Abstract  This paper presents the performance of a dielectric barrier discharge (DBD) device, when powered by a single phase, voltage source, 4-pulse, PWM inverter. The main focus of this paper is to investigate the applicability of switch-mode inverters in supplying DBD devices to generate plasma body forces. Also, this paper aims to establish relationships between the frequency of the inverter output voltage, switching frequency, and modulation index with the plasma-generated body force. A plate made of Plexiglas dielectric material, which has a relative permittivity of epsilon approximate to 3.2, is utilized in all experimental tests. Moreover, the test dielectric barrier discharge device is modeled using the linear high frequency model in order to demonstrate its applicability to simulate the responses of these devices. Test results show that the plasma-generated body force has a direct dependence on the frequency of the inverter output voltage and modulation index, while it has a minor dependence on the switching frequency. Furthermore, test results show close matches between the experimental and simulation results that support the use of the linear high frequency model in designing, controlling, and operating inverters for supplying dielectric barrier discharge devices.

Abstract  Zearalenone (ZEN) and ochratoxin A (OTA) are secondary toxic metabolites of fungi that can contaminate a wide range of food and feedstuff. In this study, the effects of ozone treatment on ZEN and OTA and the quality of ozonised corn are investigated. Ozone significantly affects ZEN and OTA solutions. ZEN was undetectable 5 s after being treated with 10 mg l-1ozone. However, OTA was resistant to ozonation with a degradation rate of 65.4% after 120 s of treatment. Moreover, ZEN and OTA solutions were difficult to degrade after being dried by a nitrogen stream. Results showed that ozone effectively degraded ZEN and OTA in corn. The degradation rates of ZEN and OTA in corn increased with ozone concentration and treatment time. The degradation of ZEN and OTA at different ozone concentrations appropriately conformed to first-order kinetics with an R2value > 0.8749. Furthermore, under the same conditions, corn with increased moisture content (MC) (19.6%) was more sensitive to ozone than corn with a low MC (14.1%). When treated with 100 mg l-1ozone for 180 min, ZEN and OTA in corn with 19.6% MC decreased by 90.7% and 70.7%, respectively. To evaluate the quality of ozonised corn, subsequent quality experiments were conducted using corn samples treated at different times with 100 mg l-1ozone. The MC of corn decreased after ozone treatment. The whiteness and yellowness of the corn increased and decreased with increasing time, respectively. The fatty acid value of the corn increased significantly (p ≤ 0.05) after 180 min of treatment. This study verified that ozone can effectively degrade ZEN and OTA in corn, but slightly affected corn quality.

Abstract  This plant-scale investigation compared two process improvement strategies for Lianyungang drinking water treatment plant (L-DWTP), a typical plant employing conventional processes to treat source water impacted by seasonal non-point pollution. Hierarchical cluster analysis grouped it into two clusters, i.e. normal period and polluted period. Originally, the L-DWTP exhibited poor organic matter removal efficiency, and 76.7% of the effluent permanganate index (CODMn) levels exceeded the state regulation requirement (<3mg/L). In addition, chloroform concentration was observed to exceed the regulation requirement (60 mu g/L) by 14.2 and 56.2% in normal and polluted periods. The combined use of FeCl3 and KMnO4 (Fe-Mn enhanced coagulation) increased the CODMn removal efficiency by 10.6%, and decreased the chloroform formation by 26.4%. It indicates that about 94.5% of effluent CODMn values and nearly all of chloroform levels may meet the standard in normal period. However, Fe-Mn enhanced coagulation shows limitation in polluted period. The advanced treatment by ozone-biological activated carbon process (O-3-BAC) increases the CODMn removal efficiency by 29.5%, and decreases the chloroform formation by 43%, indicating that effluent levels may meet the standard both in normal and polluted periods. Cost was also compared, and the extra cost for Fe-Mn enhanced coagulation is only about 20% of that for O-3-BAC. In conclusion, O-3-BAC works well both in normal and polluted periods. Fe-Mn enhanced coagulation only shows good performance in normal period, but is more economical. Therefore, it is proposed to use Fe-Mn enhanced coagulation in normal period, while O-3-BAC during polluted period. These obtained plant-scale data are valuable to optimize the operation of DWTPs with similar challenges.

