Dissertationen zum Thema „Nitrate particulaire“

La pollution de l'air est toujours un problème environnemental qui doit être résolu de toute urgence dans la Plaine de Chine du Nord (PCN). Dans le but d'explorer la formation de l’acide nitreux (HONO) et son impact sur la qualité de l'air régional dans la PCN, le développement et l'évaluation systématique d'instruments pour mesurer la concentration de HONO atmosphérique et son flux d'émission du sol ont été réalisés. Sur la base de mesures sur le terrain, un modèle 3D de chimie-transport (le système communautaire de modélisation de la qualité de l'air à plusieurs échelles : CMAQ, de l’EPA) et un modèle de boîte (0D) de mécanisme chimique (Master Chemical Mechanism : MCM) ont été utilisés pour explorer le bilan de HONO et son impact sur la pollution atmosphérique régionale, par exemple la pollution estivale à l'ozone (O3) et la pollution par la brume hivernale. Nous avons constaté que le sol agricole était une source importante de HONO avec un impact significatif sur la pollution régionale à l'ozone en été. Un nouveau mécanisme d'émission de HONO du sol lié à la nitrification a été proposé. HONO joue également un rôle important dans la capacité oxydante de l’atmosphère et la détérioration de la qualité de l'air régional en hiver
Air pollution is still an environmental problem that urgently needs to be solved in the North China Plain (NCP). With the aim to explore nitrous acid (HONO) formation and its impact on regional air quality in the NCP, the development and systematic assessment of instruments to measure atmospheric HONO concentration and soil HONO emission flux were realized. Based on field measurements, a 3D chemistry-transport model (the Community Multiscale Air Quality Modeling System, CMAQ) and a box (0D) model (Master Chemical Mechanism, MCM) were used to explore the HONO budget and its impact on regional air pollution, e.g., summer ozone (O3) pollution and winter haze pollution. We found that agricultural soil was an important HONO source with a significant impact on regional O3 pollution in the summertime. A new soil HONO emission mechanism related to nitrification was proposed. HONO also plays an important role in atmospheric oxidizing capacity and deteriorating regional air quality in the wintertime

Les particules fines troposphériques de diamètre aérodynamique inférieur à 2,5 µm (PM2.5) peuvent impacter la santé et les écosystèmes. Les aérosols inorganiques secondaires (AIS) et organiques (AO) contribuent fortement aux PM2.5. Pour comprendre leur formation et leur origine, une campagne d’1 an (août 2015 - juillet 2016) de mesures horaires de gaz précurseurs inorganiques et d’ions hydrosolubles particulaires a été menée sur un site urbain du nord de la France avec un MARGA 1S, complétées par les concentrations massiques en PM2.5, carbone suie, oxydes d’azote et éléments traces. Des niveaux élevés de nitrate d’ammonium (NA) ont été observés la nuit au printemps et de sulfate d’ammonium la journée en été. L’étude de la contribution des sources par le modèle PMF (Positive Matrix Factorization) a permis d’identifier 8 facteurs sources: 3 régionaux (riche en sulfates, riche en nitrates et marin) pour 73 à 78%, et 5 locaux (trafic, combustion de biomasse, fond industriel métallurgique, industrie locale et poussières minérales) (22-27%). De plus, un HR-ToF-AMS (spectromètre de masse à aérosols) et un SMPS (granulomètre) ont été utilisés lors d’une campagne intensive en hiver, afin de mieux documenter l’AO et la formation de nouvelles particules, respectivement. L’application du PMF aux spectres de masses d’AO a permis d’identifier 5 facteurs liés au trafic (15%), à la cuisson (11%), à la combustion de biomasse (25%), et à une oxydation plus ou moins forte de la matière organique (33% et 16%). Plusieurs événements nocturnes de formation de nouvelles particules impliquant les AIS, notamment du NA, ont été observés
