A strong correlation exists between acute and chronic exposure to traffic derived pollutants and poor respiratory health. Specifically, diesel exhaust (DE) components such as NO2 and fine particles (PM2.5) have been related to impaired lung growth and increased respiratory and allergic symptoms in children and adults living near busy roads. On this basis, implementation of strategies to reduce diesel emissions and improve air quality should provide a measureable improvement in the respiratory health of populations resident in high traffic areas. The introduction of the London Low Emission Zone (LEZ), the largest of its kind in the world, covering an area of 2,644 km2 and a resident population of more than 8 million, provided a unique opportunity to examine this, as well to quantify the impact of DE emissions on the respiratory health of London's population. London’s Low Emission Zone was introduced as part of the Mayor of London’s Air Quality Strategy, with the aim of improving public health through targeted reductions in tail pipe emissions from the most polluting vehicles entering the city. The objective of decreasing PM10 concentrations was to be achieved by restricting the entry of the oldest and most polluting diesel vehicles (heavy goods vehicles (HGVs), buses and coaches, larger vans and minibuses) into Greater London by providing incentives to operators to upgrade their fleets to lower emission vehicles. The Low Emission Zone was enacted as a phased tightening of emission standards for each vehicle class, with the first phase coming into force at the beginning of February 2008. This applied to HGVs greater than 12 tonnes and restricted entry to the zone for those vehicles not meeting the Euro III emissions standard for PM10. Phase 2 followed in July 2008 widening restrictions to include HGVs between 3.5 and 12 tonnes, buses and coaches. Vehicles failing to meet these emissions standards within the zone were initially charged £200 (£100 for vans an minibuses) per day, with enforcement achieve using cameras to identify the registration numbers of vehicles and the Driver and Vehicle Licensing Agency (DVLA) database to identify a vehicle’s emissions standard. In its initial configuration phase 3, restricting access to heavier LGVs and mini-buses not meeting Euro III PM standard was planned for October 2008. In our initial four year study design we planned to examine the respiratory health of cross sectional panels of 8-9 year old school children living within the zone from November 2008; encompassing the first two years post phases 1 and 2, and two years post phase 3 (see Figure s1). As the subject recruitment and health assessments began in November 2008, this afforded us the opportunity of addressing the impact of the third phase of the LEZ, by comparing lung function and respiratory symptoms in the two years before and after phase 3. We also planned to examine year-on-year changes related to projected reductions in vehicle emissions as newer cleaner vehicles entered the fleet, independent of the LEZ, and the increased period the children had lived within the zone, from 11-15 months (11.5-13.9% of lifetime) in year 1, to 44-60 months (45.8-55.6%) in year 4. During annual school visits, children were asked to perform spirometry and provide a urine sample for the assessment of exposure (metals, reflective of defined traffic sources) and response biomarkers (oxidative damage). In addition, the parents/guardians of the children completed a questionnaire on respiratory / allergic symptoms and the children provided DNA samples to investigate genetic susceptibility to the detrimental effects of air pollution, focusing on a panel of antioxidant and xenobiotic genes, as well as a genetic marker associated with the onset of childhood asthma. In May 2008 Boris Johnson was elected the new Mayor of London, with a manifesto commitment to review ongoing traffic management schemes within the city, including the LEZ, and on the 2nd February 2009 he announced intention to cancel the third phase of the LEZ, subject to the outcome of a public consultation later in the year. This political decision therefore robbed us of the original intervention we were planning to address in our original design. Following a further consultation, the scheme was finally fully implemented and expanded on the 3rd of January 2012 (LEZ phase 3 and 4), with Euro III emission standards for minibuses and vans and a further tightening of emission standards (Euro IV) on Lorries over 12 tonnes, between 3.5-12 tonnes, as well as buses and coaches. In light of this development we obtained additional funding to examine furthers panels of school children in Nov 2012 - March 2013 and Nov 2013 - March 2014, extending our study to six years, allowing a formal assessment of the three years pre and two years post LEZ phase 3 and 4, with year 4 straddling the periods of phase 3 and 4 implementation (Figure s2). Children at the conclusion of the study in March 2014, who have been resident within the LEZ since birth will have lived within the zone for 68.8-83.3% of their lives. The data presented in this thesis is therefore based upon the first three years of the study and therefore constitutes a baseline analysis of the relationship between air pollution in London and our key respiratory endpoints prior to the formal evaluation of Phase 3 and 4 in 2014/15. In the first experimental chapter (Chapter 3) I evaluated the associations between traffic-related air pollutants and respiratory/allergic symptoms within our cross-sectional children's cohort. Information on respiratory/allergic symptoms was obtained using a parent-completed questionnaire and linked to modelled annual air pollutant concentrations based on the residential address of each child, using a multivariable mixed effects logistic regression analysis. Exposure to traffic-related air pollutants was associated with current rhinitis (NOx [OR 1.01, 95% CI 1.00-1.02], NO2 [1.03, 1.00-1.06], PM10 [1.16, 1.04-1.28] and PM2.5 [1.38, 1.08-1.78], all per g/m3), but not with other respiratory/allergic symptoms. Furthermore, over the first three years of the operation of London's LEZ I did not observe evidence of reduced ambient air pollution levels, or year-on-year changes in the prevalence of respiratory/allergic symptoms. I found no evidence that these associations were modified by polymorphisms in gasdermin B, located at the chromosome 17q12, associated with the risk of childhood asthma. These data confirm previously reported associations between traffic-related air pollutant exposures and symptoms of current rhinitis. Importantly, whilst the data is largely confirmatory, this remains one of the few studies that has addressed respiratory symptoms in urban children over the period of rapid dieselization within Europe. In Chapter 4 I report evidence of reduced lung volumes (FVC - Forced Vital Capacity) in children living within the study area. This negative association was small and most strongly associated with modeled annual NOx concentrations, at the residential address level. A straightforward method to discriminate between acute versus chronic pollutant effects was developed for the study. Acute exposures were assessed by scaling annual mean concentrations according to a ‘Nowcast’ factor calculated for each pollutant for the period immediately prior to the health assessment. This factor was defined as the ratio between concentrations measured by a local subset of London Air Quality Network monitoring sites in the prior period, and the annual mean measured by the same sites. Using this approach I was able to dissect out whether basal lung function was related to short or long term exposures. In the absence of relationships between FEV1 and FVC with 24 hour and 7 day average exposures, the association between FVC and annual pollutant exposures was interpreted as reflecting evidence of impaired lung growth. In this initial analysis I found no evidence that polymorphisms in the commonly studied glutathione S transferases (GSTM1 and GSTP1) and NADPH quinone oxidoreducatse (NQO1) genes modified the association between lung function and pollutant exposure. In a secondary analysis I examined whether polymorphisms in Cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) and the Aryl hydrocarbon receptor (AhR) might modify the association between pollutant exposures and lung function, based on their role in the xenobiotic metabolism of Polycyclic aromatic hydrocarbons (PAHs). This is the first time polymorphisms in these genes have been investigated in the context of air pollution – lung function interactions.

