Photochemical Ozone Creation Potential Research Articles

Assessment of energy recovery potential and analysis of environmental impacts of waste to energy options using life cycle assessment

Effective waste management such as energy recovery from waste is not very successful in many cities of India. The present study is carried out in the Dhanbad city, India where all the generated wastes are managed unscientifically through open dumping. Most of the reported life cycle assessment-based studies for Indian cities have focussed on the common waste management options such as composting and recycling. This study aimed to evaluate the energy recovery potential and environmental impacts of mainly waste to energy options namely; anaerobic digestion, landfill gas to energy, mass incineration and refuse derived fuel incineration based on the characteristics and composition of wastes of the study area. The selection of waste to energy options is done based on the composition of waste suitable for the respective options, thus making it helpful in reproducing the present work in other cities as well. Anaerobic digestion technology is evaluated based on the biogas generation potential of total food waste generated in the study area using laboratory-scale batch experiments. Similarly, landfill gas to energy is evaluated based on the estimated landfill gas generation (using LandGEM model) from the existing landfill of the study area. While incineration (mass and refuse derived fuel) is evaluated based on the heating value of combustible waste fractions. For the comparison of energy recovery potential and environmental impacts, six scenarios are developed. The maximum energy recovery potential of 602 kWh/tonne of dry waste is found for the scenario mass incineration of combustible waste fractions (72%) and landfilling of remaining wastes (28%). This scenario also showed the maximum net environmental savings due to avoided electricity production. The sensitivity analysis revealed that the collection efficiency of generated landfill gas for electricity conversion significantly impacts the change in global warming and photochemical ozone creation potential. The outcomes of this study will help the concerned authorities in developing the efficient waste to energy system.

Environmental Life-Cycle Assessment of Eco-Friendly Alternative Ship Fuels (MGO, LNG, and Hydrogen) for 170 GT Nearshore Ferry

With increasing concerns about environmental pollution, the shipping industry has been considering various fuels as alternative power sources. This paper presents a study of the holistic environmental impacts of eco-friendly alternative ship fuels of marine gas oil (MGO), liquefied natural gas (LNG), and hydrogen across each of their life cycles, from their production to the operation of the ship. The environmental impacts of the fuels were estimated by life-cycle assessment (LCA) analysis in the categories of well-to-tank, tank-to-wake, and well-to-wake phases. The LCA analysis was targeted for a 170 gross tonnage (GT) nearshore ferry operating in the ROK, which was conceptually designed in the study to be equipped with the hydrogen fuel cell propulsion system. The environmental impact performance was presented with comparisons for the terms of global warming potential (GWP), acidification potential (AP), photochemical ozone creation potential (POCP), eutrophication potential (EP), and particulate matter (PM). The results showed that the hydrogen showed the highest GWP level during its life cycle due to the large amount of emissions in the hydrogen generation process through the steam methane reforming (SMR) method. The paper concludes with suggestions of an alternative fuel for the nearshore ferry and its production method based on the results of the study.

Application and adaptation of a scale-up framework for life cycle assessment to resource recovery from waste systems

Prospective life cycle assessment (LCA) studies are widely used for evaluating emerging resource recovery systems. Simulations, engineering-based process calculations and stoichiometric methods are frequently used methods to generate life cycle inventory (LCI) in prospective LCAs. The engineering-based upscaling calculation is an efficient method for LCI generation requiring fewer resources than simulations. This study aims to test an engineering-based upscaling method for LCI generation and adapt it to biochemical resource recovery processes. The method's validity for biochemical resource recovery processes was tested using data for biogas generation by anaerobic digestion in laboratory, pilot, and full scales, and using a combination of lab-scale data and kinetic equations. Biogas generation was chosen for two reasons: (1) there are several emerging technologies based on anaerobic digestion with products other than biogas, and (2) data is available for different scales. The results showed, a substantial difference between the methane production amount in actual and conceptual plants, is an important cause of the variation in impact category results. Different estimations of fugitive emissions have an important impact on the global warming potential results. Combination of lab-scale data and kinetic equations approximates best with the actual plant for the abiotic depletion, eutrophication, freshwater aquatic ecotoxicity, global warming and photochemical ozone creation potentials. The results are sensitive to biogas generation amount in several categories.