Tropospheric fine particles with aerodynamic diameters less than 2.5 µm (PM2.5) may impact health, climate and ecosystems. Secondary inorganic (SIA) and organic aerosols (OA) contribute largely to PM2.5. To understand their formation and origin, a 1-year campaign (August 2015 to July 2016) of inorganic precursor gases and PM2.5 water-soluble ions was performed at an hourly resolution at a suburban site in northern France using a MARGA 1S, complemented by mass concentrations of PM2.5, Black Carbon, nitrogen oxides and trace elements. The highest levels of ammonium nitrate (AN) and sulfate were observed at night in spring and during daytime in summer, respectively. A source apportionment study performed by positive matrix factorization (PMF) determined 8 source factors, 3 having a regional origin (sulfate-rich, nitrate-rich, marine) contributing to PM2.5 mass for 73-78%; and 5 a local one (road traffic, biomass combustion, metal industry background, local industry and dust) (22-27%). In addition, a HR-ToF-AMS (aerosol mass spectrometer) and a SMPS (particle sizer) were deployed during an intensive winter campaign, to gain further insight on OA composition and new particle formation, respectively. The application of PMF to the AMS OA mass spectra allowed identifying 5 source factors: hydrocarbon-like (15%), cooking-like (11%), oxidized biomass burning (25%), less- and more-oxidized oxygenated factors (16% and 33%, respectively). Combining the SMPS size distribution with the chemical speciation of the aerosols and precursor gases allowed the identification of nocturnal new particle formation (NPF) events associated to the formation of SIA, in particular AN

De nouveaux materiaux ferromagnetiques derives du nitrure de fer fe::(4)n ont ete prepares. La substitution partielle de l'azote par du carbone leur confere une meilleure resistance a l'oxydation. La morphologie des pigments magnetiques est induite par celle des precurseurs. Etude de la modification de la taille du fer par l'etain. Etude generale de l'influence de substituants tels que ru, os, ir sur l'anisotropie magnetocristalline

L'élaboration de matériaux composites particulaires à base de nitrure de silicium Si3N4-TiN, Si3N4-TiB2, Si3N4-HfB2, a été réalisée par compression isostatique à chaud (CIC ou HIP), avec de faibles quantités d'ajouts (Y2O 3, Al2O3 ), afin d'obtenir des matériaux denses. Grâce à la présence de la seconde phase qui leur confère une bonne conductivité électrique, les composites sont usinables par électroérosion (EDM). Leur caractérisation est effectuée par analyses DRX, MEB et MET et leurs propriétés mécaniques (dureté, ténacité, résistance à la rupture à température ambiante et élevée) ainsi que leurs modules élastiques sont analysés. L'étude de la résistance à l'oxydation de ces composites sous flux dynamique d'oxygène pur (900-1400ʿC) montre le meilleur comportement du matériau Si3N4-HfB2. Un matériau multicouche a pu être élaboré après étude de la mouillabilité et de la réactivité d'une brasure Ag-Cu-Ti
The aim of this work was the elaboration and the characterization of electroconductive silicon nitride based ceramic composites Si3N4-TiN, Si3N4-TiB2 and Si3N4-HfB2, elaborated by Hot Isostatic Pressing (HIPing). A small amount of sintering aids (Y2O3, Al2O3) led to good densification and their high electrical conductivity authorized electrodischarge machining (EDM). The characterization of the materials was done by XRD, SEM and TEM analysis. Their mechanical properties (microhardness, fracture toughness, flexural strength at low and high temperatures) and the elastic moduli were analyzed. The oxidation resistance, studied under dynamic conditions in pure oxygen, between 900 and 1400ʿC, showed the better behavior of the Si3N4-HfB2 material. A multi-layered material was elaborated after the study of the wettability and reactivity with an Ag-Cu-Ti braze

Irthing Road is situated 20 kilometres north of the small town of Lumsden in Northern Southland, New Zealand. Irthing Road is accessed from State Highway 97 and leads north-west for 7 kilometres up the Irthing Creek Valley. The research site is situated 4.4 kilometres from the Irthing Road - State Highway 97 intersection and the area is at 300 metres elevation above sea level on gently south sloping Quaternary alluvial deposits. The study was initiated by Environment Southland and Southern Geophysical Ltd with the intention of investigating the potential uses of near surface geophysics in the mapping of shallow groundwater contamination, specifically agriculturally sourced nitrates and leachates. The changes in land use and the introduction of high density grazing of dairy cattle on free draining soils in Southland has created cause for concern around the ease at which large volumes of contaminants could potentially gain access to the shallow groundwater system. The investigation of the Irthing Road field site included: (1) background research