Photochemical Ozone Creation Potential Research Articles

Kinetics of the reaction of OH radical with ethylfluoroacetate, ethyl 4,4,4-trifluorobutyrate, and butylfluoroacetate

Kinetics of the gas-phase reactions of •OH radicals with a series of fluoroesters were studied for the first time at 298 ± 3 K and atmospheric pressure. Relative rate coefficients were determined by in situ FTIR spectroscopy in nitrogen and GC-FID in air to monitor the decay of reactants and references. The following coefficient values (in 10−12 cm3/(molecule•sec)) were obtained for ethyl fluoroacetate (EFA), ethyl 4,4,4-trifluorobutyrate (ETB), and butyl fluoroacetate (BFA), respectively: k1 (EFA + OH) = 1.15 ± 0.25 by FTIR and 1.34 ± 0.23 by GC-FID; k2 (ETB + OH) = 1.61 ± 0.36 by FTIR and 2.02 ± 0.30 by GC-FID; k3 (BFA + OH) = 2.24 ± 0.37 by FTIR. Reactivity trends were developed and correlated with the number of CH3 and F substituents in the fluoroester, and structure-activity relationships (SARs) calculations were performed. In addition, the tropospheric lifetimes of EFA, ETB, and BFA upon degradation by OH radicals were calculated to be 9, 6, and 5 days, respectively, indicating that these fluorinated compounds could have a possible regional effect from the emission source. Relatively small photochemical ozone creation potentials of 9, 7, and 19 were estimated for EFA, ETB, and BFA, respectively. The Global Warming Potentials (GWPs) for EFA, ETB, and BFA were calculated for different time horizons. For a 20-year time horizon, the GWPs were 1.393, 0.063, and 0.062, respectively. In the case of a 100-year time horizon, the GWPs were 0.379, 0.017, and 0.017, and for a 500-year time horizon, the GWPs were 0.108, 0.005, and 0.005 for EFA, ETB, and BFA.

Atmospheric degradation of 2-Isopropoxyethanol: Reactions with Cl, OH and NO3

The use of glycol ethers as solvents and chemical intermediates has increased markedly in recent years. Once released into the atmosphere, they can undergo degradation processes mainly by reactions with the atmospheric oxidants that can have significant effects on the environment. In this work, the kinetic and products study of reactions of 2-isopropoxyethanol (2-iPE, (CH3)2CHOCH2CH2OH) with OH and NO3 radicals and Cl atoms have been performed using FTIR (Fourier Transform Infrared Spectroscopy) and GC-MS (Gas Chromatography/Mass Spectrometry) as detection techniques. The rate coefficients obtained were (units cm3 molecule−1 s−1): (2.18 ± 0.15) × 10−10, (1.88 ± 0.10) × 10−11 and (3.16 ± 0.45) × 10−15 for Cl, OH· and NO3· reactions, respectively. The kinetic results obtained have been included in comparison tables of the general reactivity of hydroxy ethers to extract conclusions of the atmospheric behaviour of this type of compounds. The main products detected and quantified have been isopropyl formate, formaldehyde, 2-hydroxyethyl acetate and, in the case of NO3· reactions, nitrated compounds. A reaction mechanism has been proposed according to the reaction products obtained. The calculated lifetimes have been determined and Global Warming Potential (GWP) and Photochemical Ozone Creation Potential (POCPE) have been estimated, concluding, first, that the reaction with OH radicals is the main pathway of degradation of this and others glycol ethers in the atmosphere, second, that these compounds have GWP negligible and third, that they could have influence on ozone generation at local and regional level.

Research on Life Cycle Assessment and Performance Comparison of Bioethanol Production from Various Biomass Feedstocks

Bioethanol, as a renewable energy source, has been widely used in the energy sector, particularly in replacing traditional petroleum energy, and holds great potential. This study involves a whole life cycle assessment of bioethanol production and the co-production of high-value by-products—xylose, lignin, and steam—using three types of waste biomass: corn cobs, corn straw, and wheat straw as feedstocks by chopping, pretreatment, hydrolysis, fermentation, and distillation methods. Secondly, the benefits of three raw materials are compared for preparing bioethanol, and their impact on the environment and energy production is analyzed. The comparison indicates that corn cobs offer the best overall benefits, with a net energy balance (NEB) of 6902 MJ/Mg of ethanol and a net energy ratio (NER) of 1.30. The global warming potential (GWP) is 1.75 × 10−2, acidification potential (AP) is 1.02 × 10−2, eutrophication potential (EP) is 2.63 × 10−4, photochemical ozone creation potential (POCP) is 3.19 × 10−8, and human toxicity potential (HTP) is 1.52 × 10−4. This paper can provide a theoretical reference and data supporting the green refining of bioethanol and the high-value utilization of by-products, and broaden its application prospects.

