Non-methane Organic Compounds Research Articles

A Projection Study of Gaseous Pollutants Formed, Potential Health Effects and Clinical Codification in Piyungan Landfill

The world is currently facing significant environmental challenges due to increasing urbanization and globalization. Human activities can produce greenhouse gases (GHGs) such as CO2 and CH4. One of the contributors to GHG generation is the open dumping of Municipal Solid Waste (MSW), particularly because much of the waste is organic. It undergoes anaerobic decomposition, leading to the formation of GHGs, particularly methane. However, CH4 has a high potential for energy generation, and if harnessed properly, it can be highly beneficial. This study aims to assess the total air pollutants emitted from the landfill gas (LFG), including methane (CH4), carbon dioxide (CO2), and nonmethane organic compounds (NMOC) at the Regional Piyungan landfill in D.I. Yogyakarta province. The study also projected the year when the production of these gaseous pollutants would peak and when they are expected to be exhausted. Additionally, the study aimed to identify the potential health problems and clinical codification caused by these gaseous pollutants. To achieve these objectives, the LandGEM 3.03 version of the model developed by USEPA was used for the period 2023-2071. Clinical coding used the 2019 version of the ICD-10 reference. The estimated values for total LFG were 1.648E+04 (2024) and 1.584E+04 (2025) Mg/year, while CH4 was estimated at 4.403E+03 (2024) and 4.230E+03 (2025) Mg/year. CO2 was estimated to be 1,208E+04 (2024) and 1,161E+04 (2025) Mg/year, and NMOC was projected at 2,839E+01 (2024) and 2,727E+01 (2025) Mg/year. Some of the toxic effects that can occur cause respiratory, visual, and mental disorders with a variety of clinical codes.

Electrically heated catalyst enabling pollutants reduction in hybrid vehicles fueled with ethanol

Plug-in hybrid electric vehicles (PHEV) have the potential of combining the benefits of a renewable electric mix with biofuels. More recently, PHEV have been designed to be equipped with a small combustion engine known as range extender (RE), thus allowing an improvement in vehicle’s range while converting fuel energy through a highly efficient path. Despite being a convenient strategy for decarbonizing light vehicles, the intermittent operation of the engine may create issues regarding the catalytic conversion of pollutants, yielding an increase in local harmful emissions. This drawback may be intensified depending on the used fuel. Hydrous ethanol is a promising alternative for gasoline and is already available in some countries, such as Brazil. However, ethanol has a great enthalpy of vaporization and it results in a charge cooling, affecting the catalyst warm-up and making the intermittent operation with ethanol more challenging. Hence, this study was motivated by the need of improving the catalytic efficiency of flexfuel RE operating with both gasoline and hydrous ethanol. Thus, a calibration was firstly performed to shorten the warm-up phase with ethanol. Then, an electrical heater was employed for accelerated catalyst heating, further improving emissions from ethanol operation, aiming at attaining future emissions regulations. Experimental tests were conducted in a vehicle under FTP72 cycle using a chassis dynamometer. The calibration adjustments resulted in a warm-up phase for ethanol <10 s longer than that for gasoline. The stable operation phase resulted in similar emissions for both fuels. On the cycle average, a reduction in CO for ethanol was observed, and although the methane and NOx emissions were slightly increased due to colder catalyst operation, significant improvements were obtained on a well-to-wheel (WTW) analysis. The use of an electrically heated catalyst (EHC) improved the emissions during the warm-up phase, significantly reducing the emission of NOx and non-methane organic compounds.