Sustainability assessment of corn production in conventional and conservation tillage systems

To develop sustainable cropping systems, the coherence between economic, environmental, and energy aspects must be considered. We aimed to assess the sustainability of corn (Zea mays) production using four tillage systems which varied in the intensity of soil disturbance (i.e., conventional till with moldboard plow (MP), conventional till with chisel plow (CP), strip-tillage (ST), and no-till (NT)) by performing life cycle assessment (LCA) analysis and Material Flow Cost Accounting (MFCA). It is common that material and energy wastage is not considered in sustainability assessment studies. When material and energy wastes are calculated in monetary terms, the hidden costs of production will be revealed. Simultaneous application of LCA and MFCA methods in sustainability assessments can provide such valuable information. Cradle-to-farm gate was considered as the system boundary in LCA-MFCA. The total annual energy input for corn production using MP, CP, ST, and NT was found to be 37472 MJ ha−1 (3092 MJ t−1), 36384 MJ ha−1 (3290 MJ t−1), 33717 MJ ha−1 (3309 MJ t−1), and 32889 MJ ha−1 (2764 MJ t−1), respectively. As energy demand increased, yield per ha also increased in all tillage systems except in NT in which yield increase was concurrent with improved energy efficiency. The gross value was calculated as 1470 $ ha−1 (121 $ t−1) for MP, 1446 $ ha−1 (131 $ t−1) for CP, 1380 $ ha−1 (128 $ t−1) for ST, and 1334 $ ha−1 (112 $ t−1) for NT system. The economic indices for each tillage system were computed. Our results showed that eliminating those negative products in corn production can increase farmers' net benefit by 200 $ ha−1. Global warming potential, acidification potential, eutrophication potential, ozone depletion potential, and photochemical ozone creation were selected to reflect the environmental impact associated with corn production in each tillage system. From an environmental standpoint, NT and MP performed much better than CP and ST. In three important impact categories (i.e., global warming potential, acidification, and eutrophication potential) MP, and in the other two impact categories (i.e., photochemical ozone creation potential and ozone depletion potential) NT system performed best among all tillage systems. It can be concluded that NT showed the best performance in terms of energy, economic and environmental indicators for corn production followed by MP system.

Implementing Artificial Intelligence Techniques to Predict Environmental Impacts: Case of Construction Products

Nowadays, product designers, manufacturers, and consumers consider the environmental impacts of products, processes, and services in their decision-making process. Life Cycle Assessment (LCA) is a tool that assesses the environmental impacts over a product’s life cycle. Conducting a life cycle assessment (LCA) requires meticulous data sourcing and collection and is often time-consuming for both practitioner and verifier. However, predicting the environmental impacts of products and services can help stakeholders and decision-makers identify the hotspots. Our work proposes using Artificial Intelligence (AI) techniques to predict the environmental performance of a product or service to assist LCA practitioners and verifiers. This approach uses data from environmental product declarations of construction products. The data is processed utilizing natural language processing (NLP) which is then trained to random forest algorithm, an ensemble tree-based machine learning method. Finally, we trained the model with information on the product and their environmental impacts using seven impact category values and verified the results using a testing dataset (20% of EPD data). Our results demonstrate that the model was able to predict the values of impact categories: global warming potential, abiotic depletion potential for fossil resources, acidification potential, and photochemical ozone creation potential with an accuracy (measured using R2 metrics, a measure to score the correlation of predicted values to real value) of 81%, 77%, 68%, and 70%, respectively. Our method demonstrates the capability to predict environmental performance with a defined variability by learning from the results of the previous LCA studies. The model’s performance also depends on the amount of data available for training. However, this approach does not replace a detailed LCA but is rather a quick prediction and assistance to LCA practitioners and verifiers in realizing an LCA.

