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Air Samples (air + sample)
Selected AbstractsEmission of legacy chlorinated pesticides from agricultural and orchard soils in British Columbia, CanadaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2006Terry F. Bidleman Abstract Air samples were collected above agricultural fields in the Fraser Valley and orchards in the Okanagan Valley, British Columbia, Canada, to investigate volatilization of organochlorine pesticides used in the past. Concentrations of pesticides in air were elevated over soils that contained higher residues. Soil/air fugacity ratios at sites with the higher soil residues were calculated relative to air sampled at 40 cm height and background air. The fugacity ratios in the first case indicated net volatilization or soil-air equilibrium for most compounds and occasional net deposition for p,p, -dichlorodiphenyldichloroethene (p,p, -DDE), whereas those in the second case showed a strong potential for net volatilization of all compounds. The enantiomer fraction (EF) of chiral compounds ,-hexachlorocyclohexane (,-HCH), trans -chlordane, cis -chlordane, and o,p, -DDT were determined in overlying air samples and soils. Enantiomer fractions in air corresponded to those in soils at fields in which soil concentrations were high but were decoupled from soil signatures at fields with low soil residues. Mean EFs in air sampled over soils were significantly (p < 0.001) nonracemic for ,-HCH and the chlordanes and agreed with published EFs in regional ambient air. The mean EF of o,p, -DDT for all air samples did not show a significant deviation from racemic EFs (p > 0.2), but EFs of individual samples reflected the ambivalent nature of o,p, -DDT degradation, sometimes preferring the (+) enantiomer and other times the (,) enantiomer. The study indicates that soils are continuing to emit "legacy" pesticides into the regional atmosphere. [source] Characterization and Variability of Endotoxin and 3-Hydroxy Fatty Acids in an Office Building During a Particle Intervention StudyINDOOR AIR, Issue 1 2000Cynthia J. Hines Abstract Air and dust samples were collected on two floors of an office building during a double-blind particle intervention study to examine spatial and temporal variability of airborne endotoxin over a period of weeks, and to characterize endotoxin activity and lipopolysaccharide (LPS) content in carpet and chair dust. Air samples were collected on multiple days within and across weeks. Dust samples were collected from carpets and chairs one day per week for three weeks. Endotoxin was measured using a Limulus assay. Dust samples were analyzed for LPS by determination of 3-hydroxy fatty acids (3-OHFAs) using gas chromatography-mass spectrometry. The geometric mean (geometric standard deviation) for 96 indoor air samples was 0.24 (1.6) EU/m3. Significant within-floor spatial variation of airborne endotoxin was found (P<0.0001, n=80). Temporal variability of airborne endotoxin was not significant across weeks. Mean (±SD) endotoxin levels in carpet dust (59±9.3 EU/mg dust, n=12) and in chair dust (38±7.7 EU/mg dust, n=10) were significantly different (P<0.001). Carbon chain length-dependent differences in 3-OHFA levels by dust source and floor were found. Enhanced air filtration did not significantly affect airborne endotoxin (P=0.62); however, total dust mass and total endotoxin in carpet dust samples increased significantly after enhanced surface cleaning (P<0.01). These findings suggest that spatial variability, dust source, and surface cleaning may influence building occupant exposures to endotoxin., [source] Determination of aerial microbiological contamination in scholastic sports environmentsJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2003C. Dacarro Abstract Aims: To assess the microbiological indoor air quality (IAQ) of high school and college gyms during physical training lessons and to evaluate the effective microbiological exposure of students. Methods and Results: Air samples from 11 high school and college gyms of Pavia, Italy were collected. Total bacterial counts, total fungal counts and characterization of fungal taxa were determined. Air quality was evaluated using three microbiological contamination indices: the global index of microbiological contamination per m3 (GIMC per m3), the index of mesophilic bacterial contamination (IMC) and the amplification index (AI). Conclusions: This work testifies that air contamination in indoor gyms is always superior to that of the outdoor environment. Nevertheless, students are exposed to relatively low concentrations of airborne micro-organisms. The highest values of fungal counts and GIMC per m3 (>14 661) were observed between April and October when the central heating systems were switched off. The lowest fungal counts were detected in modern buildings equipped with forced ventilation systems. From qualitative aeromycological studies, 45 fungal taxa were identified, and different potentially allergenic species were isolated. Significance and Impact of the Study: The standardization of air sampling methods and the correct evaluation of aeromicrobiological results allow the classification of indoor air healthiness. The proposed microbiological contamination indices together with the characterization of airborne fungal taxa are useful tools for detailed description of IAQ. [source] Pressurised liquid extraction of polycyclic aromatic