A potential coupling of reforming and electrolysis for producing renewable hydrogen from landfill gas

Organic sold waste disposed of in landfills undergoes a mostly anaerobic process which generates a mixture of methane (CH4), carbon dioxide (CO2) and other various gases such as nitrogen, oxygen, sulphides, and non-methane organic compounds (NMOC), known as landfill gas (LFG). Being composed mostly of CH4 and CO2, landfill gas is a potent greenhouse gas (GHG). As a result, various waste treatment interventions are required to minimize the potential catastrophic damage to the environment from direct greenhouse gas emissions from landfills. One effective solution is combustion to generate electricity exploiting methane’s flammability properties. Biomass-based power plants have been present for decades. However, the combustion process is accompanied by a remarkable production of thermal energy which is typically not exploited and therefore lost to the ambient. The current work presents an energetic solution to manage organic waste by employing green hydrogen production. To do so, a hybrid layout based on a cogeneration unit (CHP) fed with landfill gas is considered. The electrical power produced by the CHP is used to produce hydrogen through low-temperature water electrolysis. Furthermore, due to the significant waste heat available in the system, excess thermal power is employed for the methane steam reforming process through a heat recovery section. Hydrogen produced from the reforming section is green since the input is from landfill gas, which is considered renewable. The levelized cost of hydrogen produced from such a hybrid layout is obtained and compared with non-renewable sources in this field. In addition, the annual H2 production rate is calculated for a capacity factor equal to 70%. The results show an annual Hydrogen production of about 167 t/y. LCOH at the stack of about 2 €/kg is reported.

Estimasi Produksi Gas Metana Untuk Pemanfaatan Sebagai Sumber Energi Di TPA Talang Gulo, Jambi

Landfills (TPA) are a significant source of methane emissions into the atmosphere. In Indonesia, the estimation of methane gas production from a landfill has not been widely carried out. The purpose of this research is to measure production and measure the concentration of methane gas emitted into the atmosphere, assess methane gas emissions as an energy source, and analyze the potential costs and benefits of electrical energy that can be generated from methane gas emissions at the Talang Gulo TPA. The emission data obtained can be used as material for analysis to create a project for developing a gas processing system from a landfill. This estimation approach is carried out in three ways, namely prediction with LandGEM-v302 software, field measurements with methane flux and utilization of methane gas production as an energy source. The LandGEM-v302 simulation results obtained a total landfill gas of 29.96 Gg/year consisting of CH4 of 8.002 Gg/year, CO2 of 21.96 Gg/year and NMOC (non-methane organic compounds) of 0.344 Gg/year. The results of field measurements on the surface of the closed chamber TPA obtained CH4 emissions from TPA Talang Gulo of 4.75 Mg/year. The different characteristics of the landfill surface greatly affect the gas emissions released into the atmosphere. Moisture conditions or water content in the waste also affect the methane emission rate. The electricity potential from methane gas is 15.718 MW so that the cost benefit analysis shows an NPV of Rp. 6,028,622,852.18, B/C Ratio of 0.00196 and IRR of 2.445%.

Trends of ambient O3 levels associated with O3 precursor gases and meteorology in California: Synergies from ground and satellite observations

This study investigated the trends of ambient ozone (O3) levels and their associations with precursor gases and meteorology using ground and satellite observations in California during the peak O3 seasons of 2005-2017. The decrease in ground-level nitrogen dioxide (NO2) concentrations due to air pollution control strategies improved the O3 air quality by 0.67 ppb/year on average, while local meteorology worsened the O3 air quality by 0.11 ppb/year. The improvement of O3 air quality that was attributed to NO2 was more pronounced on higher O3 air pollution days with the largest improvement for the 90th percentile of O3 (0.85 ppb/year). The O3 trends were modified more by the reductions of NO2 (a proxy of nitrogen oxides (NOx)) than those of non-methane organic compounds (NMOC; a proxy of volatile organic compounds (VOCs)). The highest and lowest contributions of NO2 relative to NMOC to the reduction of O3 were found in the Sacramento Valley and South Coast, respectively. Satellite Ozone Monitoring Instrument (OMI) formaldehyde (HCHO) to NO2 ratios, an indicator of O3 sensitivity to precursor gases, were the lowest in the South Coast (specifically the corridor connecting downtown Los Angeles and Riverside), suggesting the highest potential of O3 to be influenced by VOCs. In addition, the OMI HCHO/NO2 ratios increased over time across California (0.23 per year), which demonstrated that the O3 air quality was increasingly sensitive to NOx. The satellite-based finding was consistent with ground NO2-NMOC-O3 associations concerning the direction and relative extent of NO2 and NMOC contributions to the O3 trends. Therefore, the NOx emission controls are expected to continue mitigating O3 levels and protect public health from adverse health outcomes associated with O3 and also NO2. Nonetheless, the O3 air quality may further benefit from local-scale strategies for VOC controls in certain localized areas (e.g., high traffic volumes).

