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In this study, a regenerative thermal oxidizer (RTO) was used to test the relationship between VOC concentration and nitrogen oxides(NOx) formed, and to estimate its performance. The RTO is electrically heated and contains two 0.152 m ¡Ñ 0.14 m ¡Ñ 1.0 m (L ¡Ñ W ¡Ñ H) beds both packed with gravel particles of around 1.11 cm in average diameter to a height of 1.0 m. The bed has a void fraction of 0.416. Experiments include two phases: (1) tests to find the VOC destruction and NOx formed with DMF only in the influent air stream in the following condition: setting temperature Tset=700-900oC, flowrate Q=0.5-1.0 Am3/min, influent concentration Co=0-500ppm, shift time ts=1.5 min. and before that, to test the effect to thermal recovery efficiency and pressure drop. (2) tests to find the VOC destruction and NOx formed for the air stream with MEK/DMF mixed in the influent air stream in the following condition: setting temperature Tset=600-900oC ,flowrate Q=0.5 Am3/min, influent MEK/DMF ratio =100/100,200/100,500/100(ppm/ppm), shift time ts=1.5 min. and before that, to test the effect to thermal recovery efficiency and pressure drop. Result show : (1)there have no NOx formed in cool-bed with DMF only in the influent air stream. DMF destruction is proportional to influent concentration(low Co > high Co ) and setting temperature(900 > 800 > 700oC).NOx formed is inversely proportional to Co.(2)in the phase two Experiment, DMF destruction is proportional to add MEK in. NOx formed is inversely proportional to Co. MEK/DMF ratio is proportional to (NOx formed/DMF removed) at Tset=600oC,but not closely related during Tset=700-800oC.NO2 formation is significant at Tset=800 oC. (3)Ergun equation is suitable to estimate pressure drop of RTO.

Regenerative oxidation is an economic and effective means of controlling volatile organic compounds (VOCs) with concentrations exceeding 1,200 mg/m3 in gas streams. Regenerative catalytic oxidizers (RCO) and regenerative thermal oxidizers are two main applications for the regenerative oxidation. However, factors influencing the performance of regenerative oxidation when treating VOCs in gas streams have seldom been addressed. Therefore, this study presents a convection-dispersion model with an effective thermal diffusivity (£\e ) as a parameter to simulate the performance of regenerative beds. To verify the effectiveness of the proposed model, a pilot-scale RCO was constructed with two 20-cm x 200-cm (ID x H) regenerative beds. Gravel was used as the thermal regenerative solid material. Experimental results indicated that the model with an £\e of 2.0-3.8 x 10-6 m2/s can be used to describe the time variation of solid temperatures with the packing height at superficial gas velocities (Ug ) of 0.080-0.382 Nm/s . Values of£\e for the bed are closer to those for the gravel solids (£\s = 1.0 x 10-6 m2/s) than for air (£\g = 54 x 10-6 m2/s). Those results demonstrate that the conductive heat transfer in the solid material in the axial direction of the bed is a major controlling factor for the performance of the RCO and the convective one is a minor factor in the present case. The above pilot RCO was then used to treat methyl ethyl ketone (MEK) and toluene, respectively, in air streams. The catalyst bed temperature was kept around 400oC and the Ug was operated at 0.234 Nm/s. This investigation measured and analyzed distributions of solid and gas temperatures with operating time and variations of VOC concentrations in the regenerative beds. The overall VOCs removal efficiency exceeded 98% for MEK of around 800 ppm as methane and 95% for toluene of around 400 ppm as methane. Degradation of MEK was believed to occur on the surface of solid material (gravel) in the temperature range of 330-400oC, which is much lower than its autoignition point, and toluene did not exhibit this phenomenon. The calculated energy conservation presents that RCO is an economic approach to treat VOCs, and it should be much further applied to industrial fields. Furthermore, based on the earlier empirical results of RCO, a series of plant scale low temperature regenerative oxidizers (LTRTOs) equipped with heating wires were constructed to treat VOC-laden gas streams. The regenerative beds were still packed with the same gravel which was applied to the above pilot RCO. Gas streams for performance tests were exhausted from manufacturing sections of varnishing, semiconductor packing, and petrochemical plants, respectively. Components of tested VOCs were comprised of several commercial solvents (e.g. ketone, toluene, iso-propanol, methanol, ethanol, formaldehyde, dimethylamine, and others). Results indicate that exceeding 98% of single or multiple VOCs with concentrations of less than 100 and increasingly to 7,000 ppm as methane would be effectively destroyed. Gas temperature variations with time at various bed depths were analyzed, and results confirm that the degradation of VOCs exists in the gravel beds at the temperatures ranging from 300 to 440oC, which are much lower than auto-ignition points of tested compounds. Moreover, the residence time for a gas stream passing through the main oxidation zone (Tg >300oC) in the regenerative beds is an essential criteria for LTRTO design and 1.0 s is recommended. These findings demonstrate that LTRTO is an effective approach to treat VOCs.