An integrated system of aerated ponds together with rafted and horizontal flow sub-surface reedbeds has been Installed to treat the glycol-contaminated runoff from two of Heathrow Airport’s susceptible catchment areas the Southern Catchment and the Eastern Catchment. The original plan was to transfer pre-treated water from the latter through the existing fire main which runs around the airport perimeter to the Mayfield Farm Treatment Facility (MFTF) which receives runoff from the Southern Catchment. However this part of the overall Heathrow treatment scheme for surface runoff has not yet been put into operation. Results from monitoring of the treatment system has shown Significant reductions In Biological Oxygen Demand (BOD) throughout the system with levels decreasing by 76 6±10 5% across the constructed wetland cells at the MFTF following high airport deicing fluids applications. However continued exposure to BOD concentrations exceeding the design target of 110 mg/l has resulted in anaerobic conditions being established in the wetland. Background nitrate and phosphate levels observed in two aerated ponds at the MFTF which are used for storage and initial treatment of airport runoff were low Initial results from laboratory experiments conducted to assess the ideal nutrient levels required to support glycol biodegradation in the aerated ponds showed efficient BOD removal (within 5 days) after repeated glycol additions There were also Increases In bacteria populations In aerated pond water samples from average background levels of 107 to 1010 Colony forming units (CFU) per litre Based on the Interpretation of the laboratory experiments a nutrient dosing protocol commenced on 12 November 2004 at the MFTF to ensure that nutrient levels in the aerated ponds were appropriate to treat the contaminated airport runoff received during the winter months Although the BOO levels recorded In the aerated ponds were still high after the commencement of the nutrient dosing regime in November 2004 the BOD removal efficiency of the aerated reservoir following the Influx of high winter BOD load increased to 47 5% (February 2005) from 25 5% recorded In March 2004. In microbiological analyses conducted on the water samples from the MFTF only 18 strains of bacteria, 3 fungal strains and 2 actinomycetes strains were culturable In the laboratory. A combination of API biochemical tests and PCR (Polymerase chain reaction) analyses showed that at least SIX of these bacteria were Pseudomonas species which have been widely reported to have high potential for biodegradation of organic pollutants. However biodegradation experiments conducted using the consortium of the bacteria fungi and actinomycetes Isolates In sterile distilled water dosed With glycol showed that they lacked the ability to efficiently remove the BOD despite the continuously high BOD reductions recorded in some of the natural systems they were isolated from.

