1,721,585 research outputs found
Ultrafine particle emission of waste incinerators and comparison to the exposure of urban citizens
No full textOn the basis of the growing interest on the impact of airborne particles on human exposure as well as the strong debate in Western countries on the emissions of waste incinerators, this work reviewed existing literature to:\ud
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(i) show the emission factors of ultrafine particles (particles with a diameter less than 100 nm) of waste incinerators, and; \ud
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(ii) assess the contribution of waste incinerators in terms of ultrafine particles to exposure and dose of people living in the surrounding areas of the plants in order to estimate eventual risks. \ud
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The review identified only a limited number of studies measuring ultrafine particle emissions, and in general they report low particle number concentrations at the stack (the median value was equal to 5.5×103 part cm-3), in most cases higher than the outdoor background value. The lowest emissions were achieved by utilization of the bag-house filter which has an overall number-based filtration efficiency higher than 99%. Referring to reference case, the corresponding emission factor is equal to 9.1×1012 part min-1, that is lower than one single high-duty vehicle. Since the higher particle number concentrations found in the most contributing microenvironments to the exposure (indoor home, transportation, urban outdoor), the contribution of the waste incinerators to the daily dose can be considered as negligible
Health effects of daily airborne particle dose in children : direct association between personal dose and respiratory health effects
No full textAir pollution is a widespread health problem associated with respiratory symptoms. Continuous exposure monitoring was performed to estimate alveolar and tracheobronchial dose, measured as deposited surface area, for 103 children and to evaluate the long-term effects of exposure to airborne particles through spirometry, skin prick tests and measurement of exhaled nitric oxide (eNO). The mean daily alveolar deposited surface area dose received by children was 1.35×103 mm2. The lowest and highest particle number concentrations were found during sleeping and eating time. A significant negative association was found between changes in pulmonary function tests and individual dose estimates. Significant differences were found for asthmatics, children with allergic rhinitis and sensitive to allergens compared to healthy subjects for eNO. Variation is a child’s activity over time appeared to have a strong impact on respiratory outcomes, which indicates that personal monitoring is vital for assessing the expected health effects of exposure to particles
Characterization of particle emission from laser printers
No full text<b>Highlights</b>\ud
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- 110 laser printers from 7 manufacturers were analyzed in an experimental chamber.\ud
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- Particle number and mass concentrations, and size distributions, were measured.\ud
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- Emission rates for all the printers were calculated under fixed operational conditions.\ud
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- Daily surface area dose received by employees was estimated from emission rates.\ud
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- Relatively low total surface area dose (2.7 mm<sup>2</sup>) was estimated for office employees.\ud
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<b>Abstract</b>\ud
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Emission of particles from laser printers in office environments is claimed to have impact on human health due to likelihood of exposure to high particle concentrations in such indoor environments. In the present paper, particle emission characteristics of 110 laser printers from different manufacturers were analyzed, and estimations of their emission rates were made on the basis of measurements of total concentrations of particles emitted by the printers placed in a chamber, as well as particle size distributions. The emission rates in terms of number, surface area and mass were found to be within the ranges from 3.39×10<sup>8</sup> part. min<sup>-1</sup> to 1.61×10<sup>12</sup> part. min<sup>-1</sup>, 1.06×10<sup>0</sup> mm<sup>2</sup> min<sup>-1</sup> to 1.46×10<sup>3</sup> mm<sup>2</sup> min<sup>-1</sup> and 1.32×10<sup>-1</sup> µg min<sup>-1</sup> to 1.23×10<sup>2</sup> µg min<sup>-1</sup>, respectively, while the median mode value of the emitted particles was found equal to 34 nm.\ud
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In addition, the effect of laser printing emissions in terms of employees’ exposure in offices was evaluated on the basis of the emission rates, by calculating the daily surface area doses (as sum of alveolar and tracheobronchial deposition fraction) received assuming a typical printing scenario. In such typical printing conditions, a relatively low total surface area dose (2.7 mm<sup>2</sup>) was estimated for office employees with respect to other indoor microenvironments including both workplaces and homes. Nonetheless, for severe exposure conditions, characterized by operating parameters falling beyond the typical values (i.e. smaller office, lower ventilation, printer located on the desk, closer to the person, higher printing frequency etc.), significantly higher doses are expected
Adverse health effects to air pollution and guidelines to prevent them
No full textThis is the first in a series of four articles which will explore different aspects of air pollution,\ud
its impact on health and challenges in defining the boundaries between impact and nonimpact\ud
on health. Hardly a new topic one might say. Indeed, it’s been an issue for centuries,\ud
millennia even! For example, Pliny the Elder (AD 23-79), a Roman officer and author of the\ud
‘Natural History’ recommended that: “…quarry slaves from asbestos mines not be purchased\ud
because they die young”, and suggested: “…the use of a respirator, made of transparent\ud
bladder skin, to protect workers from asbestos dust.” Closer to modern times, a Danish\ud
Proverb states: "Fresh air impoverishes the doctor". While none of these statements are an air\ud
quality guideline in a modern sense, they do illustrate that, for a very long time, we have\ud
