When the miners working there tried to expand it even closer, he decided he had to do something. First he had to prove there was something wrong with the air. Dybwad said. But nothing he could find was both cheap and accurate. So he made his own. Neighbors got interested. Dybwad, who has a background in computer networking and surface-mount electronics, asked for donations and raised a few thousand dollars, and the community installed 80 sensors.
The amount of floating particles in the air called particulate matter was high, especially on windy days. The closest government-run sensor was more than 10 miles away, and not picking up any of this. As the community gathered with sensors, plans for the mine expansion vaporized. In the last year, interest in the project has spiked.
Now he has more than 3, monitors reporting data every day. He has built a map to show what every PurpleAir around the world is reporting green is good, red is bad. Local government air quality monitoring groups are using the devices. Since the California wildfires in November, Mr. Dybwad said, traffic has been up 10, percent. In November, he moved production out of his backyard and into a new 2,square-foot workshop.
Vera Kozyr, the chief executive of Atmotube, said her company sold 8, of its first version and is introducing a new tube in December.
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Kozyr said. Fans of the new pollution monitors tend to also be skeptical of government efforts to keep air clean and say they are wary of the air quality data that the government provides. The Trump administration has urged the Environmental Protection Agency to ease air quality rules. New E. The administration is working to overhaul restrictions on coal, which by its own estimates could lead to as many as 1, more premature deaths annually by from an increase in the airborne particulate matter.
President Trump claimed in October that the United States has the cleanest air in the world, which is inaccurate. The administration in August unveiled plans to freeze antipollution and fuel-efficiency standards for cars. Granulomatous inflammation represents one type of chronic inflammation which is characterized by inflammatory lesions with large numbers of macrophages forming interlacing palisades, lymphocytes, and plasma cells Renne et al. Other cells of the mononuclear phagocyte system epithelioid and multinucleated cells also contribute to maintain the inflammatory process.
However, in the present studies, later stages of granuloma formation, transformation of macrophages to epithelioid, or giant cells were not observed. However, granulomatous inflammation can lead to tissue damage and fibrosis at later stages as observed by Ma et al. A regression of the BALF parameter e. It was concluded that during a sustained inflammation in the lungs, parameters in BALF do not represent the current inflammatory state and damage in the lungs.
Lymphatic clearance of inhaled Ceria via the lymphatic vessels from the pulmonary region to the lung-associated lymph nodes was demonstrated by histological evaluations and confirmed by measured Cerium lymph node burdens. Accumulation of free particles or particles within macrophage aggregates was detected in the BALT or mediastinal and tracheobronchial lymph nodes.
Moderate macrophage aggregates with particles in the lung-associated lymph nodes, combined with lympho-reticulocellular hyperplasia, were considered to be adverse.
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It is more likely that the particles reached the associated lymph nodes by phagocytizing macrophages than by entering the interstitium. BALF parameters proved to be more sensitive to short-term effects but less predictive for the progression of these effects. The observations of the current study resemble the findings of previously published inhalation and instillation studies with different Ceria Gosens et al. In an day inhalation study with the Ceria NM, Gosens et al. These effects were less pronounced compared to the current study.
The dose-equivalent concentration of 2. The difference in daily exposure times and dose rate may account for the differences in the severity of the effects. Aalapati et al. Substance-related adverse effects after inhalation exposure to two Ceria in the short-term studies were limited to the lung. Potential systemic genotoxicity was assessed by micronuclei test MNT. This in vivo assay is able to demonstrate the potential interaction of nanomaterials with chromosomes or mitotic apparatus of replicating erythroblasts as well as their influence on erythropoiesis in the bone marrow LeBaron et al.
No genotoxic potential after inhalation of Ceria NM or NM was observed in both short-term studies. Cerium bone marrow content was not determined in our inhalation studies, but a tissue concentration of 6. Ceria inhalation exposure has been reported to result in a wide range of systemic responses ranging from no effects to severe effects in blood or extrapulmonary organs, such as liver or kidneys Aalapati et al.
Furthermore, a whole panel of extrapulmonary organs and tissues was examined histologically as required by OECD test guideline None of the other extrapulmonary organs showed any morphological abnormalities. The absence of systemic effects is consistent with the very low extrapulmonary tissue Ceria concentrations in this and other studies Gosens et al.
However, after a single intravenous i. The Ceria-induced adverse effects were explained by mechanical irritation or its chemical catalytic activity Yokel et al. The high Cerium concentrations in the liver after i. The findings comprised necrosis in kidneys, hepatocytomegaly, and cytoplasmatic vacuolization in the heart Aalapati et al.
However, even i. Ceria NM and NM have identical composition, agglomeration state, crystallinity, and insolubility. Compared to Ceria NM, NM has considerably smaller primary particles, larger specific surface, significantly fewer organic contaminations on the surface, and reduced photocatalytic activity. Despite these differences, Ceria NM and NM share the same tendency to recrystallize in acidic PSF, which simulates the lysosome of macrophages.
These properties are comparable to each other, but significantly different from other metal oxide nanomaterials and seem to be primarily substance-related themselves. When biological effects e. Morrow first introduced volume as dose metric for overload Morrow Pauluhn modified the overload hypothesis by introducing agglomerate density instead of physical density into the calculation of volumetric loading Pauluhn The effective particle density is needed to calculate the particle volume.
