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Anthropogenic emissions of ozone-depleting substance CH3Cl during 2000–2020 in China
2022
Hu, Xiaoyi | Yao, Bo | Fang, Xuekun
Methyl Chloride (CH₃Cl) is the largest source of stratospheric chlorine, which has a significant impact on the depletion of the stratospheric ozone layer. Detailed information on anthropogenic CH₃Cl emissions in China is still lacking. This study establishes a comprehensive bottom-up inventory of anthropogenic CH₃Cl emissions in China during 2000–2020. Results show that China's anthropogenic CH₃Cl emissions have increased significantly, from 34.1 ± 11.6 Gg/yr (gigagrams per year) in 2000 to 128.5 ± 26.5 Gg/yr in 2018 with a slight decrease to 124.9 ± 26.0 Gg/yr in 2020. The main sources of anthropogenic emissions of CH₃Cl in China are chemical production (37.1%), solvent use (35.4%), and coal combustion (13.6%) in 2020. China's contribution to global anthropogenic emissions of CH₃Cl reached almost 50%. Moreover, the ratios of CH₃Cl CFC-11-eq emissions relative to emissions of ozone-depleting substances (ODSs) controlled under the Montreal Protocol in China have increased from 0.8% in 2000 to 11.6% in 2020 and are estimated to continue increasing in the future. In summary, China's anthropogenic CH₃Cl emissions have shown an increasing trend in the past two decades, made a huge contribution to the total global anthropogenic emissions, and presented a potential increasing impact on the depletion of the ozone layer and global warming.
Mostrar más [+] Menos [-]Estimate of hydrochlorofluorocarbon emissions during 2011–2018 in the Yangtze River Delta, China
2022
Yu, Yan | Xu, Honghui | Yao, Bo | Pu, Jingjiao | Jiang, Yujun | Ma, Qianli | Fang, Xuekun | O'Doherty, Simon | Chen, Liqu | He, Jun
Hydrochlorofluorocarbons (HCFCs) are used as temporary substitutes for chlorofluorocarbons and other ozone-depleting substances because they have reduced ozone depletion and global warming potentials. The consumption and production of HCFCs are regulated via the Montreal Protocol and its amendments till 2013, with a complete phase-out being scheduled by 2030 for Article 5 parties (developing countries). To better understand the characteristics and emissions of HCFCs in the Yangtze River Delta (YRD), which is the largest metropolitan area in China, weekly flask samples were collected at the Lin'an regional background station located in the YRD from 2011 to 2018 and measured for four HCFCs (HCFC-22, HCFC-141b, HCFC-142b, and HCFC-124). The HCFC-132b and HCFC-133a measurements began in 2018. The ambient mixing ratios of the HCFCs exhibited higher concentrations and larger variabilities than those at the Shangri-la regional background station at similar latitudes in southwest China. The HCFC emissions in the YRD were estimated based on the tracer ratio method using CO and HFC-134a as tracers, and were comparable within the uncertainties. Our results are generally consistent with previous estimates obtained using top-down approaches. HCFC-22 and HCFC-141b contributed 52% ± 23% and 41% ± 24% of the total ODP-weighted (CFC-11-equivalent) HCFC emissions from the YRD, respectively, whereas HCFC-22 contributed the most (83% ± 36%) to the total CO₂-equivalent HCFC emissions from the YRD. The cumulative ODP-weighted and CO₂-equivalent emissions of HCFCs from the YRD accounted for 25% ± 15% and 20% ± 11% of the national corresponding totals, respectively, for 2011–2017. The HCFC-141b emissions from the YRD contributed approximately half of the total Chinese emissions. HCFC-133a emissions in the YRD accounted for approximately one-fifth of the global total in 2018. Thus, the YRD is an important contributor of HCFC emissions on national and global scales.