into historical land use changes that may have affected the area 2) a study of the Lumsden area geological and hydrogeological setting 3) six trips to the field site throughout the year to collect near surface geophysical data using a Geonics Ltd EM31-MK2, Dualem Inc. DUAL-EM 421s, and Sensors & Software pulseEKKO Pro GPR system; 4) ground- water testing conducted by Environment Southland; 5) an evaluation of the geophysical and groundwater data sets to identify whether leachate concentrations were high enough to register an anomalous response 6) the identification of how the groundwater system at the Irthing Road field site behaves 7) a conclusion as to the effectiveness of all three near surface geophysical techniques in this application. The major conclusions that emerged from this study are: (1) the groundwater system is transporting a large volume of water beneath the site and this leads to such effi- cient removal of contaminants that the concentrations are not high enough to register a response in the geophysical data 2) the groundwater system is highly sensitive to rain- fall and this is a contributing factor to the variation within the geophysical data 3) the Geonics Ltd EM31-MK2 and Sensors & Software pulseEKKO Pro GPR system returned highly consistent results and have great potential in further contaminated groundwater applications 4) Environment Southlands' DUAL-EM 421s needs more consistency, how- ever the device has a lot of potential once reliability can be ensured 5) further research is needed to determine the contamination ow paths and destinations at a larger, regional scale.

Ce travail concerne l'etude de reactions d'oxydo-reduction au sein de verres fondus. L'azote des verres oxyazotes peut reagir avec certains cations metalliques et les reduire. On a effectue une etude thermodynamique des reactions possibles avec un verre fondu du systeme li-si-al-o-n et des oxydes de metaux de la premiere serie de transition, de zinc, de cadmium et de plomb. L'etude effectuee avec le nitrure d'aluminium a ete etendue au carbure de calcium comme reducteur. Ces recherches fondamentales trouvent des applications finalisees dans deux types de domaines : - recuperation de metaux dans des dechets industriels. Les exemples choisis concernent la recuperation de fe-cr-ni et de zn a partir de fumees et scories d'acierie et la recuperation de pb dans des tubes crt usages (crt = cathodic ray tubes). - obtention de composites a matrice vitreuse du systeme y-mg-si-al-o-n et un renfort particulaire de tin prepare in situ. Les caracterisations microstructurales, mecaniques et thermiques de ces composites montrent qu'ils possedent des modules elastiques eleves et une conductivite thermique nettement superieure a celle des verres industriels.

Shelf seas represent an important source of iron (Fe) to the open ocean. Additionally, shelf seas are highly productive environments which contribute to atmospheric carbon dioxide drawdown and support large fisheries. The work presented in this thesis describes the seasonal cycle of Fe in the Celtic and Hebridean Shelf Seas, and determines the physico-chemical speciation of Fe supplied from oxic margins. The results from repeated field surveys of the central Celtic Sea showed a nutrient type seasonal cycling of dissolved Fe (< 0.2 µm; dFe), which is surprising in a particle rich shelf system, suggesting a balance of scavenging and remineralisation processes. Coincident drawdown of dFe and nitrate (NO3-) was observed during the phytoplankton spring bloom. During the bloom, preferential drawdown of soluble Fe (< 0.02 µm; sFe) over colloidal Fe (0.02-0.2 µm; cFe) indicated greater bioavailability of the soluble fraction. Throughout summer stratification, it is known that NO3- is drawn down to < 0.02 µM in surface waters. This study revealed that both dFe and labile particulate Fe (LpFe) were also seasonally drawn down to < 0.2 nM. Consequently, it is hypothesised that the availability of Fe seasonally co-limits primary production in this region. At depth both dFe and NO3- concentrations increased from spring to autumn, indicating that remineralisation is an important process governing the seasonal cycling of dFe in the central Celtic Sea. In spring, summer and autumn, distinctive intermediate nepheloid layers (INL) were observed emanating from the Celtic Sea shelf slope. The INLs were associated with elevated concentrations of dFe (up to 3.25 ± 0.16 nM) and particulate Fe (up to 315 ± 1.8 nM) indicating that they are a persistent conduit for the supply of Fe to the open ocean. Typically > 15% of particulate Fe was labile and 60-90% of dFe was in the colloidal fraction. Despite being < 50 km from the 200 m isobath, the concentration of dFe was < 0.1 nM in surface waters at several stations. Broadly, the concentration of nutrients in surface waters described an oligotrophic environment where co-limitation between multiple nutrients, including Fe, appears likely. Over the Hebridean shelf break, residual surface NO3- concentrations (5.27 ± 0.79 µM) and very low concentrations of dFe (0.09 ± 0.04 nM) were observed during autumn, implying seasonal Fe limitation. The dFe:NO3- ratio observed is attributed to sub-optimal vertical supply of Fe relative to NO3- from sub-surface waters. In contrast to the shelf break, surface water in coastal regions contained elevated dFe concentrations (1.73 ± 1.16 nM) alongside low NO3-. Seasonal Fe limitation is known to occur in the Irminger and Iceland Basins; therefore, the Hebridean shelf break likely represents the eastern extent of sub-Arctic Atlantic seasonal Fe limitation, thus indicating that the associated weakening of the biological carbon pump exists over a wider region of the sub-Arctic Atlantic than previously recognised. These key findings demonstrate that the availability of Fe to phytoplankton may seasonally reach limiting levels in temperate shelf waters and that oxic margins persistently supply Fe dominated by colloidal and particulate fractions to the ocean.

The fate of the carbon and nitrogen in dairy farm effluent (DFE) applied onto soil was investigated through laboratory experiments and field lysimeter studies. They resulted in the development and testing of a complex carbon (C) and nitrogen (N) simulation model (CaNS-Eff) of the soil-plant-microbial system. To minimise the risk of contamination of surface waters, regulatory authorities in New Zealand promote irrigation onto land as the preferred treatment method for DFE. The allowable annual loading rates for DFE, as defined in statutory regional plans are based on annual N balance calculations, comparing N inputs to outputs from the farming system. Little information is available, however, to assess the effects that these loading rates have on the receiving environment. It is this need, to understand the fate of land-applied DFE and develop a tool to describe the process, that is addressed in this research. The microbially mediated net N mineralisation from DFE takes a central role in the turnover of DFE, as the total N in DFE is dominated by organic N. In a laboratory experiment, where DFE was applied at the standard farm loading rate of 68 kg N ha⁻¹, the net C mineralisation from the DFE was finished 13 days after application and represented 30% of the applied C, with no net N mineralisation being measured by Day 113. The soluble fraction of DFE appeared to have a microbial availability similar to that of glucose. The low and gradually changing respiration rate measured from DFE indicated a semi-continuous substrate supply to the microbial biomass, reflecting the complex nature and broad range of C compounds in DFE. The repeated application of DFE will gradually enhance the mineralisable fraction of the total soil organic N and in the long term increase net N mineralisation. To address the lack of data on the fate of faecal-N in DFE, a ¹⁵N-labelled faecal component of DFE was applied under two different water treatments onto intact soil cores with pasture growing on them. At the end of 255 days, approximately 2% of the applied faecal ¹⁵N had been leached, 11 % was in plant material, 11 % was still as effluent on the surface, and 40% remained in the soil (39% as organic N). Unmeasured gaseous losses and physical losses from the soil surface of the cores supposedly account for the remaining ¹⁵N (approximately 36%). Separate analysis of the total and ammonium nitrogen contents and ¹⁵N enrichments of the DFE and filtered sub-samples (0.5 mm, 0.2µm) showed that the faecal-N fraction was not labelled homogeneously. Due to this heterogeneity, which was exacerbated by the filtration of DFE on the soil surface, it was difficult to calculate the turnover of the total faecal-N fraction based on ¹⁵N results. By making a simplifying assumption about the enrichment of the ¹⁵N in the DFE that infiltrated the soil, the