Development and application of a supervised pattern recognition algorithm for identification of fuel-specific emissions profiles

Abstract. Wildfires have increased in frequency and intensity in the western United States (US) over the past decades, with negative consequences for air quality. Wildfires emit large quantities of particles and gases that serve as air pollutants and their precursors, and can lead to severe air quality conditions over large spatial and long temporal scales. Therefore, characterization of the chemical constituents in smoke as a function of combustion conditions, fuel type and fuel component is an important step towards improving the prediction of air quality effects from fires and evaluating mitigation strategies. Building on the comprehensive characterization of gaseous non-methane organic compounds (NMOCs) identified in laboratory and field studies, a supervised pattern recognition algorithm was developed that successfully identified unique chemical speciation profiles among similar fuel types common in western coniferous forests. The algorithm was developed using laboratory data from single fuel species and tested on simplified synthetic fuel mixtures. The fuel types in the synthetic mixtures were differentiated, but as the relative mixing proportions became more similar, the differentiation became poorer. Using the results from the pattern recognition algorithm, a classification model based on linear discriminant analysis was trained to differentiate smoke samples based on the contribution(s) of dominant fuel type(s). The classification model was applied to field data and, despite the complexity of the contributing fuels and the presence of fuels “unknown” to the classifier, the dominant sources/fuel types were identified. The pattern recognition and classification algorithms are a promising approach for identifying the types of fuels contributing to smoke samples and facilitating the selection of appropriate chemical speciation profiles for predictive air quality modeling using a highly reduced suite of measured NMOCs. The utility and performance of the pattern recognition and classification algorithms can be improved by expanding the training and test sets to include data from a broader range of single and mixed fuel types.

Next‐Generation Isoprene Measurements From Space: Detecting Daily Variability at High Resolution

AbstractIsoprene is the dominant nonmethane organic compound emitted to the atmosphere, where it drives ozone and aerosol production, modulates atmospheric oxidation, and interacts with the global nitrogen cycle. Isoprene emissions are highly variable and uncertain, as is the nonlinear chemistry coupling isoprene and its primary sink, the hydroxyl radical. Space‐based isoprene measurements can help close the gap on these uncertainties, and when combined with concurrent formaldehyde data provide a new constraint on atmospheric oxidation regimes. Here, we present a next‐generation machine‐learning isoprene retrieval for the Cross‐track Infrared Sounder (CrIS) that provides improved sensitivity, lower noise, and thus higher space‐time resolution than earlier approaches. The Retrieval of Organics from CrIS Radiances (ROCR) isoprene measurements compare well with previous space‐based retrievals as well as with the first‐ever ground‐based isoprene column measurements, with 20%–50% discrepancies that reflect differing sources of systematic uncertainty. An ensemble of sensitivity tests points to the spectral background and isoprene profile specification as the most relevant uncertainty sources in the ROCR framework. We apply the ROCR isoprene algorithm to the full CrIS record from 2012 to 2020, showing that it can resolve fine‐scale spatial gradients at daily resolution over the world's isoprene hotspots. Results over North America and Amazonia highlight emergent connections between isoprene abundance and daily‐to‐interannual variations in temperature and nitrogen oxides.

