P’yŏngyang — ancient and modern —the capital of North Koreangyang — ancient and modern —the capital of North Korea

The capital of the Democratic People’s Republic of Korea (North Korea) is both the oldest and the newest settlement in Korea. The basic concepts in its early urban development made it the model for Korean cities of later ages. In the 6th and 7th century AD P’yôngyang was one of the largest cities in Asia, second only to the imperial capital of China, but it later declined. It partly recovered its former position when it became the capital of North Korea after World War II. Its reconstruction since the Korean War has made it one of the most striking examples of socialist city planning.     

A Stucture—mineralogical Study of Ringwoodite

The powder XRD analysis of ringwoodite(γ-Fe2SiO4),which was synthesized in a II-stage anvil high-pressure capsule,was made,Its unit-cell parameter was calculated:a=8.219A,After the refinements,for several cycles,of the oxygen parameter x and the occupancy rate of Si in octahedron site,i.e.,the iversion degree u,the final result is R=0.077,when x=0.379A and u=27.5%,with the structural formula (Fe1.725 Si0.275)VI(Si0.725Fe0.275)IV O4 and atomic distances(Fe,Si)VI-O=2.022 A and (Si,Fe)IV-O=1.836A,Meanwhile,the Moessbauer spectroscopic analysis of the sample was conducted and the results obtained are in good agreement with those of X-ray structural analysis ,This paper focuses on the phase transformation and the properties of bonds of α－Fe2SiO4→γ-Fe2SiO4.     

Stratabound ore deposits related to synsedimentary tectonics: South-West Sardinia (Italy) and Sierra de Aracena (Spain); a comparison

Deposition of stratabound Zn-Pb-Ba ores in the Lower Cambrian carbonates in South-west Sardinia show a distinct relation with the prominent tensional tectonics in the area. A part of the mineral deposits are syngenetic (sedimentary-exhalative), other massive sulfides and/or barite are early diagenetic. Other occurrences (MVT) are from early to late-diagenetic. They are mostly confined to matrix- and cementbreccias which might be dependent on the Cambrian tectonics. The Precambrian-Lower Cambrian (?) carbonates occupying the core of the Aracena anticline, at the boundary between the provinces of Huelva and Badajoz (South-west Spain), are also an important metallotect for Zn-Pb-Ag-Ba mineralization. The ores at Aracena are stratabound (to stratiform) (Sedex) and occur as disseminations or layers in a volcano-sedimentary sequence with carbonate intercalations. Both the carbonate intervals and the ores show evidence of synsedimentary tectonics, like slumpings, slump breccias and neptunian dykes. Their deposition most likely occurred in a subtidal environment controlled by faults. Apparently, in South-west Sardinia and in the Sierra de Aracena, both sedimentary evolution and ore deposition were strictly related, and conditioned by several pulses of tensional tectonics.     

Growth and breakup of supercontinents and evolution of oceans and continental margins during the global tectonic megacycles

