Indoor Atmosphere Research Articles

Measurement of radon and thoron levels in soil, water and indoor atmosphere of Budhakedar in Garhwal Himalaya, India

Environmental radiation exists as a consequence of cosmic, terrestrial and man made sources. Terrestrial radiation are emitted from natural radionuclide present in varying amounts in all types of soils, rocks, air, water and other environmental materials; radon is emitted from the soil surface, although secondary contributors include the oceans, natural gas, geothermal fluids, volcanic gases, ventilation from caves and mines, and combustion of coal. Radon and thoron levels were measured in soil-gas, ground water and indoor air in Budhakedar area of Tehri Garhwal, India. Radon concentrations in soil and groundwater of the Budhakedar area were found to vary from 1.10 ± 0.29 to 31.8 ± 1.6 kBq / m 3 with an average value 7.46 ± 0.69 kBq / m 3 and 8 ± 1 Bq / l to 3.05 ± 0.02 kBq / l with mean value 0.51 ± 0.01 kBq / l , respectively. Measurement of indoor radon, thoron and their daughter products were also measured in the houses of the same area for four different seasons (autumn, winter, summer and rainy) using LR–115 plastic track detectors. The detector is fixed in a twin chamber radon dosimeter, which can record the values of radon, thoron and their decay products separately. The film fixed in bare mode holder gives the concentrations of radon, thoron and their progeny while the films fixed inside the cup with filter and membrane modes give the concentrations of radon/thoron gases and of pure radon gas, respectively. Detailed analysis of the effects of seasonal variation on radon, thoron and their decay products inside the houses are reported in this paper.

The Airborne Metagenome in an Indoor Urban Environment

The indoor atmosphere is an ecological unit that impacts on public health. To investigate the composition of organisms in this space, we applied culture-independent approaches to microbes harvested from the air of two densely populated urban buildings, from which we analyzed 80 megabases genomic DNA sequence and 6000 16S rDNA clones. The air microbiota is primarily bacteria, including potential opportunistic pathogens commonly isolated from human-inhabited environments such as hospitals, but none of the data contain matches to virulent pathogens or bioterror agents. Comparison of air samples with each other and nearby environments suggested that the indoor air microbes are not random transients from surrounding outdoor environments, but rather originate from indoor niches. Sequence annotation by gene function revealed specific adaptive capabilities enriched in the air environment, including genes potentially involved in resistance to desiccation and oxidative damage. This baseline index of air microbiota will be valuable for improving designs of surveillance for natural or man-made release of virulent pathogens.

Effect of Aging on the Physico Chemical Properties of Glass Fiber under Different Environmental Conditions

AbstractGlass fibers were characterized for physical and chemical changes before and after subjecting to aging under different environmental conditions. The conditions selected were: low temperature, outdoor atmosphere, indoor atmosphere, chemical environment, 95% humidity & water soaking treatment. The results show that glass fiber is a good candidate to resist sunlight, corrosive atmosphere, low temperature and shady atmosphere. The influence of prolonged time exposure to water caused a detrimental effect on the properties of the glass fiber. Hence, prolonged exposure to water should be avoided for the integrity of the glass fiber under study.

Comparison of a gas chromatography-optical fibre (GC-OF) detector with a gas chromatography-flame ionization detector (GC-FID) for determination of alcoholic compounds in industrial atmospheres

An analytical methodology based on an optical fibre detector coupled to gas chromatograph has been developed for the speciation of some volatile alcoholic compounds. This methodology combines the separation capability of gas chromatography with an optical fibre detector made of an optical fibre sensitized with a thin polymeric film of poly[methyl(3,3,3-trifluoropropyl)siloxane] (PMTFPS). The response of the detector has been characterized at 650 nm for nine different alcohols (allyl alcohol, n-propyl alcohol, sec-butyl alcohol, isobutyl alcohol, n-butyl alcohol, isoamyl alcohol, methyl isobutyl carbinol, cyclohexanol and diacetone alcohol). An alternative method based on gas chromatography-flame ionization detector (GC-FID) was also used in order to evaluated the performance and compare the analytical results with the proposed method. The time of analysis, the analytical error and the analytical performance were similar for both methods. However, the analytical apparatus based on the GC-OF detector is much less expensive than the GC-FID and show high accuracy and suitability for actual monitoring on indoor atmospheres.

Computational fluid dynamics (CFD) modelling applied to the ripening of fermented food products: Basics and advances

With reference to numerical studies conducted in ripening rooms over the last 15 years, we present basics and advances concerning the ripening of fermented food products and the application thereto of CFD modelling of airflow and indoor atmosphere patterns. CFD developments based on the programming of specific user-defined functions are also described; they are designed (i) to implement the “mean age of air” concept as an alternative criterion to mean air velocity for characterising ventilation effectiveness and (ii) to accurately predict heat and water transfers of unwrapped food products subjected to a turbulent airflow.

