Guidance note: risk management of workers with medical electronic devices and metallic implants in electromagnetic fields.

Medical electronic devices and metallic implants are found in an increasing number of workers. Industrial applications requiring intense electromagnetic fields (EMF) are growing and the potential risk of injurious interactions arising from EMF affecting devices or implants needs to be managed. Potential interactions include electromagnetic interference, displacement, and electrostimulation or heating of adjacent tissue, depending on the device or implant and the frequency of the fields. A guidance note, which uses a risk management framework, has been developed to give generic advice in (a) risk identification--implementing procedures to identify workers with implants and to characterise EMF exposure within a workplace; (b) risk assessment--integrating the characteristics of devices, the anatomical localisation of implants, occupational hygiene data, and application of basic physics principles; and (c) risk control--advising the worker and employer regarding safety and any necessary changes to work practices, while observing privacy.     

The impact of the 2004 tsunami on coastal Thai communities: assessing adaptive capacity

The suddenness and scale of the 26 December 2004 tsunami and the challenges posed to affected communities highlighted the benefits of their members having a capacity to confront and adapt to the consequences of such a disaster. Research into adaptive capacity or resilience has been conducted almost exclusively with Western populations. This paper describes an exploratory study of the potential of a measure of collective efficacy developed for Western populations to predict the capacity of members of a collective society, Thai citizens affected by the 2004 tsunami, to confront effectively the recovery demands associated with this disaster. Following a demonstration that this measure could predict adaptive capacity, the role of religious affiliation, ethnicity and place of residence in sustaining collective efficacy is discussed. The implications of the findings for future research on, and intervention to develop, adaptive capacity among Thai citizens in particular and collectivist societies in general are discussed.     

Relating Background NO2 Concentrations in Air to Air Mass History Using Non-Parametric Regression Methods: Application at Two Background Sites in Ireland

The concentration of nitrogen dioxide (NO₂) in background air varies temporally and spatially and is influenced by meteorological and anthropogenic factors. Background concentrations used in local air quality modelling studies have a significant effect on the accuracy of the overall result and when based on short-term monitoring data, variation in concentrations with air mass history is often unaccounted for. The current paper presents a powerful tool for the quantification and separation of local and regional air mass effects on background air quality. The origin of and the regions traversed by an air mass prior to reaching a receptor has been modelled using HYsplit-4. Trajectories (between 12 and 96?h duration) were defined based on the frequency with which they passed into 16 predefined compass quadrants and each represented as a vector. Using this vector as the predictor variable and the background concentration as the response variable, non-parametric regression using a Gaussian kernel function was carried out. A graphical output indicated the trajectory direction of maximum NO₂ concentration, while allowing distinction to be made between spurious and true peaks. In all cases, air mass history was found to have a statistically significant effect on NO₂ concentrations. Incorporating emissions data into the analysis local and regional effects were separated and quantified. It was found that emissions in the UK and Europe have a significant effect on background NO₂ concentrations in Ireland and in some instances supersede domestic emissions. The methods can be used to identify source regions, separate local and regional effects and improve predictions of background concentrations based on limited monitoring data. In particular, the results highlight the importance of considering air mass history when assessing background concentration levels for use in local air quality modelling studies.     

Measuring the effectiveness of landscape approaches to conservation and development

Landscape approaches attempt to achieve balance amongst multiple goals over long time periods and to adapt to changing conditions. We review project reports and the literature on integrated landscape approaches, and found a lack of documented studies of their long-term effectiveness. The combination of multiple and potentially changing goals presents problems for the conventional measures of impact. We propose more critical use of theories of change and measures of process and progress to complement the conventional impact assessments. Theories of change make the links between project deliverables, outputs, outcomes, and impacts explicit, and allow a full exploration of the landscape context. Landscape approaches are long-term engagements, but short-term process metrics are needed to confirm that progress is being made in negotiation of goals, meaningful stakeholder engagement, existence of connections to policy processes, and effectiveness of governance. Long-term impact metrics are needed to assess progress on achieving landscapes that deliver multiple societal benefits, including conservation, production, and livelihood benefits. Generic criteria for process are proposed, but impact metrics will be highly situation specific and must be derived from an effective process and a credible theory of change.     

Future implications of urban intensification on residential water demand

Over recent decades Auckland, New Zealand, metropolitan area has vastly expanded as a result of rapid population growth and low-density housing developments. In order to manage the uncontrolled low-density urban sprawl, Auckland Council proposed a compact city model through promoting higher density housing developments. In order to understand the implications of this transition on future residential water demand, this study first evaluated water consumption in three major housing types in Auckland including single houses, low-rise and high-rise apartments. Using the geographic information system, the water consumption information, estimated from a large sample of 60,000 dwellings across Auckland, was subsequently integrated with the Proposed Auckland Unitary Plan outlining the future housing composition over different areas in Auckland. Through developing different growth scenarios, the study showed that the housing transition from single houses to more intensified multi-unit houses cannot considerably affect the average per capita water consumption in Auckland.     