Abstract  Cobalt-rich slag from blister refining is leached with an oxidising acid, and Co3O4 powder is prepared by an ozonation-precipitation-calcination method after iron has been removed from the solution by the goethite process at different pH values. The effects of stirring speed, gas flow rate, ozone concentration, pH and solution temperature on the precipitation rate of cobalt are investigated. The solution pH has an obvious effect on the precipitation rate, as do the stirring speed, gas flow rate and ozone concentration, but the temperature has little effect. With almost all the cobalt precipitated from the solution, the losses of copper and zinc are about 10% and 1.5%, respectively. The cobalt is precipitated in the form of amorphous CoOOH, identified by X-ray diffraction and with some physicochemical properties similar to those of cobalt hydroxide. The amorphous CoOOH is transformed into spherical Co3O4 powder by the calcination treatment.

Abstract  A process utilizing ozone as the precipitant for the oxidation-precipitation of cobalt from cobalt chloride solution has been studied. The main factors affecting the oxidation rate such as the stirring speed, solution temperature, ozone partial pressure, initial concentration and flow rate were investigated comprehensively. The results demonstrated that the precipitate was CoOOH and the precipitation reaction is diffusion-controlled. The oxidation rate was independent of the initial concentration or solution temperature. The oxidation rate increases obviously with increasing the stirring speed. The Linear Relationship Between ozone partial pressure or flow rate and oxidation rate was found in this paper.

Abstract  Fusarium head blight is a plant disease with significant agricultural and health impact which affects cereal crops such as wheat, barley, and maize and is characterized by reduced grain yield and the accumulation of trichothecene mycotoxins such as deoxynivalenol (DON). Studies have identified trichothecene production as a virulence factor in Fusarium graminearum and have linked DON resistance to the ability to form DON-3-O-glucoside in wheat. Here, the structures of a deoxynivalenol:UDP-glucosyltransferase (Os79) from Oryza sativa are reported in complex with UDP in an open conformation, in complex with UDP in a closed conformation, and in complex with UDP-2-fluoro-2-deoxy-d-glucose and trichothecene at 1.8, 2.3, and 2.2 Å resolution, respectively. The active site of Os79 lies in a groove between the N-terminal acceptor and the C-terminal donor-binding domains. Structural alignments reveal that Os79 likely utilizes a catalytic mechanism similar to those of other plant UGTs, with His 27 activating the trichothecene O3 hydroxyl for nucleophilic attack at C1' of the UDP-glucose donor. Kinetic analysis of mutant Os79 revealed that Thr 291 plays a critical role in catalysis as a catalytic acid or to position the UDP moiety during the nucleophilic attack. Steady-state kinetic analysis demonstrated that Os79 conjugates multiple trichothecene substrates such as DON, nivalenol, isotrichodermol, and HT-2 toxin, but not T-2 toxin. These data establish a foundation for understanding substrate specificity and activity in this enzyme and can be used to guide future efforts to increase DON resistance in cereal crops.

Abstract  Organic micropollutants (OMP), e.g. pharmaceuticals and household/industrial chemicals, are not fully eliminated in state-of-the-art municipal wastewater treatment plants and can potentially harm the aquatic environment. Therefore, several pilot and large-scale investigations on the elimination of organic micropollutants have taken place in recent years. Based on the present findings, the most efficient treatment steps to eliminate organic micropollutants have proven to be ozonation, adsorption on powdered activated carbon (PAC), or filtration through granular activated carbon (GAC). Yet a further treatment step implies an increase in energy demand of the wastewater treatment plant, which has to be considered along with OMP elimination. To this aim, data on energy demand of ten large-scale municipal wastewater treatment plants (WWTP) with processes for OMP elimination was collected and analyzed. Moreover, calculations on energy demand beyond the WWTP for production and transport of ancillary materials were performed to assess the cumulative energy demand of the processes. An assessment of the greenhouse gas emissions of the processes was achieved, which shall facilitate future life cycle analyses. The results show that energy demand of ozonation at the wastewater treatment plant is dependent upon the ozone dosage and is significantly higher than energy demand of PAC addition or GAC filtration (2 to 4 times higher without consideration of delivery heads). Despite uncertainties regarding the energy demand for production of activated carbon, it could be shown that the cumulative energy demand of adsorption steps is significantly higher than the energy demand at the WWTP. Using reactivated GAC can lead to energy and greenhouse gas emissions savings compared to using fresh GAC/PAC. Moreover, energy demand is always plant-specific and depends on different factors (delivery heads, existing filtration or post-treatment etc.). Since processes for elimination of organic micropollutants are still in a developing phase, future optimization steps shall minimize their energy demand.