Phthalates: Toxicology and exposure

Phthalates are used as plasticizers in PVC plastics. As the phthalate plasticizers are not chemically bound to PVC, they can leach, migrate or evaporate into indoor air and atmosphere, foodstuff, other materials, etc. Consumer products containing phthalates can result in human exposure through direct contact and use, indirectly through leaching into other products, or general environmental contamination. Humans are exposed through ingestion, inhalation, and dermal exposure during their whole lifetime, including intrauterine development. This paper presents an overview on current risk assessments done by expert panels as well as on exposure assessment data, based on ambient and on current human biomonitoring results. Some phthalates are reproductive and developmental toxicants in animals and suspected endocrine disruptors in humans. Exposure assessment via modelling ambient data give hints that the exposure of children to phthalates exceeds that in adults. Current human biomonitoring data prove that the tolerable intake of children is exceeded to a considerable degree, in some instances up to 20-fold. Very high exposures to phthalates can occur via medical treatment, i.e. via use of medical devices containing DEHP or medicaments containing DBP phthalate in their coating. Because of their chemical properties exposure to phthalates does not result in bioaccumulation. However, health concern is raised regarding the developmental and/or reproductive toxicity of phthalates, even in environmental concentrations.

Corrosión atmosférica del zinc en ambientes exteriores e interiores

Good behaviour of zinc against atmospheric corrosion has leaded this material to be widely used, mainly for protection of steel. For this reason since approximately 50 years it have been making systematic studies in order to understand the mechanisms of its interaction with the atmosphere and nowadays it continues being object of intensive research. In this paper a review of the state-of-the-art in the knowledge of atmospheric corrosion of zinc is presented, when it is exposed in both outdoor and indoor atmospheres.

투과체에 적용된 채광방식이 사무소공간의 색도 및 색온도분포에 미치는 영향 분석

One basic function of glazing system has always been the maintenance of visual contact with the natural environment-a fundamentally ecological function. In addition, penetration light through glazing system have an effect on variable atmosphere of interior. In this study, a typical office space was selected as a evaluation model and a 1/10 scale model was made. The conventional window, differentiated window and interior lightshelf were designed to enhance daylighting performance. The chromaticity and color temperature of interior space was measured using Prometric 1421. The result showed that transmittance by wavelength range of the glazing had an effect on chromaticity and color temperature. Also, color temperature of indoor environment were increased by using differentiated window and interior lightshelf. Accordingly, it is thought that the use of a daylighting system will create activate indoor atmosphere.

Application of Passive Samplers in Monitoring of Organic Constituents of Air

The principles of passive dosimetry, which has been known for over 100 years, are finding an ever increasing use in analytical practice and are being used as a convenient technique for isolation and enrichment of analytes from various environmental media. Due to its simplicity, a variety of designs, as well as the possibility of using a number of different final determination techniques, passive dosimetry has been applied in the analysis of organic and inorganic air pollutants, both in the outdoor and the indoor and workplace atmospheres, as well as in the monitoring of water and soil pollution. This paper is an attempt to review the designs of existing passive samplers, the media used to trap analytes and the techniques used for the release of the trapped analytes and their final determination.

Environmental radon studies in Mexico

Radon has been determined in soil, groundwater, and air in Mexico, both indoors and outdoors, as part of geophysical studies and to estimate effective doses as a result of radon exposure. Detection of radon has mainly been performed with solid-state nuclear track detectors (SSNTD) and, occasionally, with active detection devices based on silicon detectors or ionization chambers. The liquid scintillation technique, also, has been used for determination of radon in groundwater. The adjusted geometric mean indoor radon concentration (74 Bq m-3) in urban developments, for example Mexico City, is higher than the worldwide median concentration of radon in dwellings. In some regions, particularly hilly regions of Mexico where air pollution is high, radon concentrations are higher than action levels and the effective dose for the general population has increased. Higher soil radon levels have been found in the uranium mining areas in the northern part of the country. Groundwater radon levels are, in general, low. Soil-air radon contributing to indoor atmospheres and air pollution is the main source of increased exposure of the population.