Validation of Three New Methods for Determination of Metal Emissions Using a Modified Environmental Protection Agency Method 301

Abstract

Three new methods applicable to the determination of hazardous metal concentrations in stationary source emissions were developed and evaluated for use in U.S. Environmental Protection Agency (EPA) compliance applications. Two of the three independent methods, a continuous emissions monitor-based method (Xact) and an X-ray-based filter method (XFM), are used to measure metal emissions. The third method involves a quantitative aerosol generator (QAG), which produces a reference aerosol used to evaluate the measurement methods. A modification of EPA Method 301 was used to validate the three methods for As, Cd, Cr, Pb, and Hg, representing three hazardous waste combustor Maximum Achievable Control Technology (MACT) metal categories (low volatile, semivolatile, and volatile). The modified procedure tested the methods using more stringent criteria than EPA Method 301; these criteria included accuracy, precision, and linearity. The aerosol generation method was evaluated in the laboratory by comparing actual with theoretical aerosol concentrations. The measurement methods were evaluated at a hazardous waste combustor (HWC) by comparing measured with reference aerosol concentrations. The QAG, Xact, and XFM met the modified Method 301 validation criteria. All three of the methods demonstrated precisions and accuracies on the order of 5%. In addition, correlation coefficients for each method were on the order of 0.99, confirming the methods’ linear response and high precision over a wide range of concentrations. The measurement methods should be applicable to emissions from a wide range of sources, and the reference aerosol generator should be applicable to additional analytes. EPA recently approved an alternative monitoring petition for an HWC at Eli Lilly’s Tippecanoe site in Lafayette, IN, in which the Xact is used for demonstrating compliance with the HWC MACT metal emissions (low volatile, semivolatile, and volatile). The QAG reference aerosol generator was approved as a method for providing a quantitative reference aerosol, which is required for certification and continuing quality assurance of the Xact.     

A Comparative Study of Particulate Loadings in Plumes Using Multiple Sampling Devices

Particle size distributions, particulate concentrations, and particle identities must be known to relate effluents to reduction in visibility and soiling. Similar types of emissions were measured with cascade impactor, membrane filter, and rotorod samplers. The different particle size distributions, concentrations, and identifications are reported. Discussion of and recommendations for utilization of these three methods of sampling are made.     

The Survival of Airborne Serratia marcescens in Urban Concentrations of Sulfur Dioxide

Aerosols of Serratia marcescens ATCC 274 were suspended in a 709L rotating drum at 20 ± 1 °C and high to mid-range relative humidities. At specified times after bacterial aerosolization, sulfur dioxide was added to concentrations of 2.5, or 5 mg/m³. Viable cell decay rate constants, in control aerosols without added sulfur dioxide, increased rapidly from near 100% to 60% RH in the first hour (termed: young aerosol) of suspension, and from a minimum rate constant at 80% in the succeeding four hours (termed: old aerosol).Upon addition of sulfur dioxide to a cloud of S. marcescens, generally, viable cell decay rate constants increased further. One exception was at 80% relative humidity where maximum resistance to SO₂ accelerated death was observed for old aerosols. Cells in young aerosols were particularly sensitive to SO₂ addition at mid-range humidities, while in older aerosols the cells were insensitive to up to 5 mg SO₂/m³ introduced at high RH; but were up to 10 times more sensitive than cells in young aerosols to a given increase (from 2.5 to 5 mg/m³) in SO₂ concentration at mid-range humidities.     

Combustion-derived substances in deep basins of Puget Sound: historical inputs from fossil fuel and biomass combustion

Reconstructions of 250 years historical inputs of two distinct types of black carbon (soot/graphitic black carbon (GBC) and char-BC) were conducted on sediment cores from two basins of the Puget Sound, WA. Signatures of polycyclic aromatic hydrocarbons (PAHs) were also used to support the historical reconstructions of BC to this system. Down-core maxima in GBC and combustion-derived PAHs occurred in the 1940s in the cores from the Puget Sound Main Basin, whereas in Hood Canal such peak was observed in the 1970s, showing basin-specific differences in inputs of combustion byproducts. This system showed relatively higher inputs from softwood combustion than the northeastern U.S. The historical variations in char-BC concentrations were consistent with shifts in climate indices, suggesting an influence of climate oscillations on wildfire events. Environmental loading of combustion byproducts thus appears as a complex function of urbanization, fuel usage, combustion technology, environmental policies, and climate conditions.     

一种改进的多学习教与学优化算法

针对传统教与学算法在解决复杂多峰函数优化问题时,具有局部最优且搜索开发能力较差的缺点,提出了一种改进的多学习教与学优化算法,新算法为学员的每一维加入不同的教学因子,设计了基于学员均值比较的教师选择策略和向教师及学员学习的多学习策略。基于多个单峰和多峰函数的仿真结果表明,新算法跟传统的、改进的教与学算法相比,在稳定性、寻优精度和收敛速度方面更具优势。