Due to the westward-directed off-centre rotation of the spinning Earth around the gravitational centre of the Earth-Moon (-Sun) system the lower mantle should be displaced eastwards in relation to the upper mantle-crust system (principle of hypocycloid gearing). In consequence, the shape of the Pacific is displaced eastwards above gravity anomalies of the lower mantle in relation to the Earth's crust (once around the globe in 200 to 250 my; 20 to 16 cm/y East drift), thus causing the Global Tectonic Megacycles (Oceanic/Wilson Cycle, Orogenic Cycle, Cycle of the Collisional Mountain Belt, etc.)The continents migrate westwards around the shape of the Pacific in the N and S. They collide sequentially W of the Pacific continuously adding segments to a collisional mountain belt, that becomes older towards the W (zip fastener principle) and since the Permian has lapped some 1 1/3 times around the cratonic nucleus of Laurasia in the form of a spiral (explanation for lateral continental growth and the cyclical repetition of orogenic events for a certain continental margin). Following half an E drift lapping of the Earth's crust by the shape of the Pacific, the Pacific appears again in the W. In the Mediterranean/Caribbean setting (tongue of the Pacific) the continents of the N and S hemispheres that had previously collided sequentially W of the Pacific separate again (rift propagation towards the E), whereby parts of the N margins of the S continents remain attached to the N continents in the form of tectonostratigraphic terranes, which will subsequently migrate westwards around the shape of the Pacific in the N.The Earth's crust is subdivided into a Pacific area and a continental or Pangaea area with Intra-Pangaea Oceans (Atlantic, Red Sea-Indian Ocean, etc.). The Pangaea area in turn is subdivided into a North Pangaea area and a South Pangaea area with the North and South Pangaea continents broadly distributed over the N and S hemispheres. The Earth's history appears to be subdivided into alternating North Pangaea growth/South Pangaea breakup eras (Permian to present Alpine Cycle; Late Proterozoic Panafrican-Brasiliano Cycle) and South Pangaea growth/North Pangaea breakup eras (Late Proterozoic and Early to Middle Paleozoic Baikalian-Caledonian Cycle; Middle Proterozoic Kibaran-Grenvillian Cycle).In the hemisphere of the Pangaea growing (since the Permian the N hemisphere) the continents are subjected to pendular movements (alternating clockwise and counterclockwise rotations combined with movements between high and low latitudes). They always face either the equator or the Pacific with the same margin. Otherwise, a collisional mountain belt would not form. The remaining two margins alternate between an Arctic- and a North Atlantic-type setting. The Cordilleran-type margin of the NE-Pacific is therefore the forerunner of the NW-Pacific island arc-type and both types are one-sided, embryonic states of the two-sided collisional mountain belt forming at the equator W of the Pacific. Since the Jurassic/Cretaceous, the Pacific margins of the N hemisphere are remobilized segments from the older lap of the North Pangaea collisional mountain belt spiral.In the hemisphere of the Pangaea breaking up (since the Permian the S hemisphere) a continent passing through the Antarctica setting rotates through approximately 120° (clockwise during a South Pangaea breakup — Permian to present; counterclockwise during a North Pangaea breakup — Late Proterozoic and Early to Middle Paleozoic) and breaks up into several India-, Australia- and Antarctica-size fragments. The one-sided Andes-type margin of the SE-Pacific (previously evolved from a West Africa-type margin) develops therefore into a one-sided New Guinea-type and into the equatorwards facing thrust zone of the two-sided collisional mountain belt forming at the equator W of the Pacific. On the other hand the SW-Pacific island arc-type margin has evolved from a North-type that might still carry fragments from the older lap of the collisional mountain belt (Atlas, parts of the N Andes and West Antarctica, New Zealand), the main parts of which migrate around the shape of the Pacific in the N in the form of tectonostratigraphic terranes.Due to the pendular movements of a continent from the Pangaea growing and the 120° rotation of a continent from the Pangaea breaking up passing through the Antarctica setting, between its birth in a rift and its death in the collision zone at the equator W of the Pacific, a continental margin will normally need much more time (Cycle of Continental Margins) than the 200 to 250 my necessary for one E drift lapping of the Earth's crust by the shape of the Pacific and the ocean states of the Wilson Cycle or Oceanic Cycle. The eugeosynclinal evolution of an ocean in most cases will therefore be comparatively shorter than the miogeosynclinal evolution of the continental margins bordering that ocean.     

Sources and history of PAHs in lake sediments from oil-producing and industrial areas,northeast China

Abundance, sources, and historical records of polycyclic aromatic hydrocarbons (PAHs) in sediment cores of three lakes located in northeast China were evaluated. One lake was located in a rural oil field area, one in an industrial urban oil field area, and the third in an urban industrialized area without oil field influence. Cores from each lake were divided into 1-cm sections, dated using ¹³⁷Cs techniques, and 16 priority PAH compounds were measured. Total PAH concentrations were greater in industrial areas than in rural area, regardless of associated oil production. Only petroleum sources of PAHs were identified in lakes near oil fields between 1950s and 1980s, while sources of liquid fossil fuel combustion were persistently identified in the industrial urban lake. From 1990s to 2000s, PAH concentrations, especially high molecular weight PAHs, significantly increased in all lakes, which were consistent with the economic development in China, suggesting a change in energy use from wood burning and petroleum (oil) to liquid fossil fuel combustion. Environmental risk was low to moderate in sediments of the three lakes studied, and increases in high molecular weight PAHs during 1900s–2000s is a concern.     

