Personal exposure to particulate matter (PM₁₀ and PM₂.₅) for ten children aged 9 - 11 years was measured between January and September 1997 in the London Borough of Barnet. Personal, home, garden and classroom micro environmental monitoring was successfully completed for all ten children. Each child was monitored for five consecutive days during winter, spring and summer, with the exception of one child who did not complete the summer session. All children completed daily time activity diaries to provide infonnationon any activities that could potentially influence their exposure patterns. Each evening parents completed a household activity questionnaire providing information on all particle generating activities such as cooking and cleaning. Personal Environmental Monitors were used for the personal sampling and Harvard Impactors for the microenvironmental sampling. The children's mean personal exposure concentrations for PM₁₀ during winter, spring and summer were 69, 69 and 32 ug/m³ respectively and for PM₂.₅ 21, 24 and 15 ug/m³ respectively. The strongest and most consistent associations were found between the personal and indoor exposure concentrations. The most significant correlations were observed between personal and home PM₁₀ with a median rs = 0.66. Classroom concentrations were the highest of all the sampled environments which could be attributed to the number of children present and the resuspension of particles. Ambient contributions of PM₂.₅ to PM₁₀ during the day were estimated to be 56%, which is comparable to other UK research. Indoor/outdoor concentrations were influenced by heating in the homes, however no significant specific particle generating activities in the home were found during the day. At night, home concentrations of PM₂.₅ appeared to be influenced by the presence of smokers. To determine potential sources of particulate matter, analysis of a sub sample of filters was undertaken using Scanning Electron Microscopy. Within the home particle composition was influenced by human activities predominantly; resuspended soil dust, skin flakes and fibres. The outdoor particles were predominantly biological in origin; pollen and insect debris. The composition of the personal exposure filters was a mixture of both environments and was dependant upon how much time each child spent in each of these environments. Smooth globular particles c.2um in diameter were found on all filters and could be combustion related, possible vehicle derived or from cooking activities. Measured data, along with the reviewed literature, provides some insight into the source apportionment of particulate matter. Analysis of questionnaire and time activity diaries also provides information on individual children's exposure patterns. Some estimation of potential health outcomes is discussed.

In England, 1264 historic landfills are in coastal and estuarine locations that are low-lying and at risk of flooding and/or erosion if flood defences are not adequately maintained. With increases in sea level, extreme weather events and coastal erosion predicted due to climate change, it is increasingly likely that these landfills will be inundated or breached, which could result in the release of contaminants through leaching or direct release of waste into the intertidal zone. Prior research has focused on the risk of pollution from landfill leachates under normal operating conditions, i.e. waste is fully contained and the landfill is not flooded. This is the first research to assess the risk of estuarine and coastal pollution in the event of historic coastal landfills in England being inundated or waste eroding from them. An investigation of two landfills in Essex has found that contaminant concentrations in a variety of solid waste materials exceeded sediment quality guidelines, indicating there is potential for adverse effects on flora and fauna if historic landfills erode and waste is incorporated into coastal sediments. Leaching experiments have demonstrated that seawater flooding of landfills could increase the proportions of metal contaminants released by up to 5,450% compared to freshwater flooding, but adverse effects on surface water quality from leached metals are unlikely for the research sites due to high levels of dilution in the estuary. The large number of historic coastal landfills, and limited management resources, mean it is necessary to prioritise allocation of remediation funds to sites which pose the greatest pollution risk. Previous methods required extensive data collection to assess the risk of pollution from eroding waste. A new risk screening assessment method is proposed that utilises existing datasets to assess the risk of pollution from historic coastal landfill sites and prioritise them for further investigation/remediation.