Abstract  Thanks to its excellent insulation and cutoff performances, SF6 gas has been applied to power equipment since the 1960s and is now widely used for several kV to 1,000 kV-class GIS, GCB, and GIL. However, since 1997, when SF6 was designated at COP3 as a greenhouse gas to be reduced, there has been a wish to use an alternative insulating gas to pure SF6 gas. In the present study, alternative gases were selected from among mixtures excluding SF6 with the need to reduce GWP (global warming potential) in mind. Gas mixtures containing such substances and with a boiling point of -20 degrees C or less, chemically stable, non-toxic, and not ozone-depleting were prioritized. Furthermore, the availability and environmental performance were taken into consideration when deciding on component gases. Consequently, to launch this series of studies, four types of gas mixtures were used combining a gas in Group A (C2F6, C3F8) - electronegative gases with relatively high dielectric strength - and a gas in Group B (N-2, CO2) - gases existing in the natural world. The GWP of SF6 is 22,800 whereas that of C2F6 is 12,200 and that of C3F8 is 8,830, or several times smaller than that of SF6. In the present paper, insulation characteristics were experimentally obtained while varying the mixture ratio under a quasi-uniform electric field assuming GIS. Consequently, compared to the GWP of pure SF6, the GWP was about 12% to 38% for gas mixtures with C3F8/N-2 or C3F8/CO2 and 18% to 70% for gas mixtures with C2F6/N-2 or C2F6/CO2. Consequently, it emerged that, while assuming breakdown voltage proportional to gas pressure, the GWP was likely to be reduced by 30% to 90% while maintaining dielectric strength. In addition, a study was conducted on the synergism of a gas mixture through analysis using the Boltzmann equation. Consequently, the synergism was confirmed while its degree varied depending on the type of each gas mixture, and the mechanism thereof was clarified.

Abstract  Studies of grain drying with ozone-air mixture were carried out to detect the ozone penetration patterns through the grain mound of various moisture content (14.6 <= w(0) <= 23.0%) at different ozone concentrations (500 <= C-0 <= 1250 ppb) in the supplied air. The ozone penetration through the grain layer depends on the initial ozone concentration in the supplied air, ozonation time, velocity of the supplied air, height of the grain mound, initial grain moisture content and mycobiotic contamination of grain surface. It was determined that in a 60 cm height of the grain layer ozone is first recorded after 12 h, and at 105 cm - only after 34 h at w(0) = 19.0%, C-0 = 500 ppb. If the initial concentration of ozone is higher, it is first recorded sooner. Ozone penetration through the grain layer with higher moisture level is slower, and ozone reaction with grain surface and microflora present on it is longer.

Hypothesis about the adequacy of the model (how it reflects the real process) has been verified by calculating reproduction and adequacy variance. The mathematical model could be applied for prediction of the course of grain ozonation process.

Abstract  Air-conditioning systems in PWR nuclear power plants employ activated carbon filters to remove radioactive iodine compounds. Although the removal efficiency of radioactive iodine by activated carbon is very high, the total removal efficiency of iodine decreases if there is a bypass leak from a filter frame, gasket or elsewhere when the filters are attached to the unit. Thus, when the filters have been installed, it is necessary to ensure that the leak rate is below the tolerance level. The leak rate is determined by measuring the bypass leak of tracer gas that does not pass through the activated carbon bed. However, use of the conventional chlorofluorocarbon (R112) as tracer gas has now been abolished because of the accompanying risk of ozone depletion, so it is necessary to find an alternative reagent. Here, we report the results of a series of basic experiments to examine the applicability of alternative reagents.

Abstract  The medical use of ozone has been based on its antibacterial and oxidative characteristics. Currently ozone is being discussed in dentistry as a possible alternative oral antiseptic agent. In this study, we examined the hemostatic effect of water and gel contains aqueous ozone in animal testing. The mean of bleeding time using ozonated water and ozonated gel were observed for significant difference compared with no treatment. 0.5 ppm diluted ozonated water shortened bleeding time the same as 4.0 ppm ozonated water. These results suggest that ozonated water and gel which contains aqueous ozone show hemostatic ability which is almost equal to the Bosmin solution and Liquid Thrombin.

