased traffic congestion, high levels of air pollution, and, to some measure, a rise in summer temperatures. As a result of these changes in urban form over the last decade, anthropogenic heat fluxes for ozone production have increased. However, an observational study on the effects of growing urbanisation on trace gases in Bengaluru for various seasons and periods of the day is missing. Hence, in situ measurements of O3, NO, NO2, and NOX concentrations were carried out at Bengaluru, India, from January 2015 to December 2018. The data were examined for diurnal and interannual variations in trace gas mixing concentrations. The diurnal trend in O3 exhibits unimodal behaviour. Changes in photochemistry, local meteorology, and the planetary boundary layer's distinctive features cause a rise in the value of concentrations and lead to a peak. In contrast, the diurnal trend in NO, NO2, and NOX displayed a bimodal peak due to the combined effect of vehicular emissions and the planetary boundary layer. The link involving the oxidant OX (O3 + NO2) and NOx levels were investigated to determine the NOx-independent regional and NOx-dependent local contributions to OX in the atmosphere. Daytime contributions are higher than night-time contributions, according to the present study. The observed anomalies could be the consequence of photochemical processes that produce OX.

Indoors ventilation in times of confinement by SARS-CoV-2 epidemic: A comparative approach between Spain and Italy.

With the arrival of the SARS-CoV-2 coronavirus, the scientific academia, as well as policymakers, are striving to conceive solutions as an attempt to contain the spreading of contagion. Among the adopted measures, severe lockdown restrictions were issued to avoid the diffusion of the virus in an uncontrolled way through public spaces. It can be deduced from recent literature that the primary route of transmission is via aerosols, produced mainly in poorly ventilated interior areas where infected people spend a lot of time with other people. Concerning contagion rates, accumulated incidence or number of hospitalizations due to COVID-19, Spain, and Italy have reached very high levels. In this framework, a regression analysis to assess the feasibility of the indoor ventilation measures established in Spain and Italy, with respect to the European framework, is here presented. To this aim, ten cases of housing typology were and analyzed. The results show that the measures established in the applicable regulations to prevent and control the risk of contagion by aerosols are not adequate to guarantee a healthy environment indoors. The current Italian guidelines are more restrictive than in Spain, yet the ventilation levels are still insufficient in times of pandemic.

Assimilative capacity approach for air pollution control in automotive engines through magnetic field-assisted combustion of hydrocarbons.

Deterioration of air quality through the combustion of hydrocarbon fuels has been one of the global transboundary problems put before the research community since last five decades. According to the updated statistics, 79% of energy needs in India are met by fossil fuel combustion which results in the emission of toxic pollutants like carbon monoxide, oxides of nitrogen, and unburned hydrocarbons. Air quality has seriously been affected in many parts of India, and statistically, 13 out of 15 most polluted cities in the world lie in India. Magnetic field-assisted combustion has been proven as a reliable technology in internal combustion engines for enhancing the combustion of fuels and reduction of harmful emissions that are the byproducts of incomplete combustion of fuels. In the present work, the magnetic field-assisted combustion of a liquid-phase and a gas-phase fuel (gasoline and LPG) has been studied in a multicylinder automobile engine replicating on road driving conditions in a laboratory focusing on the levels of emissions in comparison with normal combustion of both the fuels. The experimental study concludes that the applied magnetic field positively influences combustion, resulting in reduced level of emission of toxic components irrespective of the phase of hydrocarbon fuels. It is also observed that the percentage reduction in emissions increases with increase in intensity of magnetization. The maximum reduction obtained for CO and UBHC emissions through this technique is 20.58% and 14.47%, respectively. The effectiveness of MFAC in countering air pollution from vehicular exhaust is also studied with respect to fuel phase and mode of operation. The effectiveness of MFAC is observed to be more in high-speed operation of the engine and decreases in the order CO > UBHC > NO. The obtained emission results have a cumulative significance as 45% of total air pollution in India is caused by combustion of hydrocarbons in automotive engines.

Influence of nano-additive on performance and emission characteristics of a diesel engine running on neat neem oil biodiesel.