In silico study of hybrid renewable energy in microalgae facilities: A path towards net-zero emissions

The decarbonization of electricity use has become indispensable in the fight against climate change and can be seen as a business opportunity. Investing in green electricity is becoming a trend and, in the microalgae industry, the initiative can improve the sustainability of the processes and products. In this sense, we seek to assess the environmental and economic sustainability of the commercial microalgae-based products by the solar–wind hybrid renewable electricity integration into manufacturing processes. Besides that, geospatial variability and availability of hybrid renewable electricity resources have been mapped. The results indicate that the production of 1 ton/month of the main commercial microalgae-based products (whole dry biomass, β-carotene, phycocyanin, astaxanthin, docosahexaenoic acid, and eicosapentaenoic acid), using solar-wind electricity saves on the order of 70 to 89% of the environmental impacts in the categories of ozone depletion potential, global warming potential, photochemical ozone creation potential, acidification potential, eutrophication potential, and ecotoxicity. Also indicate that the implementation of an on-grid solar-wind electrical system can reduce the plant's electricity invoice by more than 80% per year. The greatest theoretical potential for implementing solar-wind systems is experienced in West and North Africa, Australasia, and the Middle East. The results found in this study provide substantial evidence that investing in renewable electricity can bring environmental and economic benefits.

Life cycle assessment comparison between zircon and alumina sand applied to ceramic tiles

The goal of the study is to assess and compare the use of opacifier (whitener) materials zircon sand and alumina applied in ceramic tiles production. This study provides a comparison using a cradle-to-gate life cycle assessment (LCA) approach, giving an overview of the differences from an environmental perspective between these materials in body mixtures to obtain tiles with a high degree of whiteness. This ISO compliant study is backed by an independent critical review panel and presents the first European-representative LCA comparison between zircon and alumina, using primary data from industry. A super white (with CIELab coordinate L*>85) ceramic tile can be produced using zircon or alumina as opacifier, with different mixtures. For zircon data, a previous ISO reviewed LCA and its associated paper has been used. This data comes from Zircon Industry Association members. For alumina, the eco-profile of alumina and bauxite developed by the European Aluminium has been used and is available in the “Environmental Profile Report for the European Aluminium Industry”. This study considers the use phase of the compared materials as whiteners. Milling phase data was collected from specific producers and tile mixture preparation data was taken from wider industrial bodies. Sensitivity and scenario analysis were used to understand the main differences between mixtures and influences between materials. Comparing the use of zircon sand with alumina in different ceramic mixtures, the primary result is that tiles using zircon had lower environmental burdens for almost all the analysed impact potentials. The alumina mixtures investigated show about 20% higher Global Warming Potential (GWP), Eutrophication Potential (EP), Acidification Potential (AP), Photochemical Ozone Creation Potential (POCP), Abiotic Depletion Element and Fossil Potential (ADPe/f) and Primary Energy Demand (PED). The Ozone Depletion Potential (ODP) is the only potential impact that is similar for zircon mixtures and alumina mixtures. The milling process is not negligible for all the impact categories considered in this study. The results of the study show that main differences between zircon and alumina mixtures are closely tied to the environmental performance of regional grid electricity generation. This study quantifies and compares the environmental impacts associated with the production of super-white ceramic tile mixture with two different whiteners: zircon and alumina. With this study, ceramic tile producers are given a tool to guide their choices in opacifier material selection, using a rational, scientific and peer-reviewed methodology, ensuring objective comparison between two materials.

Comparative environmental and economic life cycle assessment of dry and wet anaerobic digestion for treating food waste and biogas digestate

Anaerobic digestion (AD) has proven to be a promising option for food waste (FW) management, due to the significant potential of recovering energy from waste. In this study, the environmental and economic impacts of six scenarios for FW and biogas digestate management in Shenzhen, China, were evaluated using life cycle assessment (LCA) and life cycle cost (LCC) analysis. GaBi model was employed to perform LCA on the basis of CML 2001 methodology, while LCC analysis was conducted using net present value to evaluate the economic efficiency. Results showed that dry AD coupled with biogas digestate incineration not only exhibited the best net environmental benefits with the reduction of 195 kg CO2 per ton of FW, but also appeared to be the most economically feasible option with the lowest LCC (446.223 thousand CNY). With respect to the FW treatment technology, dry AD scenarios exhibited better environmental benefits associated with global warming, human toxicity, marine aquatic ecotoxicity and photochemical ozone creation potential, compared to those in wet AD. Regarding post treatment for biogas digestate, incineration appeared to be the best option compared to the landfill and compost. Moreover, sensitivity analysis indicated that dry AD coupled with biogas digestate incineration exhibited least vulnerable to the change in biogas production environmentally. The outcomes of this study will contribute to developing the optimal FW management strategy for mitigating the environmental and economic impacts in terms of both environmental and economic sustainability.