Abstract  Ultrasound (US) guided medical devices placement is a widely used clinical technology, yet many factors affect the visualization of these devices in the human body. In this research, an ultrasound-activated film was developed that can be coated on the surface of medical devices. The film contains 2 mu m silica microshells and poly(methyl 2-cyanoacrylate) (PMCA) adhesive. The air sealed in the hollow space of the microshells acted as the US contrast agent. Ozone and perfluorooctyltriethoxysilane (PFO) were used to treat the surface of the film to enhance the US signals and provide durable antifouling properties for multiple passes through tissue, consistent with the dual oleophobic and hydrophobic nature of PFO. In vitro and in vivo tests showed that hypodermic needles and tumor marking wires coated with US activated film gave strong and persistent color Doppler signals. This technology can significantly improve the visibility of medical devices and the accuracy of US guided medical device placement.

Abstract  Recent satellite observations of sun-induced chlorophyll fluorescence (SIF) are thought to provide a large-scale proxy for gross primary production (GPP), thus providing a new way to assess the performance of land surface models (LSMs). In this study, we assessed how well SIF is able to predict GPP in the Fenno-Scandinavian region and what potential limitations for its application exist. We implemented a SIF model into the JSBACH LSM and used active leaf-level chlorophyll fluorescence measurements (Chl F) to evaluate the performance of the SIF module at a coniferous forest at Hyytiala, Finland. We also compared simulated GPP and SIF at four Finnish micrometeorological flux measurement sites to observed GPP as well as to satellite-observed SIF. Finally, we conducted a regional model simulation for the Fenno-Scandinavian region with JSBACH and compared the results to SIF retrievals from the GOME-2 (Global Ozone Monitoring Experiment-2) space-borne spectrometer and to observation-based regional GPP estimates. Both observations and simulations revealed that SIF can be used to estimate GPP at both site and regional scales. At regional scale the model was able to simulate observed SIF averaged over 5 years with r(2) of 0.86. The GOME-2-based SIF was a better proxy for GPP than the remotely sensed fA-PAR (fraction of absorbed photosynthetic active radiation by vegetation). The observed SIF captured the seasonality of the photosynthesis at site scale and showed feasibility for use in improving of model seasonality at site and regional scale.

Abstract  The potential energy surface of O(D-1) + CH3CH2Br reaction has been studied using QCISD(T)/6-311++G(d,p)//MP2/6-311G(d,p) method. The calculations reveal an insertion-elimination reaction mechanism of the title reaction. The insertion process has two possibilities: one is the O(D-1) inserting into C-Br bond of CH3CH2Br producing one energy-rich intermediate CH3CH2OBr and another is the O(D-1) inserting into one of the C-H bonds of CH3CH2Br producing two energy-rich intermediates, IM1 and IM2. The three intermediates subsequently decompose to various products. The calculations of the branching ratios of various products formed though the three intermediates have been carried out using RRKM theory at the collision energies of 0, 5, 10, 15, 20, 25, and 30 kcal/mol. CH3CH2O + Br are the main decomposition products of CH3CH2OBr. CH3COH + HBr and CH2CHOH + HBr are the main decomposition products for IM1; CH2CHOH + HBr are the main decomposition products for IM2. As IM1 is more stable and more likely to form than CH3CH2OBr and IM2, CH3COH + HBr and CH2CHOH + HBr are probably the main products of the O(D-1) + CH3CH2Br reaction. Our computational results can give insight into reaction mechanism and provide probable explanations for future experiments. (C) 2009 Wiley Periodicals, Inc. Int J Quantum Chem 111: 631-643, 2011

Abstract  Seismological observations show that, in some regions of the lower mantle, an increase in bulk sound velocity, interestingly, occurs in the same volume where there is a decrease in shear velocity. We show that this anti-correlated behavior occurs on cation substitution in bridgmanite by making single crystal elasticity measurements of MgSiO3 and (Mg,Fe,Al)(Si,Al)O3 using inelastic x-ray scattering in the ambient conditions. Cation substitution of ferrous iron and aluminum may explain large low shear velocity provinces in the lower mantle.