hydrocarbons from gas and particulate phases of atmospheric samplesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 7 2009Maria Rosa Ras Abstract Pressurised liquid extraction (PLE) was applied to determine the atmospheric levels of 16 polycyclic aromatic hydrocarbons (PAHs) in the gas and particulate phases. The method involved high-volume air sampling with quartz fibre filters (QFFs) and polyurethane foam (PUF) plugs and analytes were subsequently extracted from the samples by PLE, and determined with GC-MS. We optimised the PLE conditions for the solvent, the number of cycles and extraction temperature. Recoveries were higher than 90% for most compounds. Method LODs and LOQs were between 0.001 and 0.02 ng/m3 and between 0.01 and 0.05 ng/m3. Air samples were taken from a site in the region of Tarragona in Catalonia, Spain, where one of the largest petrochemical complexes in southern Europe is located. The total concentration of PAHs were from 6.7 to 27.66 ng/m3, with predominant levels of PAHs appearing in the gas phase (48,81%), and an average level of benzo[a]pyrene, the most carcinogenic PAH, of 0.86 ng/m3. [source] Spatial distribution of polychlorinated naphthalenes in air over the Great Lakes and air-water gas exchange in Lake OntarioENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2003Paul A. Helm Abstract High-volume air sample were collected during research cruises of Lake Superior in August 1996 and May 1977 and of Lake Ontario (North America) in July and September 1998 and June 2000 and analyzed for polychlorinated naphthalenes (PCNs). Levels of tetra- to octachloronaphthalene (,PCN) varied spatially, with mean values (±SD) of 1.78 ± 0.74 and 1.46 ± 1.07 pg m,3 for Lake Superior in 1996 and 1997, respectively, and of 5.53 ± 2.19 and 5.60 ± 2.24 pg m,3 for Lake Ontario in 1998 and 2000, respectively. Evaporative sources were predominant, although combustion marker congeners such as tetrachloronaphthalenes 44 and 29 and pentachloronaphthalene 54 were present in most samples and were enhanced relative to technical PCN mixtures. The ,PCN concentrations were higher in Lake Ontario samples collected in the western half of the lake and when winds were from the west. Greater proportions of the population and industrial areas are located around the western part of Lake Ontario. Water-air fugacity ratios, calculated from air and water samples collected in June 2000, indicate that the trichloronaphthalenes are volatilizing from Lake Ontario, whereas the tetrachloronaphthalenes are close to equilibrium and the net deposition of tetrachloronaphthalenes can occur when the urban air plume influences levels over the lake. [source] Survival of Salmonella in bathrooms and toilets in domestic homes following salmonellosisJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2000J. Barker The survival and environmental spread of Salmonella bacteria from domestic toilets was examined in homes, where a family member had recently suffered an attack of salmonellosis. In four out of six households tested, Salmonella bacteria persisted in the biofilm material found under the recess of the toilet bowl rim which was difficult to remove with household toilet cleaners. In two homes Salmonella bacteria became incorporated into the scaly biofilm adhering to the toilet bowl surface below the water line. Salmonella enteritidis persisted in one toilet for 4 weeks after the diarrhoea had stopped, despite the use of cleaning fluids. Salmonellas were not isolated from normally dry areas such as, the toilet seat, the flush handle and door handle. Toilet seeding experiments were set up with Salmonella enteritidis PT4 to mimic environmental conditions associated with acute diarrhoea. Flushing the toilet resulted in contamination of the toilet seat and the toilet seat lid. In one out of three seedings, Salmonella bacteria were also isolated from an air sample taken immediately after flushing, indicating that airborne spread of the organism could contaminate surfaces in the bathroom. In the seeded toilet Salmonella bacteria were isolated from the biofilm in the toilet bowl below the waterline for up to 50 d after seeding, and also on one occasion from the bowl water. The results suggest that during diarrhoeal illness, there is considerable risk of spread of Salmonella infection to other family members via the environment, including contaminated hands and surfaces in the toilet area. [source] Mycotoxin identification in moldy dwellingsJOURNAL OF APPLIED TOXICOLOGY, Issue 6 2006Carmel Charpin-Kadouch Abstract The objective of this study was to assess the level of macrocyclic trichothecenes (MCT), one of the most potent mycotoxins, on wall surfaces, ßoor dust and air samples from moldy dwellings. The study was based on an index group comprising 15 ßooded dwellings contaminated by Stachybotrys chartarum or Chaetomium and a control group comprising nine dwellings without molds on visual inspection and mold sampling. Three samples were collected from each dwelling: a sample from the moldy wall, using a swab, a ßoor dust sample on a 0.5 m2 surface with a cloth and an air sample using a pump comprising a 1 µm Teßon filter. The MCT level was measured using a monoclonal, antibody-based ELISA test. Compared with measurements performed in index dwellings, higher MCT values were measured on ßoor dust samples from moldy dwellings (P = 0.02). Samples from wall surfaces demonstrated nearly significant