Atmospheric chemistry of (Z)- and (E)-1,2-dichloroethene: kinetics and mechanisms of the reactions with Cl atoms, OH radicals, and O3.

Smog chambers interfaced with in situ FT-IR detection were used to investigate the kinetics and mechanisms of the Cl atom, OH radical, and O3 initiated oxidation of (Z)- and (E)-1,2-dichloroethene (CHClCHCl) under atmospheric conditions. Relative and absolute rate methods were used to measure k(Cl + (Z)-CHClCHCl) = (8.80 ± 1.75) × 10-11, k(Cl + (E)-CHClCHCl) = (8.51 ± 1.69) × 10-11, k(OH + (Z)-CHClCHCl) = (2.02 ± 0.43) × 10-12, k(OH + (E)-CHClCHCl) = (1.94 ± 0.43) × 10-12, k(O3 + (Z)-CHClCHCl) = (4.50 ± 0.45) × 10-21, and k(O3 + (E)-CHClCHCl) = (1.02 ± 0.10) × 10-19 cm3 molecule-1 s-1 in 700 Torr of N2/air diluent at 298 ± 2 K. Pressure dependencies for the Cl atom reaction kinetics were observed for both isomers, consistent with isomerization occurring via Cl atom elimination from the chemically activated CHCl-CHCl-Cl adduct. The observed products from Cl initiated oxidation were HC(O)Cl (117-133%), CHCl2CHO (29-30%), and the corresponding CHClCHCl isomer (11-20%). OH radical initiated oxidation gives HC(O)Cl as a major product. For reaction of OH with (E)-CHClCHCl, (Z)-CHClCHCl was also observed as a product. A significant chlorine atom elimination channel was observed experimentally (HCl yield) and supported by computational results. Photochemical ozone creation potentials of 12 and 11 were estimated for (Z)- and (E)-CHClCHCl, respectively. Finally, an empirical kinetic relationship is explored for the addition of OH radicals or Cl atoms to small alkenes. The results are discussed in the context of the atmospheric chemistry of (Z)- and (E)-CHClCHCl.

A Comparative Life Cycle Assessment (LCA) of Gasoline Blending with Different Oxygenates in India

This paper includes a cradle-to-gate life cycle impact evaluation of gasoline blends in India. The potential environmental impacts of gasoline blends with three major components, i.e., methanol, ethanol, and n-butanol are assessed. The production of methanol from the natural gas reforming process, ethanol from hydrogenation with nitric acid, and n-butanol from the oxo process are considered in the current study. The results show that the gasoline blending with methanol has the lowest impact (11 categories) and is nearly constant from 5 to 15%. For gasoline with ethanol as an additive, the global warming potential, ozone depletion potential, and abiotic depletion potential rise with increasing ethanol addition. Meanwhile, increasing ethanol addition reduces the acidification potential and terrestric ecotoxicity potential impact of gasoline blends. Similarly, gasoline with n-butanol as an additive has higher acidification potential, eutrophication potential, human toxicity potential, terrestric ecotoxicity potential, marine aquatic ecotoxicity potential, and photochemical ozone creation potential compared to methanol and ethanol.

Mechanism, Kinetics, and Ecotoxicity Assessment of ·OH-Initiated Oxidation Reactions of Sulfoxaflor.

The ·OH-initiated reaction mechanism and kinetics of sulfoxaflor were investigated by using electronic structure calculations. The possible hydrogen atom and cyano group abstraction reaction pathways were studied, and the calculated thermochemical parameters show that the hydrogen atom abstraction from the C7 carbon atom is the more favorable reaction pathway. The subsequent reactions for the favorable intermediate (I4) with other atmospheric reactive species, such as O2, H2O, HO2·, and NOx· (x = 1, 2), were studied in detail. The products identified from the subsequent reactions could contribute to secondary organic aerosol (SOA) formation in the atmosphere. The intermediates and products formed from the initial and subsequent reactions are equally as toxic as the parent sulfoxaflor. At 298 K, the rate constant calculated for the formation of the favorable intermediate I4 is 2.54 × 10-12 cm3 molecule-1 s-1, which shows that the lifetime of sulfoxaflor is 54 h. The excited-state calculation performed through time-dependent density functional theory shows that the photolysis of the title molecule is unlikely in the atmosphere. The global warming potentials (GWPs) for different time horizons, photochemical ozone creation potential (POCP), and ecotoxicity analysis were also studied for the insecticide sulfoxaflor.