Abstract  During the treatment process of drinking water, disinfectants (chlorine, ozone, chlorine dioxide) react on water containing organic matter and bromide to produce disinfection by-products at trace levels. Among them, five of the nine existing halo-acetic acids (HAAs) are commonly found in drinking water (monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), monobromoacetic acid (MBAA), dibromoacetic acid (DBAA), and Trichloroacetic acid (TCAA)), including four classified in the 2B IARC group of potential carcinogens (BCAA, DBAA, DCAA, TCAA). With respect to drinking water quality, guidelines are proposed by WHO (2006) and water quality standards are imposed in many countries such as less than 100 mu g/L for the sum of the five HAAs by US EPA (1998) and Canadian Health Department (2008). For this purpose, two analytical methods are commonly used, GC/MS with derivatization and LC/MS, UV or conductivity. A new method, based on two-dimensional ion chromatography (IC 2D) with suppressed conductivity is proposed. This method presents the main advantage of offering a quick implementation compared to GC or LC methods: direct injection, slight maintenance, lower cost of investment, by leading to good performances (specificity and sensitivity). The use of two different selectivity columns, and the fractionation on the first dimension canceling interferences, improves the specificity. The sensitivity is enabled by interfacing a preconcentration column between the two different internal diameter columns. The analytical conditions are optimized for the analysis of nine HAAs. The performances of the method are evaluated. The optimized method applied to natural water samples demonstrates its ability to quantify HAAs at trace levels in drinking water. (C) 2013 Elsevier B.V. All rights reserved.

Abstract  A detailed study of the structural, surface, and gas-sensing properties of nanostructured CoxZn1-xO films is presented. X-ray diffraction (XRD) analysis revealed a decrease in the crystallization degree with increasing Co content. The X-ray absorption near-edge structure (XANES) and X-ray photoelectron spectroscopies (XPS) revealed that the Co2+ions preferentially occupied the Zn2+sites and that the oxygen vacancy concentration increased as the amount of cobalt increased. Electrical measurements showed that the Co dopants not only enhanced the sensor response at low ozone levels (ca. 42 ppb) but also led to a decrease in the operating temperature and improved selectivity. The enhancement in the gas-sensing properties was attributed to the presence of oxygen vacancies, which facilitated ozone adsorption.

Abstract  A low-temperature (<120 °C) route to pinhole-free amorphous TiO2 compact layers may pave the way to more efficient, flexible, and stable inverted perovskite halide device designs. Toward this end, we utilize low-temperature thermal atomic layer deposition (ALD) to synthesize ultrathin (12 nm) compact TiO2 underlayers for planar halide perovskite PV. Although device performance with as-deposited TiO2 films is poor, we identify room-temperature UV-O3 treatment as a route to device efficiency comparable to crystalline TiO2 thin films synthesized by higher temperature methods. We further explore the chemical, physical, and interfacial properties that might explain the improved performance through X-ray diffraction, spectroscopic ellipsometry, Raman spectroscopy, and X-ray photoelectron spectroscopy. These findings challenge our intuition about effective electron selective layers as well as point the way to a greater selection of flexible substrates and more stable inverted device designs.

Abstract  This research aims to study the influence of preozonation on the adsorptivity of humic substances onto activated carbon, which are usual stages in drinking water treatment. Three different types of humic substances were used in this study: natural fulvic and humic acids extracted from the Úzquiza Reservoir (Burgos, Spain) and a commercially supplied humic acid. The fractionation of the humic substances by ultrafiltration showed a very different molecular weight (MW) distribution for them: the lowest fraction of <1 kDa comprises the vast majority of the fulvic acids (around 86 %), whereas the main fraction for the commercial humic acids was the highest one of >30 kDa (around 40 %). The natural humic acids show an intermediate distribution between the two aforementioned humic substances. The 1-5-kDa fraction turned out to be the most reactive toward trihalomethane formation for the commercial humic acids. The adsorptive capacity of activated carbon for the humic substances was in the following order: natural fulvic acids > natural humic acids > commercial humic acids. The most adsorbable fraction was that of <1 kDa for the fulvic acids, whereas the 5-10-kDa fraction was the most adsorbable for both humic acids. Preozonation changes the MW distribution of the humic substances, decreasing the abundance of the high MW fractions and generating smaller molecules within the low to medium MW range. Adsorption isotherms show that preozonation has a beneficial effect on the adsorptivity of the commercial humic acids onto activated carbon, whereas no appreciable effect was observed for the case of the fulvic acids.