Gate-to-gate approach in life cycle assessment of steel pipe products

The iron and steel industry is of great strategic importance in Indonesia and is expected to continue its growth. One sector within this industry that is projected to see increased production is the steel pipe manufacturing sector. However, the significant emissions produced during steel pipe production have prompted many countries to seek ways to reduce these emissions. One such method is the implementation of the Life Cycle Assessment (LCA) technique, which assesses the environmental impact and serves as a valuable decision-making tool alongside other important methods. This approach aims to enhance sustainable production and consumption effectively and efficiently. In a specific case study, two types of steel pipe products were analyzed using LCA, focusing on various stages from material transportation to steel pipe production and delivery. The study assessed the environmental impact using the midpoint impact category, which includes factors like Global Warming Potential (GWP), Photochemical Ozone Creation Potential (POCP), Acidification Potential (AP), and Ecological Toxicity Potential (ETP) using the CML2001 characterization methods. The findings revealed that the production of SAWH pipes has a higher environmental impact in terms of GWP, AP, and POCP compared to HFW pipes, while HFW pipes had a greater ETP value. GWP was identified as the most significant potential impact for both products, with the pipeline production stage contributing the most to GWP. Overall, these results offer an initial understanding of the sustainability levels of steel pipe production, serving as a foundation for the development of pollution control measures to maintain the competitiveness of the industrial plant.

Chemical Investigation on the Mechanism and Kinetics of the Atmospheric Degradation Reaction of Trichlorofluoroethene by OH⋅ and Its Subsequent Fate in the Presence of O2 /NOx.

The M06-2X/6-311++G(d,p) level of theory was used to examine the degradation of Trichlorofluoroethene (TCFE) initiated by OH⋅ radicals. Additionally, the coupled-cluster single-double with triple perturbative [CCSD(T)] method was employed to refine the single-point energies using the complete basis set extrapolation approach. The results indicated that OH-addition is the dominant pathway. OH⋅ adds to both the C1 and C2 carbons, resulting in the formation of the C(OH)Cl2 -⋅CClF and ⋅CCl2 -C(OH)ClF species. The associated barrier heights were determined to be 1.11 and -0.99 kcal mol-1 , respectively. Furthermore, the energetic and thermodynamic parameters show that pathway 1 exhibits greater exothermicity and exergonicity compared to pathway 2, with differences of 8.11 and 8.21 kcal mol-1 , correspondingly. The primary pathway involves OH addition to the C2 position, with a rate constant of 6.2×10-13  cm3 molecule-1 sec-1 at 298 K. This analysis served to estimate the atmospheric lifetime, along with the photochemical ozone creation potential (POCP) and ozone depletion potential (ODP). It yielded an atmospheric lifetime of 8.49 days, an ODP of 4.8×10-4 , and a POCP value of 2.99, respectively. Radiative forcing efficiencies were also estimated at the M06-2X/6-311++G(d,p) level. Global warming potentials (GWPs) were calculated for 20, 100, and 500 years, resulting in values of 9.61, 2.61, and 0.74, respectively. TCFE is not expected to make a significant contribution to the radiative forcing of climate change. The results obtained from the time-dependent density functional theory (TDDFT) indicated that TCFE and its energized adducts are unable to photolysis under sunlight in the UV and visible spectrum. Secondary reactions involve the [TCFE-OH-O2 ]⋅ peroxy radical, leading subsequently to the [TCFE-OH-O]⋅ alkoxy radical. It was found that the alkoxy radical resulting from the peroxy radical can lead to the formation of phosgene (COCl2 ) and carbonyl chloride fluoride (CClFO), with phosgene being the primary product.