Environmental Impact Assessment of Captive Power Plant Using LCA for Sustainable Development

The capacity of captive power plants has grown at a high rate in India in the recent past. As a result, harmful emissions have increased that need to be accounted for the overall sustainability of the parent plant. The aim of this research work is to quantify the environmental impact which is associated with the captive power plant usage through life cycle assessment approach. In the present study, Life cycle assessment (LCA) methodology is adopted from gate to grave system boundary. LCA of the CPP was conducted to assess the actual effect of power plant on the environment. The GaBi 6.4 software was used to analyze the energy input and emissions of harmful gases in the CPP. The study suggests that the Photochemical Ozone Creation Potential (POCP) created by the power plant is high and should be reduced.

Reaction of •OH with CHCl=CH-CHF2 and its atmospheric implication for future environmental-friendly refrigerant

Abstract In order to understand the atmospheric implication of the chlorinated hydrofluoroolefin (HFO), the geometrical structures and the IR absorption cross sections of the stereoisomers 1-chloro-3,3-difluoropropene were studied using the B3LYP/6-31G(3df) and M06-2X/6-31G(3df) methods in the gas phase. The cis-trans isomerization was assessed using the M06-2X/6-311++G(3df,p)//6-31+G(3df,p) method. The latter method was also employed for thermochemistry and the rate coefficients of the reactions of •OH with the cis- and trans-isomers in the temperature ranging from 200 to 400 K. The computational method CCSD/cc-pVTZ//M06-2X/6-31+G(3df,p) was used to benchmark the rate coefficients. It turns out that, the trans-isomer is more stable than cis-isomer and the trans- to cis-isomerization is thermodynamically unfavorable. The rate coefficient follows the Gaussian law with respect to the inverse of temperature. At the global temperature of stratosphere, the calculated rate coefficients served to estimate the atmospheric lifetime along with the photochemical ozone creation potential (POCP). This yielded lifetimes of 4.31 and 7.31 days and POCPs of 3.80 and 2.23 for the cis- and trans-isomer, respectively. The radiative forcing efficiencies gave 0.0082 and 0.0152 W m−2 ppb−1 for the cis- and trans-isomer, respectively. The global warming potential approached zero for both stereoisomers at 20, 100, and 500 years time horizons.

A Combined Experimental and Theoretical Study to Determine the Kinetics of 2-Ethoxy Ethanol with OH Radical in the Gas Phase.

The reactivity of 2-ethoxy ethanol with OH radicals was experimentally measured in the temperature range of 278-363 K using the pulsed laser photolysis-laser-induced fluorescence (PLP-LIF) technique. The rate coefficient at room temperature was measured to be (1.14 ± 0.03) × 10-11 cm3 molecule-1 s-1, and the Arrhenius expression was derived to be kexpt278-363K = (1.61 ± 0.35) × 10-13 exp{(1256 ± 236)/T} cm3 molecule-1 s-1. Computational calculations were performed to compute the kinetics of the titled reaction in the temperature range of 200-400 K using advanced methods incorporated with tunneling correction at the CCSD(T)/aug-cc-pVTZ//M06-2X/6-31+G(d,p) level of theory. The Arrhenius expression derived from the computationally calculated rate coefficients is ktheo200-400K = (1.59 ± 0.35) × 10-13exp{(1389 ± 62)/T} cm3 molecule-1 s-1. The feasibility of each reaction pathway was also determined using the calculated thermochemical parameters. Atmospheric implication parameters such as cumulative atmospheric lifetime and photochemical ozone creation potential were calculated and are discussed in this paper.