contribution from DFE-N to all plant available N fractions including soil inorganic N was estimated to have been approximately 11 % of the applied DFE-N. An initial two-year study investigating the feasibility of manipulating soil water conditions through controlled drainage to enhance denitrification from irrigated DFE was extended a further two years for this thesis project. The resulting four-year data set provided the opportunity to evaluate the sustainability of DFE application onto land, an extended data set against which to test the adequacy of CaNS-Eff, and to identify the key processes in the fate of DFE irrigated onto soil under field conditions. In the final year of DFE irrigation, 1554 kg N ha⁻¹ of DFE-N was applied onto the lysimeters, with the main removal mechanism being pasture uptake (700 kg N ha⁻¹ yr⁻¹ removed). An average of 193 kg N ha⁻¹ yr⁻¹ was leached, with 80% of this being organic N. The nitrate leaching decreased with increasing soil moisture conditions through controlled drainage. At the high DFE loading rate used, the total soil C and N, pH and the microbial biomass increased at different rates over the four years. The long-term sustainability of the application of DFE can only be maintained when the supply of inorganic N is matched by the demand of the pasture. The complex simulation model (CaNS-Eff) of the soil-plant-microbial system was developed to describe the transport and transformations of C and N components in effluents applied onto the soil. The model addresses the shortcomings in existing models and simulates the transport, adsorption and filtration of both dissolved and particulate components of an effluent. The soil matrix is divided into mobile and immobile flow domains with convective flow of solutes occurring in the mobile fraction only. Diffusion is considered to occur between the micropore and mesopore domains both between and within a soil layer, allowing dissolved material to move into the immobile zone. To select an appropriate sub-model to simulate the water fluxes within CaNS-Eff, the measured drainage volumes and water table heights from the lysimeters were compared to simulated values over four years. Two different modelling approaches were compared, a simpler water balance model, DRAINMOD, and a solution to Richards' equation, SWIM. Both models provided excellent estimation of the total amount of drainage and water table height. The greatest errors in drainage volume were associated with rain events over the summer and autumn, when antecedent soil conditions were driest. When soil water and interlayer fluxes are required at small time steps such as during infiltration under DFE-irrigation, SWIM's more mechanistic approach offered more flexibility and consequently was the sub-model selected to use within CaNS-Eff. Measured bromide leaching from the lysimeters showed that on average 18% of the bromide from an irrigation event bypassed the soil matrix and was leached in the initial drainage event. This bypass mechanism accounted for the high amount of organic N leached under DFE-irrigation onto these soils and a description of this bypass process needed to be included in CaNS-Eff. Between 80 and 90% of the N and C leached from the lysimeters was particulate (> 0.2 µm in size), demonstrating the need to describe transport of particulate material in CaNS-Eff. The filtration behaviour of four soil horizons was measured by characterising the size of C material in a DFE, applying this DFE onto intact soil cores, and collecting and analyzing the resulting leachate using the same size characterisation. After two water flushes, an average of 34% of the applied DFE-C was leached through the top 0-50 mm soil cores, with a corresponding amount of 27% being leached from the 50-150 mm soil cores. Most of the C leaching occurred during the initial DFE application onto the soil. To simulate the transport and leaching of particulate C, a sub-model was developed and parameterised that describes the movement of the effluent in terms of filtering and trapping the C within a soil horizon and then washing it out with subsequent flow events. The microbial availability of the various organic fractions within the soil system are described in CaNS-Eff by availability spectra of multiple first-order decay functions. The simulation of microbial dynamics is based on actual consumption of available C for three microbial biomass populations: heterotrophs, nitrifiers and denitrifiers. The respiration level of a population is controlled by the amount of C that is available to that population. This respiration rate can vary between low level maintenance requirements, when very little substrate is available, and higher levels when excess substrate is available to an actively growing population. The plant component is described as both above and below-ground fractions of a rye grass-clover pasture. The parameter set used in CaNS-Eff to simulate the fate of DFE irrigated onto the conventionally drained lysimeter treatments over three years with a subsequent 10 months non-irrigation period was derived from own laboratory studies, field measurements, experimental literature data and published model studies. As no systematic calibration exercise was undertaken to optimise these parameters, the parameter set should be considered as "initial best estimates" and not as a calibrated data set on which a full validation of CaNS-Eff could be based. Over the 42 months of simulation, the cumulative drainage from CaNS-Eff for the conventionally drained DFE lysimeter was always within the 95% CI of the measured value. On the basis of individual drainage bulking periods, CaNS-Eff was able to explain 92% of the variation in the measured drainage volumes. On an event basis the accuracy of the simulated water filled pore space (WFPS) was better than that of the drainage volume, with an average of 70% of the simulated WFPS values being within the 95% CI for the soil layers investigated, compared to 44% for the drainage volumes. Overall the hydrological component of CaNS-Eff, which is based on the SWIM model, could be considered as satisfactory for the purposes of predicting the soil water status and drainage volume from the conventionally drained lysimeter treatment for this study. The simulated cumulative nitrate leaching of 4.7 g NO₃-N m⁻² over the 42 months of lysimeter operation was in good agreement to the measured amount of 3.0 (± 2.7) g NO₃-N m⁻². Similarly, the total simulated ammonium leaching of 2.7g NH₄- N m⁻² was very close to the measured amount of 2.5 (± 1.35) g NH₄- N m⁻² , however the dynamics were not as close to the measured values as with the nitrate leaching. The simulated amount of organic N leached was approximately double that measured, and most of the difference originated from the simulated de-adsorption of the dissolved fraction of organic N during the l0-month period after the final DFE irrigation. The 305 g C m⁻² of simulated particulate C leached was close to the measured amount of 224 g C m⁻² over the 31 months of simulation. The dissolved C fraction was substantially over-predicted. There was good agreement in the non-adsorbed and particulate fractions of the leached C and N in DFE. However, the isothermic behaviour of the adsorbed pools indicated that a non-reversible component needed to be introduced or that the dynamics of the de-adsorption needed to be improved. Taking into account that the parameters were not calibrated but only "initial best estimates", the agreement in the dynamics and the absolute amounts between the measured and simulated values of leached C and N demonstrated that CaNS-Eff contains an adequate description of the leaching processes following DFE irrigation onto the soil. The simulated pasture N production was in reasonable agreement with the measured data. The simulated dynamics and amounts of microbial biomass in the topsoil layers were in good agreement with the measured data. This is an important result as the soil microbial biomass is the key transformation station for organic materials. Excepting the topsoil layer, the simulated total C and N dynamics were close to the measured values. The model predicted an accumulation of C and N in the topsoil layer as expected, but not measured. Although no measurements were available to compare the dynamics and amounts of the soil NO₃-N and NH₄-N, the simulated values appear realistic for an effluent treatment site and are consistent with measured pasture data. Considering the large amount of total N and C applied onto the lysimeters over the 42 months of operation (4 t ha⁻¹ of N and 42 t ha⁻¹0f C), the various forms of C and N in dissolved and particulate DFE as well as in returned pasture, and that the parameters used in the test have not been calibrated, the simulated values from CaNS-Eff compared satisfactorily to the measured data.