Assessment of Commercially Available Hydrogen Supply Chains for Gas-Fired Boilers

Hydrogen energy is a clean and efficient secondary energy source, and hydrogen derived from renewable sources is regarded as the key to achieving a low-carbon clean energy supply. Currently, the hydrogen energy supply chain is still in its development stage and requires a comprehensive comparative analysis of various hydrogen production technologies as well as storage and transportation methods to ensure the optimal application route for hydrogen energy. In this study, GaBi 10 software is used to conduct a comparative and evaluative analysis of the potential environmental impact associated with hydrogen energy application. The life cycle assessment encompasses all stages of the hydrogen supply chain, including production, transportation and utilization. The results indicate that hydrogen production from wind power has the lowest global warming potential (GWP), acidification potential (AP), eutrophication potential (EP) and photochemical ozone creation potential (POCP). Due to the high energy consumption of the liquefaction process, liquid hydrogen transportation is currently associated with the largest carbon emissions among all modes of hydrogen transport. However, if renewable energy sources are utilized to power hydrogen liquefaction, significant reductions in carbon emissions can be achieved. An evaluation of the carbon footprint associated with the completed hydrogen supply chain indicates that hydrogen produced from renewable sources is cost-effective for use in gas-fired boilers from an environmental perspective.

ComLife cycle assessment of municipal solid waste management systems in Ho Chi Minh City

Life cycle assessment (LCA) is a methodology used to evaluate the environmental impacts of municipal solid waste management (MSWM) systems. In this article, the authors apply the LCA method to investigate the best solution for the MSWM system in Ho Chi Minh city, supported by GaBi software. The LCA results from three scenarios of waste-to-energy, composting, and landfilling reveal their effects on global warming potential, acidification potential, eutrophication potential, and photochemical ozone creation potential. Overall, the results indicate that waste-to-energy and composting scenarios are competitive options.Waste-to-energy is environmentally friendly with a total environmental impact of 62%, which is only a quarter of the impact of landfilling. The composting scenario in the mechanical-biological treatment plant shows promising results of 81% reduction in environmental impact, while landfilling is the most polluting scenario with a total environmental impact potential of 257%. In this study, the scenarios are only investigated from an environmental perspective, for the economic and social impacts of waste management, other decision-making tools should be considered.

The influence of air pollution control devices on gas organic pollutants emission from coal-fired power plants based on LCA

Air pollutants (e.g., NOx, SO2) emitted from coal-fired power plants in China have been effectively controlled by Air Pollution Control Devices (APCDs) since 1996. However, the gas organic pollutants (typically Volatile Organic Compounds (VOCs) and Polycyclic Aromatic Hydrocarbons (PAHs)) have been overlooked for a long time. In this study, based on the life cycle assessment method, the effect of APCDs (mainly Selective Catalytic Removal (SCR), Electrostatic Precipitator (ESP), Wet Flue Gas Desulfurization (WFGD), and Wet Electrostatic Precipitator (WESP)) on gas organic pollutants (without methane) from three typical coal-fired power plants in China has been evaluated in terms of direct emission removal and indirect emissions. Detecting the gas organic pollutants concentrations at the inlet and outlet of APCDs in these three cases, it is found that the total direct emission removal efficiency is up to more than 71.97%, with SCR’s contribution being the highest. However, the manufacture and equipping of APCDs will lead to indirect emission of gas organic pollutants. The result shows that the SCR system is also the main process that induces indirect emissions of gas organic pollutants, associated with the utilization of liquid ammonia and catalyst. Compared to the direct emission of gas organic pollutants, indirect gas organic pollutants emissions can not be ignored. The calculation of net emission removal and the degree of co-effects shows that APCDs can reduce gas organic pollutants, which results in reducing the photochemical ozone creation potential of 1.81E-06~5.93E-06kg(Ethene eq.)/MW·h and human toxicity potential of 2.51E-03~8.06E-03kg (DCB eq.)/MW·h.