Draff was compared to a number of commonly used and commercially available treatments for the amelioration of CAH contaminants. Draff was found to be a suitable treatment under all conditions investigated except when it had been irradiated and performed as well (if not better than) all of the commercial treatments. It was concluded that Draff as a CAH ameliorant merits further investigation involving a scaled-up pilot study in the laboratory which if successful would be followed by field trials at contaminated sites. The quantitative data from the field site which was imputed in to the contaminant visualisation model (Sequence) indicated that attenuation as occurring at the site, albeit rather slowly. The comparison which included revised reaction rates derived from the Draff investigations implied that treatment with Draff at the site would enhance overall attenuation. An investigation regarding the efficacy of biosensors as site evaluation and monitoring tools found that the sensors were of limited value when remediation goals are considered. None of the sensors investigated supplied sufficient sensitivity. It was therefore concluded that the sensors should only be utilised on a cursory “toxic or non toxic” basis. It was concluded that Draff proved effective as an ameliorant for CAH contamination under the conditions tested and merits further investigation at the pilot and potentially the field scale. The contaminant visualisation model proved invaluable for the simplification and analysis of a large data set and furthermore estimated that Draff would enhance attenuation rates at the field site in question.

Air pollution is one of the gravest problems being faced by modern world, and urban traffic emissions are the single major source of air pollution. This work is founded on collaboration with environmental scientists who need fine grained data to enable better understanding of pollutant distribution in urban street canyons. “Wireless sensor networks” can be used to deploy a significant number of sensors within a space as small as a single street canyon and capture simultaneous readings both in the time and space domain. Sensor energy management becomes the most critical constraints of such a solution, because of the energy hungry gas sensors. Hence, the main research objective addressed in this thesis is to propose novel temporal and spatial adaptive sampling techniques for wireless pollution sensor nodes that take into account the pollution data characteristics, and enable the sensor nodes to sample, only when, an important event happens to collect accurate statistics in as efficient a manner as possible. The major contributions of this thesis can be summarised as: 1) Better understanding of underlying pollution data characteristics (based on real datasets collected during pollution trials in Cyprus and India) using techniques from time series analysis and more advanced methods from multi-fractal analysis and nonlinear dynamical systems. 2)Proposal of novel adaptive temporal sampling algorithm called Exponential Double Smoothing based Adaptive Sampling (EDSAS) that exploits the presence of slowly decaying autocorrelations and local linear trends. The algorithm uses a time series prediction method based upon exponential double smoothing for irregularly sampled data. This algorithm has been compared against a random walk based stochastic scheduler called e-Sense and found to give better sampling performance. EDSAS has been extended to the spatial domain by incorporating distributed hierarchical agglomerative clustering mechanism. 3)Proposal of a novel spatial sampling algorithm called Nearest Neighbour based Adaptive Spatial Sampling (NNASS) that exploits the non-linear dynamics existing in pollution data to compute predictability measures to adapt the sampling intervals for the sensor nodes. NNASS has been compared against another spatial sampling algorithm called ASAP and found to give comparable or better sampling performance.

No description available.