differences (P = 0.06). No significant differences were observed for air samples (P = 0.15), but some samples showed increased MCT levels. Significant correlations were observed between the levels measured on wall surfaces, ßoor dust and air samples (P = 0.02 to 0.05). In contrast, no correlation was observed between moldy surface and MCT levels. In conclusion, this paper reports for the first time direct evidence for the presence of MCT in moldy dwellings. Copyright © 2006 John Wiley & Sons, Ltd. [source] DNA damage in leukocytes of workers occupationally exposed to arsenic in copper smeltersENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2 2005Jadwiga Palus Abstract Inorganic arsenic (i-As) is a known human carcinogen; however, humans continue to be exposed to i-As in drinking water and in certain occupational settings. In this study, we used the Comet assay to evaluate DNA damage in the somatic cells of workers from three Polish copper smelters who were occupationally exposed to i-As. Blood samples were collected from 72 male workers and 83 unexposed male controls and used for the detection of DNA damage, oxidative DNA damage, and DNA damage after a 3-hr incubation in culture. Urine samples were collected to assess the level of exposure. The mean concentration of arsenic metabolites in urine [the sum of arsenite (AsIII), arsenate (AsV), monomethylarsenate (MMA) and dimethylarsenate (DMA)] and the concentrations of DMA (the main metabolite in urine) were higher in workers than in controls, but the differences were not statistically significant. By contrast, the level of DNA damage, expressed as the median tail moment, was significantly higher in the leukocytes of workers than in the controls. Comet assays conducted with formamidopyrimidine glycosylase (FPG) digestion to detect oxidative DNA damage indicated that oxidative lesions were present in leukocytes from both the exposed and control groups, but the levels of damage were significantly higher among the workers. Incubation of the cells in culture resulted in a significant reduction in the levels of DNA damage, especially among leukocytes from the workers, suggesting that the DNA damage was subject to repair. Our findings indicate that copper smelter workers have increased levels of DNA damage in somatic cells, suggesting a potential health risk for the workers. Although i-As was present in air samples from the smelters and in urine samples from workers, no clear association could be made between i-As exposure and the DNA damage. Environ. Mol. Mutagen., 2005. © 2005 Wiley-Liss, Inc. [source] Use of a high-throughput umu -microplate test system for rapid detection of genotoxicity produced by mutagenic carcinogens and airborne particulate matterENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2004Yoshimitsu Oda Abstract In the present study, we developed a rapid umu -microplate test system that uses the nitroreductase- and O -acetyltransferase-overproducing Salmonella typhimurium strain NM3009 and the O -acetyltransferase-overproducing S. typhimurium strain NM2009 to detect genotoxic activity in small volume samples. The assay was used to test the genotoxicity of several standard mutagens and environmental samples. Exponentially growing cultures of NM3009, NM2009, and the parental strain TA1535/pSK1002 were incubated in 96-well microplates with test chemicals both in the presence and in the absence of rat liver S9. The relative ,-galactosidase activities were then determined colorimetrically using either chlorophenol red-,- D -galactopyranoside (CPRG) or O -nitrophenyl-,- D -galactopyranoside (ONPG) as a measure of umuC gene induction activity. The sensitivities of NM3009 without S9 mix and NM2009 with S9 mix to nitroarenes and aromatic amines were up to 24- to 75-fold higher than those of the parent strain. Induction of umuC gene expression was detected more readily with CPRG than ONPG. The umu -microplate assay also detected genotoxicity in organic extracts of particulate matter from air samples collected in Osaka City, Japan. The pattern of the responses suggested that the genotoxic activity of the particulate extract was due primarily to nitrated polycyclic aromatic hydrocarbons. Our results indicate that the umu -microplate assay may be a useful way of carrying out rapid screens for genotoxicity in small-volume environmental samples. Environ. Mol. Mutagen. 43:10,19, 2004. © 2004 Wiley-Liss, Inc. [source] Emission of legacy chlorinated pesticides from agricultural and orchard soils in British Columbia, CanadaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2006Terry F. Bidleman Abstract Air samples were collected above agricultural fields in the Fraser Valley and orchards in the Okanagan Valley, British Columbia, Canada, to investigate volatilization of organochlorine pesticides used in the past. Concentrations of pesticides in air were elevated over soils that contained higher residues. Soil/air fugacity ratios at sites with the higher soil residues were calculated relative to air sampled at 40 cm height and background air. The fugacity ratios in the first case indicated net volatilization or soil-air equilibrium for most compounds and occasional net deposition for p,p, -dichlorodiphenyldichloroethene (p,p, -DDE), whereas those in the second case showed a strong potential for net volatilization of all compounds. The enantiomer fraction (EF) of chiral compounds ,-hexachlorocyclohexane (,-HCH), trans -chlordane, cis -chlordane, and o,p, -DDT were determined in overlying air samples and soils. Enantiomer fractions in air corresponded to those in soils at fields in which soil concentrations were high but were decoupled from soil signatures at fields with low soil residues. Mean EFs in air sampled over soils were significantly (p < 0.001) nonracemic for ,-HCH and the chlordanes and agreed with published EFs in regional ambient air. The mean EF of o,p, -DDT for all air samples did not show a significant deviation from racemic EFs (p > 0.2), but EFs of individual samples reflected the ambivalent nature of o,p, -DDT degradation, sometimes preferring the (+) enantiomer and other times the (,) enantiomer. The study indicates that soils are continuing to emit "legacy" pesticides into the regional atmosphere. [source] Persistent organic pollutants in air and vegetation from the canadian rocky mountainsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2004Deborah A. Davidson Abstract The exchange of chlorinated organic pollutants between air and vegetation in cold, mountain environments was investigated through the extraction of coniferous vegetation and high-volume air samples collected from the Canadian Rocky Mountains during the summers of 1999 and 2000. Concentrations of several compounds in vegetation increased as temperatures decreased, whereas atmospheric concentrations were not related to temperature. Daily cycling of these compounds between air and vegetation as a result of diurnal temperature changes was not observed. Compared with concentrations in vegetation from the Canadian Rocky Mountains, plant samples from the western valley in British Columbia (Canada) showed higher pollutant levels. Chemical partitioning between vegetation and air was not correlated with temperature, indicating that air contamination is governed by long-range transport and not by local revolatilization events. Based on these observations, we show that both deposition at higher altitudes and long-range atmospheric transport influence chemical accumulation in vegetation from the Canadian Rocky Mountains. [source] Vapor Intrusion in Homes over Gasoline-Contaminated Ground Water in Stafford, New JerseyGROUND WATER MONITORING & REMEDIATION, Issue 1 2006Paul F. Sanders The potential for chemical vapor intrusion from contaminated ground water to the interior of homes was investigated at a site with a leaking underground gasoline storage tank in Stafford Township, New Jersey. This location exhibited conditions favorable to vapor intrusion, with sand soil and a water table depth of 3.3 m. Concentrations of volatile organic chemicals in the ground water were as high as 82 mg/L for total benzene, toluene, ethylbenzene, and xylene (BTEX) and up to 590 mg/L for methyl- t -butyl ether (MTBE). Soil vapor samples at multiple depths were taken adjacent to several homes. Inside the homes, air samples were taken on the main floor, in the basement, and under the foundation slab. Despite high ground water concentrations, only one home had measurable impacts to indoor air quality attributable to some of the ground water contaminants. In this house, the BTEX chemicals were not detected in the basement, indicating a lack of indoor air impacts from the ground water for these chemicals. Oxygen measurements suggested that degradation attenuated these chemicals as they diffused through the vadose zone. However, MTBE, 2,2,4-trimethylpentane (isooctane), and cyclohexane were found in the indoor air. The first two of these chemicals served as gasoline-specific tracers and indicated that vapor intrusion was occurring. Attenuation factors (the ratio of the indoor air concentration to a source soil vapor concentration) for the BTEX chemicals between the ground water and the indoor air were <1 × 10,5, and for MTBE was 1.2 × 10,5. Attenuation factors between the deep-soil vapor and the basement air were as follows: BTEX compounds, <1 × 10,5; MTBE, 2.2 × 10,5; 2,2,4-trimethylpentane, 3.6 × 10,4; and cyclohexane, 1.2 × 10,4. Attenuation factors between the subslab vapor and the basement air were 7 to 8 × 10,3. [source] Characterization and Variability of Endotoxin and 3-Hydroxy Fatty Acids in an Office Building During a Particle Intervention StudyINDOOR AIR, Issue 1 2000Cynthia J. Hines Abstract Air and dust samples were collected on two floors of an office building during a double-blind particle intervention study to examine spatial and temporal variability of airborne endotoxin over a period of weeks, and to characterize endotoxin activity and lipopolysaccharide (LPS) content in carpet and chair dust. Air samples were collected on multiple days within and across weeks. Dust samples were collected from carpets and chairs one day per week for three weeks. Endotoxin was measured using a Limulus assay. Dust samples were analyzed for LPS by determination of 3-hydroxy fatty acids (3-OHFAs) using gas chromatography-mass spectrometry. The geometric mean (geometric standard deviation) for 96 indoor air samples was 0.24 (1.6) EU/m3. Significant within-floor spatial variation of airborne endotoxin was found (P<0.0001, n=80). Temporal variability of airborne endotoxin was not significant across weeks. Mean (±SD) endotoxin levels in carpet dust (59±9.3 EU/mg dust, n=12) and in chair dust (38±7.7 EU/mg dust, n=10) were significantly different (P<0.001). Carbon chain length-dependent differences in 3-OHFA levels by dust