Carbonyl compounds indoors in a changing climate

<p>Abstract</p> <p>Background</p> <p>Formic acid, acetic acid and formaldehyde are important compounds in the indoor environment because of the potential for these acids to degrade calcareous materials (shells, eggs, tiles and geological specimens), paper and corrode or tarnish metals, especially copper and lead. Carbonyl sulfide tarnishes both silver and copper encouraging the formation of surface sulfides.</p> <p>Results</p> <p>Carbonyls are evolved more quickly at higher temperatures likely in the Cartoon Gallery at Knole, an important historic house near Sevenoaks in Kent, England where the study is focused. There is a potential for higher concentrations to accumulate. However, it may well be that in warmer climates they will be depleted more rapidly if ventilation increases.</p> <p>Conclusions</p> <p>Carbonyls are likely to have a greater impact in the future.</p

Technological requirements for solutions in the conservation and protection of historic monuments and archaeological remains

Executive summary: This Study has discovered many achievements associated with European support for scientific and technological research for the protection and conservation of cultural heritage. The achievements to date are: 1. Creation of an active research community 2. A body of research of unparalleled and enviable international quality and character 3. Ongoing effectiveness of research beyond initial funding 4. Substantial rate of publication 5. Imaginative tools of dissemination and publication 6. Clear spin-offs and contribution to European competitiveness often going outside the European cultural heritage area 7. Contribution to emerging European legislation, for example, air quality management. The Study has also uncovered important research gaps associated with this field that have yet to begin to be investigated. It has also discovered the need for continuing fine scale advancement in areas where researchers have been active for a number of years. The overall picture is that European research in the field of cultural heritage protection must be put on a secure footing if it is to maintain its commanding lead over other regions of the world. This Study concludes that: 1. It would be invidious to attempt to separate basic and applied research in this area of research. Like any other scientific endeavour, this field needs to integrate basic and applied research if it is to continue to thrive. 2. Small, flexible, focused interdisciplinary teams responsive to European needs, must be sustained, promoted and celebrated as models of sustainability and that what is proposed under the European Research Area (ERA) for large and complex research projects, could inflict serious damage on this area of research. 3. Resources cannot be delegated to Member States because of the interdisciplinary nature of cultural heritage and the need for a co-ordinated pan-European perspective across this research that helps to define the essential character of European cultural heritage. National programmes only serve local needs, leading to loss of strategic output, lessening of competitiveness and risk of duplication. 4. A mechanism needs to be created to help researchers working in this field to communicate and exchange information with related sectors such as construction, urban regeneration, land reclamation and agriculture. 5. There is overwhelming agreement over the need for sustainable research funding for cultural heritage and for an iterative process of exchange among researchers, decision-makers and end-users in order to maximize benefits from project inception through to dissemination, audit and review. For all the reasons mentioned above, the most significant recommendation in this Report is the identification of the need for a European Panel on the Application of Science for Cultural Heritage (EPASCH)