This work investigates the experimental study to examine the operation characteristics of a neat neem oil methyl ester (BD100) along with silver oxide nano-particles as a metal-based additive in various mass fractions. Silver oxide nano-particle is mixed into 100% of BD100 at 5 and 10 ppm. The experimental investigation on diesel engine reveals that the addition of silver oxide nano-particles to BD100 resulted in enhancement of brake thermal efficiency (BTE) with a reduction in brake specific fuel consumption (BSFC). The tested emission parameters such as CO, HC, NOx, and smoke were decreased by 12.22, 10.89, 4.24, and 6.61% for BD100+ Ag2O (5 ppm) and 16.47, 14.21, 6.66, and 8.34% for BD100 respectively when compared to BD100. Overall, improvement in ignition characteristics of the engine was finer by adding 5 and 10 ppm of silver oxide nano-particle to BD100 on account of the enhanced surface area to volume ratio.

Mitigation of NOx and smoke emissions in a diesel engine using novel emulsified lemon peel oil biofuel.

Lemon peel oil (LPO) is considered to be a viable alternative fuel for diesel engine applications due to its wider availability, renewable nature, easy extraction process, almost equivalent calorific value as neat diesel, and low viscosity. The present work aims to investigate the effect of novel emulsified LPO in a diesel engine in order to reduce the NOx emission without compromising the engine performance. A new ionic surfactant is introduced in the present study, namely methyl-dihydroxy propyl imidazolium chloride due to its higher hydrophilic-lipophilic balance value which helps to prepare stable water in oil emulsion. Also, Span 80 has been selected as another suitable surfactant for water in oil emulsion. Four emulsified fuel samples have been prepared using LPO, water, and different concentrations of surfactants. All the fuel samples are tested for their stability through gravitational technique for 7 days. Among the emulsified samples, 92% LPO + 5% water + 2% Span 80 + 1% methyl-dihydroxy propyl imidazolium chloride by volume (LPOE2) and 93.5% LPO + 5% water + 1.5% surfactant Span 80 by volume (LPOE4) have showed better stability when compared to other emulsion fuel samples. It is also revealed that the stability of LPO emulsion is improved by the addition of two emulsions. The experimental results showed that the brake thermal efficiency of LPO emulsion is reduced to 29.87 from 34.58% of pure LPO at full load condition. Oxides of nitrogen emission and smoke emission are reduced by 21-32 and 6-15% for the LPO emulsion samples compared to pure LPO. Moreover, the diesel engine operation with emulsified form of LPO increases the HC emission about 0.1 g/kWh for LPOE4 and 0.15 g/kWh for LPOE2 fuels from 0.053 g/kW for pure LPO at maximum power output condition. The reformulation of LPO into emulsified form increases the CO emission by 25-53% compared to pure LPO. Moreover, the reformulation of LPO into emulsions has resulted in lower cylinder pressure and heat release rate compared to pure LPO and diesel fuels.

IL-17A[G197G]-Association between NOx and gestational age in a South African birth cohort.

Interleukin (IL-)17A, plays a role in pathogenic defence, but is implicated in chronic inflammatory diseases, and has recently been associated with variable pregnancy outcomes. We investigated the role of maternal IL-17-[G197A]-specific effects of third-trimester IL-17 mRNA expression, NOx exposure levels and other variables on gestational age, in the Mother and Child in the Environment (MACE) birth cohort in South Africa. A total of 327 participants were genotyped for IL-17-[G197A] by polymerase chain reaction restriction-fragment length polymorphism (PCR-RFLP). Quantitative real-time PCR was used to quantitate IL-17-mRNA expression in whole blood. Multivariate linear regression analysis, stratified by IL-17-[G197A] genotype, was used to test for effects of NOx , IL17A/GAPDH, haemoglobin, body mass index, HIV-1 positivity, maternal education and income level on gestational age. Lower expression was associated with the IL-17-GG versus GA in the cohort and HIV-1-negative group (p = .0007, p = .0058), while no difference was observed in the HIV-1 positives. Elevated IL-17A expression was observed in the high NOx exposure groups, within IL-17[G197G] (p = .0004). IL-17[G197G] was associated with PTB (p < .0001), and the PTB group had lower IL-17A expression compared to the full-term group (p = .0002). IL-17 expression was associated with an increase in gestational age (p = .038), and NOx was associated with a decrease in gestational age in the IL-17[G197G] model (p = .046).

Evaluation of air quality at the Birmingham New Street Railway Station.

