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Measurements of OH, HO2, RO2i (alkene and aromatic-related RO2) and total RO2 radicals taken during the ClearfLo campaign in central London in the summer of 2012 are presented. A photostationary steady-state calculation of OH which considered measured OH reactivity as the OH sink term and the measured OH sources (of which HO2+ NO reaction and HONO photolysis dominated) compared well with the observed levels of OH. Comparison with calculations from a detailed box model utilising the Master Chemical Mechanism v3.2, however, highlighted a substantial discrepancy between radical observations under lower NOx conditions ([NO] < 1 ppbv), typically experienced during the afternoon hours, and indicated that the model was missing a significant peroxy radical sink; the model overpredicted HO2 by up to a factor of 10 at these times. Known radical termination steps, such as HO2 uptake on aerosols, were not sufficient to reconcile the model-measurement discrepancies alone, suggesting other missing termination processes. This missing sink was most evident when the air reaching the site had previously passed over central London to the east and when elevated temperatures were experienced and, hence, contained higher concentrations of VOCs. Uncertainties in the degradation mechanism at low NOx of complex biogenic and diesel related VOC species, which were particularly elevated and dominated OH reactivity under these easterly flows, may account for some of the model-measurement disagreement. Under higher [NO] (> 3 ppbv) the box model increasingly underpredicted total [RO2]. The modelled and observed HO2 were in agreement, however, under elevated NO concentrations ranging from 7 to 15 ppbv. The model uncertainty under low NO conditions leads to more ozone production predicted using modelled peroxy radical concentrations (~3 ppbv h-1) versus ozone production from peroxy radicals measured (~1 ppbv h-1). Conversely, ozone production derived from the predicted peroxy radicals is up to an order of magnitude lower than from the observed peroxy radicals as [NO] increases beyond 7 ppbv due to the model underprediction of RO2 under these conditions. [ABSTRACT FROM AUTHOR]

Providing a healthy school environment is a priority for child health. The aim of this study is to develop a methodology that allows quantification of the potential economic benefit of reducing indoor exposure to nitrogen dioxide (NO 2 ) in children attending primary schools. Using environmental and health data collected in primary schools in London, this study estimates that, on average, 82 asthma exacerbations per school can be averted each year by reducing outdoor NO 2 concentrations. The study expands upon previous analyses in two ways: first it assesses the health benefits of reducing children’s exposure to indoor NO 2 while at school, second it considers the children’s perspective in the economic evaluation. Using a willingness to pay approach, the study quantifies that the monetary benefits of reducing children’s indoor NO 2 exposure while at school would range between £2.5 k per school if a child’s perspective based on child’s budget is adopted up to £60 k if a parent’s perspective is considered. This study highlights that designers, engineers, policymakers and stakeholders need to consider the reduction of outdoor pollution, and particularly NO 2 levels, near primary schools as there may be substantial health and monetary benefits. [ABSTRACT FROM AUTHOR]

Urban greenspaces can provide a significant cooling service, which extends beyond the greenspace boundaries. Consequently, greenspaces are recognised for their ability to locally reduce the urban heat island, a phenomenon that has negative implications for the thermal comfort and health of urban citizens. However, the amount of cooling provided by a greenspace and the distance over which that cooling extends depend on factors such as greenspace size and characteristics. Based on data collected in and around eight London greenspaces, with areas ranging from 0.2 to 12.1 ha, this work models the distance and magnitude of cooling provided by each greenspace and defines the relationships between cooling extent and the size of greenspace or the areas of tree canopy and grass. Such data, illustrating the value of expanding the area of urban greenspaces and explaining how cooling relates to greenspace size/coverage characteristics, will be of use to urban planners and climatologists concerned with finding solutions to the urban heat island. Modelling was statistically valid on calm warm nights (with mean air temperatures ≥10 °C and wind speed ≤3 m s −1 ). On those nights, cooling distance increased linearly with increasing area of greenspace, tree canopy and grass, but the relationship between those factors and the amount of cooling was non-linear. Cooling distance was most strongly related with tree canopy whereas the amount of cooling was most strongly linked to the grass coverage. Our results suggest that a comprehensive cooling service on calm warm nights within cities with similar climate/characteristics to London may come from greenspaces with 3–5 ha, situated 100–150 m apart. [ABSTRACT FROM AUTHOR]