High anthropogenic emissions are a global problem with clear links existing between poor air quality and premature mortality, which is of great alarm to organisations such as the World Health Organisation (WHO). In Europe, high emissions of nitrogen oxides (NOx) are a concern with concentrations plateauing over the last 15 years. Emission assessment is a key part of the UK’s air quality strategy; this is done so by using tools such as the National Atmospheric Emissions Inventory (NAEI), to report annual emissions to the EU to meet strict air quality regulations. Due to the high importance placed on inventories such as the NAEI, their accuracy is vital. This thesis details the development and implementation of an airborne eddy−covariance (AEC) strategy to measure anthropogenic fluxes over highly polluted areas, and compare these findings to UK emission inventories. The Ozone Precursor Fluxes in an Urban Environment (OPFUE) campaign was run over two consecutive years, aiming at evaluating emissions from London and Southern England. NOx emissions were evaluated over London showing high emissions coming from central areas. Comparison to the NAEI found NOx emissions were being underestimation by up to a factor of 2. Refinement using the NAEI + road transport estimates scaled via road side measurements showed good improvement, suggesting the need to refine road transport estimates used in the NAEI. A variety of VOC emissions were also measured over London and Southern England. Measured VOCs over London showed good agreement to the NAEI, and highlighted the successful reduction of VOC emissions through air quality strategies. Measured biogenic emissions of isoprene were found to be higher than air quality model estimates, which could have implications towards regional air quality due to ground level ozone formation. Overall, the described methodology allows for real-time assessment of emission inventories which is key if the UK is to see improvements in its air quality.

Both low river flows from surface water extraction for irrigation and diffuse nitrogen pollution are agricultural externalities. Efficient environmental regulation at the catchment level requires that the two be considered together. An economic analysis of policies to control non-point source nitrogen pollution in the presence of minimum river flow controls in a Scottish agricultural catchment was undertaken. A realistic nonlinear Bio-Physical Economic model was constructed which related farming activities (crop/soil land allocation, nitrogen fertiliser application, livestock husbandry, surface water extraction for irrigation etc.) with catchment profitability and environmental externalities (low river flow and diffuse nitrogen pollution). Numerous economic, managerial and mixed regulatory policies were ranked in terms of overall reduction in welfare arising from loss of profitability under regulation. The presence of minimum river flow controls in the catchment was found to reduce nitrogen pollution. This reduction was sufficient to be considered in the design of diffuse pollution policies. However river flow controls did not, for the most part, alter the relative ranking of instruments. By themselves, river flow controls were found not to be a cost effective means to reduce diffuse nitrogen pollution. The effect of varying weather patterns on the relative ranking of polices and the levels required to meet the standard was considered. Although the overall efficiency of economic controls targeting emissions was established, mixed instrument policies did particularly well in 'wet' weather conditions, while economic controls targeting nitrogen as an input performed poorly in the representative 'wet' weather conditions.

This thesis takes an interdisciplinary approach to investigate factors that influence the extent to which environmental policy and practice are founded on the best available knowledge of the environment. The study focuses on the "forest effect", a long-contested environmental impact whereby afforestation is seen to exacerbate freshwater acidification. A social constructivist approach is taken to focus on the factors that impact the inclusion and exclusion of different forms of knowledge (scientific and lay, local and outside knowledges) held by different environmental actors within the environmental decision making process. The methodology follows a stakeholder-based approach. It works alongside a group including policy makers, land managers, environmental regulators and NGO "interested parties" to develop an understanding of the contested nature of the "forest effect". Many methods from the social sciences such as participant observation, semi-structured interviews and discussion of participatory maps are utilised. Key differences in the ways that stakeholders conceptualise the "forest effect" are identified. These differences in conceptualisation are identified as being the primary factors contributing to the prevention of information from local knowledge being included within the decision making process. Two significantly different conceptions of the "forest effect" were identified. The first, the "mechanism-down" effect, draws on scientific understandings of the sulphate-scavenging role of forestry and is reflected in policy by a risk- based approach using catchment-based Critical Loads analysis. The second view of a wider "forest effect" was drawn from local knowledge of unusually high acidity and damage to fish populations in afforested areas. To explore these two "forest effects" in a statistical manner, regional datasets were collated in a catchment-based database that included contemporary and long-term regional field surveys of water quality data, forest maps generated from satellite imagery. Statistical analysis supports a wider "forest effect" than that represented by the "mechanism-down" effect represented in the Forestry Commission's Forest and Water Guidelines. A statistically significant "forest effect" of decreasing pH, charge balance ANC and increasing sulphate, chloride, sodium, CI:Na ratio and DOC with increasing catchment forest in areas outside of those identified as at risk by the Forest and Water Guidelines. Furthermore, further supporting evidence for a "forest effect" as a factor reducing the potential for long-term recovery from acidification is identified. Three factors are identified as having influenced the extent to which knowledge of this wider "forest effect" is recognised by environmental policy and practice. Firstly, it was shown that privilege was given by policy makers to one interpretation of science surrounding the "forest effect". The faith put in the science-derived risk-based approaches as sufficient to control for the "forest effect" lead to the exclusion of local knowledge that contradicted this. Furthermore, this lead to real but pragmatic factors (such as the impracticalities of wide-scale water chemistry survey or the cost of felling large proportions of the forest estate) often being either couched in terms of Science, or not being directly discussed, rather than raised frankly as legitimate issues. Secondly, there was little recognition of the complexity and uncertainty surrounding either the nature of the "forest effect" itself, the scientific process used to study it and the ramifications for the varied actors depending on both the forest and water resources. Finally, it was shown that relationships between organisations played a key role in encouraging/deterring the transmission of knowledge; decisions were shown to be based on Better Available Knowledge when the parties involved integrate knowledge from other actors. Hierarchical and institutional ties, on the other hand, were shown to have the potential to restrict the openness to knowledge transfer. This thesis suggests a social learning approach is taken. This approach encourages the recognition of environmental problems as resource uncertainties to which there is no one determinable answer that suits all and around which decisions can best be legitimised through consensus between impacted parties, informed by the best available scientific data and with recognition of the wider social, political and economic consequences of any action taken.