Mostrar más [+] Menos [-]Decrease in life expectancy due to COVID-19 disease not offset by reduced environmental impacts associated with lockdowns in Italy
2022
Rugani, Benedetto | Conticini, Edoardo | Frediani, Bruno | Caro, Dario
The consequence of the lockdowns implemented to address the COVID-19 pandemic on human health damage due to air pollution and other environmental issues must be better understood. This paper analyses the effect of reducing energy demand on the evolution of environmental impacts during the occurrence of 2020-lockdown periods in Italy, with a specific focus on life expectancy. An energy metabolism analysis is conducted based on the life cycle assessment (LCA) of all monthly energy consumptions, by sector, category and province area in Italy between January 2015 to December 2020. Results show a general decrease (by ∼5% on average) of the LCA midpoint impact categories (global warming, stratospheric ozone depletion, fine particulate matter formation, etc.) over the entire year 2020 when compared to past years. These avoided impacts, mainly due to reductions in fossil energy consumptions, are meaningful during the first lockdown phase between March and May 2020 (by ∼21% on average). Regarding the LCA endpoint damage on human health, ∼66 Disability Adjusted Life Years (DALYs) per 100,000 inhabitants are estimated to be saved. The analysis shows that the magnitude of the officially recorded casualties is substantially larger than the estimated gains in human lives due to the environmental impact reductions. Future research could therefore investigate the complex cause-effect relationships between the deaths occurred in 2020 imputed to COVID-19 disease and co-factors other than the SARS-CoV-2 virus.
Mostrar más [+] Menos [-]The atmospheric concentrations and emissions of major halocarbons in China during 2009–2019
2021
Yi, Liying | Wu, Jing | An, Minde | Xu, Weiguang | Fang, Xuekun | Yao, Bo | Li, Yixi | Gao, Ding | Zhao, Xingchen | Hu, Jianxin
Due to the characteristics of ozone-depleting and high global warming potential, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) have been restricted by the Montreal Protocol and its amendments over the world. Considering that China is one of the main contributors to the emission of halocarbons, a long-term atmospheric observation on major substances including CFC-11 (CCl₃F), CFC-12 (CCl₂F₂), HCFC-22 (CHClF₂), HCFC-141b (CH₃CCl₂F), HCFC-142b (CH₃CClF₂) and HFC-134a (CH₂FCF₃) was conducted in five cities (Beijing, Hangzhou, Guangzhou, Lanzhou and Chengdu) of China during 2009–2019. The atmospheric concentrations of CFC-11, CFC-12, HCFC-141b and HCFC-142b all showed declining trends on the whole while those of HCFC-22 and HFC-134a were opposite. A paired sample t-test showed that the ambient mixing ratios of HCFC-22 and HFC-134a in cities were 41.9% and 25.7% higher on average than those in suburban areas, respectively, while the other substances did not show significant regional differences. The annual emissions of halocarbons were calculated using an interspecies correlation method and the results were generally consistent with the published estimates. Discrepancies between bottom-up inventories and the estimates in this study for CFCs emissions were found. Among the most consumed ozone depleting substances (ODSs) in China, CFCs accounted for 75.1% of the ozone depletion potential (ODP)-weighted emissions while HCFCs contributed a larger proportion (58.6%) of CO₂-equivalent emissions in 2019. China's emissions of HCFC-141b and HCFC-142b contributed the most to the global emission (17.8%–48.0%). The elimination of HCFCs in China will have a crucial impact on the HCFCs phase-out in the world.
Mostrar más [+] Menos [-]Seasonal acclimation of the moss Polytrichum juniperinum Hedw. to natural and enhanced ultraviolet radiation
2010
Lappalainen, Niina M. | Huttunen, Satu | Suokanerva, Hanne | Lakkala, Kaisa
Short- and long-term changes in the methanol-extractable UV-absorbing compounds and biomass of the pioneer moss Polytrichum juniperinum in response to natural and enhanced UV radiation were studied. Under natural conditions, the compounds were found to fluctuate seasonally. In summer these compounds correlated negatively with irradiation. The concentration was low in July after a period of simultaneous heat, drought and high irradiation. Transient positive correlation between daily concentration and UV was seen in June. The concentration increased towards autumn and was relatively high under snow. Two enhanced UV experiments were performed. Seasonality in the compounds was again observed, with negative correlations with irradiation. During the first weeks, a transient inhibition of compound production was observed after the daily UV-B treatment. After six years of modulated UV-treatment in situ, photosynthesising biomass decreased under UV-B and increased under UV-A. A larger variation in the UV-absorbing compounds was observed under UV-B treatment. Juniper polytrichum moss is affected by drought, overwintering conditions and UV.