This paper argues for an increased emphasis on the institutions of risk governance and management in understanding urban resilience. This moves analysis of vulnerability away from a focus on individuals to also consider risk management regimes as co-productive of vulnerability and resilience in the City. This is illustrated through the application of an Adaptive Capacity Index to unpack the role played by formal governance institutions in mediating resilience to extreme heat events in the empirical case of London. Analysis shows that the configuration of risk at the institutional level directs heat wave risk management through the health services, and operationalises it during the emergency phase of hazard onset. This misses an important opportunity for integrating individual and regime level risk management initiatives, which we proposed can be worked out through greater collaboration with social services and interaction with those caring for the vulnerable, has yet to be fully integrated into planning and practice in London and elsewhere. [ABSTRACT FROM PUBLISHER]

This paper aims to address the characteristics of urban microclimates that affect the building energy performance and implementation of the renewable energy technologies. An experimental campaign was designed to investigate the microclimate parameters including air and surface temperature, direct and diffuse solar irradiation levels on both horizontal and vertical surfaces, wind speed and direction in a dense urban area in London. The outcomes of this research reveal that the climatic parameters are significantly influenced by the attributes of urban textures, which highlight the need for both providing the microclimatic information and using them in buildings design stages. This research provides a valuable set of microclimatic information for a dense urban area in London. According to the outcomes of this research, the feasibility study for implementation of renewable energy technologies and the thermal/energy performance assessment of buildings need to be conducted using the microclimatic information rather than the meteorological weather data mostly collected from non-urban environments. [ABSTRACT FROM AUTHOR]

Climate change may create risks that, without sufficient adaptation measures in place, endanger lives and damage natural, semi-natural and designed landscapes. This article explores the use of green infrastructure in climate change adaptation in London. A review of the current literature identifies how and where green infrastructure can deliver climate adaptation services and considers the benefits of taking a green infrastructure (or ecosystems services) approach to development. Selected examples are used to demonstrate how green infrastructure is being integrated into London's urban landscape. The article considers how existing mechanisms are facilitating the growth of green infrastructure in the capital and identifies three key focus areas for future research and policy. It concludes by suggesting that a more collaborative and imaginative approach to optimising the potential for green infrastructure benefits is needed. [ABSTRACT FROM AUTHOR]

Over the past decade, a growing body of research has examined the role of cities in addressing climate change and the institutional and political challenges which they encounter. For the most part, in these accounts, the infrastructure networks, their material fabric, everyday practices and political economies, have remained unexamined. In this paper, it is argued that this is a critical omission and an approach is developed for understanding how urban responses to climate change both configure and are configured by infrastructure networks. Central to any such analysis is the conception of how and why (urban) infrastructure networks undergo change. Focusing on urban energy networks and on the case of London, the paper argues for an analysis of the ‘urban infrastructure regimes’ and ‘experiments’ through which climate change is governed. It is found that climate change experiments serve as a means through which dominant actors articulate and test new ‘low-carbon’ logics for urban infrastructure development. It is argued that experiments work by establishing new circuits, configuring actors in new sets of relations and through these means realising the potential for addressing climate change in the city. At the same time, experiments become sites of conflict, a means through which new forms of urban circulation can be confined and marginalised, leaving dominant energy regimes (relatively) intact. [ABSTRACT FROM PUBLISHER]

The environmental impact of diesel-fueled buses can potentially be reduced by the adoption of alternative propulsion technologies such as lean-burn compressed natural gas (LB-CNG) or hybrid electric buses (HEB), and emissions control strategies such as a continuously regenerating trap (CRT), exhaust gas recirculation (EGR), or selective catalytic reduction with trap (SCRT). This study assessed the environmental costs and benefits of these bus technologies in Greater London relative to the existing fleet and characterized emissions changes due to alternative technologies. We found a >30% increase in CO2 equivalent (CO2e) emissions for CNG buses, a <5% change for exhaust treatment scenarios, and a 13% (90% confidence interval 3.8-20.9%) reduction for HEB relative to baseline CO2e emissions. A multiscale regional chemistry-transport model quantified the impact of alternative bus technologies on air quality, which was then related to premature mortality risk. We found the largest decrease in population exposure (about 83%) to particulate matter (PM2.5) occurred with LB-CNG buses. Monetized environmental and investment costs relative to the baseline gave estimated net present cost of LB-CNG or HEB conversion to be $187 million ($73 million to $301 million) or $36 million ($-25 million to $102 million), respectively, while EGR or SCRT estimated net present costs were $19 million ($7 million to $32 million) or $15 million ($8 million to $23 million), respectively. [ABSTRACT FROM AUTHOR]

