Application of ADMS-Urban for an area with a high contribution of residential heating emissions - model verification and sensitivity study for PM2.5

Air pollution poses a significant risk to both human health and the environment in the contemporary world. Among the various pollutants, particulate matter with a diameter <2.5 μm (PM2.5) is regarded as the most hazardous. It has been implicated in over four million global fatalities in 2019 alone. This research paper divulges the outcomes of modelling the spatial-temporal fluctuations of PM2.5 concentrations within the confines of Wroclaw, a city situated in Poland, Central Europe. The model's output was evaluated through comparison with collected data from two government-operated monitoring stations within the city. For this study, we used the ADMS-Urban model and tested two different sources of background data (low-cost sensors and the EMEP MSC-W atmospheric chemistry transport model). The statistical analysis conducted in the paper indicates that the model reproduces the temporal variability of PM2.5. The conclusions from this research indicate that the average annual PM2.5 concentration within Wroclaw is 13.8 μg/m3, with the concentration peaking in the month of March. The spatial distribution reveals the highest PM2.5 concentrations primarily in the southern and western zones of the city, with additional elevated concentrations observed sporadically throughout the city. The study unveils that 1.3 % of Wroclaw's area experiences PM2.5 concentrations exceeding the EU's annual limit of 20 μg/m3. When considered in relation to the WHO's suggested annual average level of 5 μg/m3, Wroclaw city experiences exceedances throughout. When background concentrations are excluded from the model, the annual average PM2.5 concentration across the city is noted to be reduced by >50 %. A thorough investigation of the city's emission structure, taking into account only emissions from the city without background, indicates that the residential sector contributes about 77.3 % of the total annual average PM2.5 concentration in Wroclaw. The transportation and industrial sectors account for nearly 19.5 % and 3.2 %, respectively.

Do we need high temporal resolution modelling of exposure in urban areas? A test case

Roadside concentrations of harmful pollutants such as NO_x are highly variable in both space and time. This is rarely considered when assessing pedestrian and cyclist exposures. We aim to fully describe the spatio-temporal variability of exposures of pedestrians and cyclists travelling along a road at high resolution. We evaluate the value added of high spatio-temporal resolution compared to high spatial resolution only. We also compare high resolution vehicle emissions modelling to using a constant volume source. We highlight conditions of peak exposures, and discuss implications for health impact assessments. Using the large eddy simulation code Fluidity we simulate NO_x concentrations at a resolution of 2 m and 1 s along a 350 m road segment in a complex real-world street geometry including an intersection and bus stops. We then simulate pedestrian and cyclist journeys for different routes and departure times. For the high spatio-temporal method, the standard deviation in 1 s concentration experienced by pedestrians (50.9 μg.m^-3) is nearly three times greater than that predicted by the high-spatial only (17.5 μg.m^-3) or constant volume source (17.6 μg.m^-3) methods. This exposure is characterised by low concentrations punctuated by short duration, peak exposures which elevate the mean exposure and are not captured by the other two methods. We also find that the mean exposure of cyclists on the road (31.8 μg.m^-3) is significantly greater than that of cyclists on a roadside path (25.6 μg.m^-3) and that of pedestrians on a sidewalk (17.6 μg.m^-3). We conclude that ignoring high resolution temporal air pollution variability experienced at the breathing time scale can lead to a mischaracterization of pedestrian and cyclist exposures, and therefore also potentially the harm caused. High resolution methods reveal that peaks, and hence mean exposures, can be meaningfully reduced by avoiding hyper-local hotspots such as bus stops and junctions.

Reduced-form and complex ACTM modelling for air quality policy development: A model inter-comparison

Simulation models can be valuable tools in supporting development of air pollution policy. However, exploration of future scenarios depends on reliable and robust modelling to provide confidence in outcomes which cannot be tested against measurements. Here we focus on the UK Integrated Assessment Model, a fast reduced-form model with a purpose to support policy development with modelling of multiple alternative future scenarios, and the EMEP4UK model which is a complex Eulerian Atmospheric Chemistry Transport Model requiring significant computing resources. The EMEP4UK model has been used to model selected core scenarios to compare with UKIAM, and to investigate sensitivity studies such as the interannual variability in response to meteorological differences between years. This model intercomparison addresses total PM_2.5, primary PM_2.5 and Secondary Inorganic Aerosol concentrations for a baseline of 2018 and selected scenarios for projections to 2040. This work has confirmed the robustness of the UK Integrated Assessment Model for assessing alternative futures through a direct comparison with EMEP4UK. Both models have shown good agreement with measurements, and EMEP4UK shows an ability to replicate past trends. These comparisons highlight how a combination of reduced-form modelling (UKIAM) and complex chemical transport modelling (EMEP4UK) can be effectively used in support of air pollution policy development, informing understanding of projected futures in the context of emerging evidence and uncertainties.

