Lung-deposited dose of particulate matter from residential exposure to smoke from wood burning

Residential settings are of utmost importance for human exposure, as it is where people spend most of their time. Residential wood combustion is a widespread practice known as a source of indoor particulate matter (PM). Nevertheless, research on the risks of exposure associated with this source is scarce, and a better understanding of respiratory deposition of smoke particles is needed. The dosimetry model ExDoM2 was applied to determine the deposited dose of inhalable particulate matter (PM10) from residential biomass combustion in the human respiratory tract (HRT) of adults and children. The dose was estimated using PM10 exposure concentrations obtained from a field campaign carried out in two households during the operation of an open fireplace and a woodstove. Simultaneously, PM10 levels were monitored outside to investigate the outdoor dose in a rural area strongly impacted by biomass burning emissions. Indoors, the 8-h average PM10 concentrations ranged from 88.3 to 489 μg m-3 and from 69.4 to 122 μg m-3 for the operation of the fireplace and the woodstove, respectively, while outdoor average PM10 concentrations ranged from 17.3 to 94.2 μg m-3. The highest amount of the deposited particles was recorded in the extrathoracic region (68-79%), whereas the deposition was much lower in the tracheobronchial tree (5-6%) and alveolar-interstitial region (16-21%). The total dose received while using the fireplace was more than twofold the one received in the room with a woodstove and more than 10 times higher than in the absence of the source. Overall, indoor doses were higher than the ones received by a subject exposed outdoors, especially at the alveolar-interstitial region. After 24 h of exposure, it was estimated that approximately 35 to 37% of the particles deposited in the HRT were transferred to the gastrointestinal tract, while approximately 2.0-2.5% were absorbed into the blood. The results from exposure and dose of indoor particles gathered in this work suggest that homeowners should be encouraged to upgrade the wood burning technology to reduce the PM levels inside their residences. This study also provides biologically relevant results on the lung deposition of particles from residential biomass burning that can be used as a reference for future research.publishe

Number Concentrations and Modal Structure of Indoor/Outdoor Fine Particles in Four European Cities

Indoor/outdoor aerosol size distribution was measured in four European cities (Oslo-Norway, Prague-Czech Republic, Milan-Italy and Athens-Greece) during 2002 in order to examine the differences in the characteristics of the indoor/outdoor modal structure and to evaluate the effect of indoor sources to the aerosol size distributions. All the measurement sites were naturally ventilated and were occupied during the campaigns by permanent residents or for certain time periods by the technical staff responsible for the instrumentation. Outdoor particle number (PN) concentrations presented the higher values in Milan and Athens (median values 1.4 x 10(4) # cm(-3) and 2.9 x 10(4) # cm(-3) respectively) as a result of elevated outdoor emissions and led to correspondingly higher indoor values compared to Oslo and Prague. In absence of indoor activities, the indoor concentrations followed the fluctuations of the outdoor concentrations in all the measurement sites. Indoor activities (cooking, smoking, etc.) resulted in elevated indoor PN concentrations (maximum values ranging between 1.7 x 10(5) # cm(-3) and 3.2 x 10(5) # cm(-3)) and to I/O ratios higher than one. The I/O ratios were size dependant and for periods without indoor activities, they presented the lowest values for particles <50 nm (0.51 +/- 0.15) and the ratios increased with fine particle size (0.79 +/- 0.12 for particles between 100-200 nm). The analysis of the modal structure showed that the indoor aerosol size distribution characteristics differ from the outdoors under the effect of indoor sources. The percentage of unimodal size distributions increased during indoor emissions, compared to periods without indoor sources, along with the number concentration of Aitken mode particles, indicating emissions in specific size ranges according to the type of the indoor source.Peer reviewe

Study of the Immersion Freezing Theory Using the Classical Nucleation Framework

The classical nucleation theory for immersion freezing was used for the simulation of ice nuclei particle activation under atmospheric conditions. A modification of the surface diffusion energy was introduced that was based on the concept of a two-dimensional diffusion of the adsorbed molecules on the surface of the substrate. Comparison with available laboratory data for kaolinite dust and bacteria cells were performed and qualitative agreement of ice nucleation onset was found. Simulations were performed for specific airborne microorganisms including P. syringae. Additionally, model simulations were performed for a set of 140 different bacteria. Model simulations showed that bacteria activation occurs in the atmosphere, which may be enhanced at lower temperatures. Increasing pre-existing available surface for ice nucleation resulted in higher nucleation probability in agreement with experimental observations. The current study showed that a critical parameter for the determination of IN is the value of the contact angle between the substrate and the critical cluster. Comparison with available parameterizations for P. syringae and dust particles was also performed, and classical nucleation theory showed similar nucleation rates in the temperature range of laboratory experiments from which the parameterizations were derived. In addition, a correction factor to bulk surface tension was applied for small ice clusters. Higher nucleation rates were calculated from this correction by a few orders of magnitude but their effect on nucleation probability was not significant. The classical nucleation theory is based on physical principles and can be further incorporated in General Circulation Models to determine the IN activation in the atmosphere for a mixture of different pre-existing particles including bacteria cells and dust

Contribution of natural sources to PM emissions over the metropolitan areas of Athens and Thessaloniki

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Human Exposure to Pollutants via Dermal Absorption and Inhalation

The human body is exposed to pollution on a daily basis via dermal exposure and inhalation. This book reviews the information necessary to address the steps in exposure assessment relevant to air pollution

Resuspension of Small Particles by Turbulent Flow

Abstract not availableJRC.(STI)-Institute For Safety Technolog