source and floor were found. Enhanced air filtration did not significantly affect airborne endotoxin (P=0.62); however, total dust mass and total endotoxin in carpet dust samples increased significantly after enhanced surface cleaning (P<0.01). These findings suggest that spatial variability, dust source, and surface cleaning may influence building occupant exposures to endotoxin., [source] Mycotoxin identification in moldy dwellingsJOURNAL OF APPLIED TOXICOLOGY, Issue 6 2006Carmel Charpin-Kadouch Abstract The objective of this study was to assess the level of macrocyclic trichothecenes (MCT), one of the most potent mycotoxins, on wall surfaces, ßoor dust and air samples from moldy dwellings. The study was based on an index group comprising 15 ßooded dwellings contaminated by Stachybotrys chartarum or Chaetomium and a control group comprising nine dwellings without molds on visual inspection and mold sampling. Three samples were collected from each dwelling: a sample from the moldy wall, using a swab, a ßoor dust sample on a 0.5 m2 surface with a cloth and an air sample using a pump comprising a 1 µm Teßon filter. The MCT level was measured using a monoclonal, antibody-based ELISA test. Compared with measurements performed in index dwellings, higher MCT values were measured on ßoor dust samples from moldy dwellings (P = 0.02). Samples from wall surfaces demonstrated nearly significant differences (P = 0.06). No significant differences were observed for air samples (P = 0.15), but some samples showed increased MCT levels. Significant correlations were observed between the levels measured on wall surfaces, ßoor dust and air samples (P = 0.02 to 0.05). In contrast, no correlation was observed between moldy surface and MCT levels. In conclusion, this paper reports for the first time direct evidence for the presence of MCT in moldy dwellings. Copyright © 2006 John Wiley & Sons, Ltd. [source] Nitrous Oxide Determination in Postmortem Biological Samples: A Case of Serial Fatal Poisoning in a Public Hospital,JOURNAL OF FORENSIC SCIENCES, Issue 1 2010Diana Poli Ph.D. Abstract:, In a public hospital, eight cases of fatal poisoning by nitrous oxide (N2O) occurred under oxygen administration, due to an erroneous swapping of the lines in the gas system. The aim of the study was to clarify the factors involved in asphyxia by characterizing gases from different lines and measuring N2O concentrations in postmortem biological samples from bodies exhumed. Analyses carried out on the gas system confirmed the erroneous substitution of O2 line with N2O and air line with O2. Consequently, high N2O amounts were revealed in several tissues and gaseous biological samples. All specimens were analyzed by headspace gas chromatography technique. A rigorous quantitative analysis was possible only in blood (11.29,2152.04 mg/L) and urine (95.11 mg/L) and in air samples from stomach and trachea (from 5.28 to 83.63 g/m3). This study demonstrates that N2O can be detected in biological samples even 1 month after death. [source] Optimized sample preparation for isotopic analyses of CO2 in air: systematic study of precision and accuracy dependence on driving variables during CO2 purification processJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 8 2005T. Bertolini Abstract A systematic analysis of efficiency, reproducibility and accuracy of cryogenic purification of CO2 from air samples for isotopic analyses is presented. The technical characteristics of the cryogenic line are given in detail. To study the cryogenic process, three different operating parameters are considered: flow rate of the gas entering the line, pressure of the gas in the line, and CO2 -trap shape. Experimental results demonstrate that efficiency, reproducibility and accuracy strongly depend on the CO2trap shape. Moreover, a dependence of reproducibility and accuracy on the flow rate of the gas is found, but not on its pressure. High precision (,0.02, for ,13C and ,0.05, for ,18O) and good accuracy (<0.09, for ,13C and <0.14, for ,18O) is achieved after applying the N2O correction. Copyright © 2005 John Wiley & Sons, Ltd. [source] Prevalence of Campylobacter spp. in a subset of intensive poultry flocks in IrelandLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2009A. Patriarchi Abstract Aim:, The aim of this study was to investigate the prevalence of Campylobacter species in a subset of intensive poultry flocks by examining samples collected in geographically disparate areas on the island of Ireland. Methods and Results:, Faecal, water and environmental samples were collected from the interior of poultry houses on nine farms. Three cultural methods were used for Campylobacter isolation: direct plating, enrichment culture and a recovery method for emerging Campylobacter spp. Presumptive Campylobacter isolates were confirmed using biochemical tests and further identified to species level by multiplex PCR. All flocks sampled in this study were found to be contaminated with Campylobacter at the time of sampling. Structural and air samples taken from the interior of broiler houses were also found to be Campylobacter positive. All water samples were found to be Campylobacter negative. The Campycheck method was used for the isolation of emerging Campylobacter spp. Conclusions:,Campylobacter spp. were recovered (as contaminants) from the poultry house interior, air and environmental samples in all intensive poultry flocks