碩士
國立高雄海洋科技大學
海洋環境工程研究所
103
Atmospheric aerosols are solid or liquid particles suspended in the atmosphere; in accordance with their origin, they can be broadly divided into: Primary pollutants and Secondary pollutants; according to the differences of aerodynamic diameter range, they can be divided into total suspended particulates TSP, PM10 and PM2.5. Statistics shows that in Chiayi area (Singang, Puzi, Chiayi) when the air quality is poor, the indicator pollutant PM10 accounts for 62%, higher than O3, which shows that PM10 is the primary pollutant affecting the air quality in Chiayi area. The study shows that atmospheric aerosols cause impact on regional visibility, air quality, and human health effects. In this study, with Chiayi county and city air quality monitoring and testing data (between 2007-2013), the concentration trends of pollutants (TSP, PM10, PM2.5), and the composition of sulfate and nitrate proportion among the particles have been discussed, in order to grasp the pollution characteristics with various concentration level for reference of establishing future pollution control strategies. The Monitoring results, from the statistics in three air quality stations in Chiayi county and city, show that the poor air quality (PSI> 100) period falls between January to May and September to December. The index pollutants are mainly suspended particles, accounting for 62%; if during the northeast monsoon coming south (November to April the following year), the number of bad days of suspended particles reaches as high as 89%; the concentration of suspended particles is highly related to seasons. In Chiayi, Puzi, Singang areas, the concentration of TSP showed the situation—winter&spring > autumn> summer, and so do the concentration of PM10 and PM2.5 seasonal trends; the PM10 concentration is bigger in Puzi> Chiayi> Singang; PM2.5 Chiayi> Singang> Puzi; the relation between the concentration of sulfate and nitrate particles in TSP particles and seasons presented: spring and autumn> spring> summer. However, in Chiayi, the two salt concentration in winter and spring is higher than Singang and Puzi. Based on the level of pollutant concentration to identify different pollution conditions, sulfates and nitrations in the moderately polluted state were higher than low pollution state; the higher the concentration of particulate pollutants, the higher trend sulfate and nitrate concentrations; among them, the increasing amount of nitrates is bigger than sulfates. Therefore, how to effectively reduce the concentration of nitrates and sulfates can effectively control the concentration of particulate pollutants in Chiayi. As for sulfur oxidation ratio (SOR) and nitrigen oxidation ratio (NOR), in Chiayi, the seasonal trends for SOR values is spring> summer, autumn> winter, 0.57 on average; NOR value is spring> autumn> summer> winter, 0.16 on average, the correlation of SOR and NOR conversion rate, compared to Chiayi, Puzi and Singang areas, is 0.18, 0.13, 0.13 respectively, with low correlation, showing that the sources of pollution are not consistent, but the conversion rate SOR was higher than 0.25; NOR higher than 0.1, showing as the typical highly oxidized with the possibility of long-range transmission. In summary, the results of this study show that we need to strengthen the particulate pollutants regulation in Chiayi county and city, and it will be the focus on local air quality improvement. The concentration of nitrate should be effectively controlled, and it will help improve particulate pollutants; with the display of SOR, NOR conversion rate, it is possible for oxidation transmission, showing that the local pollution control and cross area joint control are more important.

碩士
國立交通大學
環境工程研究所
84
Annular denuder system, owing to its excellent efficiency on acidic and basicgas and their particulate salts as proved by many laboratory studies, is themost widely used sampling method. But its sampling efficiency was alsoquestioned while detecting nitric acid gaseous concentration during fieldsampling. The interferences were suspected from nitrogen- containing compoundswhich cause positive errors from the real concentration. For example, theinterference of nitrogen dioxide and nitrous acid gas, the adsorption of nitratecontaining particle deposited to the denuder wall by diffusional process, andthe evaporation of ammonium nitrate etc., will produce positive errors to thesampling result.The comparison of Annular denuder sampling system （ ADS ） and Filter pack （FP ） sampling system was made in this study in terms of the sampling of nitricacid gas and particulate nitrate. The results show similar sampling efficienciesfor total nitrate ion, but there were some differences on particulate nitrateand gaseous nitric acid. The collection of particulate nitrate by FP isinterfered probably by nitric acid and nitrous acid gas. The nitrate evaporationrates from the Teflon filter of FP are lower than that from ADS.The ADS has a better efficiency for particulate nitrate than the FP method. Butfor collecting nitric acid gas the ADS is easily interfered by other compounds.According to experimental results, the sampling error of ADS for nitric acid gasusing only one denuder tube may be larger than 100 ﹪. The precipitation orevaporation of particulate nitrate accounts for around 10 ﹪ error, thereforemost of the error may be contributed by other nitrogen-containing gaseouscompounds such as nitrous acid and nitrogen dioxide.

