Search results for "Aerosols"
showing 10 items of 105 documents
Occupational hygiene in a waste incineration plant
2003
Abstract The Turku incineration plant was renovated in 1995 to meet the emission requirements of modern waste combustion facilities. It treats presorted municipal waste from 170,000 residents in the Turku area. In the plant, the incineration process produces several types of by-products having importance in terms of occupational hygiene. Although not obligated by the law, the management of the plant has a keen interest in occupational hygiene at the plant, which was studied from 1998 to 2001. Concentrations of microbes, endotoxins, and dust and the noise level were investigated in three different working areas. Microbe measurements were conducted with a six-stage impactor and using the CAMN…
Polar organic marker compounds in PM2.5 aerosol from a mixed forest site in western Germany
2008
The molecular composition of PM2.5 (particulate matter with an aerodynamic diameter2.5 microm) aerosol samples collected during a very warm and dry 2003 summer period at a mixed forest site in Jülich, Germany, was determined by gas chromatography/mass spectrometry in an effort to evaluate photooxidation products of biogenic volatile organic compounds (BVOCs) and other markers for aerosol source characterization. Six major classes of compounds represented by twenty-four individual organic species were identified and measured, comprising tracers for biomass combustion, short-chain acids, fatty acids, sugars/sugar alcohols, and tracers for the photooxidation of isoprene and alpha-/beta-pinene.…
Exposure to bioaerosols and noise at a Finnish dry waste treatment plant
2004
Repeated measurements were carried out during two different campaigns between 1998 and 2001 to assess the occupational hygiene at a Finnish dry waste treatment plant. The analytical determinations were done in four different places within the processing hall of the plant: near a conveyor belt, near a jigger screen, near an after-crusher and near a bailer. Measurements were also carried out in a coffee room for employees. Concentrations of bacteria, fungi and actinomycetes were determined by two methods (six-stage impactor and Camnea method) and levels of endotoxins, dust and noise were also investigated. High concentrations of microbes and endotoxins and the noise level were found to be a …
TGF-beta regulates airway responses via T cells.
2003
Abstract Allergic asthma is characterized by airway hyperreactivity, inflammation, and a Th2-type cytokine profile favoring IgE production. Beneficial effects of TGF-β and conflicting results regarding the role of Th1 cytokines have been reported from murine asthma models. In this study, we examined the T cell as a target cell of TGF-β-mediated immune regulation in a mouse model of asthma. We demonstrate that impairment of TGF-β signaling in T cells of transgenic mice expressing a dominant-negative TGF-β type II receptor leads to a decrease in airway reactivity in a non-Ag-dependent model. Increased serum levels of IFN-γ can be detected in these animals. In contrast, after injection of OVA …
Combined effect of turbulence and aerosol on free-space optical links
2017
[EN] Despite the benefits of free-space optical (FSO) communications, their full utilization is limited by the influence of atmospheric weather conditions, such as fog, turbulence, smoke, snow, etc. In urban environments, additional environmental factors such as smog and dust particles due to air pollution caused by industry and motor vehicles may affect FSO link performance, which has not been investigated in detail yet. Both smog and dust particles cause absorption and scattering of the propagating optical signal, thus resulting in high attenuation. This work investigates the joint impact of atmospheric turbulence and dust particle-imposed scattering on FSO link performance as part of the…
Biofuel blending reduces particle emissions from aircraft engines at cruise conditions.
2017
Aviation-related aerosol emissions contribute to the formation of contrail cirrus clouds that can alter upper tropospheric radiation and water budgets, and therefore climate1. The magnitude of air-traffic-related aerosol–cloud interactions and the ways in which these interactions might change in the future remain uncertain. Modelling studies of the present and future effects of aviation on climate require detailed information about the number of aerosol particles emitted per kilogram of fuel burned and the microphysical properties of those aerosols that are relevant for cloud formation. However, previous observational data at cruise altitudes are sparse for engines burning conventional fuel…
Interfacial photochemistry of biogenic surfactants: a major source of abiotic volatile organic compounds
2017
Films of biogenic compounds exposed to the atmosphere are ubiquitously found on the surfaces of cloud droplets, aerosol particles, buildings, plants, soils and the ocean. These air/water interfaces host countless amphiphilic compounds concentrated there with respect to in bulk water, leading to a unique chemical environment. Here, photochemical processes at the air/water interface of biofilm-containing solutions were studied, demonstrating abiotic VOC production from authentic biogenic surfactants under ambient conditions. Using a combination of online-APCI-HRMS and PTR-ToF-MS, unsaturated and functionalized VOCs were identified and quantified, giving emission fluxes comparable to previous …
A DERIVATION OF THE VLASOV-NAVIER-STOKES MODEL FOR AEROSOL FLOWS FROM KINETIC THEORY
2016
This article proposes a derivation of the Vlasov-Navier-Stokes system for spray/aerosol flows. The distribution function of the dispersed phase is governed by a Vlasov-equation, while the velocity field of the propellant satisfies the Navier-Stokes equations for incompressible fluids. The dynamics of the dispersed phase and of the propellant are coupled through the drag force exerted by the propellant on the dispersed phase. We present a formal derivation of this model from a multiphase Boltzmann system for a binary gaseous mixture, involving the droplets/dust particles in the dispersed phase as one species, and the gas molecules as the other species. Under suitable assumptions on the colli…
Oral Sustained-Release Aminophylline and Bronchodilator Response to Inhaled Fenoterol in Patients with Chronic Airflow Obstruction
1985
The bronchodilator response to inhaled fenoterol (400 micrograms) was examined in the morning and in the afternoon before and during oral sustained-release aminophylline treatment in eight patients with chronic reversible airway obstruction. Bronchodilatation was evaluated by measuring serial peak expiratory flow rates (PEFR) for eight hours after inhaled fenoterol and calculating the area under the time-response curves and the percentage increment from the baseline values. The patients showed an enhancement of the bronchodilatation achieved with fenoterol in the morning during aminophylline treatment. In the afternoon, instead, the effect of the fenoterol was not improved by oral aminophyl…