Although incipient fungal decay of wood may be difficult to detect early, it causes a significant decrease in wood strength. Developing a reliable method of decay identifica-tion to overcome wood replacement costs by non-destructive methods is necessary. This study investigates a possibility of identifying fungal volatile organic compounds (VOCs) as means of fungal detection using solid phase micro-extraction (SPME) coupled with gas chromatography–mass spectrometry (GC-MS). Volatile emissions from two brown rot (Gloeophyllum trabeum and Postia pla-centa) and two white rot (Trametes versicolor and Irpex lacteus) fungi on pine and aspen and their profiles related to wood mechanical strength and mass loss were investigated over 12 weeks. Principal component analysis of VOCs spectra differentiated volatiles from decayed and sound wood. Volatiles from two fungal species revealed distinct pat-terns of early and late degradation stages. SPME combined with GC-MS showed promissing results for non-destructive identification of incipient decay in wood struc-tures.

The EPA recently completed a major study to evaluate exposure and risk associated with a primary contaminant, radon and its progeny in drinking water (EPA, 1995). This work resulted in the development of a Monte Carlo Simulation model written in the programming language C. The model developed by the EPA has been used to estimate the cancer fatality risk from radon in water for exposed populations served by community ground water supplies, and to provide a quantitative analysis of the uncertainty associated with the calculations (EPA, 1995). This research is a continuation of the study conducted by the EPA. In this project, a Monte Carlo computer model will be developed to evaluate the risk associated with exposure to volatile compounds in drinking water. The model will be based on a computer program (developed previously by the EPA) for estimating the risks associated with exposure to radon in drinking water. The model will be re-implemented in the form of a computer program written in C. The analysis for radon will be extended to include the entire range of contaminants found in drinking water supplies. The initial focus of the project has been on extending the analysis to cover the ingestion exposure pathway for volatile compounds, but ultimately the risk via ingestion and dermal sorption will also be evaluated. The integrated model can estimate the risks associated with various levels of contaminants in drinking water and should prove valuable in establishing Maximum Contaminant Levels (MCLs) for the entire range of contaminants found in water supplies and generated in water treatment and distribution systems. / Master of Science

Volatile organic compounds (VOCs) are emitted into the atmosphere from biogenic and anthropogenic sources with atmospheric lifetimes ranging from minutes to months, depending on the specific VOC compound considered. It is estimated that biogenic VOCs (BVOCs) (e.g. isoprenes, terpenes) make up 90% of the global atmospheric VOC budget. However, in highly industrialised regions, anthropogenic VOCs (e.g. benzene, toluene, ethylbenzene and xylene, combined abbreviated as BTEX) might dominate. VOCs have various reversible and irreversible effects on human health. They also have environmental impacts that range from changes in the population of terrestrial and aquatic ecosystems to the extinction of vulnerable species. VOCs are precursors for the formation of ozone (O3) during solar radiation initiated reactions in the presence of NOx. Tropospheric O3 is considered a pollutant, with negative impacts on human health, ecosystems and food security. O3 is also a short-lived greenhouse gas. Through reactions with radical species, VOCs lead to the formation of higher molecular weight organic compounds, which produce carbon monoxide (CO), peroxyacytyl nitrate (PAN) and ultimately secondary organic aerosol (SOA) particles. SOA particles impact directly on air quality and visibility, as well as directly and indirectly on the radiation balance of the earth that contributes to the regulation of climate. Notwithstanding the importance of atmospheric VOCs, limited data is available for VOCs in South Africa. In this study, a comprehensive dataset of BVOC and anthropogenic VOC species was obtained at the Welgegund measurement station in the North West Province, South Africa. Measurements were conducted from 9 February 2011 to 4 February 2012. Samples were collected on Tenax-TA and Carbopack-B adsorption tubes twice a week for two hours during day time and two hours during night time. The first 1.25m of the stainless steel sampling inlet was heated to 120ºC to remove O3 that could lead to sample degradation. Analyses of the sampled adsorption tubes were conducted by thermal desorption, cryofocusing, re-desorption, followed by gas chromatography separation