Modelling, pollution monitoring and epidemiological studies all have a role to play in developing effective policies to improve air quality and human health. Epidemiological studies have shown that of particular importance are the effects of fine particulate matter, PM10 and PM2.5 which can penetrate into human lungs. At present it is not clear which components of PM are responsible for health effects although toxicological studies have identified several potential factors. Hence, based on WHO guidance, current legislation has focused on the total mass, with the EC setting limit values on total PM10, followed by target reductions for population exposure to PM2.5 in urban agglomerations. Trends in measured concentrations at selected urban monitoring stations are required as evidence for achievement of these reductions. This paper addresses these issues at the borough level in London using the integrated assessment model UKIAM, developed originally for application at the national scale, with illustrations comparing abatement of two contrasting sources – domestic combustion and road transport. The former, dominated by natural gas generating NOX emissions, contributes to longer range secondary PM formation extending beyond the city. The latter is an important source of black carbon as a primary pollutant causing local exposure, as well as NOX. WHO data is used in relation to impacts of particle concentrations by mass, and response functions for black carbon are taken from the literature. The results show that from a city perspective there are enhanced benefits from reducing the road transport emissions, especially with regard to potential toxicity of black carbon. The scenarios modelled also highlight the spatial variations of benefits across London, and illustrate deviations from trends as represented by limited monitoring data from the different boroughs, together with the influence upon exposure of mobile population within the city.

Under the UNECE LRTAP Convention protection of ecosystems is routinely evaluated in integrated assessment by calculating exceedance of critical loads, defined as the maximum levels of deposition sustainable without adverse effects. Such assessments using the UK Integrated Assessment Model are able to quantify the extent of exceedance regionally for different broad habitat categories. Although this provides an aggregated view useful for policy development, it cannot quantify impacts upon individual sites of special scientific interest (SSSI) or other sites designated under the Habitats Directive or the Birds Directive of the European Union.Compilation of critical load data for designated sites by JNCC has enabled a more detailed consideration of those ecosystem areas of concern, leading to the development of a "protectability index" which indicates different degrees of risk for different habitats within designated sites, ranging from "protected with a high level of confidence" to "un-protectable" where exceedance is so large that reducing deposition to eliminate it is not feasible.As designated sites are often nearby, or adjacent to agricultural livestock, they can be unduly affected by short-range dry deposition of ammonia emissions. We evaluate current (2010) and projected (2020) impacts upon a range of habitats in designated sites which display very low to very high sensitivities to nitrogen deposition. With agricultural emissions of ammonia consistently difficult to reduce, we compare these impacts with an hypothetical scenario in which dry deposition of ammonia - which is dominated by local sources - has been reduced, indicating where local control measures may be useful. We conclude that local mitigation measures may present an effective means for reducing eutrophication in designated sites.

Air pollution models developed for policy support have traditionally generated aggregated population exposure metrics - such as population weighted mean concentrations, years-of-life-lost or disability-adjusted-life-years - as a proxy for impacts upon human health. With the latter also using results from epidemiological studies, these metrics are useful for gauging whether policies potentially reduce health impacts, but they do not account for the movement of individuals, and air pollution models could provide more focussed information for evaluating real-world health impacts. However, annualised air pollution models can describe the spatial variation of different pollutants for use in health impact assessments based upon daily activity patterns of individuals.Focussing on airborne particulate matter (PM), we acknowledge that there is no consensus on the relative toxicity of different components of PM, with reviews by the WHO investigating various causative mechanisms, implying specific components as particularly toxic, such as diesel particulates which are also identified as a carcinogen. Recognising that epidemiological studies already utilise outputs from air pollution models, we highlight the complexity of airborne PM in relation to size fractions, species composition, source attribution, control of emissions, and health impacts, and show how air pollution models can provide more focussed information to benefit epidemiological assessments.Drawing on work attributing health effects to individual PM constituents, and source apportionment by the UK Integrated Assessment Model, we are able to distinguish the spatial distribution of concentrations of components which may have differing impacts upon human health. Understanding these spatial variations and their coincidence with vulnerable populations (eg. schools or hospitals) represents a step towards air pollution models providing outputs of greater utility for epidemiological studies.With the emphasis upon reducing health impacts under the Directive on ambient air quality and cleaner air for Europe, the provision of more focussed metrics within air pollution models should enable policy makers to direct abatement strategies towards the industrial and residential sectors with the greatest combined impact on human health, simultaneously providing better data for epidemiological studies evaluating the impacts upon mobile populations.