Assessment of the energy-saving and environment effects of China's gasoline vehicle withdrawal under the impact of geopolitical risks

With the increasing number of geopolitical events, energy and economy have been affected in all regions of the world. Uncertain geopolitical risks have led to the instability of the energy supply chain, thus affecting the future planning of fuel vehicles. Accordingly, the environmental effects of “Banning gasoline vehicle sales policy” (BGVSP) will also be affected by geopolitical risks. Therefore, using life-cycle assessment and the Lotka–Volterra model, this study evaluated the environmental effects of BGVSP in terms of energy consumption, carbon emissions, human toxic potential (HTP), global warming potential (GWP), acidification potential (AP), air quality potential (AQP), and photochemical ozone creation potential (POCP). We further analyzed the effects of differences in policy timing on the energy-conservation and emission-reduction benefits of BGVSP under multiple scenarios. The results show that the implementation of BGVSP in 2025 reduces the energy consumption, carbon emissions, GWP and POCP of the Chinese passenger vehicle market by 17.2%, 18.6%, 17.9% and 46.2%, respectively. However, it may also enhance HTP, AQP, and AP impact by 5.3%, 5.6%, and 18.2%, respectively. Meanwhile, lightweight automobile development could also help reduce energy consumption and carbon emissions in the passenger vehicle market. In this situation, the environmental effects of BGVSP implementation are superimposed. Moreover, the emission-reduction effect of new-energy vehicles is linked to the energy structure in terms of the whole life cycle; thus, the environmental effect of BGVSP in the context of energy cleaning is “super additive”. Regarding environmental effects, 2030 would be the optimal time for China to implement BGVSP as it transitions to clean energy.

Hydroxy esters atmospheric degradation: OH and Cl reactivity, products distribution and fate of the alkoxy radicals formed

Kinetic studies of the reaction of ethyl glycolate HOCH2C(O)OCH2CH3 with OH radicals (kOH) and Cl atoms (kCl) have been conducted by the relative method using a glass atmospheric reactor by “in situ” Fourier Transform Infrared (FTIR) and Gas Chromatography equipped with flame ionization detection by Solid Phase Micro Extraction (GC-FID/SPME) at room temperature and atmospheric pressure. The following relative rate coefficients were determined using several reference compounds and two different techniques: kEG + OH-FTIR = (4.36 ± 1.21) × 10−12; kEG + OH-GC-FID= (3.90 ± 0.74) × 10−12; and kEG + Cl-GC-FID= (6.40 ± 0.72) × 10−11 all values in units of cm3.molecule−1.s−1. Complementary product studies were performed under comparable conditions to the kinetic tests, in order to identify the reaction products and to postulate their tropospheric oxidation mechanisms. The reaction of OH radicals and Cl atoms with ethyl glycolate initiates via H-atom abstraction from alkyl groups of the molecule. Formic acid was positively identified as a reaction product by FTIR. On the other hand, formaldehyde, acetaldehyde, glycolic acid; and formic acid were identified by the GC-MS technique. The Structure–Activity Relationship, (SAR) calculations were also implemented to estimate the more favorable reaction pathways and compare them with the products identified. Tropospheric lifetimes of τOH = 34 h and τCl = 5.5 days were estimated to determine how these investigated reactions might affect the air quality. In this sense, average ozone production of [O3] = 0.75 and a Photochemical Ozone Creation Potential, POCP, of 38 were calculated for the hydroxyl ester studied.

Life cycle assessment of environmental impacts for two-stage anaerobic biogas plant between commercial and pilot scales

This study presents the detailed life cycle assessment (LCA) of environmental impact potential for two-stage anaerobic biogas plants between commercial and pilot scales. It provides a comprehensive and systematic approach to evaluating the environmental impacts of producing biogas from livestock wastes in several phases: collecting, processing, and production. The commercial biogas plant (C-BP) system is located in Central Taiwan's pig farm, with 1500–2000 pigs a year. The Symnergy (symbiosis bioenergy model) biogas pilot plant (S-BP) is installed in Manado City, Indonesia. The Institute of Green Products, Feng Chia University, designed both C-BP and S-BP systems. The environmental impacts of both systems' gate-to-grave life cycles were assessed and compared using Simapro 9.0.0 software. The pilot-scale biogas plants produce bioenergy from the wastewater of the slaughterhouse. Therefore, 10,950 tonne/year of slurry feedstock flowing into the commercial biogas plant was considered a functional unit equal to 21 times larger than the pilot scale biogas plant. The LCA analyzes the impacts of three processes for feedstock collection, biogas production, and digestate production. It was found that Photochemical Ozone Creation Potential had the highest total impact on C-BP (33%), and Eutrophication had the highest impact on S-BP (33%). Both the biogas production systems of C-BP and S-BP showed very low environmental impacts, and the impacts of C-BP are lower than the S-BP. However, implementing digesters considerably reduced the potential environmental impacts of well manure feedstock handling and fertilizer applications. The LCA analysis among the three individual processes is developed to allow critical points and environmental impacts for local government. Consequently, the LCA report could help establish regional sustainability strategies for the management of livestock wastes by anaerobic two-stage biogas plant from manure.