and analysis with a mass selective detector (GC-MS). The results indicated that toluene was the most abundant aromatic hydrocarbon and heptane the most abundant alkane. Benzene is currently the only VOC listed as a criteria pollutant in the South African Air Quality Act with an annual average standard of 1.6ppb. The annual median benzene concentration was 0.13 ppb, while the highest daily benzene concentration measured was 8.7 ppb. No distinct seasonal cycles were identified for anthropogenic VOC species measured, i.e. aromatic hydrocarbons and alkanes. However, air mass history analysis indicated that air masses that passed over the Mpumalanga Highveld, the Vaal Triangle and the Johannesburg-Pretoria conurbation (collectively referred to as Area I) had significantly higher concentrations of these anthropogenic VOCs compared to air masses that passed over the western and eastern Bushveld Igneous Complex, and a region over which air masses typically followed an anti-cyclonic movement pattern (collectively referred to as Area II). Anthropogenic VOC levels in air masses that passed over the regional background (areas with no large point sources) had levels similar to air masses that had passed over Area II. Relatively good interspecies correlations (r > 0.8) between most of the aromatic hydrocarbons in air masses that had passed over Area I, with the exception of benzene, indicated that these species had common sources. Benzene, however, correlated well with CO, indicating that sources associated with incomplete combustion were most likely the origin of benzene in air masses that had passed over Area I. The interspecies concentration ratios for plumes passing over Area I indicated that this source region is relatively close to the Welgegund monitoring station and air masses that passed over this source region were substantially influenced by anthropogenic activities. The concentration ratios for plumes that passed over Area II and the Regional Background indicated that these were aged air masses. Furthermore, the concentration ratios of toluene, ethylbenzene and o,m,p-xylene (TEX) to the total aromatic concentration for air masses that passed over the various source regions showed a greater contribution to the total VOC concentration during periods of higher temperature, i.e. summer. This proved that the evaporation of solvents contributes significantly to VOC levels during the months with higher temperatures. The relative contribution of aromatic hydrocarbons to photochemical O3 formation in air masses that passed over the various source regions indicated the highest contribution was observed for air masses that passed over Area I, with Area II and the Regional Background in the same order of magnitude. The annual temporal variations of the measured BVOCs indicated that 2-methyl-3-buten-2-ol (MBO) and isoprene exhibited distinct seasonal patterns, i.e. higher values in summer and lower values in winter. The monoterpenes (MT) and the sesquiterpenes (SQT) did not follow distinct seasonal patterns. BVOC concentrations correlated relatively well to seasonal variations in temperature, photosynthetically active radiation (PAR), rainfall, relative humidity (RH) and CO2 flux. This proved that biogenic activity is responsible for BVOCs emitted. The most abundant MT was -pinene, while -caryophyllene was the most abundant SQT with annual median concentrations of 0.468 ppb and 0.022 ppb, respectively. Pollution roses for isoprene showed a dominance of sources from the north-west to the north-east, as well as the south-east. These directions correlated to areas where pockets of the savannah biome are located. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2013

Volatile organic compounds (VOCs) are emitted into the atmosphere from biogenic and anthropogenic sources with atmospheric lifetimes ranging from minutes to months, depending on the specific VOC compound considered. It is estimated that biogenic VOCs (BVOCs) (e.g. isoprenes, terpenes) make up 90% of the global atmospheric VOC budget. However, in highly industrialised regions, anthropogenic VOCs (e.g. benzene, toluene, ethylbenzene and xylene, combined abbreviated as BTEX) might dominate. VOCs have various reversible and irreversible effects on human health. They also have environmental impacts that range from changes in the population of terrestrial and aquatic ecosystems to the extinction of vulnerable species. VOCs are precursors for the formation of ozone (O3) during solar radiation initiated reactions in the presence of NOx. Tropospheric O3 is considered a pollutant, with negative impacts on human health, ecosystems and food security. O3 is also a short-lived greenhouse gas. Through reactions with radical species, VOCs lead to the formation of higher molecular weight organic compounds, which produce carbon monoxide (CO), peroxyacytyl nitrate (PAN) and ultimately