Abstract: The study investigates thermal stratification effects of approach flows on dispersion in urban environments. This is in some ways analogous to a well-developed non-neutral flow (e.g. through a large urban area) approaching a neighbourhood-scale urban region, where the effect of the local heat transfer was assumed less important. A generic urban-type geometry, i.e. a group of staggered cubes, was taken as the first test case. The DAPPLE site, which was about a one-km2 region near the intersection of Marylebone Road and Gloucester Place in central London, was taken as the second test case. Only weakly unstable conditions (i.e. bulk Richardson number ) of approach flows were considered, with adiabatic boundary conditions at the ground and building surfaces. A number of numerical experiments were performed. The modelled mean concentration for R b = −0.1 gave the best agreement with the field data at all DAPPLE stations. This suggests that stratification effects on dispersion in weakly unstable conditions (e.g. in London) are not negligible. [Copyright &y& Elsevier]

In urban areas, a highly variable mixture of pollutants is deposited as particulate matter. The concentration and bioavailability of individual pollutants within particles need to be characterised to ascertain the risks to ecological receptors. This study, carried out at two urban parks, measured the deposition and water-solubility of metals to four species common to UK urban areas. Foliar Cd, Cr, Cu, Fe, Ni, Pb and Zn concentrations were elevated in at least one species compared with those from a rural control site. Concentrations were, however, only affected by distance to road in nettle and, to a lesser extent, birch leaves. Greater concentrations of metal were observed in these species compared to cypress and maple possibly due to differences in plant morphology and leaf surfaces. Solubility appeared to be linked to the size fraction and, therefore, origin of the metal with those present predominantly in the coarse fraction exhibiting low solubility. [Copyright &y& Elsevier]

Short-term human exposure concentrations to PM2.5, ultrafine particle counts (particle range: 0.02-1 μm), and carbon monoxide (CO) were investigated at and around a street canyon intersection in Central London, UK. During a four week field campaign, groups of four volunteers collected samples at three timings (morning, lunch, and afternoon), along two different routes (a heavily trafficked route and a backstreet route) via five modes of transport (walking, cycling, bus, car, and taxi). This was followed by an investigation into the determinants of exposure using a regression technique which incorporated the site-specific traffic counts, meteorological variables (wind speed and temperature) and the mode of transport used. The analyses explained 9, 62, and 43% of the variability observed in the exposure concentrations to PM2.5, ultrafine particle counts, and CO in this study, respectively. The mode of transport was a statistically significant determinant of personal exposure to PM2.5, ultrafine particle counts, and CO, and for PM2.5 and ultrafine particle counts it was the most important determinant. Traffic count explained little of the variability in the PM2.5 concentrations, but it had a greater influence on ultrafine particle count and CO concentrations. The analyses showed that temperature had a statistically significant impact on ultrafine particle count and CO concentrations. Wind speed also had a statistically significant effect but smaller. The small proportion in variability explained in PM2.5 by the model compared to the largest proportion in ultrafine particle counts and CO may be due to the effect of long-range transboundary sources, whereas for ultrafine particle counts and CO, local traffic is the main source. [ABSTRACT FROM AUTHOR]

The article explores the book "The Climate of London," by T. J. Chandler which is said to be the first textbook on climatology. It examines the book's overall structure including the physical and cultural setting, the synoptic weather setting and nine weather elements. It mentions that the book is an exposition of the general and urban climatology of the city of London.