This thesis reports research undertaken to better understand the factors that influence norovirus (NoV) contamination in shellfish production areas (SPAs). This knowledge is necessary to develop control measures for mitigating risk from NoV contamination in SPAs. Predictive models were developed for concentrations of NoV (as measured by the reverse transcription polymerase chain reaction method) and Escherichia coli (as measured by the culture method) in shellfish from 31 harvesting sites and climatic, hydrometric, demographic and pollution source-related characteristics of upstream river catchments. Concentrations of NoV in shellfish increased as water temperature decreased and volume of sewage discharges and river flows increased. Concentrations of E. coli increased as rainfall also increased. Field studies were conducted in an estuary and in a coastal embayment to inform risk management measures for these sites. Concentrations of NoV and E. coli and their removal efficiencies were quantified in effluents from primary, secondary and tertiary treatments at four sewage treatment works. Shellfish were placed at different distances downstream of sewage discharges and tested for NoV and E. coli. Dye tracing and drogue tracking studies were conducted to quantify the dispersion and dilution of sewage effluents. Significant NoV reductions were found as sewage treatment levels increased. Activated sludge was more effective in reducing NoV than trickling filters. Norovirus was frequently detected in sewage effluents and in shellfish. It was found that a NoV limit for shellfish established at 100 copies/g would have a high compliance impact on SPAs. The dispersive characteristics of the dye-tagged effluents were consistent with the variation of NoV contamination in the study sites. A buffer zone established at 1,000:1 dilution of estuarine water to treated effluent would afford a high level of public health protection while a buffer zone established at much lower dilution ratios (e.g. 300:1) would represent a much higher health risk.

Vehicle exhaust emissions predicted based on the outputs of traffic flow models are used directly to calculate traffic-related emissions, but also indirectly as input to 'air quality - human exposure' models. Both of which inform transport and environmental policies aimed at achieving sustainable mobility. To be effective, these must be based on robust modelling approaches that not only provide point-based emission predictions, but also inform these with an interval of confidence that properly accounts for the propagation of uncertainties and errors through the complex chain of models involved. This research develops a data-driven methodological framework to probabilistic average speed-based emission predictions using two widely deployed macroscopic traffic flow models. These are the Cell Transmission Model (CTM), a discretised first-order LWR-type model, and METANET, a discretised second-order Payne-type model. Studying both allows quantitative comparison in their application to predicting emissions. While this research discusses all potential sources of uncertainty in this modelling chain, it focusses on those arising from the traffic flow modelling output. The methodology starts with an ensemble-based optimisation approach to estimate both calibration and validation prediction errors in the traffic flow model, and then proposes a Monte Carlo sampling approach to propagate these to emission predictions. This allows predicting emissions alongside their upper and lower bounds for any time period and road network, at different levels of detail. To ensure transferability of findings, this methodology has been tested on three motorway road networks, one of which operates under Variable Speed Limits (VSL). This permits the quantitative assessment of VSL-modified traffic flow models. In the results of this research, emissions of Oxides of Nitrogen (NOx) and uncertainty associated with their prediction are specifically reported for each road network under study. Finally, this research argues that the methodological framework developed can (and should) be applied to any other (relatively) simple or complex integrated 'traffic flow - emission' modelling chain used as part of policy and decision making process.

Pesticides are active substances with potentially adverse effects on human health, and therefore great effort is addressed to study the relation between their widespread use and human exposure. Human biomonitoring (HBM) is the most widely used and powerful tool to evaluate the exposure of the population to these substances. However, novel approaches are needed in order to give additional information on exposure at population level and overcome the limitations of HBM studies. A novel approach, called Wastewater-Based Epidemiology (WBE), was proposed as an alternative “biomonitoring tool” with the aim to assess the population exposure to organophosphates, triazines and pyrethroids. A specific analytical method based on liquid chromatography tandem mass spectrometry was developed and validated to measure human urinary metabolites of pesticides in influent wastewater. This method was applied to samples collected from wastewater treatment plants of fifteen European cities. Pyrethroids metabolites were suitable to back-calculate human exposure to this class. Generally, the results obtained from wastewater were in agreement with the urinary biomarker levels of HBM studies, taking into account the dilution of urine in wastewater. Spatial differences were observed on pesticide exposure in Italy and Europe and seasonal variations in human intake of pyrethroids were found, as expected, with higher intakes during spring/summer. Mass loads profiles of pesticides metabolites in the different European cities were in accordance with the use reported in the Eurostat official statistics. This novel WBE method can be used for obtaining objective and updated, direct information on the real levels of pesticide exposure in the general population, and can complement the findings of HBM studies. The method can also provide valuable information for public health organizations, such as the United States Environmental Protection Agency, the World Health Organization and the Centers for Disease Control and Prevention.