secondary organic aerosol (SOA) particles. SOA particles impact directly on air quality and visibility, as well as directly and indirectly on the radiation balance of the earth that contributes to the regulation of climate. Notwithstanding the importance of atmospheric VOCs, limited data is available for VOCs in South Africa. In this study, a comprehensive dataset of BVOC and anthropogenic VOC species was obtained at the Welgegund measurement station in the North West Province, South Africa. Measurements were conducted from 9 February 2011 to 4 February 2012. Samples were collected on Tenax-TA and Carbopack-B adsorption tubes twice a week for two hours during day time and two hours during night time. The first 1.25m of the stainless steel sampling inlet was heated to 120ºC to remove O3 that could lead to sample degradation. Analyses of the sampled adsorption tubes were conducted by thermal desorption, cryofocusing, re-desorption, followed by gas chromatography separation and analysis with a mass selective detector (GC-MS). The results indicated that toluene was the most abundant aromatic hydrocarbon and heptane the most abundant alkane. Benzene is currently the only VOC listed as a criteria pollutant in the South African Air Quality Act with an annual average standard of 1.6ppb. The annual median benzene concentration was 0.13 ppb, while the highest daily benzene concentration measured was 8.7 ppb. No distinct seasonal cycles were identified for anthropogenic VOC species measured, i.e. aromatic hydrocarbons and alkanes. However, air mass history analysis indicated that air masses that passed over the Mpumalanga Highveld, the Vaal Triangle and the Johannesburg-Pretoria conurbation (collectively referred to as Area I) had significantly higher concentrations of these anthropogenic VOCs compared to air masses that passed over the western and eastern Bushveld Igneous Complex, and a region over which air masses typically followed an anti-cyclonic movement pattern (collectively referred to as Area II). Anthropogenic VOC levels in air masses that passed over the regional background (areas with no large point sources) had levels similar to air masses that had passed over Area II. Relatively good interspecies correlations (r > 0.8) between most of the aromatic hydrocarbons in air masses that had passed over Area I, with the exception of benzene, indicated that these species had common sources. Benzene, however, correlated well with CO, indicating that sources associated with incomplete combustion were most likely the origin of benzene in air masses that had passed over Area I. The interspecies concentration ratios for plumes passing over Area I indicated that this source region is relatively close to the Welgegund monitoring station and air masses that passed over this source region were substantially influenced by anthropogenic activities. The concentration ratios for plumes that passed over Area II and the Regional Background indicated that these were aged air masses. Furthermore, the concentration ratios of toluene, ethylbenzene and o,m,p-xylene (TEX) to the total aromatic concentration for air masses that passed over the various source regions showed a greater contribution to the total VOC concentration during periods of higher temperature, i.e. summer. This proved that the evaporation of solvents contributes significantly to VOC levels during the months with higher temperatures. The relative contribution of aromatic hydrocarbons to photochemical O3 formation in air masses that passed over the various source regions indicated the highest contribution was observed for air masses that passed over Area I, with Area II and the Regional Background in the same order of magnitude. The annual temporal variations of the measured BVOCs indicated that 2-methyl-3-buten-2-ol (MBO) and isoprene exhibited distinct seasonal patterns, i.e. higher values in summer and lower values in winter. The monoterpenes (MT) and the sesquiterpenes (SQT) did not follow distinct seasonal patterns. BVOC concentrations correlated relatively well to seasonal variations in temperature, photosynthetically active radiation (PAR), rainfall, relative humidity (RH) and CO2 flux. This proved that biogenic activity is responsible for BVOCs emitted. The most abundant MT was -pinene, while -caryophyllene was the most abundant SQT with annual median concentrations of 0.468 ppb and 0.022 ppb, respectively. Pollution roses for isoprene showed a dominance of sources from the north-west to the north-east, as well as the south-east. These directions correlated to areas where pockets of the savannah biome are located. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2013