Modified biomass of Phanerochaete chrysosporium immobilized on luffa sponge for biosorption of hexavalent chromium

Phanerochaete chrysosporium, a white rot basidiomycete, was immobilized over Luffa cylindrica sponge discs, treated with 0.1 N HCl and its potentiality for the removal of hexavalent chromium [Cr(VI)] from water was investigated in both batch and in up-flow fixed-bed bioreactor. The acid treatment of biomass increased the uptake capacity and percentage removal of Cr(VI) from 33.5 to 46.5 mg g^?1 and 67 to 92 %, respectively. Maximum uptake of Cr(VI) was achieved at pH 2, temperature 40 °C after 100 min of contact time. The Cr(VI) sorption on the biomass was better explained by Langmuir isotherm. Thermodynamic studies indicated that the process was spontaneous and endothermic. Sorption kinetic study showed that pseudo-second-order model best correlates the Cr(VI) sorption on the biomass as compare to pseudo-first-order kinetic model. The performance of fixed-bed bioreactor was evaluated at different bed heights (5, 15 and 25 cm) and flow rates (1.66, 4.98 and 8.33 mL min^?1) by using bed depth service time model. Response surface methodology statistical method was applied for optimizing the process parameters. FTIR analysis showed that amino groups were mainly involved in adsorption of Cr(VI).     

Temporal and spatial patterns in abundance and diversity of fish assemblages in Elkhorn Slough,California

Assemblages of ichthyofauna of shallow inshore habitats along Californía’s central coast are described in terms of species composition, abundance, and life-style categories. A total of 22,334 fishes from 65 species and 27 families was collected with otter trawls at six sites in the main channel and tidal creeks of Elkhorn Slough, a tidal embayment and seasonal estuary, and two nearshore ocean stations in Monterey Bay during 44 months between August 1974 and June 1980. Greater than 90% of the catch comprised 10 species. The four dominant species,Cymatogaster aggregata, Leptocottus armatus, Phanerodon furcatus, andEmbiotoca jacksoni, occurred during most or all seasons and were classified as residents or partial residents. Several abundant species were marine immigrants that seasonally use the slough as spawning and nursery grounds; this resulted in higher abundance and species richness during summer. Species collected during winter largely were slough residents. Species compsosition and richness varied with distance from the slough entrance. The ocean assemblage was most different, and its similarity to other stations decreased progressively with distance inland and into the tidal creeks. During our study, 5,074 fishes were collected by beach seine in Bennett Slough, a remote shallow marsh basin adjacent to the entrance of Elkhorn Slough. Species richness was relatively low and three euryhaline species accounted for >80% of the total catch. The species assemblage was most similar to those at the tidal creek and most shallow stations of Elkhorn Slough. Resident species numerically dominated assemblages in Bennett Slough and the most inland areas of Elkhorn Slough. The high relative abundance of marine-related fishes (classified as marine, marine immigrant, and partial resident), entering Elkhorn Slough early in life or as spawning adults indicates the importance of this habitat to nearshore fish assemblages.     

A prefetching technique for prediction of porous media flows

In many applications in flows through porous media, one needs to determine the properties of subsurface to detect, monitor, or predict the actions of natural or induced forces. Here, we focus on two important subsurface properties: rock permeability and porosity. A Bayesian approach using a Markov Chain Monte Carlo (MCMC) algorithm is well suited for reconstructing the spatial distribution of permeability and porosity, and quantifying associated uncertainty in these properties. A crucial step in this approach is the computation of a likelihood function, which involves solving a possibly nonlinear system of partial differential equations. The computation time for the likelihood function limits the number of MCMC iterations that can be performed in a practical period of time. This affects the consistency of the posterior distribution of permeability and porosity obtained by MCMC exploration. To speed-up the posterior exploration, we can use a prefetching technique, which relies on the fact that multiple likelihoods of possible states into the future in an MCMC chain can be computed ahead of time. In this paper, we show that the prefetching technique implemented on multiple processors can make the Bayesian approach computationally tractable for subsurface characterization and prediction of porous media flows.     

Geochemistry of Ordovician Keli Group basalts associated with Besshi-type Cu-Zn deposits from the southern Trondheim and Sulitjelma mining districts of Norway

Besshi-type volcanogenic Cu-Zn deposits in the Scandinavian Caledonides are hosted by Ordovician metabasalts and clastic sediments of the Storen, Fundsjo and Sulitjelma groups. The basalts are transitional between T-MORB and marginal basin tholeiites in composition and are characterised by Nd and Pb isotopic compositions which overlap the more radiogenic values of Lower Palaeozoic MORB. These features, along with the intercalation of the basalts with tuffs and continentally derived sediments, indicate an epicontinental rift or marginal basin origin, possibly analogous to the present Red Sea and Gulf of Aden rifts. This implies the development of a restricted ocean basin in the north of Iapetus between the Laurentian and Baltoscandian microcontinents during the Cambrian and Early Ordovician.     

