Analytical Methods and Typical Atmospheric Concentrations for Gases and Particles

Finlayson-Pitts, B. J.

doi:10.1016/b978-012257060-5/50013-7

Cited by 14 publications

(7 citation statements)

References 642 publications

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“…Although the ATOFMS response is matrix-sensitive and may not directly reflect the quantitative composition of the measured aerosol (Gross et al, 2000;Fergenson et al, 2001;Bhave et al, 2002;Sullivan and Prather, 2005;Allen et al, 2006;Dall'Osto et al, 2006), relative peak intensities can be meaningful when particle constitution within a measured sample has not changed considerably during a given investigation (Gard et al, 1998;Finlayson-Pitts and Pitts, 2000). In this sense, the use of ATOFMS as a semi-quantifiable approach for the analysis of aged OL particles as a function of particle size is justifiable because individual laboratory based particles studied under experimentally controlled conditions are far less complex -and variable -than atmospheric aerosol (Allen, 2004).…”

Section: Aerosol Time-of-flight Mass Spectrometermentioning

confidence: 99%

Size-dependent chemical ageing of oleic acid aerosol under dry and humidified conditions

et al. 2016

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Abstract. A chemical reaction chamber system has been developed for the processing of oleic acid aerosol particles with ozone under two relative humidity conditions: dry and humidified to 65 %. The apparatus consists of an aerosol flow tube, in which the ozonolysis occurs, coupled to a scanning mobility particle sizer (SMPS) and an aerosol time-of-flight mass spectrometer (ATOFMS) which measure the evolving particle size and composition. Under both relative humidity conditions, ozonolysis results in a significant decrease in particle size and mass which is consistent with the formation of volatile products that partition from the particle to the gas phase. Mass spectra derived from the ATOFMS reveal the presence of the typically observed reaction products: azelaic acid, nonanal, oxononanoic acid and nonanoic acid, as well as a range of higher molecular weight products deriving from the reactions of reaction intermediates with oleic acid and its oxidation products. These include octanoic acid and 9- and 10-oxooctadecanoic acid, as well as products of considerably higher molecular weight. Quantitative evaluation of product yields with the ATOFMS shows a marked dependence upon both particle size association (from 0.3 to 2.1 µm diameter) and relative humidity. Under both relative humidity conditions, the percentage residual of oleic acid increases with increasing particle size and the main lower molecular weight products are nonanal and oxononanoic acid. Under dry conditions, the percentage of higher molecular weight products increases with increasing particle size due to the poorer internal mixing of the larger particles. Under humidified conditions, the percentage of unreacted oleic acid is greater, except in the smallest particle fraction, with little formation of high molecular weight products relative to the dry particles. It is postulated that water reacts with reactive intermediates, competing with the processes which produce high molecular weight products. Whilst the oleic acid model aerosol system is of limited relevance to complex internally mixed atmospheric aerosol, the generic findings presented in this paper give useful insights into the nature of heterogeneous chemical processes.

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Section: Aerosol Time-of-flight Mass Spectrometermentioning

confidence: 99%

Size-dependent chemical ageing of oleic acid aerosol under dry and humidified conditions

et al. 2016

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“…Les valeurs obtenues 0,2 et 0,3 respectivement pour Fann et Faidherbe indiquent une déficience en chlore dans la formation du sel marin. Ceci pourrait se justifier par le fait que le Cl -est utilisé lors des réac-tions rapides du NaCl avec les acides sulfurique et nitrique lorsque l'humidité relative est comprise entre 50-100 %, contribuant ainsi à la production du HCl gazeux [24]. En effet, l'humidité relative moyenne de cette période est de 79 % [25].…”

Section: Discussionunclassified

Caractérisation physico-chimique et effets cytotoxiques de particules atmosphériques PM_2,5de la ville de Dakar (Sénégal)