碩士
國立高雄師範大學
化學系
94
Nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) which are formed in incomplete combustion processed and also formed in the atmosphere through photo-oxidation of parent PAHs. Some of these nitrated and oxygenated compounds have mutagenic and carcinogenic properties, which is of concern for environmental and human health. Due to the complexity of the sample matrix interferences , NPAHs, and OPAHs from diesel engine particulate extracts have to pretreatment before analyse. The principle of this work was to extract NPAHs and OPAHs by soxhlet extraction method, cleanup with liquid-liquid extraction technique, and group separation by LC silica column to isolate the NPAHs and OPAHs fractions.Chromatograms of a mixture of NPAHs and OPAHs reference compounds were used to define the fractions windows to be collected. The fractions were concentrated to 1.0 ml prior to GC-MS or GC-ECD analysis. The method detection limits for NPAHs were in a range between 0.01~0.08 pg/μL . The correlation coefficients exceeded 0.997 for the linear dynamic range from 0.0005~10 ng/μL for all analytes.The method detection limits for OPAHs expect phenanthrenequinone were between 0.46~13.1pg/μL . The correlation coefficients exceeded 0.995 for the linear dynamic range from 0.05~5 ng/μL for all analyses except for phenanthrenequinone which the detection limits was 294.5 pg/μL for the linear dynamic range from 10~200 ng/μL. Recoveries of liquid-liquid extraction for most of NPAHs and OPAHs were in a range between 52.0 % ~ 111.7 % , respectively. Recoveries from HPLC separation for NPAHs and OPAHs were in a range between 81.7% ~ 95.7% and 64% ~ 106% , respectively. The proposed methodwas applied to the analyses of references materials SRM1975 , SRM2975 disel engine particulate sample collected from Automotive Research and Testing center in central Taiwan and real ambient air samples collected from Kaohsiung city.

碩士
朝陽科技大學
環境工程與管理系碩士班
91
The technology of thin-film reaction method coated by nitron in the vacuum evaporator to detect particulate nitrate was first established in this study. This technology was then used to investigate the characteristics of particulate nitrate collected by dry deposition plate and micro-orifice uniform deposition impactor (MOUDI) at four different sampling sites (highway intersection, industrial area, coastal area and suburban area). The major results of this study are as follows: 1. Highway intersection has the highest shape factor (Sv) for dry deposition and MOUDI samples, showing that the particles from intersection are most irregular. 2. Highway intersection has the highest total particle dry deposition fluxes, which was caused by heavy traffic from the vehicle exhaust emission and resuspension of soil dust. 3. The percentage of dry deposition fluxes contributed by particulate at diameter less than 10 mm is lowest for nitrate containing particulates, non-nitrate containing particulate and total particles at the highway intersection. More than 90% of particulate dry deposition are contributed from the particulate larger than 10 µm. 4. The NMDs of total particulate are 0.47, 0.33 and 0.61 µm, and MMDs are 27.7, 27.6 and 26.9 µm at the highway intersection, coastal, and suburban sites. Highway intersection site has highest average MMD. Coastal area site has lowest NMD and high MMD. Low NMD is caused by secondary aerosol in the form of non-sea-salt sulfate and organic species, formed by gas-to-particle conversion processes. High MMD is caused by coarse sea-salt aerosol. 5. All number size distributions had much higher sg than mass size distributions at the four sampling sites. The result shows that the number size distributions disperse wider than mass size distribution. 6. The number frequencies of NCP for particle diameter less than 2.5 mm were 84.9%, 83.2% and 79.1% for the highway intersection, coastal and suburban areas, respectively, showing that most NCPs appeared in fine size ranges. 7. For these four sampling sites, fine particulate dominates in the nitrate containing particulate. It is the same for MOUDI samples. 8. A model was used to calculate dry deposition speed and compare with that estimated by this study. The simulated dry deposition speed is greater than that estimated in this study for particle diameter smaller than 10 mm. For the particle size greater than 10 mm, the result is opposite. 9. In this study, a particulate density of 1.77 g cm-3 for fine particulates (diameter £ 2.5 mm) and 2.64 g cm-3 for coarse particulates (diameter > 2.5 mm) was adopted. The estimated dry deposition fluxes were almost the same as those calculated by weighing the collected particulate. The adoption of SD value was examined by comparing the mass of particles collected by weighing and that calculated by the method in this study for each stage of MOUDI. SD values of 1.21 for fine particle (diameter £ 2.5 mm) and 1.38 for coarse particle (diameter > 2.5 mm) would provide more precise estimation of particulate dry deposition flux.