Life cycle GHG emissions of MSW landfilling versus Incineration: Expected outcomes based on US landfill gas collection regulations

From a GHG perspective, most LCA studies find incineration (MSWI) to be preferred over landfilling because of high energy recovery offsets. In some studies, however, landfilling results in less greenhouse gases (GHG) emissions than MSWI. We investigated using LCA, the landfill gas (LFG) collection efficiencies and waste composition that led to landfills resulting in less GHG emissions. Then, we explored what theoretical minimum lifetime gas collection efficiencies can be expected when following US LFG regulations. Only landfills with high LFG collection efficiencies (at least 81%) and recovery of methane for energy resulted in less GHG emissions compared to the management of the same waste stream in MSWI; required efficiency increased to 93% without LFG energy recovery. Expected theoretical lifetime LFG collection efficiencies were modeled in the range of 30–80%, with the lower rates associated with landfills having smaller input masses, high decay rates, and low concentrations of nonmethane organic compounds (CNMOC). Our modeling found that only under a limited combination of conditions (e.g., high CNMOC, high waste input rate, low decay rate) could a landfill expect to achieve a LFG collection efficiency as high as 80%, and that this value falls just under the 81–93% collection efficiency threshold needed for a landfill to result in less GHG emissions than MSWI. When exploring the influence of higher oxidation rates, changing decay rates, varying electricity grids, and inclusion of nonferrous metals recovery offsets the collection effciency range needed increased in nearly all cases; the electricity grid and nonferrous metals offsets had the greatest influence.

Life-Cycle Assessment of a Regulatory Compliant U.S. Municipal Solid Waste Landfill.

Landfills receive over half of all U.S. municipal solid waste (MSW) and are the third largest source of anthropogenic methane emissions. Life-cycle assessment (LCA) of landfills is complicated by the long duration of waste disposal, gas generation and control, and the time over which the engineered infrastructure must perform. The objective of this study is to develop an LCA model for a representative U.S. MSW landfill that is responsive to landfill size, regulatory thresholds for landfill gas (LFG) collection and control, practices for LFG management (i.e., passive venting, flare, combustion for energy recovery), and four alternative schedules for LFG collection well installation. Material production required for construction and operation contributes 68-75% to toxicity impacts, while LFG emissions contribute 50-99% to global warming, ozone depletion, and smog impacts. The current non-methane organic compound regulatory threshold (34 Mg yr-1) reduces methane emissions by <7% relative to the former threshold (50 Mg yr-1). Requiring landfills to continue collecting LFG until the flow rate is <10 m3 min-1 reduces emissions by 20-52%, depending on the waste decay rate. In general, for landfills already required to collect gas, collecting gas longer is more important than collecting gas earlier to reduce methane emissions.

Estimating greenhouse emissions from sanitary landfills using Land-GEM and IPCC model based on realistic scenarios of different urban areas: a case study of Iran.

This study examined the emission of greenhouse gases from municipal solid waste disposal centers in different regions of Iran based on different scenarios. Assuming landfill site opening in 2012 and considering the 20-year plan period for its usage, the amount of wastes entering the landfill site was calculated for 2012-2032. For calculating the production of methane (CH4) and other gases during different years of the project, Land-GEM and IPCC model were used. We defined 9 scenarios for these two models based on the growth rate of population and waste generation. The results revealed that the lowest amount of gas emission in nine scenarios by Land- GEM model was related to non-methane organic compounds (NMOCs). According to the results obtained, the total emissions of greenhouse gases from sanitary landfills for Iran in 2032 were 3,844,000 Mg/year, the largest and lowest amounts of gas emission were related to Tehran region, 860,400 Mg/year, and the South Coast area of the country,138,200 Mg/year, respectively. The major section of the gas production in both landfills was related to greenhouse gas and carbon dioxide emissions. The difference in gas production in the studied regions was due to differences in the percentage of moisture and organic compounds.