surveyed. Significance and Impact of the Study:, This study highlights the need for improved biosecurity on selected poultry farms. [source] A novel gaseous dimethylamine sensor utilizing cataluminescence on zirconia nanoparticlesLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 5 2009Chao Yu Abstract A novel cataluminescence (CTL) sensor using ZrO2 nanoparticles as the sensing material was developed for the determination of trace dimethylamine in air samples based on the catalytic chemiluminescence (CL) of dimethylamine on the surface of ZrO2 nanoparticles. The CTL characteristics and the different factors on the signal intensity for the sensor, including nanomaterials, working temperature, wavelength and airflow rate, were investigated in detail. The CL intensity on ZrO2 nanoparticles was the strongest among the seven examined catalysts. This novel CL sensor showed high sensitivity and selectivity to gaseous dimethylamine at optimal temperature of 330°C. Quantitative analysis was performed at a wavelength of 620 nm. The linear range of CTL intensity vs concentration of gaseous dimethylamine was 4.71 × 10,3 to 7.07 × 10,2 mg L,1 (r = 0.9928) with a detection limit (3,) of 6.47 × 10,4 mg L,1. No or only very low levels of interference were observed while the foreign substances such as benzene, hydrochloric acid, methylbenzene, chloroform, n -hexane and water vapor were passing through the sensor. The response time of the sensor was less than 50 s, and the sensor had a long lifetime of more than 60 h. The sensor was successfully applied to the determination of dimethylamine in artificial air samples, and could potentially be applied to analysis of nerve agents such as Tabun (GA). Copyright © 2009 John Wiley & Sons, Ltd. [source] Detection of pollen grains in multifocal optical microscopy images of air samplesMICROSCOPY RESEARCH AND TECHNIQUE, Issue 6 2009Sander H. Landsmeer Abstract Pollen is a major cause of allergy and monitoring pollen in the air is relevant for diagnostic purposes, development of pollen forecasts, and for biomedical and biological researches. Since counting airborne pollen is a time-consuming task and requires specialized personnel, an automated pollen counting system is desirable. In this article, we present a method for detecting pollen in multifocal optical microscopy images of air samples collected by a Burkard pollen sampler, as a first step in an automated pollen counting procedure. Both color and shape information was used to discriminate pollen grains from other airborne material in the images, such as fungal spores and dirt. A training set of 44 images from successive focal planes (stacks) was used to train the system in recognizing pollen color and for optimization. The performance of the system has been evaluated using a separate set of 17 image stacks containing 65 pollen grains, of which 86% was detected. The obtained precision of 61% can still be increased in the next step of classifying the different pollen in such a counting system. These results show that the detection of pollen is feasible in images from a pollen sampler collecting ambient air. This first step in automated pollen detection may form a reliable basis for an automated pollen counting system. Microsc. Res. Tech., 2009. © 2009 Wiley-Liss, Inc. [source] Exposure to respirable dust and crystalline silica in bricklaying education at Dutch vocational training centersAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 6 2010Daan Huizer MSc Abstract Background Construction workers are educated at vocational training centers before they begin their working lives. Future bricklayers and their instructors are exposed to respirable dust and possibly to hazardous respirable crystalline silica from trial mortar. Methods Thirty-six personal air samples were collected at six training centers to estimate exposure to respirable dust for both students and teachers. A selection of 22 samples was analyzed for crystalline silica. Results Average respirable dust exposures ranged from 0.59,mg/m3 for teachers to 1.45,mg/m3 for students performing recycling and cleaning tasks. In 45% of the analyzed samples, respirable crystalline silica was detected. Exposure to silica remained below the Dutch OEL (75,µg/m3). Exposure was significantly less for teachers than for students. This effect was found in both types of vocational training centers present in the Netherlands. Dry sweeping, as performed at all locations in this study, contributed considerably to the exposure to respirable dust. A first step in reducing exposure to dust and silica at training centers would therefore be to avoid dry sweeping. The presence of a dust extraction system, although not optimally designed, also significantly lowered exposure. Conclusions To assess a construction worker's lifetime exposure to respirable dust and crystalline silica, the vocational training period should also be taken into account. Several epidemiological studies have shown that time since first exposure can be an important risk factor for chronic health effects. Am. J. Ind. Med. 53: 628,634, 2010. © 2010 Wiley-Liss, Inc. [source] The quantification of carbon dioxide in humid air and exhaled breath by selected ion flow tube mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 10 2009David Smith The reactions of carbon dioxide, CO2, with the precursor ions used for selected ion flow tube mass spectrometry, SIFT-MS, analyses, viz. H3O+, NO+ and