Sampling and Analysis of Quaternary Ammonium Compounds (QACs) Traces in Indoor Atmosphere

Quaternary Ammonium Compounds (QACs) are widely found in disinfectants used in hospitals. Benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC) predominate in the disinfecting formulations. These compounds are strong irritants and can play a role in the induction of Occupational Asthma among the professionals of health and cleaning. In order to evaluate the potential health effect of these quaternary ammonium compounds to hospital employers, the development of an analytical method for their quantification in indoor air was developed. DDAC aerosols are trapped by adsorption on XAD-2 resin SKC tube. The air in hospital buildings was sampled using a constant debit Gillian pump at a flow of 1.0 l/min (+/-5%). Ion Chromatography (IC) was chosen for the analysis of DDAC especially for its high sensitivity and specificity. The Limit of Detection (LOD) by IC for DDAC is 0.56 mug/ml. Therefore the LOD of atmospheric DDAC is 28 microg/m(3) with an air volume of 100 l and a desorption volume of 5 ml. All DDAC air samples were lower than the LOD of the analytical method by IC. Under the standard conditions of use of the disinfecting solutions (Surfanios, Ampholysine Plus and Amphospray 41), the insignificant volatility of DDAC would not seem to be able to contaminate the indoor hospital atmosphere during the disinfection process. However, the DDAC can contaminate working atmospheres if it is put in suspension by aerosolisation.

Indoor microclimate, ozone and nitrogen oxides in two medieval churches in Cyprus

A number of indoor atmosphere parameters that may affect the preservation of artefacts in two churches in Cyprus, were studied. Temperature, relative humidity (RH), total ultra-violet and total solar radiation, that were continuously recorded during two campaigns (summer and winter), exhibited large diurnal and seasonal variations. Indoor concentrations of nitrogen oxides, determined at the same periods, also exhibited diurnal dependence on air exchange rate (AER) and on their indoor sources from the burning of candles and oil lamps. Indoor concentrations of ozone exhibited dependence on the AER and on the concentration of other indoor pollutants. On a large number of occasions these concentrations exceeded the proposed air quality standards for the preservation of works of art in both churches.

Raman imaging of ancient rust scales on archaeological iron artefacts for long‐term atmospheric corrosion mechanisms study

AbstractIron archaeological artefacts were studied to understand long‐term corrosion by the atmosphere. Indeed, these samples collected on the construction elements of ancient monuments present ancient rust layers formed during their exposure over centuries to the indoor atmosphere. Thanks to Raman spectroscopy and the acquisition of hyperspectral images of the corrosion scales, several zones of the samples observed on cross sections could be characterised. It has been shown on six dated samples that the main phase is goethite (α‐FeOOH). Lepidocrocite and akaganeite (γ‐FeOOH and β‐FeOOH) occur locally in the corroded products, often correlated with cracks. A less crystallised phase, a hydrated oxy‐hydroxide, has been identified abundantly in more or less extended zones inside the layer. This phase could play an important role in atmospheric corrosion mechanisms. Copyright © 2006 John Wiley & Sons, Ltd.

Formaldehyde measurements in libraries: Comparison between infrared diode laser spectroscopy and a DNPH-derivatization method

Formaldehyde concentrations have been measured in the university libraries in Strasbourg (east of France). Infrared diode laser spectroscopy and a conventional DNPH-derivatization method followed by liquid chromatography coupled to UV detection have been used simultaneously for comparison purposes. The formaldehyde concentrations obtained by both the techniques were always in excellent agreement, showing that the infrared diode laser spectroscopy can be used for formaldehyde monitoring in indoor atmosphere, with a time resolution of few minutes. Formaldehyde concentrations were generally found to be in the range 8–33 μg m −3, except for two libraries where concentrations of 82 and 105 μg m −3 have been measured. Using the results obtained by both techniques, the resulting mean formaldehyde level in the investigated libraries was then 33.5±31.2 μg m −3, where the quoted error correspond to the standard deviation. Acetaldehyde and hexanal levels have also been quantified by duplicated measurements in the same libraries by the DNHP-derivatization method. They ranged from 0.0 to 11.3 μg m −3 for acetaldehyde and from 1.0 to 16.7 μg m −3 for hexanal and their mean values were found to be 2.1±3.2 μg m −3 (acetaldehyde) and 4.0±4.4 μg m −3 (hexanal), where the quoted errors correspond to the standard deviation.

Effects of an ozone-generating air purifier on indoor secondary particles in three residential dwellings

The use of indoor ozone generators as air purifiers has steadily increased over the past decade. Many ozone generators are marketed to consumers for their ability to eliminate odors and microbial agents and to improve health. In addition to the harmful effects of ozone, recent studies have shown that heterogeneous and homogeneous reactions between ozone and some unsaturated hydrocarbons can be an important source of indoor secondary pollutants, including free radicals, carbonyls, carboxylic acids, and fine particles. Experiments were conducted in one apartment and two detached single-family dwellings in Austin, TX, to assess the effects of an ozone generator on indoor secondary organic aerosol concentrations in actual residential settings. Ozone was generated using a commercial ozone generator marketed as an air purifier, and particle measurements were recorded before, during, and after the release of terpenes from a pine oil-based cleaning product. Particle number concentration, ozone concentration, and air exchange rate were measured during each experiment. Particle number and mass concentrations increased when both terpenes and ozone were present at elevated levels. Experimental results indicate that ozone generators in the presence of terpene sources facilitate the growth of indoor fine particles in residential indoor atmospheres. Human exposure to secondary organic particles can be reduced by minimizing the intentional release of ozone, particularly in the presence of terpene sources. Past studies have shown that ozone-initiated indoor chemistry can lead to elevated concentrations of fine particulate matter, but have generally been completed in controlled laboratory environments and office buildings. We explored the effects of an explicit ozone generator marketed as an air purifier on the formation of secondary organic aerosol mass in actual residential indoor settings. Results indicate significant increases in number and mass concentrations for particles <0.7 microns in diameter, particularly when an ozone generator is used in the presence of a terpene source such as a pine oil-based cleaner. These results add evidence to the potentially harmful effects of ozone generation in residential environments.