Abstract  The integrated microwave with Mn/zeolite and ozone (MCO) and combined microwave with Mn/zeolite (MC) was employed to oxidize elemental mercury (Hg-0) in simulated flue gas. The results show that mercury removal efficiency attained 35.3% in the MC, over 92% of Hg-0 removal efficiency could be obtained in the MCO. The optimal microwave power and empty bed residence time (EBRT) in the microwave plasma catalytic oxidation were 264 W and 0.41 s, respectively. The effect of Hg0 oxidation in the MCO was much higher than that in the MC. Microwave accentuated catalytic oxidation of mercury, and increased mercury removal efficiency. The additional use of ozone to the microwave-catalysis over Mn/zeolite led to the enhancement of mercury oxidation. Mn/zeolite catalyst was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM) and the Brunauer Emmett Teller (BET) method. Microwave catalytic mercury over Mn/zeolite was dominated by a free radical oxidation route. Ozone molecules in air could enhance free radical formation. The coupling role between ozone and radicals on mercury oxidation in the MCO was formed. The MCO appears to be a promising method for emission control of elemental mercury.

Abstract  In this work, a time modulated RF driven DBD-like atmospheric pressure plasma jet in Ar + 2%O-2, operating at a time averaged power of 6.5W is investigated. Spatially resolved ozone densities and gas temperatures are obtained by UV absorption and Rayleigh scattering, respectively. Significant gas heating in the core of the plasma up to 700K is found and at the position of this increased gas temperature a depletion of the ozone density is found. The production and destruction reactions of O-3 in the jet effluent as a function of the distance from the nozzle are obtained from a zero-dimensional chemical kinetics model in plug flow mode which considers relevant air chemistry due to air entrainment in the jet fluent. A comparison of the measurements and the models show that the depletion of O-3 in the core of the plasma is mainly caused by an enhanced destruction of O-3 due to a large atomic oxygen density.

Abstract  Accurate quantum chemical calculations were employed to investigate the mechanism of ozone-initiated oxidation of C-H bonds of saturated hydrocarbons and polymers. Step wise hydrogen atom abstraction generates the first resting state the trihydroxide -COOOH, which undergoes decomposition to produce the free radical species alkoxyl -CO˙ and peroxyl ˙OOH thereby setting off a complex chain of radical processes. The H transfer from peroxyl radical to alkoxyl allows formation of inactive alcohol and the singlet excited dioxygen. Other competitive processes include the self fragmentation or β-scission of the alkoxyl -CO˙ to give rise to a carbonyl (ketone or aldehyde) and a C-centred free radical species. Tertiary C-H bonds are most susceptible to O3 oxidation followed by secondary and primary. Among the polymers studied, poly(styrene) is the least resistant to C-H bond ozonation, followed by poly(propylene), poly(methacrylate), poly(methyl methacrylate) and poly(vinyl chloride). Calculations also reveal catalytic effects of water in promoting the C-H bond oxidation process in polymer systems without competing H-bond donor groups.

Abstract  This work presents a Life Cycle Assessment (LCA) of bioethanol (EtOH) from perennial Arundo donax L. feedstock. A "cradle-to-wheel" approach was applied considering primary data for the cultivation of dedicated crops on hilly marginal lands and innovative "second generation technologies" for feedstock conversion into EtOH. The goals of the study were to: (i) quantify impacts of lignocellulosic EtOH production/use chain, (ii) identify hotspots and (iii) compare the environmental performance of different bioethanol-gasoline vehicles, E10 (10% EtOH and 90% gasoline) and E85 (85% EtOH and 15% gasoline), with a conventional gasoline passenger car. Results for E85 underlined that the feedstock production and the use phase were the prevailing contributors, whilst for E10 the gasoline production phase shared the largest part of impacts. The comparison showed that vehicles using lignocellulosic bioethanol have potentially significant benefits on global warming, ozone depletion, photochemical oxidant formation and fossil depletion in respect to conventional passenger car.

Abstract  Fast radical reactions are central to the chemistry of planetary atmospheres and combustion systems. Laser-induced fluorescence is a highly sensitive and selective technique that can be used to monitor a number of radical species in kinetics experiments, but is typically limited to low pressure systems owing to quenching of fluorescent states at higher pressures. The design and characterisation of an instrument are reported using laser-induced fluorescence detection to monitor fast radical kinetics (up to 25 000 s(-1)) at high temperatures and pressures by sampling from a high pressure reaction region to a low pressure detection region. Kinetics have been characterised at temperatures reaching 740 K and pressures up to 2 atm, with expected maximum operational conditions of up to ∼900 K and ∼5 atm. The distance between the point of sampling from the high pressure region and the point of probing within the low pressure region is critical to the measurement of fast kinetics. The instrumentation described in this work can be applied to the measurement of kinetics relevant to atmospheric and combustion chemistry.