Atmospheric oxidation of new “green” solvents – Part 2: methyl pivalate and pinacolone

Abstract. Lab-based experimental and computational methods were used to study the atmospheric degradation of two promising “green” solvents: pinacolone, (CH3)3CC(O)CH3, and methyl pivalate, (CH3)3CC(O)OCH3. Pulsed laser photolysis coupled to pulsed laser-induced fluorescence was used to determine absolute rate coefficients (in 10−12 cm3 molec.−1 s−1) of k1(297 K) = (1.2 ± 0.2) for OH + (CH3)3CC(O)CH3 (Reaction R1) and k2(297 K) = (1.3 ± 0.2) for OH + (CH3)3CC(O)OCH3 (Reaction R2), in good agreement with one previous experimental study. Rate coefficients for both reactions were found to increase at elevated temperature, with k1(T) adequately described by k1(297–485 K) = 2.1 × 10−12 exp(-200/T) cm3 molec.−1 s−1. k2(T) exhibited more complex behaviour, with a local minimum at around 300 K. In the course of this work, k3(295–450 K) was obtained for the well-characterised reaction OH + C2H5OH (ethanol; Reaction R3), in satisfactory agreement with the evaluated literature. UV–Vis spectroscopy experiments and computational calculations were used to explore cross-sections for (CH3)3CC(O)CH3 photolysis (Reaction R4), while (CH3)3CC(O)OCH3 showed no sign of absorption over the wavelengths of interest. Absorption cross-sections for (CH3)3CC(O)CH3, σ4(λ), in the actinic region were larger, and the maximum was red-shifted compared to estimates (methyl ethyl ketone (MEK) values) used in current state-of-science models. As a consequence, we note that photolysis (Reaction R4) is likely the dominant pathway for removal of (CH3)3CC(O)CH3 from the troposphere. Nonetheless, large uncertainties remain as quantum yields φ4(λ) remain unmeasured. Lifetime estimates based upon Reactions (R1) and (R4) span the range 2–9 d and are consequently associated with a poorly constrained estimated photochemical ozone creation potential (POCPE). In accord with previous studies, (CH3)3CC(O)OCH3 did not absorb in the actinic region, allowing for straightforward calculation of an atmospheric lifetime of ≈ 9 d and a small POCPE ≈ 11.

Optimization model for selecting optimal prefabricated column design considering environmental impacts and costs using genetic algorithm

Prefabricated columns are commonly used in construction projects due to their advantages, such as high quality, fast construction, environmental friendliness, and cost-effectiveness. Toward achieving the minimization of environmental impacts and costs through the prefabricated system at the same time, the optimal design should be conducted during the pre-construction phases. Therefore, this research aims to develop an optimization model that uses a genetic algorithm to select optimal prefabricated column designs considering both environmental impacts and costs. This study was conducted in four steps: (i) Data collection, (ii) Calculation of environmental impacts, (iii) Economic assessment, and (iv) Optimization using a genetic algorithm. The results showed that the average environmental impacts for global warming potential (GWP), ozone layer depletion potential (ODP), acidification potential (AP), eutrophication potential (EP), photochemical ozone creation potential (POCP), and abiotic depletion potential (ADP), were 8382.10 kg-CO2, 1.76 × 10−4 kg-CFC-11, 11.03 kg-SO2, 1.89 kg-PO43-, 6.94 kg-C2H4, and 47.60 kg-sb, respectively, with an integrated value of $177.14. The average total cost of the prefabricated column was $4591.17. The overall environmental impacts and costs of the prefabricated columns were $26,020.37 and $680,477.36, respectively, whereas the optimal columns were $19,219.56 and $492,708.32, representing reductions of 26.14% and 27.59%, respectively. The implications of this research are of great importance for sustainable construction practices, as it provides a practical framework for selecting optimal prefabricated column designs that simultaneously minimize environmental impacts and costs. The integration of genetic algorithms within the optimization model enables the identification of environmentally friendly and cost-effective solutions, contributing to the overall reduction of environmental impacts associated with construction activities.