Whilst grounding is often undertaken in industry as a matter of good practice in situations where the risk of excess charge exists, little thought is usually given to the biological effects that such measures may have, or possible benefits that may arise from the more widespread application of electrostatic and other 'electromagnetic hygiene' measures in hospitals and the general built environment. Research, which is still in its infancy, indicates that grounding the human body using suitable methodologies, particularly in low electromagnetic field environments, can significantly enhance biological functioning. It is proposed that there are often a number of electrostatic and 'electromagnetic hygiene' factors that need to be addressed before the beneficial effects of grounding the human body can be fully realised in many everyday environments.

Non-technical pollution abatement measures have become increasingly significant in order to meet current policy targets for meeting both commitments of the Gothenburg Protocol and EU air quality targets; the importance of capturing what amount to behavioural changes in integrated assessment modelling has been addressed at a number of UN/ECE workshops. The work presented here responds to these needs and provides the basis for linking air quality issues at the local level with the policy requirements to comply with international agreements on transboundary air pollution and national emissions ceilings. We describe a high resolution module for the UK Integrated Assessment Model which provides a mechanism for introducing structural and behavioural changes in the transport sector into integrated assessment modelling, source-apportionment of local, national and transboundary contributions to air quality, and captures the roadside concentrations of air pollutants in urban street canyons. Focussing upon urban air quality (NO"2 and PM"1"0), and both technical and non-technical abatement (changes in behaviour and activity levels), we find that policy measures are required at multiple scales in order to achieve improvements on air quality at the local scale. Contrasting scenarios illustrate that it may be easier to control levels of NO"2 than PM"1"0 by using local measures, since PM"1"0 concentrations are dominated by secondary particles and background components. Combining technical and behavioural measures is more likely to be effective in simultaneously achieving reductions in emissions, concentrations and health effects. However, there is a need to assess the cost effectiveness of local abatement measures in relation to the cost effectiveness of national and transboundary measures affecting the long-range components.

Lifestyles and the built environment have changed considerably during the past century and have greatly influenced the electric field, small air ion and charged submicron aerosol regimes to which individuals are often exposed. In particular the use of electrical items, synthetic materials/finishes and low humidity levels that can lead to the generation of high electrostatic charges, along with inadequate grounding protocols and building techniques which create 'Faraday cage'–like conditions, have all greatly altered the electromagnetic nature of the microclimates many people occupy for prolonged periods of time. It is suggested that the type, polarity and strengths of electric fields individuals are exposed to may affect their likelihood of succumbing to ill-health through influencing biological functioning, oxygen-uptake and retention rates of inhaled submicron contaminants to a far greater degree than previously realised. These factors can also influence the degree of local surface contamination and adhesion that occurs. It is further suggested that both health and work productivity can be affected by such factors, and that improved 'best practice' electro-hygiene/productivity protocols should be adopted wherever practical.

Integrated Assessment Modelling in the field of air pollution has advanced greatly since the 1985 Helsinki Protocol on the reduction of Sulphur emissions and their transboundary fluxes. With subsequent protocols and increased understanding of the inter-relationships between local air quality, transboundary air pollution and climate change, a variety of spatio-temporal issues must be addressed in order to model the multi-scalar processes involved and nest Integrated Assessment Models. We describe the state-of-the-art in Integrated Assessment Modelling using a conceptual framework which locates the research activities driving integrated assessment in relation both to each other and to flows of information between activities, and identify inter-relationships with scientific and policy domains beyond the scope of the UN/ECE Convention on Long Range Transboundary Air Pollution, recognising the utility of social science in understanding the effects of policy on socio-cultural behaviours. We discuss how the issues identified are being captured by integrated assessment models, with particular focus on the treatment of non-technical pollution abatement measures, noting current developments at the micro-scale addressing the dynamics of behavioural responses to abatement policies. Finally, we identify three key challenges for issue-driven Integrated Assessment Modelling: (i) capturing the dynamics of behavioural responses to value-driven policy mechanisms designed to promote non-technical abatement measures; (ii) the development of new tools to handle the delay times, inter-dependencies and multi-pollutant effects of abatement measures; and (iii) the identification of boundaries between knowledge domains and the effective transfer of multi-disciplinary scientific and socio-cultural knowledge to an increasingly trans-disciplinary policy domain.