Identifying an unknown compound in flue gas of semiconductor industry – Forensics of a perfluorocarbon

This study investigated the source of a false positive signal in the measurement of total non-methane organic compounds (TNMOCs) by an on-line analyzer based on flame ionization detection (FID) in the flue gas released from a semiconductor fabrication plant. Since no release of volatile organic compounds (VOCs) into the waste gas stream in acid/base ventilation was assured by the plant authority, the positive detection of VOCs became a subject of dispute. In addition to the TNMOC analysis of 5 samples, the investigation used the method that coupled thermal desorption (TD) with gas chromatography mass spectrometry (GC/MS), dubbed TD-GC/MS, to identify the substance that produced the FID signals of TNMOCs. The waste gas was collected with sampling canisters and analyzed by in-laboratory TD-GC/MS. However, mass scanning from 45 to 250 m/z to remove interference from air matrix of O2, N2 and CO2 forbid detecting any ion fragments smaller than 45 m/z and, thus, led to poor match in mass (MS) library search. As a result, a highly retentive porous layer open tubular (PLOT) capillary column was employed to separate the unknown away from the air peak. The success of acquiring all key ion fragments of 31, 50, 69, and 131 m/z resulted in an excellent match with octafluorocyclobutane (C4F8) in the NIST database. A gas standard was then prepared and injected to confirm the identity of C4F8 by the identical mass spectrum and GC retention time. The concentrations of C4F8 found in the 5 flue gas samples varying from 3.32 to 6.21 ppmv were very close to the NMOC range of 3.48–6.62 ppmv as reported by the TNMOC analyzer, proving that the FID signals observed from TNMOC method were mostly produced from C4F8. Consequently, the method of TD-GC/MS would be an ideal method to pre-screen the presence of PFCs before a non-distinguishable TNMOC analyzer is applied to approximate the VOC level as part of the integrated effort to monitor VOC in flue gas.

Satellite isoprene retrievals constrain emissions and atmospheric oxidation.

SUMMARY:Isoprene is the dominant non-methane organic compound emitted to the atmosphere1–3. It drives ozone and aerosol production, modulates atmospheric oxidation, and interacts with the global nitrogen cycle4–8. Isoprene emissions are highly uncertain1,9, as is the non-linear chemistry coupling isoprene and the hydroxyl radical, OH—its primary sink10–13. Here we present the first global isoprene measurements from space, using the Cross-track Infrared Sounder (CrIS). These isoprene measurements, together with observations of its oxidation product formaldehyde, provide new constraints on isoprene emissions and atmospheric oxidation. We find that isoprene:formaldehyde relationships measured from space are broadly consistent with current understanding of isoprene-OH chemistry, with no indication of missing OH recycling at low-NOx. We analyze these datasets over four global isoprene hotspots in relation to model predictions, and present a first demonstration of isoprene emission quantification based directly on satellite measurements of isoprene itself. A major discrepancy emerges over Amazonia, where current underestimates of natural NOx emissions bias modeled OH and hence isoprene. Over southern Africa, we find that a prominent isoprene hotspot is missing from bottom-up predictions. A multi-year analysis sheds light on interannual isoprene variability, and suggests the role of El Niño.