Simultaneous electrokinetic removal of polycyclic aromatic hydrocarbons and metals from a sediment using mixed enhancing agents

The maintenance of harbor waterways generates large amounts of dredged sediments which are often rich in coexisting organic and inorganic contaminants. Electrokinetic remediation treatments have recently been developed for the simultaneous removal of heavy metals and polycyclic aromatic hydrocarbons (PAHs), using various enhancing agents generally tested sequentially. In this study, different processing fluids were tested, alone or mixed, to improve the decontamination of aged model sediment contaminated with cadmium, lead, chromium, copper, zinc, and five PAHs. Nitric acid (NA) and citric acid (CA) were tested to avoid the formation of an alkaline front into the sediment and favor the metals removal, while an anionic surfactant [sodium dodecyl sulfate (SDS)] and a nonionic surfactant (Tween 20) were tested to solubilize and mobilize PAHs. Processing fluids were circulated under a constant voltage gradient of 1 V cm^?1 for 10–14 days. NA showed an excellent potential to remove metals (76.8–99.9 % removal) and PAHs (70.3–89.7 % removal) in a single run. Besides, the mixture of Tween 20 and CA, more environmental friendly, could be considered as a relatively good processing fluid for the simultaneous removal of metals (10.3–90.8 % removal) and PAHs (53.6–61.6 % removal) from the fine-grained sediment, while SDS mixed to CA was not a good candidate for this purpose (0.1–65 % removal for metals and 34.1–41.0 % removal for PAHs).     

Clicking graphene oxide and Fe3O4 nanoparticles together: an efficient adsorbent to remove dyes from aqueous solutions

Nanohybrid of graphene oxide (GO) and azide-modified Fe₃O₄ nanoparticles (NPs) were fabricated using click reaction. First, Fe₃O₄ NPs were modified by 3-azidopropionic acid. Then, click-coupling of azide-modified Fe₃O₄ NPs with alkyne-functionalized GO was carried out in the presence of CuSO₄·5H₂O and sodium l-ascorbate at room temperature. The attachment of Fe₃O₄ NPs onto the graphene nanosheets was confirmed by Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy, thermogravimetric analysis, energy dispersive X-ray spectrometry and X-ray diffraction spectrometry. As the FTIR spectroscopy and energy dispersive X-ray spectrometry analysis showed, the final magnetic graphene nanosheets were also reduced by sodium ascorbate which is a merit for click-coupling reactions. The specific saturation magnetization of the Fe₃O₄-clicked GO was 44.3 emu g^?1. The synthesized hybrid was used in the adsorption of methylene blue and congo red (CR). The adsorption capacities in the studied concentration range were 109.5 and 98.8 mg g^?1 for methylene blue and CR, respectively.     

The application of a hierarchical Bayesian spatiotemporal model for forecasting the SAA trapped particle flux distribution

We implement a hierarchical Bayesian spatiotemporal (HBST) model to forecast the daily trapped particle flux distribution over the South Atlantic Anomaly (SAA) region. The National Oceanic and Atmospheric Administration (NOAA)-15 data from 1–30 March 2008 with particle energies as >30 keV (mep0e1) and >300 keV (mep0e3) for electrons and 80–240 keV (mep0p2) and > 6900 keV (mep0p6) for protons were used as the model input to forecast the flux values on 31 March 2008. Data were transformed into logarithmic values and gridded in a 5^°×5^° longitude and latitude size to fulfill the modelling precondition. A Monte Carlo Markov chain (MCMC) was then performed to solve the HBST Gaussian Process (GP) model by using the Gibbs sampling method. The result for this model was interpolated by a Kriging technique to achieve the whole distribution figure over the SAA region. Statistical results of the root mean square error (RMSE), mean absolute percentage error (MAPE), and bias (BIAS) showed a good indicator of the HBST method. The statistical validation also indicated the high variability of particle flux values in the SAA core area. The visual validation showed a powerful combination of HBST-GP model with Kriging interpolation technique. The Kriging also produced a good quality of the distribution map of particle flux over the SAA region as indicated by its small variance value. This suggests that the model can be applied in the development of a Low Earth Orbit (LEO)-Equatorial satellite for monitoring trapped particle radiation hazard.     