An extensive indoor 222Rn/ 220Rn monitoring in North-East India

The behaviour of ubiquitous radon ( Rn 222 ), thoron ( Rn 220 ) and their progeny in the indoor atmosphere generally reflect a complex interplay between a number of processes, the most important of which are radioactive α -decay, ventilation, attachment to aerosols and deposition on the surfaces. The present work involved a long-term (1997–2000) passive monitoring of Rn 222 and Rn 220 in the indoor environment of the North-Eastern region of India. This region being a zone of high seismicity, the indoor radon and thoron measurement of the region will provide a better insight and a valuable database for any study related to radon and thoron anomalies.

Study on Tritium Removal Performance by Gas Separation Membrane with Reflux Flow for Tritium Removal System of Fusion Reactor

Addition of gas separation membrane process into the usual tritium removal process from an indoor atmosphere is attractive for a fusion plant, where a large amount of atmosphere should be processed. As a manner to improve the partial pressure difference between feed and permeated side, intended reflux of vapor and the hydrogen concentrated at permeated side is conceived to enlarge the partial pressure difference. Membrane separation with reflux flow has been proposed as an attractive process to enhance the recovery ratio of tritium component. Effect of reflux on the recovery ratio of tritium component was evaluated by numerical analysis. The effect of reflux on separation performance becomes striking as the target species have higher permeability coefficients. Hence, the gas separation by membrane with reflux flow is favorable for tritium recovery.

Mercury Vapor Determination in Hospitals

The measurements of metallic mercury vapor were carried out in seven local hospitals, where mercury-containing products are widely used, as well as in one residence to check effectiveness of decontamination after mercury spillage. Hopcalite as a solid sorbent was used in active and passive sampling methods, and mercury was analyzed by CV-AAS technique. Good agreement was found between results of mercury measurements using active samplers (pumped hopcalite adsorption tubes) and passive (diffusion) monitors applied in indoor atmosphere. The results indicated the presence of metallic mercury vaporization sources in the assessed hospital rooms but in the majority of cases mercury levels did not exceed 1 microg/m3 i.e. Polish permissible concentration for residence. However, in some of the hospital rooms, elevated concentrations of mercury vapor were found and airborne levels of up to 13.9 microg/m3 were recorded. Higher concentrations of mercury vapor were observed in autumn season when compared to summer.

Indoor atmosphere hazard identification in person entry urban utility tunnels

Urban underground space is a finite and non-renewable resource. Sustainable use of valuable shallow subsurface space requires the wide use of utility tunnels. However, traditional trenching has been adopted in many projects arguing utilidors present atmosphere hazards related to any multipurpose confined space. Utility tunnel operational risks might seem discouraging at first, but urban planning for an underground sustainable future needs these efficient facilities. The aim of this work is to characterize utilidor indoor atmosphere hazards to show how these risks could be minimised, in order to guarantee a better standard of safety and health protection.

A Study on Seasonal Variations of Indoor Gamma Dose in Bangladesh

Monthly variation of gamma dose rate measured in indoor air of buildings of Bangladesh was found to vary cosinusoidally through a period of 1 year. Significant seasonal variations were observed. Maximum dose rate, however, was observed in January and a minimum in July. Dose rate in January was 32% higher than the annual average, whereas dose rate in July was 50% lower. Seasonally varied ventilation and air exchange rates of the houses might play an important role in the observed variation. The average reduction with respect to winter dose was 59% in summer. Because of lower ventilation and air exchange rates between indoor and outdoor atmosphere, it is expected that the indoor dose rate would be higher in basements than that of upper floors. Monthly dose rate was also found to be influenced by the meteorological conditions. Correlations between dose rate and temperature (r2=0.85), rainfall (r=-0.83) and atmospheric pressure (r=0.92) were obtained, but no significant correlation (r=-0.45) was seen between dose rate and humidity. The results show that the seasonal variations of indoor dose rates should be taken into account to estimate annual effective dose equivalent.