Development of a Municipal Solid Waste Management Life Cycle Assessment Tool for Banepa Municipality, Nepal

In this study, the life cycle assessment (LCA) method has been used to evaluate the environmental impacts of various municipal solid waste (MSW) management system scenarios in Banepa municipality, Nepal, in terms of global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), human toxicity potential (HTP), abiotic depletion potential (ADP), and photochemical ozone creation potential (POCP). There are at least six possible scenarios of MSW management in Banepa: the current or baseline scenario (Scenario 1); composting with landfilling (Scenario 2); material recovery facility (MRF) recycling, composting, and landfilling (Scenario 3); MRF and anaerobic digestion (AD); composting, and landfilling (Scenario 4); MRF, composting, AD, and landfilling (Scenario 5); and, finally, incineration with landfilling (Scenario 6). Using both information from Ecoinvent 3.6 (2019) and published research articles, a spreadsheet tool based on the LCA approach was created. The impact of the recycling rate on each of the six abovementioned scenarios was evaluated using sensitivity analysis, which showed that the recycling rate can considerably decrease the life-cycle emissions from the MSW management system. Scenario 3 was found to have the least overall environmental impact with a GWP of 974.82 kg CO2 eq. per metric ton (t), EP of 0.04 kg PO4 eq./t, AP of 0.15 kg SO2 eq./t, HTP of 4.55 kg 1,4 DB eq./t, ADP of −0.03 kg Sb eq./t, and POCP of 0.06 kg C2H4 eq./t. By adoption of MRF and biological treatments such as composting and AD, environmental impact categories such as AP, EP, HTP, ADP, POCP, and GWP can be significantly reduced. The findings of this study can potentially serve as a reference for cities in the developing world in order to aid in both the planning and the operation of environmentally friendly MSW management systems.

Atmospheric oxidation of unsaturated hydrofluoroethers initiated by OH radicals

Hydrofluoroethers (HFEs) are perfluorinated chemicals that were developed as alternative for chlorofluorocarbons (CFCs) in various applications. Among notable unsaturated HFEs are perfluoro methyl vinyl ether (PMVE, CF3OCFCF2) and perfluoro ethyl vinyl ether (PEVE, C2F5OCF = CF2). During the implementation of PMVE and PEVE, they spill and release to the atmosphere. Due to the tendency of perfluorinated compounds to have strong infrared absorption features and long atmospheric lifetimes, they are among the most potent greenhouse gases. Thus, it is important to accurately assess their atmospheric sink routes in order to assess their impact on climate change. Herein, we illustrated detailed mechanistic pathways and developed kinetic models with the underlying aim to comprehend the atmospheric fate of the title HFEs and the likely products of decomposition. It was found that the production of main products to stem from the addition of OH radical to the inner carbon-carbon double bond atoms. Atmospheric lifetimes of PMVE and PEVE were calculated to be ∼23 and ∼56 h; respectively. Time-dependent molar yields are acquired for the experimentally major products; namely carbonyl fluoride (CF2O), perfluorinated glyoxal (CFOCFO), perfluorinated methylformates (CF3OCFO and CF3CF2OCFO). Photochemical Ozone Creation Potentials (POCPs) of PMVE and PEVE were calculated to be 1.78 and 1.18, respectively. Obtained results tap into efforts that aim to understand the atmospheric chemistry cycles of perfluorinated chemicals in general.

Gas‐phase kinetics, POCPs, and an investigation of the contributions of VOCs to urban ozone production in the UK