O, are so slow that the presence of CO2 in exhaled breath has, until recently, not had to be accounted for in SIFT-MS analyses of breath. This has, however, to be accounted for in the analysis of acetaldehyde in breath, because an overlap occurs of the monohydrate of protonated acetaldehyde and the weakly bound adduct ion, H3O+CO2, formed by the slow association reaction of the precursor ion H3O+ with CO2 molecules. The understanding of the kinetics of formation and the loss rates of the relevant ions gained from experimentation using the new generation of more sensitive SIFT-MS instruments now allows accurate quantification of CO2 in breath using the level of the H3O+CO2 adduct ion. However, this is complicated by the rapid reaction of H3O+CO2 with water vapour molecules, H2O, that are in abundance in exhaled breath. Thus, a study has been carried out of the formation of this adduct ion by the slow three-body association reaction of H3O+ with CO2 and its rapid loss in the two-body reaction with H2O molecules. It is seen that the signal level of the H3O+CO2 adduct ion is sensitively dependent on the humidity (H2O concentration) of the sample to be analysed and a functional form of this dependence has been obtained. This has resulted in an appropriate extension of the SIFT-MS software and kinetics library that allows accurate measurement of CO2 levels in air samples, ranging from very low percentage levels (0.03% typical of tropospheric air) to the 6% level that is about the upper limit in exhaled breath. Thus, the level of CO2 can be traced through single time exhalation cycles along with that of water vapour, also close to the 6% level, and of trace gas metabolites that are present at only a few parts-per-billion. This has added a further dimension to the analysis of major and trace compounds in breath using SIFT-MS. Copyright © 2009 John Wiley & Sons, Ltd. [source] A field and laboratory method for monitoring the concentration and isotopic composition of soil CO2RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 4 2008Dan Breecker The stable isotope composition of nmol size gas samples can be determined accurately and precisely using continuous flow isotope ratio mass spectrometry (IRMS). We have developed a technique that exploits this capability in order to measure ,13C and ,18O values and, simultaneously, the concentration of CO2 in sub-mL volume soil air samples. A sampling strategy designed for monitoring CO2 profiles at particular locations of interest is also described. This combined field and laboratory technique provides several advantages over those previously reported: (1) the small sample size required allows soil air to be sampled at a high spatial resolution, (2) the field setup minimizes sampling times and does not require powered equipment, (3) the analytical method avoids the introduction of air (including O2) into the mass spectrometer thereby extending filament life, and (4) pCO2, ,13C and ,18O are determined simultaneously. The reproducibility of measurements of CO2 in synthetic tank air using this technique is: ±0.08, (,13C), ±0.10, (,18O), and ±0.7% (pCO2) at 5550,ppm. The reproducibility for CO2 in soil air is estimated as: ±0.06, (,13C), ±0.06, (,18O), and ±1.6% (pCO2). Monitoring soil CO2 using this technique is applicable to studies concerning soil respiration and ecosystem gas exchange, the effect of elevated atmospheric CO2 (e.g. free air carbon dioxide enrichment) on soil processes, soil water budgets including partitioning evaporation from transpiration, pedogenesis and weathering, diffuse solid-earth degassing, and the calibration of speleothem and pedogenic carbonate ,13C values as paleoenvironmental proxies. Copyright © 2008 John Wiley & Sons, Ltd. [source] Isotope analysis of hydrocarbons: trapping, recovering and archiving hydrocarbons and halocarbons separated from ambient airRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 4 2005M. Pupek It is argued that isotope analysis of atmospheric non-methane hydrocarbons (NMHCs) and, in particular, the analysis of the deuterium/hydrogen (D/H) ratio is valuable because the dominant self-cleansing property of the troposphere is based on the OH radical which removes, e.g., CH4 and other alkanes by H-atom abstraction, which induces large kinetic isotope effects. The major obstacle in applying D/H isotope analysis to atmospheric NMHCs is not only the low abundance of D itself but, in particular, the low concentrations of NMHCs in the parts per trillion range. We show how a selection of NMHCs can be quantitatively separated from 300,L air samples together with CO2 as carrier gas matrix, by using high efficiency cryogenic traps. After diluting the extracted NMHC mixtures with hydrocarbon free air, and determining the mixing ratios, good agreement with original whole air sample analysis exists for alkanes and several halocarbons. For unsaturated hydrocarbons and some other halocarbons the extraction and recovery yield under the given conditions fell considerably, as a function of boiling point. Furthermore, the mixture of NMHCs in the CO2 matrix is proven to remain unchanged over several years when conveniently stored in glass ampoules. The ,extracts' or ,concentrates' of condensables extracted from larger air samples will enable the D/H isotope analysis of ultra trace gases in the atmosphere. Copyright © 2005 John Wiley & Sons, Ltd. [source] Automated system for simultaneous analysis