Clinopyroxene on the join CaMgSi2O6-CaFe3+AlSiO6-CaTiAl2O6 at low oxygen fugacity

Subsolidus phase relations on the join CaMgSi₂O₆-CaFe³⁺ AlSiO₆-CaTiAl₂O₆ were studied by the ordinary quenching method at \(f_{O_2 } = 10^{ - 11} \) atm and 1,100°C. Crystalline phases encountered are clinopyroxene_ss (ss:solid solution) (Cpx_ss), melilite (Mel), perovskite (Pv), spinel_ss (Sp_ss), magnetite_ss (Mt_ss) and anorthite (An). There is no Cpx_ss single phase field, and the following assemblages were found; Cpx_ss+Mel, Cpx_ss+Mel+Sp_ss, Cpx_ss+Mel+Pv, Cpx_ss+Mel+Sp_ss+Pv, Cpx_ss+Pv+Sp_ss+An, Sp_ss+Pv+Mel+An+Cpx_ss, Mel+Mt_ss+An+Sp_ss+Cpx_ss+liquid and Mel+Mt_ss+An+Sp_ss+Cpx_ss+Pv. Mössbauer spectral study revealed that Cpx_ss contains both Fe²⁺ and Fe³⁺ in the octahedral site, and it was confirmed that the CaFe³⁺ AlSiO₆ content in the Cpx_ss at low \(f_{O_2 } \) is considerably less than that in the Cpx_ss crystallized in air, whereas the CaFe²⁺Si₂O₆ component increases. The maximum solubility of CaTlAl₂O₆ component in the Cpx_ss at low \(f_{O_2 } \) is higher than that in air. The decrease of CaFe³⁺ AlSiO₆ in the Cpx_ss at low \(f_{O_2 } \) may cause increase of CaTial₂O₆ in the Cpx_ss.     

Towards hydrological and geochemical understanding of an ephemeral palustrine perched water table “wetland” (Lanseria Gneiss,Midrand, South Africa)

Wetland delineation is commonly based on terrain unit, soil form, soil wetness and vegetation indicators which along with the shallow groundwater or proximate surface water are often absent in many ephemeral inland South African areas due to, for instance, prolonged dry periods (seasons to years) which mask these indicators, as well as disruption of surface materials due to construction, agricultural activities and field fires. Furthermore, many “wetlands” in South Africa comply with the four indicators, but the notable absent requirement for wetlands is missing, namely the shallow groundwater table, as many of these systems form in hillslope seeps, catenas or from perched water tables. A 200-m-long excavation through one such a system is being studied in Midrand (Gauteng, South Africa). The site is underlain by Lanseria Gneiss and is waterlogged after long and intense periods of intense rainfall. Frequent downslope soil profiling, horizon-specific laboratory analyses for grading and Atterberg Limits, X-Ray Diffraction and X-Ray Fluorescence Spectroscopy data are interpreted together with soil percolation tests to generate a conceptual model of the system. The results are discussed in terms of the need to consider these temporary systems that do not have a shallow groundwater table and that are not in direct contact with surface drainage features as a possible special type of wetlands, notably in arid regions where they play a very important role in biodiversity and should, therefore, be protected.     

Stability conditions of polycyclic aromatic hydrocarbons at high pressures and temperatures

The first results of study of stability of diverse polycyclic aromatic hydrocarbons at around 7 GPa and 773–1073 K are reported. Experiments were carried out in hydraulic multi-anvil presses. The run products after quenching were analyzed using a method of matrix-assisted laser desorption-ionization (MALDI). The formation of polymers of starting matters was determined at 7 GPa and 773–883 K. The polymers are characterized by atomic masses up to 5000 Da, that are multiple by masses of starting matters. At higher temperatures (873–1073 K), the selected PAHs and their polymers become unstable. The decomposition temperature of PAHs and their polymers exclude their stability under Earth’s mantle conditions. The studies could be of great significance for the low-temperature near-surface geodynamics of small and large planetary bodies, which supposedly contain hydrocarbon compounds.     