AbstractAmbient concentrations of 22 volatile organic compounds (VOCs) measured at London Marylebone Road (LMR), an urban traffic site, and London Eltham (LE), an urban background site, were analyzed over a period of 23 years (1997–2019) to assess the impact of pollution control strategies. A significant decrease in ambient concentration is seen for the majority of VOCs analyzed with total VOC burden decreasing by 76% and 59% for LMR and LE, respectively, across the period studied. This is likely as a result of legislative controls. This analysis was extended to consider the dominant contribution of VOCs to ozone formation at the sites utilizing photochemical ozone creation potential (POCP) values. Similarly, the overall reactivity of the VOC burden at the sites has resulted in a significant decrease of 11% and 7% per year in ozone formation potential (OFP) for LMR and LE, respectively. At LMR, the declines in OFP for VOCs associated with road traffic emissions are all in good agreement at 11%–13% decrease per year. Reasonable agreement is also seen at LE with a decrease of 6%–11% per year in OFP of the VOCs related to traffic sources. VOCs related to non‐traffic sources, namely ethane and propane from natural gas leakage, did not see a significant decline over the study period at either site. The variation and composition of the overall VOC burden was compared across three decadal time periods (1997–2000, 2001–2010, 2011–2019) and saw an increase in significance of these pollutants at both sites. At LMR, ethane and propane moved from the fifth and eleventh largest contributors to total VOC burden in 1997–2000 to the first and second largest contributors in 2011–2019. At LE, a similar trend is seen with ethane and propane becoming the first and second largest contributors in the most recent time period, up from second and eighth at the beginning of the dataset. The similarity between these sites suggests such pollutants are not sufficiently controlled under current legislation. The increase in significance of ethane and propane was mirrored in their contribution to ozone generation potential at both sites but ethene continues to dominate in contribution to OFP. At LMR, ethene dominates by a factor of 4 and 5 compared with ethane and propane, respectively, however, at LE, ethene dominates to a lesser extent over ethane and propane at factors of 1 and 3, respectively. Alkanes are typically considered to be less important in the context of OFP due to their low reactivity in comparison to other VOCs. Analysis presented herein demonstrates the negative impact of ignoring such emissions as their influence begins to grow such that alkanes now represent 3 of the 5 highest contributors to tropospheric ozone formation at both sites (in order of contribution at LMR: ethene > propene > n‐butane > ethane > propane; and LE: ethene > ethane > n‐butane > propane > propene). The importance of high‐quality gas‐phase kinetic studies to determine the impact of VOCs in ozone production is clear and the usefulness of metrics such as POCPs is demonstrated.

Single Score Environmental Performances of Roof Coverings

Buildings and constructions are responsible for a great amount of global energy and energy-related carbon dioxide emissions. Because of these negative impacts, there is an increase in Life cycle assessment research in the construction sector to measure these effects and evaluate the sustainability performances. Life cycle assessment is a tool that can facilitate the decision-making process in the construction sector for material selection, or for the selection of the best environmentally friendly option in the building component level or building level. In this study, a comparative life cycle assessment analysis is conducted among 12 roof coverings of 1 square meter in the 60-year lifetime of a building. Impact categories that are available in environmental product declarations and included in this study are the global warming potential, ozone depletion potential, acidification potential, eutrophication potential, photochemical ozone creation potential, abiotic depletion potential of non-fossils and abiotic depletion potential of fossils resources. To facilitate the decision-making process, panel and monetary weightings are applied to convert environmental product declaration data of seven impact categories into one single-score. Monetary weightings applied in the study are in Euro 2019, differentiating itself from other comparative life cycle assessment studies. The single-score results are ranked and compared. R04 has the best performance for all panel weightings, while for monetary weightings, R03, R07 and R08 have the best performance for EPS, MMG and EVR, respectively. As a result, for 12 roof coverings, the weighted results could not address one single roof-covering material for numerous reasons. Among the weighting methods, panel weighting sets show more similarity in ranking results, while monetary-weighting sets results are more diverse.

Evaluating the feasibility of air environment management system for VOCs through ‘VOCs specification’ of petroleum refining industry

The chemical industry releases various types of volatile organic compounds (VOCs) into the atmosphere, and the concentration of VOCs emitted from chimneys is regulated worldwide. However, some VOCs such as benzene are highly carcinogenic, while others such as ethylene and propylene may cause secondary air pollution, owing to their high ozone-generating ability. Accordingly, the US EPA(United State, Environment Protect Agency) introduced a fenceline monitoring system that regulates the concentration of VOCs at the boundary of a facility, away from the chimney source. This system was first introduced in the petroleum refining industry, which simultaneously emits benzene, affecting the local community because of its high carcinogenicity, and ethylene, propylene, xylene, and toluene, which have a high photochemical ozone creation potential (POCP). These emissions contribute to air pollution. In Korea, the concentration at the chimney is regulated; however, the concentration at the plant boundary is not considered. In accordance with the EPA regulations, Korea’s petroleum refining industries were identified and the limitations of the Clean Air Conservation Act were studied. The average concentration of benzene at the research facility examined in this study was 8.53 µg/m3, which complied with the benzene action level of 9 µg/m3. However, this value was exceeded at some points along the fenceline, in proximity to the benzene-toluene-xylene (BTX) manufacturing process. The composition ratios of toluene and xylene were 27% and 16%, respectively, which were higher than those of ethylene or propylene. These results suggest that reduction measures in the BTX manufacturing process are necessary. This study shows that legal regulations should enforce reduction measures through continuous monitoring at the fenceline of petroleum refineries in Korea.