Coordinated reduction of CO2 emissions and environmental impacts with integrated city-level LEAP and LCA method: A case study of Jinan, China

The evaluation of the efficiency and feasibility of energy transition and air pollution control at the city level is one of the key points in addressing environmental problems and achieving the goals of CO2 emission reduction and carbon neutrality in China. In this study, an integrated method is developed on the basis of the Low Emissions Analysis Platform (LEAP) and life cycle assessment (LCA). The energy demands and environmental co-benefits in Jinan, one of the low-carbon city pilots in China, are quantitatively evaluated under three policy scenarios: low-carbon (LC) policy scenario, pollution control (PC) policy scenario, and deep-level cut of CO2 emissions (DCC) scenario from 2016 to 2050. From 2016 to 2030, the PC policies would be more powerful than the LC policies in terms of energy demand decrease. From 2030 to 2050, the LC policies would be more efficient than all the other policies. Promoting energy-saving buildings in the LC scenario would contribute to the continual decline in energy demands. In the DCC scenario, CO2, PM2.5, PM10, CO, NOX and SO2 emissions would decline by more than 71.4% relative to the records in 2016. Global warming potential, human toxicity potential, photochemical ozone creation potential, particulate matter formation potential, and acidification potential would also decrease by 81.8%–88.5%. On the basis of the integrated city-level LEAP and LCA method, this study quantifies the various environmental impacts of urban decarbonization policies and provides science-based references for urban low-carbon transformation.

Life Cycle Assessment of Mortars Produced Partially Replacing Cement by Treated Mining Residues

The use of secondary mining resources to replace conventional constituents in mortars production has proved the effectiveness to preserve the quality of mechanical, physical, and chemical properties. However, minimal research has been performed to quantify the environmental impacts of mortars with mining residues. In the present work, a life cycle assessment of 10 mortars was carried out. A reference mortar (100% of cement binder) and mortars with cement substitutions in 10%, 25%, and 50% by raw, electrodialytic treated, and electrodialytic plus thermal treated mining residues were analysed. The impacts were studied in six environmental categories: (1) abiotic depletion; (2) global warming; (3) ozone depletion; (4) photochemical ozone creation; (5) acidification; and (6) eutrophication potentials. The results demonstrated that mortars formulated with raw mining residues may decrease the environmental impacts, namely in global warming potential (55.1 kg CO2 eq./t modified mortar). Considering the treatments applied to mining residues, the major mitigations were reported in photochemical ozone creation (−99%), ozone depletion (−76 to −98%), and acidification potential (−90 to −94%), mainly due to the disposal impacts avoided in comparison to the reference mortar. Analysing all mortars’ constituents and their management options, products with electrodialytic treated mining residues showed higher influence in ozone depletion (18 to 52%). Coupling a thermal procedure, mining residues contributed for 99% of the abiotic depletion potential of mortars.

Theoretical investigations on the OH radical mediated kinetics of cis- and trans-CH3CF=CHF and CH3CH=CF2 over temperature range of 200-400K

Global reactivity for the OH-radical mediated kinetics of three Hydrofluoroolefins (HFOs), cis-CH3CF=CHF, trans-CH3CF=CHF and CH3CH=CF2 was evaluated at the CCSD(T)/cc-pVTZ//M062x/6-31G+(d,p) level of theory. The overall kinetics was computed using the Canonical Variational Transition State Theory (CVT) in combination with Small Curvature Tunneling (SCT) and Interpolated Single Point Energy (ISPE) corrections over the temperature range of 200 and 400 K. The total rate coefficients (k, in units of cm3 molecule−1 sec−1) for the reaction of OH radical with these HFOs at 298 K were computed to be, k298Kcis−CHF=CFCH3+OH=1.69×10−12, k298Ktrans−CHF=CFCH3+OH=3.12×10−12, and k298KCF2=CHCH3+OH=5.40×10−12. To further corroborate the computed kinetics, thermodynamic parameters and branching ratios were also computed for all the reaction pathways. Atmospheric lifetimes, Radiative forcing (RF), Global Warming Potentials (GWP) and Photochemical Ozone Creation Potentials (POCP) of these HFOs were also calculated and are presented in this manuscript.