known that there is a link between air quality and health, and that some measures were taken\ud
to reduce the impact of the exposure to the pollutants. Obviously, we are much more\ud
sophisticated now
Air quality and its impact on health: focus on particulate matter
No full textInadequate air quality and the inhalation of airborne pollutants pose many risks to human health and wellbeing, and are listed among the top environmental risks worldwide. The importance of outdoor air quality was recognised in the 1950s and indoor air quality emerged as an issue some time later and was soon recognised as having an equal, if not greater importance than outdoor air quality. Identification of ambient air pollution as a health hazard was followed by steps, undertaken by a broad range of national and international professional and government organisations, aimed at reduction or elimination of the hazard. However, the process of achieving better air quality is still in progress. The last 10 years or so have seen an unprecedented increase in the interest in, and attention to, airborne particles, with a special focus on their finer size fractions, including ultrafine (< 0.1 m) and their subset, nano particles (< 0.05 m). This paper discusses the current status of scientific knowledge on the links between air quality and health, with a particular focus on airborne particulate matter, and the directions taken by national and international bodies to improve air quality
Measurement of Airborne Particles
No full textAbstract only:\ud
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This chapter examines instrumental methods for the determination of particle physical properties. The main properties which are considered include particle mass and number concentrations, number and mass size distribution, and to a lesser extent, particle surface area. \ud
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Some of the methods discussed require sample collection on a medium, for further analyses and determination of the property under investigation. An example of this is the collection of particles on a filter, from the sampled airflow, for further gravimetric determination of particle mass or chemical composition. In cases like this only the mechanisms and instrumentation for capturing the particles are discussed, not the further analytical methods for microscopic, gravimetric, chemical or biological analyses. Methods for chemical and biological characterization of particles are discussed in more detail in chapters 3.1 and 2.4. \ud
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Many of the methods available for characterization of particle physical properties yield real-time data and do not require capture of the analyzed particles. Such methods are particularly desirable for indoor investigations as they usually enable shorter measurement times and provide information relating to time variation of the properties investigated. \ud
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However, a shortcoming of some of these methods is that they do not directly measure the property of interest, but recalculate its value based on another measured property. For example, an optical instrument does not measure particle mass, and if the reading of the instrument indicates mg m-3, without previous calibration of the instrument for the specific measured aerosol, the quantity measured must be regarded as a very crude approximation. \ud
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To ensure the proper application of instruments and to avoid misinterpretation of the results it is thus important to understand the principles of operation of the instruments used for particle characterization; their advantages and shortcomings for specific applications; as well as the properties which are measured directly and those which are determined indirectly, . \ud
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This chapter briefly discusses principles of operation of the most common methods for characterization of particle physical properties and provides an overview of measurement \ud
devices and methods and their features, for indoor measurements
Program and knowledge transfer in teaching indoor air science
No full textThe focus of this paper is the universality of teaching and training in the area of science of indoor air quality and the practice of indoor air quality management. The key questions, which the paper addresses, are: (i) how universal are approaches to teaching and training in the area of science and practice of indoor air quality, and (ii) is it possible, practical or desirable to transfer training or university degree programs from one geographical, cultural or economical reality to another? The paper is an attempt to answer the two questions from the broad perspective of linking parallels between teaching in indoor air sciences and teaching in an interdisciplinary area in general, and also from the perspective of personal experience from university and training course teaching in various places in the world. The conclusion drawn is that transfer of knowledge and technology in teaching in the area of indoor air sciences is possible and desirable. The success of program transfer depends on the understanding of the philosophy of teaching in this area as well as on understanding local needs requirements and limitations
Elemental characterisation and detection of heavy metals in house dusts collected from sites in South-East Queensland, Australia
No full textKnowledge of the elements present in house dusts is important in understanding potential health effects on humans. In this study, dust samples collected from 10 houses in south-east Queensland have been analysed by scanning electron microscopy and X-ray microanalysis to measure the inorganic element compositions and to investigate the form of heavy metals in the dusts. The overall analytical results were then used to discriminate between different localities using chemometric techniques. The relative amounts of elements, particularly of Si, Ca, and Fe, varied between size fractions and between different locations for the same size fraction. By analysing individual small particles, many other constituents were identified including Ti, Cr, Mn, Ni, Cu, Zn, Ba, Ag, W, Au, Hg, Pb, Bi, La and Ce. The heavy metals were mostly concentrated in small particles in the smaller size fractions, which allowed detection by particle analysis, though their average concentrations were very low
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