The risk of dust explosions affects many industries. The range of particulate substances that are explosible is very wide; it includes natural products such as grain dust and sugar, synthetic materials such as pharmaceuticals and metal powders such as aluminium and magnesium. One of the earliest recorded dust explosions occurred in a Bakery in December 1785 and it was not until the nineteenth century, that the mechanisms of dust explosions were recognised and that research programmes were established to investigate this phenomenon. Explosion relief venting is a commonly used form of explosion protection, employed in a wide range of industries, to protect vessels and production units from the overpressures generated by dust or gas explosions. Considerable research has been undertaken on the control of the internal explosion pressure by relief venting and this has resulted in the production of a number of guidance documents for the use and sizing of explosion relief vents. However, the safe use of explosion relief vents requires that buildings and process plant be designed, constructed and sited in such a way that the pressure generated from vented explosions will not cause unacceptable damage. In spite of this, there is very little published guidance relating to the pressure and flames effects resulting from the vented explosion and how their magnitude can be estimated and what measures should be taken to minimise them. Based on a full-scale experimental programme involving over three hundred vented Maize starch and Coal dust explosions in chamber volumes of 20 m3 and 40 m3, this thesis provides techniques for characterising the external effects of vented dust explosions and assessing their effect on brick and steel structures in the surrounding environment. The structural response and loading data was obtained by using both specifically designed, brick and steel targets, which were representative of current UK building design, located directly in-line with the vented explosions and by using buildings already within the laboratory structure. In all cases these buildings were instrumented to provide information on both their structural characteristics and response to applied loads. By using this data comparisons were also made on the characteristics of the pressure time curves observed in complex geometries located away from the direct venting line with the results obtained in the direct venting line. Appendix A4 offers guidance to industry based on the findings from this research. Based on the results from the experimental study, a number of numerical techniques for predicting the response of structures were assessed. This work showed that many of the current methods were not applicable to this work as they were developed to study the response of complex steel structures, unrepresentative of typical building designs, subjected to relatively high pressure internal gas explosion loading scenarios. The methods identified for predicting the response of brickwork buildings to explosions were designed around vented gas explosions with simple impulse loading characteristics. It has been shown that these tools were unable to predict the structural response of the brickwork buildings to the vented dust explosions in this study with any degree of accuracy although they appear to offer a basis for future development.