Measurements of small air ion concentrations, electrostatic potential and AC electric field strengths were taken in an office setting to investigate the link between electric fields and charged molecule and particle concentrations in individual microenvironments. The results obtained indicate that the electromagnetic environments individuals can be exposed to whilst indoors can often bear little resemblance to those experienced outdoors in nature, and that many individuals may spend large periods of their time in "Faraday cage"-like conditions exposed to inappropriate levels and types of electric fields that can reduce localised concentrations of biologically essential and microbiocidal small air ions. Such conditions may escalate their risk of infection from airborne contaminants, including microbes, whilst increasing localised surface contamination. The degree of "electro-pollution" that individuals are exposed to was shown to be influenced by the type of microenvironment they occupy, with it being possible for very different types of microenvironment to exist within the same room. It is suggested that adopting suitable electromagnetic hygiene/productivity guidelines that seek to replicate the beneficial effects created by natural environments may greatly mitigate such problems. (c) 2007 Elsevier Ltd. All rights reserved.

Ammonia (NH3) is emitted mainly from agricultural practices, with NH3 concentrations decreasing rapidly away from sources. As a consequence there is a high spatial variability in nitrogen deposition and its consequent ecological effects in agricultural landscapes that is in addition to differences in sensitivity between habitat types. This variability points to the potential to include spatial planning measures as part of strategies to protect sensitive vegetation from ammonia deposition.National abatement policies typically include uniform recommendations for technical abatement measures, such as ploughing in manures after land spreading. In this study, the complementary potential of spatial planning to reduce effects on target locations is analysed through model scenarios for an example landscape in central England. Scenarios included defining buffer zones of low-emission agriculture and establishing tree belts surrounding either emission sources or priority areas for the protection of semi-natural habitats.The analysis showed that tree belts can reduce deposition to sensitive areas, with trees surrounding the sensitive habitats being more effective than trees around the sources. Low emission buffer zones around sink areas also result in useful reductions in N deposition. Smaller nature reserve sites benefit to a greater degree from such spatial planning measures, as large reserves can provide their own buffer zone to some degree. Similarly, relocating point sources or using planning policies to ensure the location of large NH3 point sources are at least 2-3 km from the sensitive habitats results in substantial reductions in N deposition. (c) 2006 Elsevier Ltd. All rights reserved.

Tightening of air quality standards for populated urban areas has led to increasing attention to assessment of air quality management areas (AQMAs) where exceedance occurs, and development of control strategies to eliminate such exceedance. Software tools that bring together data on pollutant sources, their respective contributions to atmospheric concentrations and human exposure, together with information on potential technological and other measures that may be used to reduce concentrations and their economic costs, can be used to identify cost-effective strategies for improving air quality, and hence aid policy development. The Urban Scale Integrated Assessment Model (USIAM) has been developed in this context, illustrated in this paper by application to traffic emissions which are a major contributor to exceedance of air quality objectives for fine particulate matter, PM"1"0, in London. In such a multidisciplinary approach the aim has been to provide a tool for rapid assessment of a wide range of scenarios to identify those that are most cost effective, maintaining a balance between the level of sophistication in the model and the uncertainties and assumptions involved.

To date there have been few published investigations on the levels of indoor volatile organic compounds (VOCs) in workplaces in polluted urban areas in the UK. The present investigation was carried out in a non-smoking and naturally-ventilated office building situated along one of the most polluted roads in London in conjunction with the Dispersion of Air Pollutants and their Penetration into the Local Environment (DAPPLE) 2003 field campaign. The results from the measurements taken for indoor VOCs in offices where smoking was prohibited are reported. The concentrations of hexanal, m-, p-xylene, styrene, toluene and total VOCs (TVOCs) are presented and discussed. Other VOCs, in addition to those primarily selected for analysis, were also recorded.

Considerable static and a.c. electric fields, poor specification of materials and low humidity levels can create "electrosmog" indoors capable of significantly reducing concentrations of biologically vital small air ions, such as charged oxygen. They can greatly influence the type, concentration and deposition of charged aerosols present within indoor microenvironments and individuals' personal breathing zones. When the body receives sub-optimal oxygen levels due to poorly designed electromagnetic environments it is more prone to demonstrate reduced productivity, stress and an increased likelihood of succumbing to degenerative illnesses.