LCA of Barley Production: A Case Study from Cyprus.

Greenhouse gas emissions (i.e., carbon dioxide, methane, nitrous oxide) produced by agriculture contribute to global warming and climate change. Various practices followed by farmers in different environmental conditions contribute to the increase in the phenomena, and there is a need for immediate measures. The current study examines the environmental impact of barley production under rain-fed conditions in Cyprus. For this, four different nutrient management scenarios were investigated in order to evaluate the environmental performance of crop production, namely: (1) Nitrogen (20%), Phosphorous (20%), Potassium (10%); (2) Nitrogen (20%), Phosphorous (20%), Potassium (10%) and manure; (3) Nitrogen (25%), Phosphorous (10%), Potassium (0%); and (4) Nitrogen (25%), Phosphorous (10%), Potassium (0%) and manure. Data were collected from two different areas of Cyprus (Nicosia and Larnaca) through on-site visits and questionnaires. Life Cycle Assessment (LCA) was used as a method to quantify environmental impacts which were categorized into six impact categories: (i) acidification potential (AP), (ii) eutrophication potential (EP), (iii) global warming potential (GWP), (iv) ozone depletion potential (ODP), (v) photochemical, ozone creation potential (POCP), and (vi) terrestrial ecotoxicity (TAETP). LCA was used with system boundaries from field to harvest and a functional unit (FU) of one bale of hay. Research results showed that the addition of manure increased values in all impact categories. Comparing scenarios without manure (1 and 3) and with manure (2 and 4), the main process which contributed to GWP was field preparation, which resulted in 3 t CO2-Eq∙FU-1 and 46.96 t CO2-Eq∙FU-1, respectively. Furthermore, the highest contribution of sub-processes to GWP (kg CO2-Eq∙FU-1) was machinery maintenance (scenarios 2 and 4). The potential to reduce environmental impacts from barley and moreover, to mitigate the footprint of the agriculture sector in Cyprus is proposed by changing existing practices such as decreasing fuel consumption by agricultural machinery, and monitoring fertilizing and seeding. Conclusively, the carbon footprint of barley can be decreased through the improvement of nutrient management and cropping practices.

Tropospheric Oxidation of 1,1,2,3-Tetrafluoropropene (CF2=CF–CH2F) Initiated by ·OH Radical and Aerial Degradation of Its Product Radicals

It is essential to understand the tropospheric chemistry and environmental impact of 1,1,2,3-tetrafluoropropene (CF2=CF–CH2F) before its wide-scale applications. So, in this present work, we have performed the quantum chemical calculations of the ·OH radical initiated oxidation of CF2=CF–CH2F. First, all the reaction species of the title reaction are optimized at the M06-2X/6-311+G(d,p) level of theory and then the energies are refined at the CCSD(T) level with the same basis set. The relative energy and thermochemistry estimations indicate that the addition reactions of the ·OH radical to the carbon atoms of the double bond of CF2=CF–CH2F are energetically and thermodynamically more dominant rather than the direct H-abstraction reactions by the ·OH radical. The rate constant and branching ratio analysis also indicate the favorability of the ·OH-addition reactions over the H-abstraction reactions. The estimated overall rate constant at 298.15 K for this reaction is found to be 9.27 × 10–13 cm3 molecule–1 s–1 computed by variational transition state theory. The atmospheric lifetime of CF2 = CF–CH2F is calculated as 12.5 days with respect to ·OH reaction. The radiative efficiency is calculated as 0.016 W m–2 ppb–1, and global warming potentials of CF2=CF–CH2F for the different time horizons are significantly low. Further, photochemical ozone creation potential is estimated as 5.55. Finally, aerial degradation of the ·OH-addition product radicals was studied in the presence of the NO radical using the same quantum chemical method. From this degradation study, we have observed that CF2(OH)COF, FCOCH2F, FCFO, FCOOH, and ·CH2F are formed as end products.