Diurnal photodegradation of fluorinated diketones (FDKs) by OH radicals using different atmospheric simulation chambers: Role of keto-enol tautomerization on reactivity

Rate coefficients for the gas-phase reactions of OH radicals with a series of fluorinated diketones have been determined for the first time at (298 ± 3) K and atmospheric pressure using the relative method and FTIR spectroscopy and GC-FID to monitor both reactants and references. The following values, in 10−11 cm3 molecule−1 s−1, were obtained for 1,1,1-trifluoro-2,4-pentanedione (TFP), 1,1,1-trifluoro-2,4-hexanedione (TFH) and 1,1,1-trifluoro-5-methyl-2,4-hexanedione (TFMH), respectively: k1(TFP + OH) = (1.3 ± 0.4), k2(TFH + OH) = (2.2 ± 0.8), k3(TFMH + OH) = (3.3 ± 1.0). The results are discussed with respect to the keto-enolic tautomerization specific for β-diketones.Based on the present results, the tropospheric lifetimes of TFP, TFH and TFMH upon degradation by OH radicals were calculated as 21, 13 and 8 h, respectively indicating that transport might play a role in the atmospheric fate of the studied compounds. Photochemical ozone creation potentials were estimated for TFP, TFH and TFMH to be: 23, 29 and 34, respectively.

Life-LCA: the first case study of the life cycle impacts of a human being

PurposeBesides politics and the private sector, changes in the consumption pattern of individuals can significantly contribute to sustainable development. The recently published Life-LCA method adapts life cycle assessment to analyse human beings and quantifies their impacts. This method is applied for the first time in this case study to provide insights and remaining challenges.MethodsThe environmental impacts caused by the life cycle of a middle-aged German man (“Dirk”) were determined by the Life-LCA method from his birth until his current age (0–49 years). To determine and quantify reduction options, a current 1-year period was analysed in detail by a baseline scenario of his current consumption and an optimized scenario after changing his consumption patterns. The environmental impact assessment included global warming (GWP), acidification (AP), eutrophication (EP), and photochemical ozone creation potentials (POCP).Results and discussionDirk has emitted 1,140 t CO2-eq., 4.48 t SO2-eq., 1.69 t PO4-eq., and 0.537 t C2H4-eq. emissions over his current lifetime. Transportation dominated all considered impact categories (40 up to 55%). Energy and water consumption is the second most significant product category for GWP (39%). Food products, with 10%, are the third biggest contributor to GWP, but contribute rather significantly to the impact categories AP (34%), EP (42%), and POCP (20%). The optimized scenario analysis revealed significant reductions for all studied impacts in the range of 60–65%. CO2-eq. emissions were reduced from 28 to 10 t/a. The remaining challenges include data collection for childhood, gaps and inconsistencies of existing data for consumer goods, the allocation between product users, and depreciation of long-living products.ConclusionThe first Life-LCA case study confirmed the applicability of the Life-LCA method. It showed that the Life-LCA approach allows for tracking individual consumption patterns of a human being. The impacts of behavioural changes were quantified, and significant reduction potentials of the environmental impacts were revealed. Additional case studies on people of different age, region, culture, and lifestyle are needed for further insights and methodological refinements.

Exploring the OH-initiated reactions of styrene in the atmosphere and the role of van der Waals complex

Reacting with OH provides a major sink for styrene in the atmosphere, with three possible pathways including OH-addition, H-abstraction and addition-dissociation reactions. However, the total rate coefficients of styrene + OH were measured as 1.2–6.2 × 10−11 cm3 molecule−1 s−1 under atmospheric conditions, varying by a maximum factor of 5. On the other hand, only one theoretical work reported this rate coefficient as 19.1 × 10−11 cm3 molecule−1 s−1, which exhibits up to 16 times that measured in laboratory studies. In the present study, the reaction kinetics of styrene + OH was extensively studied with high-level quantum chemical methods combined with RRKM/master equation simulations. In particular, we carried out theoretical treatments for the formation of pre-reaction Van der Waals complexes of styrene + OH, and examined their influence on the reaction kinetics. The total rate coefficient for styrene + OH is calculated to be 1.7 × 10−11 cm3 molecule−1 s−1 at 300 K, 1 atm. The main products are addβ (88.2%), add5 (6.9%), addα (1.9%) and add3 (1.7%). Using our computed rate coefficient and the global atmospheric hydroxyl radical concentration (2 × 106 radicals per cm3), the lifetime of styrene in the atmosphere is estimated at 8.0 h. The degradation of styrene might be negligible for the formation of ozone in the atmosphere based upon the photochemical ozone creation potentials calculation. The computed product yields indicate that addβ via subsequent reactions could significantly produce formaldehyde and benzaldehyde that were observed in previous experimental studies on styrene oxidation, and contribute to the formation of secondary organic aerosols.