Clear association exists between exposure to even small concentrations of ambient atmospheric particles with an aerodynamic diameter < 10 Ilm (PMIO) and adverse health outcomes. However, determination of the strength of associations between exposure and illness is limited by low spatial-resolution of particulate concentration measurements. Conventional fixed monitoring stations provide high temporal-resolution data, but cannot capture fine-scale spatial variations. Biomagnetic monitoring of PMIO deposited on tree leaves may provide a means of obtaining exposure data at high spatial resolution. To calculate ambient PMIO concentrations from leaf magnetic values, the relationship between the magnetic signal and total PMIO mass and leaf exposure time must be quantified. This thesis uses magnetic remanence measurements of roadside tree leaves and co-located pumped air filters to examine levels of vehicle - and industry - derived PMIO at three locations within the UK. At the roadside, leaf saturation remanence (SIRM) values exhibit strong correlation with both the SIRM and particulate mass of co-located, pumped-air samples, indicating that these leaf magnetic values are an effective proxy for ambient PMIO concentrations. Two broadleaf deciduous species reach dynamic equilibrium between leaf magnetic remanence and ambient PMIO over a relatively short timescale (- 6 days), indicating that the leafcalculated PMIO reflects ambient PMIO concentrations. Multiple co-located species can be robustly inter-calibrated, enabling maximisation of the spatial resolution of this technique. A different but equally strong correlation also exists between leaf SIRM and ambient PMIO around a major industrial point source. To reduce ambient PMIO concentrations, it is often necessary to identify particulate sources, particularly in complex areas where multiple sources are present andlor in complex topography. To address this issue, I combine magnetic measurements of tree leaves, putative To address this issue, I combine magnetic measurements of tree leaves, putative 11 I J 'j 11 :1 :Ij, :1 :1 I 'I , , , a -------- ,-~-- --------- sources and road dusts to examine if magnetic differentiation can be made between the potential sources and sinks. Particulate assemblages emitted from vehicle fleets (e.g. diesel/petrol) and a range of industrial sources differ in their measured magnetic characteristics, indicating the value of magnetic techniques for particulate source attribution.

This thesis is concerned with various aspects of Air Pollution due to smell, the impact it has on communities exposed to it, the means by which it may be controlled and the manner in which a local authority may investigate the problems it causes. The approach is a practical one drawing on examples occurring within a Local Authority's experience and for that reason the research is anecdotal and is not a comprehensive treatise on the full range of options available. Odour Pollution is not yet a well organised discipline and might be considered esoteric as it is necessary to incorporate elements of science and the humanities. It has been necessary to range widely across a number of aspects of the subject so that discussion is often restricted but many references have been included to enable a reader to pursue a particular point in greater depth. In a 'fuzzy' subject there is often a yawning gap separating theory and practice, thus case studies have been used to illustrate the interplay of various disciplines in resolution of a problem. The essence of any science is observation and measurement. Observation has been made of the spread of odour pollution through a community and also of relevant meterological data so that a mathematical model could be constructed and its predictions checked. It has been used to explore the results of some options for odour control. Measurements of odour perception and human behaviour seldom have the precision and accuracy of the physical sciences. However methods of social research enabled individual perception of odour pollution to be quantified and an insight gained into reaction of a community exposed to it. Odours have four attributes that can be measured and together provide a complete description of its perception. No objective techniques of measurement have yet been developed but in this thesis simple, structured procedures of subjective assessment have been improvised and their use enabled the functioning of the components of an odour control system to be assessed. Such data enabled the action of the system to be communicated using terms that are understood by a non specialist audience.

Organotin compounds still present a high risk to biota in the aquatic environment. Measuring the behaviour of the freely dissolved fractions of these compounds in sediment compartments is challenging, with costly and sensitive analytical techniques required for their measurement. Diffusive gradients in thin-films (DGT) allow for the uptake and pre-concentration of analytes in a binding gel and is used to measure dissolved metals and some organic compounds. The utility of novel silica-bound sorbents (C8, C18, mixed phases) as DGT binding gels for the sequestration of organotins in the marine environment was the primary focus of work in this project. The C8 sorbent showed the optimum performance in the uptake and recovery of organotins across pH, ionic strength and in filtered sea water. It was used subsequently as the binding layer in DGT sediment devices (160 mm × 34 mm) overlaid with a mixed-cellulose ester membrane (0.45 μm) as the single diffusion layer. These were used to investigate pore water mobilisation and concentrations of organotins in coastal sediment cores collected from a contaminated site. Organotins demonstrated a non-sustained uptake scenario, with DGT flux and freely dissolved concentrations in pore water measured to decline at 1 cm depth intervals over deployments of 2-28 days. Using time series, concentrations in pore water at t = 0 were calculated providing empirical pore water depletion curves for sediment cores. Using standard laboratory instrumentation (i.e. gas chromatography-mass spectrometry) low limits of detection were achieved (TBT = 0.4 ng L^-1 after 2 weeks of sampling).