Air pollution from diesel emissions is becoming an increased international concern, and whilst attention has been primarily focused on the automotive industry, concerns have also been raised about emissions from diesel rail vehicles. This paper reports an extensive series of measurements made at the Birmingham New Street station, a major rail interchange in the Midlands of England, with a mix of diesel and electric train movements, which is of particular concern because of the enclosed nature of the platforms. This study was undertaken in collaboration with Network Rail to better understand the environment in and around the station over a longer period to provide a more detailed analysis of the complex environment at the station. The station environment has been considered in terms of the European Union (EU) and Department of Environment, Food and Rural Affairs (DEFRA) limits as part of the monitoring methodology, but it should be noted that these limits do not apply in this environment as the Management of Health and Safety at Work Regulation 1999 and the Control of Substances Hazardous to Health Regulations 2002 are applicable. The monitoring campaign consisted of diffusion tube measurements to measure nitrogen dioxide at a large number of different locations throughout and around the station. These were followed by detailed measurements of oxides of nitrogen, particulate matter, carbon dioxide and black carbon (a diesel tracer) at a smaller number of sites at the platform level. The results are analysed to give concentrations over a wide variety of time scales, and long- and short-term averages. The effects of ambient wind conditions and individual train movements are also considered. Recommendations are made for possible remedial measures and for future work to more fully understand the physical mechanisms involved.

Tropospheric ozone pollution in India: effects on crop yield and product quality.

Ozone (O3) in troposphere is the most critical secondary air pollutant, and being phytotoxic causes substantial losses to agricultural productivity. Its increasing concentration in India particularly in Indo-Gangetic plains is an issue of major concern as it is posing a threat to agriculture. In view of the issue of rising surface level of O3 in India, the aim of this compilation is to present the past and the prevailing concentrations of O3 and its important precursor (oxides of nitrogen) over the Indian region. The resulting magnitude of reductions in crop productivity as well as alteration in the quality of the product attributable to tropospheric O3 has also been taken up. Studies in relation to yield measurements have been conducted predominantly in open top chambers (OTCs) and also assessed by using antiozonant ethylene diurea (EDU). There is a substantial spatial difference in O3 distribution at different places displaying variable O3 concentrations due to seasonal and geographical variations. This review further recognizes the major information lacuna and also highlights future perspectives to get the grips with rising trend of ground level O3 pollution and also to formulate the policies to check the emissions of O3 precursors in India.

Estimation of on-road NO2 concentrations, NO2/NOX ratios, and related roadway gradients from near-road monitoring data.

This paper describes a new regression modeling approach to estimate on-road nitrogen dioxide (NO2) and oxides of nitrogen (NOX) concentrations and near-road spatial gradients using data from a near-road monitoring network. Field data were collected in Las Vegas, NV at three monitors sited 20, 100, and 300 m from Interstate-15 between December, 2008 and January, 2010. Measurements of NO2 and NOX were integrated over 1-hour intervals and matched with meteorological data. Several mathematical transformations were tested for regressing pollutant concentrations against distance from the roadway. A logit-ln model was found to have the best fit (R2 = 94.7%) and also provided a physically realistic profile. The mathematical model used data from the near-road monitors to estimate on-road concentrations and the near-road gradient over which mobile source pollutants have concentrations elevated above background levels. Average and maximum on-road NO2 concentration estimates were 33 ppb and 105 ppb, respectively. Concentration gradients were steeper in the morning and late afternoon compared with overnight when stable conditions preclude mixing. Estimated on-road concentrations were also highest in the late afternoon. Median estimated on-road and gradient NO2 concentrations were lower during summer compared with winter, with a steeper gradient during the summer, when convective mixing occurs during a longer portion of the day On-road concentration estimates were higher for winds perpendicular to the road compared with parallel winds and for atmospheric stability with neutral-to-unstable atmospheric conditions. The concentration gradient with increasing distance from the road was estimated to be sharper for neutral-to-unstable conditions when compared with stable conditions and for parallel wind conditions compared with perpendicular winds. A regression of the NO2/NOX ratios yielded on-road ratios ranging from 0.25 to 0.35, substantially higher than the anticipated tail-pipe emissions ratios. The results from the ratios also showed that the diurnal cycle of the background NO2/NOX ratios were a driving factor in the on-road and downwind NO2/NOX ratios.