An evaluation of the risk of airborne transmission of COVID-19 on an inter-city train carriage

Experiments were conducted in an UK inter-city train carriage with the aim of evaluating the risk of infection to the SARS-CoV-2 virus via airborne transmission. The experiments included in-service CO₂ measurements and the measurement of salt aerosol concentrations released within the carriage. Computational fluid dynamics simulations of the carriage airflow were also used to visualise the airflow patterns, and the efficacy of the HVAC filter material was tested in a laboratory. Assuming an infectious person is present, the risk of infection for a 1-h train journey was estimated to be 6 times lower than for a full day in a well-ventilated office, or 10-12 times lower than a full day in a poorly ventilated office. While the absolute risk for a typical journey is likely low, in the case where a particularly infectious individual is on-board, there is the potential for a number of secondary infections to occur during a 1-h journey. Every effort should therefore be made to minimize the risk of airborne infection within these carriages. Recommendations are also given for the use of CO₂ sensors for the evaluation of the risk of airborne transmission on train carriages.

Modeling disease transmission in a train carriage using a simple 1D-model

Understanding airborne infectious disease transmission on public transport is essential to reducing the risk of infection of passengers and crew members. We propose a new one-dimensional (1D) model that predicts the longitudinal dispersion of airborne contaminants and the risk of disease transmission inside a railway carriage. We compare the results of this 1D-model to the predictions of a model that assumes the carriage is fully mixed. The 1D-model is validated using measurements of controlled carbon-dioxide experiments conducted in a full-scale railway carriage. We use our results to provide novel insights into the impact of various strategies to reduce the risk of airborne transmission on public transport.

The UK Integrated Assessment Model for source apportionment and air pollution policy applications to PM2.5

Source apportionment and the effect of reducing individual sources is important input for the development of strategies to address air pollution. The UK Integrated Assessment Model, UKIAM, has been developed for this purpose as a flexible framework, combining information from different atmospheric dispersion models to cover different pollutant contributions, and span the range from European to local scale. In this paper we describe the UKIAM as developed for SO₂, NOx, NH₃, PM_2.5 and VOCs. We illustrate its versatility and application with assessment of current PM_2.5 concentrations and exposure of the UK population, as a case-study that has been used as the starting point to investigate potential improvement towards attainment of the WHO guideline of 10 µg/m³.

The ventilation of buildings and other mitigating measures for COVID-19: a focus on wintertime

The year 2020 has seen the emergence of a global pandemic as a result of the disease COVID-19. This report reviews knowledge of the transmission of COVID-19 indoors, examines the evidence for mitigating measures, and considers the implications for wintertime with a focus on ventilation.

A systematic review of the leaf traits considered to contribute to removal of airborne particulate matter pollution in urban areas

Global urban planning has promoted green infrastructure (GI) such as street trees, shrubs or other greenspace in order to mitigate air pollution. Although considerable attention has been paid to understanding particulate matter (PM) deposition on GI, there has been little focus on identifying which leaf traits might maximise airborne PM removal. This paper examines existing literature to synthesize the state of knowledge on leaf traits most relevant to PM removal. We systematically reviewed measurement studies that evaluated particulate matter accumulated on leaves on street trees, shrubs green roofs, and green walls, for a variety of leaf traits. Our final selection included 62 papers, most from field studies and a handful from wind tunnel studies. The following were variously promoted as useful traits: coniferous needle leaves; small, rough and textured broadleaves; lanceolate and ovate shapes; waxy coatings, and high-density trichomes. Consideration of these leaf traits, many of which are also associated with drought tolerance, may help to maximise PM capture. Although effective leaf traits were identified, there is no strong or consistent evidence to identify which is the most influential leaf trait in capturing PM. The diversity in sampling methods, wide comparison groups and lack of background PM concentration measures in many studies limited our ability to synthesize results. We found that several ancillary factors contribute to variations in the accumulation of PM on leaves, thus cannot recommend that selection of urban planting species be based primarily on leaf traits. Further research into the vegetation structural features and standardization of the method to measure PM on leaves is needed.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

The performance of children with traumatic head injury on the wide range assessment of memory and learning-screening

The factor structure of the Screening version of the Wide Range Assessment of Memory and Learning (WRAML-S; Sheslow & Adams, 1990) was evaluated in the standardization sample and in a sample of 100 children with traumatic head injury (THI). A two-factor model (including verbal and nonverbal dimensions) fit the standardization data relatively best, but a one-factor model was supported in the THI sample. In the latter sample, the WRAML-S Memory Screening Index (MSI) correlated just as strongly with length of coma as did Performance IQ. Presence of diffuse lesions or right cerebral focal lesions was associated with lower MSI scores. Children with severe THI had significantly lower MSI scores than did children with mild or moderate injuries. We conclude that MSI is an adequate screening measure of immediate recall after severe THI, but we suggest caution against exclusive reliance on this measure in clinical pediatric neuropsychological evaluations.