Distribución pasada y futura del color en edificios históricos de piedra

The patterns of colour on stone buildings change with time. Buildings were blackened by coal soot, but now mostly diesel particles and in future, wind-driven rain may alter the patterns and oxidation of surface organics. Colouring patterns that outline or shadow architectural elements are publicly more acceptable than those that cut across them e.g. rain streaking. Thresholds of acceptability for blackening can be related to soot loading. When soot loading of the ambient air is high, e.g. near busy roads, buildings are dark and typically viewed as unacceptable. However at lower concentrations (2-3 μg m-3 elemental carbon), building appearance is typically seen as more acceptable. The future offers a potential for variation in building colour, arising through different biological growth under changing climates or the presence of different pollutants. In future urban atmospheres more dominated by organic pollutants a yellowing process may be more important. Diesel soot has many organic compounds that can oxidise to brownish-coloured humic-like (HULIS) materials. We illustrate the development of colour patterns on the Cathedral Church of St John the Baptist, Norwich UK from its opening (beginning of the 20th century) to the end of the 21st century derived from historic photographs, observations and predictions for the future appearance. The latter has to consider removal of deposits by changed rainwater flow and enhanced biological activity. Blackening from coal smoke may have reached a peak around 1960s and 1970s, but diesel soot predominates now.La distribución del color en edificios de piedra varía con el tiempo. En el pasado, el ennegrecimiento se debía principalmente a la combustión de carbón. Actualmente, se debe fundamnetalmente al depósito de partículas derivadas del diesel. En el futuro, se verá modificado por la acción de la lluvia y el viento. La percepción del público sobre el ennegrecimineto depende de su distribución. Si se resaltan las formas arquitectónicas, será en general aceptable. Los umbrales de aceptación también dependen de la concentración de carbono elemental. Si la concentración es elevada, como en áreas de tráfico intenso, los edificios estarán oscurecidos y probablemente se percibirán como inaceptablemente sucios. A menores concentracions de carbono elemental (2-3 μg m-3), el aspecto de los edificios es en general más aceptable. En el futuro, los cambios de color se verán favorecidos por la diferente actividad biológica, resultante del cambio climático y los diferentes tipos de contaminantes. Un proceso de amarilleamento será probalemente más relevante. Las partículas derivadas del diesel son ricas en sustancias orgánicas que se pueden oxidar a materiales similares a compuesto húmicos (HULIS) de colores marronáceos. Finalmente, se ilustra la evolución de la distribución del color en la Catedral de San Juan Bautista, Norwich (UK) desde su apertura (principios del siglo XX) hasta finales del siglo XXI, usando fotografías históricas, observaciones y prediciones del aspecto futuro, considerando la redistribución de los depósitos por el agua y la actividad biológica. El ennegrecimiento por carbón probablemte alcanzó su máximo hacia 1960-70. Actualmente el diesel es predominate

Heterogeneity of passenger exposure to air pollutants in public transport microenvironments

Epidemiologic studies have linked human exposure to pollutants with adverse health effects. Passenger exposure in public transport systems contributes an important fraction of daily burden of air pollutants. While there is extensive literature reporting the concentrations of pollutants in public transport systems in different cities, there are few studies systematically addressing the heterogeneity of passenger exposure in different transit microenvironments, in cabins of different transit vehicles and in areas with different characteristics. The present study investigated PM2.5 (particulate matter with aerodynamic diameters smaller than 2.5μm), black carbon (BC), ultrafine particles (UFP) and carbon monoxide (CO) pollutant concentrations in various public road transport systems in highly urbanized city of Hong Kong. Using a trolley case housing numerous portable air monitors, we conducted a total of 119 trips during the campaign. Transit microenvironments, classified as 1). busy and secondary roadside bus stops; 2). open and enclosed termini; 3). above- and under-ground Motor Rail Transport (MTR) platforms, were investigated and compared to identify the factors that may affect passenger exposures. The pollutants inside bus and MTR cabins were also investigated together with a comparison of time integrated exposure between the transit modes. Busy roadside and enclosed termini demonstrated the highest average particle concentrations while the lowest was found on the MTR platforms. Traffic-related pollutants BC, UFP and CO showed larger variations than PM2.5 across different microenvironments and areas confirming their heterogeneity in urban environments. In-cabin pollutant concentrations showed distinct patterns with BC and UFP high in diesel bus cabins and CO high in LPG bus cabins, suggesting possible self-pollution issues and/or penetration of on-road pollutants inside cabins during bus transit. The total passenger exposure along selected routes, showed bus trips had the potential for higher integrated passenger exposure compared to MTR trips. The present study may provide useful information to better characterize the distribution of passenger exposure pattern in health assessment studies and the results also highlight the need to formulate exposure reduction based air policies in large cities. © 2015 Elsevier Ltd.postprin

A Study into the Effect of the Presence of Moisture at the Wheel/Rail Interface during Dew and Damp Conditions

Incidents involving low levels of adhesion between the wheel and rail are a recurrent issue in the rail industry. The problem has been mitigated using friction modifiers and traction enhancers, but a significant number of incidents still occur throughout the year. The following work looks at the environmental conditions that surround periods of low adhesion in order to provide an insight into why low adhesion events occur. Network Rail Autumn data, which provided details on the time and location of low adhesion incidents, was compared against weather data on a national and then local scale. Low adhesion incidents have often been attributed to contamination on the rail, such as organic leaf matter, but other incidents occur when no contamination is visible. The time, date and location of incidents were linked to local weather data to establish any specific weather conditions that could lead to these events. The effects of precipitation, temperature and humidity on the rail were analysed in order to further the understanding of low adhesion in the wheel-rail contact, which will lead to better methods of mitigating this problem