This study addresses the anthropogenic heat emissions from buildings in London, i.e. the total energy delivered to buildings, all of which will ultimately end up as heat energy. The study was undertaken in an attempt to understand the significance of these emissions with regards to the impact on the local climate in London. In order to place the emission of this anthropogenic heat in context, it was thus compared against the net short wave solar radiation captured within the urban environment. This study provides a preliminary analysis of the spatial and temporal anthropogenic heat emissions from buildings across London as part of the urban climate modelling element of the LUCID (‘The Development of a Local Urban Climate Model and its Application to the Intelligent Design of cities’) project. Four urban environment models, representative of the range of urban density found in central London, were developed for the comparison of the anthropogenic heat emissions and the net shortwave solar radiation. It was found that the annual average anthropogenic heat emission from the built environment across London was approximately 9W/m2 (ground area). However, this average value conceals a significant spatial and temporal range. In those urban areas with deep canyons and high densities, the anthropogenic heat constitutes a significant portion of the total energy input. A comparison indicates that the total heat emission from buildings during a winter day ranges between 3 and 25 times greater than the incident solar radiation, and during a summer day between 0.04 and 0.4 times, depending on built form density. [Copyright &y& Elsevier]

We present one year of data from the first continuous measurements of carbon dioxide mixing ratio in central London. Measurements were made at an 87m tower site using the new Vaisala CARBOCAP GMP343 instrument, which was found to provide a compact and inexpensive method for mixing ratio monitoring, in an environment where conventional CO2 sensors could not be accommodated. Measurements were compared with a monitoring site outside London, showing that the city''s CO2 “dome” was an order of magnitude smaller than measured at lower levels in other cities. During the night time in the summer, the mixing ratio in central London was found to be significantly lower than at the rural site. This was thought to be explained by the proximity of biogenic sources to the rural sensor, differences between urban and rural mixing heights and/or the interception of a vertical mixing ratio gradient at two different measurement heights. Estimation of the CO2 loading of the air entering the city therefore proved problematic during the summer. As a result, we propose that monitoring of CO2 emission rate using this type of measurement may only be possible in the winter when the influence of these factors is minimal. [Copyright &y& Elsevier]

Abstract: A generalised additive modelling (GAM) approach is used to model daily concentrations of nitrogen oxides (NO X ), nitrogen dioxide (NO2), carbon monoxide (CO), benzene and 1,3-butadiene at a busy street canyon location in central London. The models were developed for the period July 1998–June 2005 using appropriate meteorological and road traffic covariates. For all models, the complex and localised wind-flow patterns resulting from the street canyon location of the monitoring site, which can be difficult to model deterministically, have a large influence on the model predictions. It is shown that GAMs built using simple covariates explain a large amount of the daily variation for these pollutants (mean r 2=0.86). It is found that concentrations of benzene and 1,3-butadiene have declined in line with detailed calculations of emissions trends, with some evidence to suggest that reductions in benzene have been greater than estimated reductions in emissions. Although measured concentrations of NO X have declined from 1998 to 2005, much of the decline appears to be associated with reductions in overall traffic and meteorological factors rather than reduced emissions of NO X . Unadjusted NO X trends show a 28.6% reduction (95% confidence interval from 21.2% to 35.8%) from 1998 to 2005, whereas meteorologically adjusted trends show a 19.3% decline (95% confidence interval from 14.8% to 23.5%) over this period. Analysis shows that there were a higher number of occasions in the early part of the time series that led to strong recirculation of exhaust emissions and higher NO X concentrations at this location, thus affecting observed trends in concentration. [Copyright &y& Elsevier]

The author reflects on the status of ecosystems around the world and their inhabitants in 2010, such as London, England, which is the host of the Ecohealth 2010 conference. The author mentions the ecosystems in Latin America, highlighting the importance of biodiversity in health and well-being. Moreover, the author discusses the environmental condition of London such as its clean air and thriving ecological life.

Points out that the crucial environmental issues for the city of London, England, have been benchmarked in the Mayor's "State of the Environment Report for London" as required by the Greater London Authority Act of 1999. Land quality and the conservation of natural resources; Flooding; Groundwater levels; Pollution incidents; River water quality; Biodiversity; Noise; Air pollution; Road traffic levels; Waste management; Energy use; Climate change.

Discusses the miasmatic theory of disease causation which was prevalent during the Victorian era in London, England. Notable proponents of this theory, including Edwin Chadwick and Neil Arnott; Drainage of London by Sir Joseph Bazalgette.

This article reports on a study conducted in London, England, which found that riders of London taxis are exposed to more particulate air pollution than in other modes of transportation, such as buses, bicycles and ordinary automobiles. Walking made for the lowest exposure to pollutants. Several factors caused taxis to be ranked as the worst polluters. Scientists pointed out that taxis are on the road much longer than average cars and that exposure comes from sitting in the cabs while stuck in traffic. The study was conducted by scientists from Imperial College, London.