165 research outputs found

    Emission and dispersion modelling of aerosols and human exposure to particulate matter

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    Atmospheric aerosols are subject to extensive research, due to their effect on air quality, human health and ecosystems, and hold a pivotal role in the Earth’s climate. The first focus of this study is to improve the modelling of aerosol emissions and its dispersion in the atmosphere, in different spatial and temporal scales, and secondly, to integrate the dispersion modelling with population activity data to estimate exposure metrics. The mathematical models used in this study are fully or partially developed by the Finnish Meteorological Institute: a regional-to-global scale chemical transport model SILAM, a local-scale point/line-source dispersion model, UDM/CAR-FMI, and a human exposure and intake fraction assessment model, EXPAND. One of the outcomes of this work was the refinement of the emission modelling for the mesoscale dispersion model. A new parameterisation for bubble-mediated sea salt flux has been developed, taking in to account the effects of wind speed and seawater salinity and temperature. The parameterization is valid for low-to-moderate wind speed, seawater salinity ranging between 0 and 33 ‰, seawater temperature ranging between -2 and 25 °C, and can be applicable to particles with dry diameters raging between 0.01 and 10 μm. The near-real time fire estimation system, IS4FIRES, based on Fire Radiative Power (FRP) measured by the remote sensing instrument MODIS, was refined to reduce the overestimation of particulate matter (PM) emissions by including more vegetation types, improving the diurnal variation, removing misattributed fires from the FRP data, and recalibrating the emission factors. Applying dynamic emission modelling brought more insight to the spatial distribution of these emissions, their contribution to the atmospheric budget, and possible impact on air quality and climate. The modelling shows that sea salt can be transported far over land and contribute up to 6 μg m-3 to PM10 (at annual level). It also indicates that the Mediterranean Sea has sharp gradients of concentration, becoming an interesting area to analyse regarding the feedbacks to the regional climate. According to the predictions, upward scattering by SSA, at TOA, can be up to 0.5 W m-2, and there will be an overall cooling in the future for the North of Europe and warming for the South, due to SSA. The simulations for wildland fires show how the system improves after calibration and the importance vegetation type for the intensity of the emissions. By including misattributed fires, there will be up to 80% overestimation in aerosol optical depth, close to the misattributed sources. The emissions for Helsinki Metropolitan Area (HMA) were revised to bring up-to-date the emissions for traffic and energy sectors, for urban-scale applications. The EXPAND model was revised to combine concentrations and activity data in order to compute parameters such as population exposure or intake fraction. EXPAND includes improvements of the associated urban emission and dispersion modelling system, time use of population, and infiltration coefficients from outdoor to indoor air. This refinement showed that PM2.5 in HMA is mainly originated from long-range transport, with the largest local contributors being vehicular and shipping (at harbours and its vicinity) emissions. At annual level, the population is mostly exposed to PM2.5 indoors (home and work), but the population is acutely exposed while commuting

    Quantification of the environmental impact of titanium dioxide photocatalytic pavements for air pollution remediation

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    Photocatalytic concrete pavements are a promising technology for mobile source air pollution remediation, however before widespread application of this technology is realized many unanswered questions remain regarding its overall environmental impact. In response to these questions, the goal of this study was to increase the understanding of the environmental impact of photocatalytic concrete pavement highways. To achieve this goal, the objectives of this study were to (A) construct a model that evaluates the nitrogen oxides (NOx) reduction from photocatalytic pavements, (B) quantify the nitrates released from the photocatalytic degradation of NOx, and (C) identify and characterize pathways for TiO2 nanoparticle exposure. To achieve objective A, a field study was conducted to evaluate the NOx reduction. Results showed evidence of minimal photocatalytic reductions with large variability due to many unknown and known parameters. As a result, this study also investigated the use of laboratory results to better understand the significance of the NOx reduction through the creation of a theoretical mass balance Lavoisier box model. Laboratory results indicated that the nitrogen monoxide (NO) oxidation rate is reaction rate mass transfer controlled following the Langmuir- Hinshelwood (L-H) model. A parametric study was completed to evaluate the L-H constants under different environmental conditions and statistical model was created to describe the NO oxidation rate. Incorporating the resulting NO oxidation rate into a Lavoisier box model the mass transfer mechanisms were compared and objective A was achieved. Objectives B and C of the project deal with evaluating potential unintended consequences resulting from implementation of photocatalytic concretes. To complete objective B, nitrates and TiO2 nanoparticles released to water were quantified. Lastly, TiO2 nanoparticles released to the air during construction activities were quantified and characterized to achieve objective C

    Health Risk Assessment Posed by the Mobile Source Air Toxics on an Urban to Regional Area