In a guidance document published by Webb , various definitions of the powder volumes are given e. It is not fully understood which characteristics of nano-Ceria lead to the effects observed in previous and current studies [Environmental Protection Agency EPA ]. Assessing the immune toxicity of another member of the group of poorly soluble particle namely Titania after instillation in rats, lower phagocytic ability and disruption of pulmonary alveolar macrophage function were correlated with surface reactivity and size of surface area Liu et al.
Furthermore, surface area of retained particles seems to correlate with acute inflammatory reactions after inhalation. The correlation of lung burden, expressed as mass, volume, and surface area, and neutrophil PMN counts in BALF as parameter for biological effects is presented in Fig. Surface area normalized the dose response of the two Ceria materials.
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This result is consistent with other studies, which used surface area as dose metric to quantify the toxicity of the PSPs Titania and barium sulfate Tran et al. Neutrophil counts in BALF correlated with deposited particle per surface lung after 5-day and 4-week exposure using the aerosol concentrations of 0. Neutrophils in BALF are a sensitive measure of this initial phase. With sustained inflammatory conditions, neutrophil recruitment undergoes a certain physiological adaptation in the body.
The number of neutrophils observed in BALF was decreasing and supplemented by mononuclear cells, especially macrophages that were visible in histopathology but not in BALF. The sustained presence of particles in the lung can drive macrophages to form granulomatous lesions.
Although a small dose rate over a long exposure time achieved the same lung burden as a high dose rate over a short time period, the effects observed may be more severe due to consistent irritation of the tissue by small dose rates of fresh materials. Apparently, the initial neutrophil reaction is directed by the dose rate while the progression of the inflammation in the lung is also driven by the continuing presence of particles in the lung. The authors wish to thank the inhalation team and pathology team of BASF for their excellent technical assistance in performing the inhalation study, the clinical, and histopathological examinations.
Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author s and the source are credited. Skip to main content Skip to sections. Advertisement Hide. Download PDF. Time course of lung retention and toxicity of inhaled particles: short-term exposure to nano-Ceria.
First Online: 02 October Introduction During the production and processing of nanomaterials in the workplace, releases into the air may occur Kuhlbusch et al. Test materials and characterization The two Ceria test materials in this work are NM and NM received from the OECD sponsorship programme for safety testing of manufactured nanomaterials Hussain et al. Animals This study was approved by the local authorizing agency for animal experiments Landesuntersuchungsamt Koblenz, Germany as referenced by the approval number G Aerosol generation and monitoring Ceria aerosols were produced by dry dispersion of powder pellets with a brush dust generator developed by the Technical University of Karlsruhe in cooperation with BASF, Germany using compressed air 1.
The mid and low aerosol concentrations were 5 and 0. The low aerosol concentration with an expected lung burden far below the overload condition should not lead to any adverse effects. The mid aerosol concentration, which was spaced tenfold higher than the low concentration, was expected to cause some biological effects. The post-exposure period and the examination time points were scheduled to address the progression or regression of the biological effects, with their correlation to lung burden and lung clearance kinetics. Open image in new window. The measured parameters comprised various cytokines, chemokines, adhesion molecules, matrix metalloproteinases, acute-phase proteins, signal proteins of apoptosis, or cell proliferation.
Briefly, a list of parameters was described previously Ma-Hock et al. Characterization of test material Both Ceria were yellowish white powders that were produced by precipitation and were nominally uncoated. We completely re-characterized the Ceria NM and NM based on the nano-specific guidance on physical—chemical properties Wohlleben et al. The Ceria NM material consisted of considerably smaller primary particles with number-based median diameter of 8. Primary particles of both materials were crystalline with cubic lattice as it is the characteristic for cerianite and had irregular, but roughly globular shapes.
The solubility in physiological media was investigated by day abiotic incubation in different fluids and detection of both the remaining particulate fraction by SEM, centrifugation, LD, zeta-potential and of the released metal ions by ICP-MS. Both Ceria were insoluble except for marginal solubility in 0.
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Under all conditions, primary particles remained recognizable in TEM scans, but both Ceria NM and NM formed large structures after day incubation in the acidic PSF medium that simulates the lysosome of macrophages see Fig. We found by selected area electron diffraction SAD that these aged structures retained the same cubic cerianite crystalline phase of the as-produced powder for both Ceria NM and NM Under identical conditions, also other nanomaterials, e.
The target concentrations were 0. The target concentrations were met and maintained well throughout the studies. Particle size distribution demonstrated that Ceria particles were in the respirable range for rats. Target conc. CINC-1 was already increased at 0. The time course of lung and lymph node burdens is presented in Fig.
The time course of the lung burdens is presented in Fig. Inhalation exposure of 0. Deposition and clearance Four weeks of exposure to 0. Oberdoerster et al. Tran et al. This is slightly below the surface burden threshold proposed by Tran et al. Therefore, it can be assumed that a threshold, however, is highly material-dependent and may not be based on one or two particle types alone. The thresholds published previously may need adaptations for the specific type of nanomaterial in order to address its toxicological properties.
One should note that the calculated dose rates still include the clearance and, therefore, reflect rather the retained than the deposited Ceria concentration in the lung. The dose rate of particles seems to influence the acute inflammatory reaction in the lung Baisch et al. Despite the same lung burdens but different dose rates, a stronger neutrophil response in BALF was observed after the shorter exposure time Figs. Eliminating emissions from just these The technology may be The polycyclic aromatic hydrocarbon PAH contents of airborne particulates Wednesday, May 29, Load more stories.
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