THE ANALYSIS OF HEAVY METAL POLLUTANTS EMITTED BY RAILWAY TRANSPORT

Recently, concern for a rapid increase in heavy metal pollutants released by railway transport has been expressed. Most of pollutant emissions from combustion processes are related to fuel consumption in the internal combustion engines of traction rolling stock. The main pollutants released into the environment cover particulate matter, volatile non-methane organic compounds, sulphur dioxide and nitrogen oxides. In this way, it is likely that the biggest polluters of the environment are traction units with internal combustion engines. However, other types of pollution are possible, where polluters can be not only traction rolling stock with the internal combustion engines, but also electric locomotive. For example, when due to friction of metals and deterioration of rolling stock wheels, heavy metals such as aerosols are released into the atmosphere, soil, surface and ground water, etc. and severely pollute the railway environment. Along with an increase in the electrification of railways, local environmental pollution is likely to be increased in the future. High pollution by heavy metals can also occur near the track storing creosote-impregnated wooden railway sleepers. Having analysed railway transport intensity and in order to assess pollution level, the stations of three major cities of Lithuania (Vilnius, Kaunas and Klaipėda) were selected to investigate heavy metal pollutants (lead (Pb), cadmium (Cd), zinc (Zn)) acting as the most toxic and widespread elements. The highest concentrations of Pb (up to 50 mg/kg) were found at a distance of 5.0 m from railway sleepers in the upper (up to 10 cm) soil layer at Vilnius Railway Station. A comparison of the results of the investigated soil across the tested stations showed that Klaipėda Railway Station was the area most polluted with Cd. The highest concentrations of Cd (up to 1.5…1.8 mg/kg) were established at a varying distance of 5…10 m from the sleepers in the upper (up to 10 cm) soil layer of light loam. Among the investigated stations, the lowest pollution by heavy metals, including Zn, was found at Kaunas Railway Station where sandy loam dominated. A comparison of heavy metal pollutants deposited on the intact used and rotten wooden railway sleepers disclosed that the latter were more heavily contaminated with heavy metals and made from 8 to 13 mg/kg for Pb, from 0.3 to 1.2 mg/kg for Cd, from 13.8 to 66 mg/kg for Zn.

Aerosols and carbonaceous and nitrogenous compounds emitted during the combustion of dead shrubs according to twigs’ diameter and combustion phases

Smoke from forest fires is hazardous to health and can result in losses of respiratory function and vision. The knowledge of the chemical constituents in such smoke is an important objective. In this study, leaves and branches and twigs of Cistus Monspeliensis were burned with a cone calorimeter and the emitted smoke was analysed by non-dispersive infrared (NDIR) spectroscopy, He–Ne laser method, Fourier-transform infrared (FTIR) spectroscopy, and automated thermal-desorption–gas-chromatography/mass-spectrometry (ATD-GC/MS). These techniques were used during various combustion phases: prior to ignition and during flaming and glowing phases. The influence of branch diameter on chemical composition was examined. Analysis of the smoke reveals the presence of CO2, H2O, CO, aerosols, CH4, NO, and other gases in smaller proportions, as well as non-methane organic compounds (NMOCs). 96% of the carbon present in the fuel was found in the emitted smoke. CO2 is the gas mainly emitted and its level is independent of the diameter of the cistus branch burned. It is mainly emitted in the flaming phase, unlike CO, which is emitted during the glowing phase. Aerosols are emitted principally during the pre-ignition stage. The mass loss is higher during the flaming phase than during the glowing one because the burning occurs under well-ventilated condition. During the glowing phase, the mass loss is only due to the char oxidation. The calculation of the modified combustion efficiency confirms those operating conditions.

Composition and variability of gaseous organic pollution in the port megacity of Istanbul: source attribution, emission ratios, and inventory evaluation