et al. 2011

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Résumé -Objectif : La pollution atmosphérique constitue un facteur de risque majeur pour la santé de l'homme. De nombreuses études épidémiologiques ont établi une corrélation entre l'exposition aux particules fines de diamètre aérodynamique inférieur à 2,5 µm (PM 2,5 ) et l'apparition de pathologies respiratoires, notamment de cancers pulmonaires. Notre travail a consisté à collecter des particules sur deux sites (P 1 et P 2 ) de la ville de Dakar caractérisés par un trafic automobile dense. Méthode : La collecte des particules a été effectuée par un impacteur en cascade. Les analyses physicochimiques effectuées sont : la granulométrie par microscopie électronique à balayage associée à une analyse par rayons X (MEB-EDX) ; la détermination des fractions inorganique par spectrométrie d'émission atomique couplée à un plasma inductif (ICP-AES) ; organiques (hydrocarbures aromatiques polycycliques et composés organiques volatils) par chromatographie en phase gazeuse couplée à un spectromètre de masse (GC-MS) ; enfin, ioniques par chromatographie ionique (CI). Résultats : L'exposition de cellules A549 à des concentrations croissantes de particules P 1 et P 2 provoque une diminution significative de l'incorporation de la bromodésoxyuridine, de l'activité de la déshydrogénase mitochondriale et une augmentation de l'activité de la lactate déshydrogénase extra-cellulaire. Ces tests ont permis de déterminer les concentrations létales pour P 1 (CL 10 = 5,11 µg/cm 2 et CL 50 = 25,56 µg/cm 2 ) et P 2 (CL 10 = 5,59 µg/cm 2 et CL 50 = 27,97 µg/cm 2 ). La toxicité la plus importante est observée dans les cellules exposées à la concentration maximale des particules P 1 (48 µg/cm 2 ). Conclusion : Ces résultats pourraient s'expliquer par les effets délétères synergiques engendrés par les fractions inorganique et organique, sources d'espèces réactives de l'oxygène potentiellement toxiques. Mots clés :Particules fines PM 2,5 , caractérisation physico-chimique, cytotoxicité, cellules A549 Abstract -Objective: Air pollution is a major risk factor for human health. Numerous epidemiological studies have clearly established a correlation between exposure to fine particulate matter (PM 2.5 ) and the occurrence of respiratory diseases, including lung cancer. Our work consisted of collecting particles from the city of Dakar, at two different sites (P 1 and P 2 ) characterized by heavy automobile traffic. Method: The collection of particles was carried out using a cascade impactor. Physico-chemical characterization of the collected PM was conducted using scanning electron microscopy coupled with X-ray diffraction (particle size), inductively coupled plasma atomic emission spectrometry (inorganic chemicals), gas chromatography coupled with mass spectrometry (PAHs and VOCs), and ionic chromatography (ions). Results: Exposure of A549 cells to increasing concentrations of P 1 and P 2 particles causes a significant decrease in the incorporation of bromodeoxyuridine, and in the activity of mitochondrial dehydrogenase, and an increase in the activi...

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“…The results using such systems provide insights about the properties of the inhaled aerosol, such as the sizes of the inhaled particles and the deposition fraction, which can be used for comparison with radionuclide imaging studies [ 19 ] or to validate in silico dosimetry models [ 20 , 21 , 22 ]. Cascade impactors consist of stages, each containing impaction plates which represent obstacles for an incoming airstream [ 23 ]. These plates create an abrupt bend in the airstream causing the particles, whose inertia exceeds a cutoff size, to deposit [ 24 ].…”

Section: Introductionmentioning

confidence: 99%

Experimental Evaluation of Dry Powder Inhalers during Inhalation and Exhalation Using a Model of the Human Respiratory System (xPULM™)

et al. 2022

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Dry powder inhalers are used by a large number of patients worldwide to treat respiratory diseases. The objective of this work is to experimentally investigate changes in aerosol particle diameter and particle number concentration of pharmaceutical aerosols generated by four dry powder inhalers under realistic inhalation and exhalation conditions. To simulate patients undergoing inhalation therapy, the active respiratory system model (xPULM™) was used. A mechanical upper airway model was developed, manufactured, and introduced as a part of the xPULM™ to represent the human upper respiratory tract with high fidelity. Integration of optical aerosol spectrometry technique into the setup allowed for evaluation of pharmaceutical aerosols. The results show that there is a significant difference (p < 0.05) in mean particle diameter between inhaled and exhaled particles with the majority of the particles depositing in the lung, while particles with the size of (> 0.5m) are least influenced by deposition mechanisms. The fraction of exhaled particles ranges from 2.13% (HandiHaler®) over 2.94% (BreezHaler®), and 6.22% (Turbohaler®) to 10.24% (Ellipta®). These values are comparable to previously published studies. Furthermore, the mechanical upper airway model increases the resistance of the overall system and acts as a filter for larger particles (> 3m). In conclusion, the xPULM™ active respiratory system model is a viable option for studying interactions of pharmaceutical aerosols and the respiratory tract regarding applicable deposition mechanisms. The model strives to support the reduction of animal experimentation in aerosol research and provides an alternative to experiments with human subjects.

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Analytical Methods and Typical Atmospheric Concentrations for Gases and Particles

Cited by 14 publications

References 642 publications

Size-dependent chemical ageing of oleic acid aerosol under dry and humidified conditions

Size-dependent chemical ageing of oleic acid aerosol under dry and humidified conditions

Caractérisation physico-chimique et effets cytotoxiques de particules atmosphériques PM_2,5de la ville de Dakar (Sénégal)

Experimental Evaluation of Dry Powder Inhalers during Inhalation and Exhalation Using a Model of the Human Respiratory System (xPULM™)

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Analytical Methods and Typical Atmospheric Concentrations for Gases and Particles

Cited by 14 publications

References 642 publications

Size-dependent chemical ageing of oleic acid aerosol under dry and humidified conditions

Size-dependent chemical ageing of oleic acid aerosol under dry and humidified conditions

Caractérisation physico-chimique et effets cytotoxiques de particules atmosphériques PM2,5de la ville de Dakar (Sénégal)

Experimental Evaluation of Dry Powder Inhalers during Inhalation and Exhalation Using a Model of the Human Respiratory System (xPULM™)

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Product

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About

Caractérisation physico-chimique et effets cytotoxiques de particules atmosphériques PM_2,5de la ville de Dakar (Sénégal)