The issue of acid deposition and associated environmental problems has received special attention during recent decades and has been the subject of extensive research in a number of countries. However, there are no recent studies on acid deposition in Cardiff. Weekly rainfall samples were obtained from two urban areas in Cardiff from February 2006 to July 2007 and analysed for pH, electrical conductivity and major ions; SO42−, NO3−, Cl−, Ca2+, Na+, Mg2+, K+ and Pb2+. The chemical composition of precipitation was analysed in conjunction with meteorological variables to evaluate temporal and seasonal variations. Annual wet deposition was estimated, and enrichment factors determined. The pH of individual precipitations fluctuated excessively with a wide range from 4.9 to 6.6 indicating high variability in the acid sources and in neutralisation processes. Correlations between calcium and sulphate imply that CaSO4 may merge with the rainfall and neutralise the acidity. The volume-weighted mean concentrations of NO3− and non-sea salt SO42− were 24.1 and 31.4 μeq l−1, respectively. With the exception of the sea salt ions, no distinct spatial variations in ion composition were observed. Enrichment factors were calculated for most ions and higher correlation coefficients were obtained among most of the ions. Sea-derived material (Na+, Mg2+ and Cl−) showed pronounced cycles in concentration with maxima in autumn/winter. The Cl- (102 kg ha-1 yr-1) and Na+ (66 kg ha-1 yr-1) showed the highest wet deposition flux compared to the other ions. Anthropogenic and crustal sources made a significant contribution to both the acidification and neutralisation of precipitation in Cardiff. In all rain samples SO4-2 concentration exceeded NO3- concentration. Statistical analysis showed no significant differences in the physico-chemical parameters of the rainfall samples between the sites when tested at p<0.05. However, the ionic concentrations of wet precipitation depicted significant seasonal differences except for rainfall volume, K+, NO3- and SO4-2

The poorly controlled disposal of chromium ore processing residue (COPR) is a globally widespread problem due to its potential to form chromium contaminated hyperalkaline (pH > 12) leachates. These highly oxidising leachates typically contain chromium in the Cr(VI) oxidation state as its chromate anion (CrO42-). This anion is highly mobile, toxic, carcinogenic, and exhibits a high degree of bioavailability. Under reducing conditions chromium exists in the non-toxic and poorly soluble Cr(III) oxidation state. Thus, the reduction of Cr(VI) to Cr(III) is often the goal of remediative strategies. In anaerobic subsurface environments where reducing conditions are established by the indigenous microbial population, chromium reduction can occur naturally. The microbial transformation of Cr(VI) to Cr(III) can be both a result of its direct use in microbial metabolism, or through its indirect reaction with microbially produced reduced species, e.g. Fe(II). This study has used a multidisciplinary approach to investigate the biogeochemical influences on the fate and stability of Cr(VI) leaching from a site of COPR in the north of England. Reducing sediments encountered directly beneath the COPR waste were found contain elevated concentrations of chromium. These sediments were shown to be able to remove aqueous Cr(VI) from solution when incubated with contaminated site groundwater in microcosm incubation experiments. This removal is likely a result of the abiotic reduction by soil associated microbially produced Fe(II), followed by precipitation as insoluble Cr(III) hydroxides. X-ray absorption spectroscopy (XAS) and electron microscopy confirms the association of chromium as Cr(III) with iron in these soils, hosted as a mixed Cr(III)-Fe(III) oxyhydroxide phase. Upon air oxidation, only minor amounts of chromium was remobilised from these sediments as Cr(VI). A diverse population of alkaliphilic microorganisms are indigenous to this horizon, capable of successful metabolism despite elevated pH values. This population was found to contain a consortium of microorganisms capable of iron reduction when incubated at pH 9 to 9.5. Microbial community analysis found taxonomic similarity to several known metal reducing alkaliphiles from the phylum Firmicutes. These results suggest that the novel action of iron reducing alkaliphiles indigenous to reducing sediments beneath COPR sites may provide zones of natural chromium attenuation via microbially mediated mechanisms of Cr(VI) transformation.