Abstract. In the framework of the TRANSport Emissions and Mitigation in the East Mediterranean (TRANSEMED/ChArMEx) program, volatile organic compound (VOC) measurements were performed for the first time in Istanbul (Turkey) at an urban site in September 2014. One commercial gas chromatograph coupled to a flame ionization detector (GC–FID) and one proton transfer mass spectrometer (PTR-MS) were deployed. In addition, sorbent tubes and canisters were implemented within the megacity close to major emission sources. More than 70 species including non-methane hydrocarbons (NMHCs), oxygenated VOCs (OVOCs), and organic compounds of intermediate volatility (IVOCs) have been quantified. Among these compounds, 23 anthropogenic and biogenic species were continuously collected at the urban site. VOC concentrations show a great variability with maxima exceeding 10 ppb (i.e., n-butane, toluene, methanol, and acetaldehyde) and mean values between 0.1 (methacrolein + methyl vinyl ketone) and 4.9 ppb (methanol). OVOCs represent 43.9 % of the total VOC concentrations followed by alkanes (26.3 %), aromatic compounds (20.7 %), alkenes (4.8 %), terpenes (3.4 %), and acetonitrile (0.8 %). Five factors have been extracted from the Positive Matrix Factorization model (EPA PMF 5.0) and have been compared to source profiles established by near-field measurements and other external variables (meteorological parameters, NOx, CO, SO2, etc.). Surprisingly, road transport is not the dominant source, only explaining 15.8 % of measured VOC concentrations contrary to the local emission inventory. Other factors are toluene from solvent use (14.2 %), biogenic terpenes (7.8 %), natural gas evaporation (25.9 %) composed of butanes, and a last factor characterized by mixed regional emissions and composed of most of the species (36.3 %). The PMF model results point out the influence of industrial emissions while there is no clear evidence of the impact of ship emissions on the measured VOC distribution. For the latter additional measurements of organic compounds of lower volatility like IVOC would be helpful. The sensitivity of PMF results to input data (time resolution, meteorological period, peak episode, interpolation method) was tested. While some PMF runs do not perform as well statistically as the reference run, sensitivity tests show that the same factors (number and type) are found with slightly different factor contributions (up to 16 % of change). Finally, the emission ratios (ERs) of VOCs relative to carbon monoxide (CO) were established. These ratios are usually higher than the ones of other cities worldwide but in the same range of magnitude. These ERs and the road transport factor from PMF were used to estimate VOC emissions and to evaluate three downscaled global emissions inventories (EDGAR, ACCMIP, and MACCity). It was found that the total annual VOC anthropogenic emissions by global inventories were either within the same range by a factor of 2 to 3 for alkanes and aromatics or underestimated by an order of magnitude, especially for oxygenated VOCs.

Study of the burning of Pteridium aquilinum L. and risk for the personnel involved: Thermal properties and chemical risk

We studied the burning of fern at the request of firefighters who felt strong irritation during its combustion. Smoke from forest fires is hazardous to health and can result acute or chronic toxicity. Also, smoke is opaque resulting in decreased vision. In this study, leaves and stems of ferns were burned according to the vegetative state ie dead and alive with a cone calorimeter. Time to ignition (tig) and Heat Release Rate (HRR) were measured. The smoke emitted was analysed by non-dispersive infrared (NDIR) spectroscopy, He–Ne laser, Fourier-transform infrared (FTIR) spectroscopy, and automated-thermal-desorption–gas-chromatography/mass-spectrometry (ATD-GC/MS). Analysis of the smoke reveals that the major compounds are CO2, H2O, CO, aerosols, NO, and SO2. Other gases in smaller proportions were observed, as well as non-methane organic compounds (NMOCs). These high levels of SO2 and HCl may be responsible of severe irritation for firefighters. Even at low concentrations, sulfur dioxide is an irritating gas for the nose and upper airways. Exposure to hydrochloric acid causes irritating effects on the skin and eyes. SO2 and HCl are corrosive to the eyes and skin. Finally, 97.8 and 96.1% of the carbon present in the fuel was identified in the emitted smoke for the dead and alive ferns respectively.

Direct retrieval of isoprene from satellite-based infrared measurements

Isoprene is the atmosphere’s most important non-methane organic compound, with key impacts on atmospheric oxidation, ozone, and organic aerosols. In-situ isoprene measurements are sparse, and satellite-based constraints have employed an indirect approach using its oxidation product formaldehyde, which is affected by non-isoprene sources plus uncertainty and spatial smearing in the isoprene-formaldehyde relationship. Direct global isoprene measurements are therefore needed to better understand its sources, sinks, and atmospheric impacts. Here we show that the isoprene spectral signatures are detectable from space using the satellite-borne Cross-track Infrared Sounder (CrIS), develop a full-physics retrieval methodology for quantifying isoprene abundances from these spectral features, and apply the algorithm to CrIS measurements over Amazonia. The results are consistent with model output and in-situ data, and establish the feasibility of direct global space-based isoprene measurements. Finally, we demonstrate the potential for combining space-based measurements of isoprene and formaldehyde to constrain atmospheric oxidation over isoprene source regions.