A 51-year retrospective study of the trends of height, weight and body mass index at the time of death in those aged 16-103

The study investigates the trends in survival age, height, weight and body mass index (BMI) in both genders for those aged 16-103 at the time of death. It also investigates the trend in the proportion of the population classified as obese using data extracted from 37,206 autopsy reports spanning the period 1947-1997. The data was analysed using the computerised statistical software SPSS with tables and figures produced of mean values per investigation value per sex per 10-year age group per decade. The data confirmed reported trends that the population is getting older, taller and heavier with the mean BMI increasing such that the proportion of individuals who can be classified as obese is increasing. These trends will potentially have an impact on healthcare as more people will have an increased risk of associated morbidity and mortality, as well as an implication on welfare and housing for the increasingly elderly population.

Parkin deletions in a family with adult-onset, tremor-dominant parkinsonism: expanding the phenotype

A gene for autosomal recessive parkinsonism, PARK2 (parkin), has recently been identified on chromosome 6q and shown to be mutated in Japanese and European families, mostly with early-onset parkinsonism. Here we present a large pedigree from South Tyrol (a region of northern Italy) with adult-onset, clinically typical tremor-dominant parkinsonism of apparently autosomal dominant inheritance. Haplotype analysis excluded linkage to the chromosome 2p, 4p, and 4q regions that harbor genes associated with autosomal dominant parkinsonism, but implicated the parkin locus on chromosome 6q. Compound heterozygous deletions in the parkin gene (one large and one truncating) were identified in 4 affected male siblings. The patients were clinically indistinguishable from most patients with idiopathic Parkinson's disease. None of them displayed any of the clinical hallmarks described in patients with previously reported parkin mutations, including diurnal fluctuations, benefit from sleep, foot dystonia, hyperreflexia, and early susceptibility to levodopa-induced dyskinesias. Two affected female individuals carried one (truncating) of the two deletions in a heterozygous state with an apparently normal allele. We conclude that the phenotypic spectrum associated with mutations in the parkin gene is broader than previously reported, suggesting that this gene may be important in the etiology of the more frequent late-onset typical Parkinson's disease.

Prediction of neurobehavioral outcome 1-5 years post pediatric traumatic head injury

OBJECTIVE

To examine the neurobehavioral status of children with traumatic head injury (THI) and to identify variables that predict outcome.

DESIGN

Retrospective chart review, with follow-up 1-5 years after injury. Outcome predictor variables were identified through stepwise regression analysis.

SETTING

Level one trauma center and pediatric rehabilitation program.

PATIENTS

71 Children with THI, selected from a four-year series of consecutive admissions.

MEASURE

Vineland Adaptive Behavior Scales-Survey Edition.

RESULTS

Significant predictors of better neurobehavioral status at follow-up included absence of a premorbid learning problem (p <.01), older age at injury (p <.01), and normal pupillary response (p <.001) and higher cerebral perfusion pressure (p <.0001) during critical care management.

CONCLUSIONS

Neurobehavioral outcome after THI is influenced by premorbid psychosocial variables as well as by critical care management.

Isolation, purification, and properties of respiratory mucus glycoproteins

The major glycoprotein from human tracheobronchial secretions and from primary explant cultures of human tracheal epithelium has been purified to apparent homogeneity. Mucin was solubilized in buffer and fractionated on Sepharose CL-4B, followed by CsBr density gradient centrifugation of the void volume fraction. High- and low-density fractions were obtained in ratios ranging from 2:1 to 5:1. The high-density (1.46) fraction appeared homogeneous by exclusion chromatography and recentrifugation in CsBr and had an amino acid composition characteristic of a mucin-type structure (threonine, serine, proline, glycine, and alanine comprise two-thirds of the amino acid residues). The carbohydrate, which is nearly 80% by weight, was O-glycosidically linked via GalNAc, sulfated (5.4% by weight), and contained fucose, galactose, glucosamine, galactosamine, and sialic acid. The low-density fraction had an amino acid composition distinct from that of the high-density fraction (threonine, serine, proline, glycine, and alanine comprise 51% of the amino acid residues) and a lower sulfate content. The size distribution of the saccharides in the low-density fraction was similar to that of the high-density fraction; the same sugars were present although the ratios were different. The low-density fraction contained 3 times more noncovalently associated lipid than did the high-density fraction. Several distinct classes of lipids were identified. Neutral lipids (mono-, di-, and triglycerides, cholesterol, and cholesteryl esters) comprised 56% of weight of the total lipid. Glycolipids and phospholipids were also identified. Palmitate (16:0), stearate (18:0), and oleate (18:1) were the major fatty acids in all classes of lipids.