Theory and numerical modeling of electrical self-potential signatures of unsaturated flow in melting snow

We have developed a new theory and numerical model of electrical self-potential (SP) signals associated with unsaturated flow in melting snow. The model is applicable to continuous natural-melt and transient-flow phenomena such as melt-water pulses, and is tested using laboratory column experiments. SP signals fundamentally depend on the temporal evolution of snow porosity and melt-water flux, electrical conductivity (EC) and pH. We infer a reversal of the sign of the zeta potential (a fundamental electrical property of grain surfaces in porous media), consistent with well-known elution sequences of ions that cause progressive increases and decreases in melt-water pH and EC respectively. Injection of fully-melted snow samples, containing the entire natural range of ions, into melting snow columns caused additional temporary reversals of the sign of the zeta potential. Widely-used empirical relationships between effective saturation, melt-water fraction, EC and pH, as well as snow porosity, grain size and permeability are found to be robust for modelling purposes. Thus, non-intrusive SP measurements can serve as proxies for snow melt-water fluxes and the temporal evolution of fundamental snow textural, hydraulic or water-quality parameters. Adaptation of automated multi-sensor SP acquisition technology from other environmental applications thus promises to bridge the widely acknowledged gap in spatial scale between satellite remote sensing and point measurements of snow properties. SP measurements and modelling may therefore contribute to solving a wide range of problems related to the assessment of water resource availability, avalanche or flood risk, or amplification of climatic forcing of ice-shelf, ice-sheet or glacier dynamics

A chronology of global air quality

Air pollution has been recognized as a threat to human health since the time of Hippocrates, ca 400 BC. Successive written accounts of air pollution occur in different countries through the following two millennia until measurements, from the eighteenth century onwards, show the growing scale of poor air quality in urban centres and close to industry, and the chemical characteristics of the gases and particulate matter. The industrial revolution accelerated both the magnitude of emissions of the primary pollutants and the geographical spread of contributing countries as highly polluted cities became the defining issue, culminating with the great smog of London in 1952. Europe and North America dominated emissions and suffered the majority of adverse effects until the latter decades of the twentieth century, by which time the transboundary issues of acid rain, forest decline and ground-level ozone became the main environmental and political air quality issues. As controls on emissions of sulfur and nitrogen oxides (SO2 and NOx) began to take effect in Europe and North America, emissions in East and South Asia grew strongly and dominated global emissions by the early years of the twenty-first century. The effects of air quality on human health had also returned to the top of the priorities by 2000 as new epidemiological evidence emerged. By this time, extensive networks of surface measurements and satellite remote sensing provided global measurements of both primary and secondary pollutants. Global emissions of SO2 and NOx peaked, respectively, in ca 1990 and 2018 and have since declined to 2020 as a result of widespread emission controls. By contrast, with a lack of actions to abate ammonia, global emissions have continued to grow

Damage Function for Historic Paper: Part II

Background As a result of use of library and archival documents, defined as reading with handling in the context of general access, mechanical degradation (wear and tear) accumulates. In contrast to chemical degradation of paper, the accumulation of wear and tear is less well studied. Previous work explored the threshold of mechanical degradation at which a paper document is no longer considered to be fit for the purpose of use by a reader, while in this paper we explore the rate of accumulation of such damage in the context of object handling. Results The degree of polymerisation (DP) of historic paper of European origin from mid-19th–mid-20th Century was shown to affect the rate of accumulation of wear and tear. While at DP > 800, this accumulation no longer depends on the number of handlings (the process is random), a wear-out function could be developed for documents with DP between 300 and 800. For objects with DP < 300, one large missing piece (i.e. such that contains text) developed on average with each instance of handling, which is why we propose this DP value as a threshold value for safe handling. Conclusions The developed model of accumulation of large missing pieces per number of handlings of a document depending on DP, enables us to calculate the time required for an object to become unfit for use by readers in the context of general access. In the context of the average frequency of document use at The UK National Archives (Kew), this period is 60 years for the category of papers with DP 300, and 450 years for papers with DP 500. At higher DP values, this period of time increases beyond the long-term planning horizon of 500 years, leading to the conclusion that for such papers, accumulation of wear and tear is not a significant collection management concern