Time-Resolved Intermediate-Volatility and Semivolatile Organic Compound Emissions from Household Coal Combustion in Northern China.

Coal combustion in low-efficiency household stoves results in the emission of large amounts of nonmethane organic compounds (NMOCs), including intermediate-volatility compounds (IVOCs) and semivolatile organic compounds (SVOCs). This conceptual picture is reasonably well established, however, quantitative assessment of I/SVOC emissions from household stoves is rare. We used a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) to quantify the emissions of organic gases from a typical Chinese household coal stove operated with anthracite and bituminous coals. Most NMOCs (approximately 64-88%) were dominated by hydrocarbons and emitted during the ignition and flaming phases. The ratio of oxidized hydrocarbons increased during the flaming and smoldering stages due to the elevated combustion efficiency. The average emission factors of NMOCs were 121 ± 25.7 and 3690 ± 930 mg/kg for anthracite and bituminous coals, respectively. I/SVOCs contributed to approximately 30% of the total emitted NMOC mass during bituminous coal combustion, much higher than the contribution of biomass burning (approximately 1.5%). Furthermore, I/SVOCs may contribute over 70% of the secondary organic aerosol (SOA) mass formed from gaseous organic species emitted as a result of bituminous coal combustion. This study highlights the importance of inventorying coal-originated I/SVOCs when conducting SOA formation simulation studies.

Dispersion Modelling of Odoriferous Compounds from Landfill

Landfills contain vast quantities of waste as they are sites for deposition of a city’s solid waste. This solid waste further undergoes the process of decomposition producing several by-products such as odorous gases and volatile organic compounds. Both of these compounds have potential to severely damage physical and mental health of human. These components were analysed using AERMOD by United States Environmental Protection Agency (USEPA). AERMOD needs uniform and horizontally consistent surface and upper air parameters of meteorology. Along with AERMOD, Landfill Gas Emission Model (LandGEM Version 3.02) was used to form an emission inventory. LandGEM analyses odorous gases and VOCs. The dispersion of odorous gases over areas adjacent to landfill of Pune, India has been estimated from information on advances in emission inventory and field monitoring operation. Four odorous gases namely Total Landfill gas, Methane, Carbon Dioxide and Non Methane Organic Compounds (NMOC) were detected at 17 discrete places and were found within permissible limits.

Spatial and temporal characteristics of ambient atmospheric hydrocarbons in an active shale gas region in North Texas

Over the past decade, significant development in shale gas extraction technologies has led to a massive increase in oil and gas production within the Barnett Shale region in North Texas. This region abuts a fast-growing Dallas-Fort Worth urban area with increasing air quality concerns. Air quality information for 2011–2015 from two urban and three non-urban monitoring sites within the Barnett Shale region were analyzed to identify the spatial and temporal trends of volatile organic compounds (VOC) concentrations. The non-urban sites had higher mean concentrations of total non-methane organic compounds (TNMOC) at 123.6 ppb-C than 77.06 ppb-C at the urban sites. Alkanes, which includes ethane, propane and n-butane, were the dominant VOC group at all five monitoring sites, with 88% of TNMOC at urban sites and 95% at the non-urban sites. Alkenes, alkynes and aromatics composition at urban sites accounted for 3.96%, 0.72% and 4.72% of TNMOC, and at the non-urban sites these were 1.55%, 0.43% and 1.94%, respectively. Seasonal variations were noted in the VOC profiles with high concentrations during the winter months and low during summer months. The alkane/TNMOC ratio also showed a similar seasonal pattern, with a median value of 0.8 at the urban sites and 0.9 at non-urban sites. Alkene/TNMOC ratios were highest during the summer months, while alkyne/TNMOC ratios were highest during spring and low in winter, due to the influence of localized urban emissions. Higher concentrations of isoprene were measured at one of the urban sites as a result of biogenic emissions from nearby urban forests. Spatial and temporal analysis of measured VOC concentrations at ambient air monitoring stations in North Texas revealed strong influence of source regions with high oil and gas activities in close proximity.