of ,13C, ,18O and CO2 concentrations in small air samplesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2002Miquel Ribas-Carbo In this paper we present an automated system for simultaneous measurement of CO2 concentration, ,13C and ,18O from small (<1,mL) air samples in a short period of time (,1 hour). This system combines continuous-flow isotope ratio mass spectrometry (CF-IRMS) and gas chromatography (GC) with an inlet system similar to conventional dual-inlet methods permitting several measurement cycles of standard and sample air. Analogous to the dual-inlet method, the precision of this system increases with the number of replicate cycles measured. The standard error of the mean for a measurement with this system is 0.7,ppm for the CO2 concentration and 0.05, for the ,13C and ,18O with four replicate cycles and 0.4,ppm and 0.03, respectively with nine replicate cycles. The mean offset of our measurements from NOAA/CMDL analyzed air samples was 0.08,ppm for the CO2 concentration, 0.01, for ,13C and 0.00, for ,18O. A specific list of the parts and operation of the system is detailed as well as some of the applications for micrometeorological and ecophysiological applications. Copyright © 2002 John Wiley & Sons, Ltd. [source] Health monitoring of plants by their emitted volatiles: trichome damage and cell membrane damage are detectable at greenhouse scaleANNALS OF APPLIED BIOLOGY, Issue 3 2009R.M.C. Jansen Abstract Pathogen attack and herbivore infestation have a major impact on plant health. In a model study, these two plant health issues were simulated to study whether plant health can be monitored at greenhouse scale through the analysis of volatile organic compounds (VOCs) in greenhouse atmosphere. To simulate pathogen attack and herbivore infestation, we repeatedly stroked the stems of tomato plants (Lycopersicon esculentum) and repeatedly removed their side shoots. In addition, we studied the effect of fruit picking on the concentration of plant-emitted VOCs in greenhouse atmosphere. Analysis of air samples obtained before these treatments revealed up to 17 VOCs that are known to be released from tomato plants, of which the most dominant one was the monoterpene ,-phellandrene. When plants were 7 weeks old, the concentration of this VOC was approximately 0.06 ppbv before treatment. When plants were 12 weeks old, this concentration was raised to approximately 0.14 ppbv. Stroking of the stems, removing the side shoots and fruit picking resulted in an increase in the concentrations of all mono- and most sesquiterpenes up to 60-fold, which was expected because these VOCs are well-known constituents of trichomes. The treatments did not result in substantially increased concentrations of the stress-related compounds ,-copaene, methyl salicylate and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene. In contrast to stroking and fruit picking, shoot removal resulted in the emission of the lipoxygenase-derived product (Z)-3-hexenol in greenhouse atmosphere expressing cell membrane degradation. The findings presented in this paper focus on the feasibility of monitoring plant health through the analysis of VOCs in greenhouse air, but findings might also be relevant for atmospheric chemistry. [source] Multiple Inert Gas Elimination Technique For Determining Ventilation/Perfusion Distributions In Rat During Normoxia, Hypoxia And HyperoxiaCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2001V Alfaro SUMMARY 1. The use of the multiple inert gas elimination technique (MIGET) in quantifying ventilation/perfusion distributions (V,A/Q,) in small animals, such as the rat, may cause results to be biased due to haemodilution produced by the large volume of liquid infused intravenously. 2. We tested two methods of administering inert gases in rats using the MIGET: (i) standard continuous intravenous administration of inert gases (method A); and (ii) a new method based on the physicochemical properties of each inert gas (method B). This method included acute simultaneous inert gas administration using three pathways: inhalation, intravenous infusion and rectal infusion. Both MIGET methods were applied to obtain data while breathing three different inspiratory fractions of oxygen (FIO2): normoxia, hypoxia and hyperoxia. 3. Inert gas levels obtained from blood or expired air samples were sufficient for chromatographic measurement, at least during a 2 h period. The V,A/Q, distributions reported using both methods were acceptable for all the physiological conditions studied; therefore, the alternative method used here may be useful in further MIGET studies in rats because haemodilution resulting from continuous intravenous infusion of less-soluble gases can be avoided. 4. Normoxic rats showed lower mean values of the V,A/Q, ratio of ventilation distribution and higher mean values of the V,A/Q, ratio of perfusion distribution with the usual method of inert gas administration (method A). These non-significant differences were observed under almost all physiological conditions studied and they could be caused by haemodilution. Nevertheless, the effect of interindividual differences cannot be discarded. An additional effect of the low haematocrit on cardiovascular changes due to low FIO2, such as pulmonary vasoconstriction or increased cardiac output, may explain the lower dispersion of perfusion distributions found in group A during hypoxia. [source] | |||||||||||||||||||