Mostrar más [+] Menos [-]Land-atmosphere fluxes and concentrations of CFC-11 and CFC-12 based on in situ observations from a coastal salt marsh in eastern China: Implications for CFC remediation
2021
Wang, Jinshu | Cao, Yingjia | Wang, Jinxin
Regional- and national-scale emissions of chlorofluorocarbons (CFCs), especially in Eastern China, are of great concern to environmentalists and policy makers. To determine the source-sink dynamics of coastal salt marshes for CFC-11 and CFC-12 in the local atmosphere, we studied a coastal salt marsh in Northern Jiangsu Province, taking measurements of the atmospheric concentrations and fluxes of CFC-11 and CFC-12 using static flux chambers in August (growing season) and December (non-growing season) of 2013, and along both creek-side and vegetated transects. We observed unexpectedly high concentrations of CFC-11 (676.5 × 10⁻¹²) and CFC-12 (794.6 × 10⁻¹²) in the salt marsh in 2013, with predominantly non-local emissions. Overall, the study salt marsh acted as a net sink for CFC-11 and CFC-12, with the average flux ranging from −11.4 μg m⁻² h⁻¹ to 5.0 μg m⁻² h⁻¹ for CFC-11 and from −7.4 μg m⁻² h⁻¹ to 0.7 μg m⁻² h⁻¹ for CFC-12. This clearly indicates that the high concentrations of CFC-11 and CFC-12 measured in the atmosphere were not caused by local emissions; terrigenous sources most likely act as the main exogenous input pathway. Our study suggests that salt marsh ecosystems may be worthy of attention as sinks for CFC-11 and CFC-12; as such, the ecological restoration of salt marshes is critical to better offset increasing CFC-11 and CFC-12 emissions.
Mostrar más [+] Menos [-]Life cycle assessment (LCA) of bio-based packaging solutions for extended shelf-life (ESL) milk
2022
Cappiello, Giulia | Aversa, Clizia | Genovesi, Annalisa | Barletta, Massimiliano
The dairy market is one of the most important sectors worldwide, and milk packaging contributes to over one-third of the global dairy packaging demand. The end of life of the disposable packages is a critical stage of their life cycle, as demonstrated by the fact that disposable bottles are one of the litter items that are most found on beach shores. The aim of this paper is to analyse the performance of bioplastic bottles compared to other alternatives currently in use in the milk packaging sector, using the life cycle assessment (LCA) methodology. Bio-compostable plastic can be a powerful means to create a circular economy for disposable items. A PLA-based bottle is compared to a PET bottle, a HDPE bottle, a multilayer carton, and a glass bottle. In the analysis, also secondary and tertiary packaging is included. The functional unit chosen is “the packaging needed to contain 1 L of ESL milk and to guarantee a shelf life of 30 days”. Two sensitivity analyses are also performed in order to assess the influence of the end-of-life stage on the total impact. The results show that, in accordance with the assumptions of an ideal scenario, bioplastic system has a better performance than fossil-based systems and multilayer carton in the categories of climate change, ozone depletion, human toxicity, freshwater eutrophication, particular matter, and land use. The recycling scenario strongly changes the impact of the glass packaging system in the considered categories.