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    Air toxics are important health concern. The purpose of this research was to develop a protocol to predict exposure concentrations of air toxics and inhalation cancer and noncancer risk that come from different gasoline and diesel-fueled sources. The protocol was developed by linking the U.S. EPA’s Models-3/CMAQ model as the exposure model and toxicological and epidemiological evidence functions. The NEI version 3 for the year 1999 was used in this analysis for point, area, and non-road sources, whereas NMIM was used to create the on-road emissions. The year 2003 was used for meteorological data and as reference to compare the monitored concentrations to model performance. The modeling domain consisted of a 36 km domain. To demonstrate the system’s effectiveness, this study was performed on priority mobile sources air toxics (1, 3-butadiene, benzene, formaldehyde, acetaldehyde, acrolein, and DPM), and was applied to Nashville, Tennessee using available air toxics monitored data. Ten emissions scenarios were selected in this study to compare the main results. This research on air toxics emission scenarios was based on relative analyses and estimates of absolute exposure concentrations and health risk values. The proposed protocol was demonstrated and can be used for decision makers in the quantitative assessment of new policies that will affect the public health and the air quality by air toxics. Eliminating emission source categories is clearly not a policy option, but rather helps gain a better understanding of the total magnitude of the health effects associated with these major sources of air toxics, principally of DPM. Higher formaldehyde and acetaldehyde exposure concentrations occurred in the summer season, while benzene and 1,3-butadiene occurred in winter. DPM did not show a strong seasonality exposure during the year 2003 in Nashville. DPM generated the higher lifetime cancer risk excess among the other air toxics in Nashville, posing a cancer risk that was 4.2 times higher than the combined total cancer risk from all other air toxics. Those high cancer risk levels were due mainly to non-road sources (57.9%). For the on-road diesel fueled sources (DFS), the principal reductions were due to the DPM contributions generated by HDDVs rather than LDDVs. An evident positive synergism in the cancer risk reduction occurred when reducing diesel on-road and non-road source emissions simultaneously. The main cancer risk reductions from acetaldehyde, benzene, 1,3-butadiene, and formaldehyde (4HAPs) were due to the contribution of biogenic sources with 32.2%. This condition was followed for the scenario that did not consider on-road sources with a 27.5% of reduction. For non-road sources, the main reductions were due to the air toxics contributions generated by gasoline LDVs, principally benzene and 1,3-butadiene. The scenario 2020 showed a DPM and 4HAPs health effect reductions of approximately 32.8 and 19.4 %, respectively in Nashville. Higher cancer and non-cancer risks occurred on Southeastern urban areas due to long-term exposure to DPM, principally in Atlanta, GA, followed by Nashville, TN, Birmingham, AL, Raleigh, NC, and Memphis, TN. This research provided strong evidence that reducing ambient DPM concentrations will lead to improvement in human health more than other air toxics in Nashville, indicating that better technologies and regulations must be applied to mobile diesel engines, principally, over non-road diesel sources

    Photodiodes

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    Photodiodes or photodetectors are in one boat with our human race. Efforts of people in related fields are contained in this book. This book would be valuable to those who want to obtain knowledge and inspiration in the related area

    The Impact of Air Pollution on Health, Economy, Environment and Agricultural Sources

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    This book aims to strengthen the knowledge base dealing with Air Pollution. The book consists of 21 chapters dealing with Air Pollution and its effects in the fields of Health, Environment, Economy and Agricultural Sources. It is divided into four sections. The first one deals with effect of air pollution on health and human body organs. The second section includes the Impact of air pollution on plants and agricultural sources and methods of resistance. The third section includes environmental changes, geographic and climatic conditions due to air pollution. The fourth section includes case studies concerning of the impact of air pollution in the economy and development goals, such as, indoor air pollution in MĂ©xico, indoor air pollution and millennium development goals in Bangladesh, epidemiologic and economic impact of natural gas on indoor air pollution in Colombia and economic growth and air pollution in Iran during development programs. In this book the authors explain the definition of air pollution, the most important pollutants and their different sources and effects on humans and various fields of life. The authors offer different solutions to the problems resulting from air pollution

    Novel gas sensors and electronic noses for optical, electrical and hybrid sensing: development, properties and applications

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    Smell is one of the most important senses of man. It is used in everyday life, influencing our behaviour. Evaluation of the quality of food and beverages or the production control in industries that require specialised personnel, are some examples of its use. The Electronic Nose mimics the human nose, through the transduction of a chemical interaction between a sensitive layer and the volatile compounds, generating a measurable signal. Conducting polymers, doped with dodecylbenzenesulfonic acid, employed in electrical gas sensors and in an electronic nose showed their applicability in monitoring the circadian emissions of fragrance by the plant Madagascar Jasmin and in the discrimination and classification of different samples of flaxseed, respectively. An innovative approach in the development of sensitive thin films based on organized liquid crystal micelles in an ionic liquid, encapsulated in a biopolymer matrix and used as sensitive layers for gas sensors, is the focus of this thesis. Liquid crystal micelles acting as sensitive elements that change reversibly their orientation in the presence of volatile compounds showed, as a proof of concept, their potential use in the classification of volatile solvents. They were also successfully tested for monitoring the quality of Tilapia fish. The combination of this optical system with the electrical system gave the so called "hybrid sensor" with dual response. Thus, a single sensor was efficient in the quantification of ethanol in gasoline. Polarized light microscopy, SEM and AFM techniques were used to study the morphology of these layers and have revealed that the formation of the micelles is closely influenced by the solvent where the liquid crystal molecules are arranged. QCM studies were conducted in order to learn more about the interaction of these films with volatile compounds, and to check the influence of parameters such as the exposure time, solvent nature, film composition and drying time, on the film. These biopolymer films were also used as immobilisation matrix for cytochrome c, forming electrochemical sensors having an additional optical response
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