ABSTRACT Being a densely populated and heavily industrialized harbor, the emissions of air pollutants in the Kaohsiung area are very huge. There is substantial amount of VOCs (volatile organic compounds) present in the ambient air. Furthermore, relative high temperature and strong sunlight tend to transform these VOCs to oznone, causing high ozone episodes. This study aimed to determine the VOCs source profiles (or fingerprints) from 20 stationary sources, 10 from each of Kaohsiung City and Kaohsiung County. These include flue gas emission from incineration plants, sewage treatment plants, petroleum plants, and others. The samples was collected using a stainless-steel thermal desorption tube, then analyzed a Hewlett-Packard 58900-II gas chromatograph, fitted with a flame ionization detector and desk-top personel computer. The OFP (ozone formation potential) of VOCs from individual sources were evaluated based on MIR (maximum incremental reactivities). The results show that the speciations of VOCs depend on the raw material and air pollution control equipments used in the processes. The major VOCs in the petro-chemical industries are benzene, toluene, xylene, and 1,3,5-trimethylbenzene. The major VOCs in the PVC processes and surface-painting industries are 2-methylbutane, 2-methylpentane, and ethylbenzene. The major VOCs in the sewage treatment plants are ethylene, hexane, benzene, toluene, and m-xylene. The highest average reaction of the samples is 27.94 g-O3/g-VOCs from intermediary process, the next are from lubrication oil distillation tower, TPE process, ABS process, and maleic anhydride process, ranging from 3 ~ 5 g-O3/g-VOCs. Thus, the reactivity of aromatic-related process is highest, the next are aldehydes - and ketones -related processes. Keywords: Volatile Organic Compounds, Fingerprints, Ozone Formation Potential

This work aims to figure out the history and footpath of the trials and combats against VOCs emission in China. As China is a country that overlooked the environmental problems for decades (e.g. VOCs emissions), China’s environmental management system has not been mature and well-functioned towards current severe environmental pollution over China. Hence, a sounder and more flexible system for controlling VOCs emission from industry should be built up, urgently. This paper also attempts to come up with some reasonable and practical suggestions for improvement of the environmental management system with inspiration from European countries and markets. In this paper, “management system” and “treatment technology” in China are both options that will be explored thoroughly. Desktop research and interviewing are the major means of investigation. As to some research on management system, China’s national policies, provincial policies, emission standards, etc. are investigated; in addition, on-going treatment technology in China by enterprises and companies are also explored, with a summary of VOCs recovery and treatment techniques. European countries are explored as pioneers and models for treatment of VOCs emission. By learning some technology created and applied in EU markets, Chinese market can also be inspired and introduced. After that, some analysis on China’s VOCs management system coming from several aspects, i.e. governance dilemma, technology application, economic initiative and public participation, is made. Finally, some recommendation for management policies and technology application have been proposed as well, as a result of this study on VOCs emission for China’s authorities. / Det här arbetet syftar till att ta reda på historien och gången i försöken och bekämpa utsläpp av VOC i Kina. Eftersom Kina är ett land som förbisedde miljöproblemen i årtionden (t ex VOC-utsläpp) har Kinas miljöledningssystem inte varit moget och välfungerat mot nuvarande allvarlig miljöföroreningar över Kina. Därför bör ett kraftigare och mer flexibelt system för kontroll av VOC-utsläpp från industrin byggas upp, snabbt. I detta försök försöker man också få fram några rimliga och praktiska förslag till förbättring av miljöledningssystemet med inspiration från europeiska länder och marknader. I detta dokument är "management system" och "behandlingsteknik" i Kina båda grenar som kommer att undersökas noggrant. Skrivbordsundersökningar och intervjuer är viktiga medel för undersökning. När det gäller viss forskning om ledningssystemet undersöks Kinas nationella politik, provinspolitik, utsläppsstandarder etc. Dessutom har även pågående behandlingsteknik i Kina av företag och företag utforskats, med en sammanfattning av VOCs återvinnings- och behandlingstekniker. Europeiska länder har utforskats som pionjärer och modeller för behandling av VOC-utsläpp. Genom att lära sig någon teknik som skapats och tillämpas på EU-marknader kan den kinesiska marknaden också inspireras och introduceras. Slutligen har man också föreslagit en del rekommendationer om förvaltningspolitik och teknikansökan, som en följd av denna studie om utsläpp av VOC i både Kina och Europa.

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