Mostrar más [+] Menos [-]Pathways of soil N2O uptake, consumption, and its driving factors: a review
2022
Liu, Hongshan | Li, Yuefen | Pan, Baobao | Zheng, Xiangzhou | Yu, Juhua | Ding, Hong | Zhang, Yushu
Nitrous oxide (N₂O) is an important greenhouse gas that plays a significant role in atmospheric photochemical reactions and contributes to stratospheric ozone depletion. Soils are the main sources of N₂O emissions. In recent years, it has been demonstrated that soil is not only a source but also a sink of N₂O uptake and consumption. N₂O emissions at the soil surface are the result of gross N₂O production, uptake, and consumption, which are co-occurring processes. Soil N₂O uptake and consumption are complex biological processes, and their mechanisms are still worth an in-depth systematic study. This paper aimed to systematically address the current research progress on soil N₂O uptake and consumption. Based on a bibliometric perspective, this study has highlighted the pathways of soil N₂O uptake and consumption and their driving factors and measurement techniques. This systematic review of N₂O uptake and consumption will help to further understand N transformations and soil N₂O emissions.
Mostrar más [+] Menos [-]Environmental impact assessment of the current, emerging, and alternative waste management systems using life cycle assessment tools: a case study of Johannesburg, South Africa
2022
Adeleke, Oluwatobi | Akinlabi, Stephen A. | Jen, Tien-Chien | Dunmade, Israel
Proper information regarding the performance of waste management systems from an environmental perspective is significant to sustainable waste management decisions and planning toward the selection of the least impactful treatment options. However, little is known about the environmental impacts of the different waste management options in South Africa. This study is therefore aimed at using the life cycle assessment tool to assess the environmental impact of the current, emerging, and alternative waste management systems in South Africa, using the city of Johannesburg as a case study. This assessment involves a comparative analysis of the unit processes of waste management and the different waste management scenarios comprising two or more unit processes from an environmental view. The lifecycle boundary consists of unit processes: waste collection and transportation (WC&T), material recycling facilities (MRF), composting, incineration, and landfilling. Four scenarios developed for the assessment are S1 (WC&T, MRF, and landfilling without energy recovery), S2 (WC&T, MRF, composting, and landfilling with energy recovery), S3 (WC&T and incineration), and S4 (WC&T, MRF, composting, and incineration). Based on the result of this study, MRF is the most environmentally beneficial unit operation while landfill without energy recovery is the most impactful unit operation. The result further revealed that no scenario had the best performance across all the impact categories. However, S3 can be considered as the most environmentally friendly option owing to its lowest impact in most of the impact categories. S3 has the lowest global warming potential (GWP) of 33.19 × 10⁶ kgCO₂eq, ozone depletion potential (ODP) of 0.563 kgCFC-11e, and photochemical ozone depletion potential (PODP) of 679.46 kgC₂H₂eq. Also, S4 can be regarded as the most impactful option owing to its highest contributions to PODP of 1044 kgC₂H₂eq, acidification potential (AP) of 892073.8 kgSO₂eq, and eutrophication potential (EP) of 51292.98 MaxPO4⁻³eq. The result of this study will be found helpful in creating a complete impression of the environmental performance of waste management systems in Johannesburg, South Africa which will aid sustainable planning and decisions by the concerned sector.
Mostrar más [+] Menos [-]Vapour absorption refrigeration system for rural cold storage: a comparative study
2021
Value addition of agro products improves the livelihood opportunities for rural farmers. Cold Storage is one of the techniques to improve the shelf life of agro product. With the increase in the utilization of refrigeration and air cooling using vapour compression refrigeration technology, global warming and ozone depletion due to the refrigerants have also been increased. So, to overcome this problem, several restrictions were placed on the refrigerant by the United Nations Framework Convention on Climate Change (UNFCCC). There is no way to slow down the growth of this technology, so the focus should be shown on finding an alternative. Various studies have been carried out on an alternate refrigeration system. This paper attempts to study the power quality challenges in the conventional vapour compression system. A comparative analysis of vapour compression refrigeration (VCR) and vapour absorption refrigeration (VAR), power factor analysis and temperature measurement on both technologies has also been carried out and reported.
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