Biodegradation of polyvinyl alcohol-low linear density polyethylene-blended plastic film by consortium of marine benthic vibrios

Marine bacteria, Vibrio alginolyticus and Vibrio parahemolyticus isolated from sediments were evaluated for their ability as a consortia, to degrade polyvinyl alcohol-low linear density polyethylene (PVA-LLDPE)-blended plastic films in shake flask conditions at 120 rpm at 37 °C over 15 weeks. Results indicated that relatively 20 % decrease in tensile strength of the film could be achieved with 25 and 30 % blend of PVA in the PVA-LLDPE plastic film compared to other ratios. Micrographs obtained with scanning electron microscope showed visible cracks and grooves on the surface of the PVA-LLDPE blend film after 15 weeks of incubation with bacterial consortium. The decrease in tensile strength of the PVA-blended plastic films after treatment and the results of the scanning electron microscopic analysis evidence that the consortium could cause degradation of PVA-LLDPE plastic blends compared to suitable controls. This is the first report on polyvinyl alcohol degrading Vibrio sp. from marine sediments and its application in microbial degradation of polyvinyl alcohol-low linear density polyethylene plastic blends. The study indicated potential of marine benthic vibrios that have novel enzymes and unique characteristics for application in bioremediation and solid waste management particularly in handling synthetic polymers such as PVA-blended plastic films.     

Modeling chromium(VI) reduction by Escherichia coli 33456 using ceramic pearl as a supporting medium

A mathematical model was developed to describe the reduction of Cr(VI) by Escherichia coli (E. coli) 33456 in a fixed biofilm reactor. A laboratory-scale column reactor was conducted to verify the model system. The batch kinetic tests were independently conducted to determine the biokinetic parameters used in the model simulation. With the assumed values of initial biofilm thickness (L _f0), the mathematical model simulated well the experimental results for Cr(VI) effluent concentration, effluent concentration of suspended E. coli cells, and Cr(III) production. The concentration of suspended E. coli cells reached up to 1.2 mg cell/L while the thickness of attached E. coli cells was estimated to be 32.6 μm at a steady-state condition. At the steady state, the removal efficiency of Cr(VI) was about 92 % and the effluent concentration of Cr(III) was approximately 1.6 mg/L. The approaches presented in this study can be employed for the design of a pilot-scale or full-scale fixed biofilm reactor to treat Cr(VI)-containing wastewater.     

Main issues of an evacuation in case of volcanic crisis: social stakes in Guadeloupe (Lesser Antilles Arc)

The last major eruption of La Soufrière volcano in Guadeloupe (Lesser Antilles) in 1976–1977 caused the mass evacuation of part of the population, whereby a total of 76,000 people were displaced for a period of 3–6 months. This evacuation has left a bitter memory among the inhabitants who believed that the political authorities of the time had not anticipated the possibility of an eruption crisis and that decisions were taken in haste. La Soufrière remains active, and future eruptions could once again lead to partial or even total evacuation of the population if there were a major Plinian eruption. This article offers an investigation of future evacuation procedures, questioning different aspects of Guadeloupe’s current territorial and social challenges (the multi-risk context, the reporting to the scientists and to the authorities, the importance of local solidarity). In order to do so, we used the Focus Group Discussion method, making it possible to identify resources and gaps in crisis management on the basis of previous event history.     

Comparative study to evaluate three ground-based optical remote sensing techniques under field conditions by a gas tracer experiment

Today, ground-based optical remote sensing (ORS) has become an intensively used method for quantifying pollutant or greenhouse gas emissions from point or area sources, and for the validation of airborne or satellite remote sensing data. In this study, we present the results of a release experiment using acetylene (C₂H₂) as a tracer gas, where three ORS techniques were simultaneously tested for two main purposes: (1) the detection of emission sources and (2) the quantification of release rates. Therefore, passive and active open-path Fourier transform infrared spectroscopy (OP-FTIR) and open-path tunable diode laser absorption spectroscopy (TDLAS) were applied and evaluated. The concentration results of the active ORS methods are compared to those estimated by a Lagrangian stochastic atmospheric dispersion model. Our results reveal that passive OP-FTIR is a valuable tool for the rapid detection and imaging of emission sources and the spatial tracer gas distribution; while with active OP-FTIR and TDLAS, C₂H₂ concentrations in the sub-ppm range could be quantified that correlated well with the concentration data obtained by our modeling approach.