Chlorofluorocarbons Research Articles

Scientists’ warning on loss of insect biodiversity and implications for sustainable agriculture

Climate change is a long-term shift in global or regional climate patterns. Climate change is among the biggest environmental challenges, humans face in the 21st century. The most imminent climatic change in recent times is the increase in atmospheric temperatures due to increased levels of greenhouse gases such as carbon dioxide (CO2), methane (CH4), ozone (O3), nitrous oxide (N2O) and chlorofluorocarbons (CFCs), largely because of industrialization and burning of fossil fuels, etc. The term biodiversity is the short form of ‘biological diversity. As per the Convention on Biological Diversity (CBD), biodiversity means the variability among all living organisms from all sources including inter alia terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part. Climate change is among the major environmental challenges for humans with catastrophic effects on faunal (especially insect) biodiversity and agricultural production. Insect biodiversity provides an array of indispensable services in agricultural production including pollination, nutrient recycling and natural control of pests. Special efforts are required for conserving and identifying insects and elucidating their role in ecosystem functioning. Intensive research, constant surveillance, early detection and rapid response are essential to face the emerging pest and disease threats to crop production. Insect Conservation, landscape heterogeneity, biological control and IPM are the keys to environmentally benign and climate-resilient crop protection for sustainable agricultural production in the future.

Ozone layer recovery could face setbacks

Earlier this year, the United Nations announced that the stratospheric ozone layer is on track to recover within 4 decades thanks to the Montreal Protocol , which guided the phaseout of ozone-depleting compounds, such as chlorofluorocarbons (CFCs). But sources of CFCs and other chemicals not covered by the international agreement could extend this recovery timeline. A new study has found that atmospheric concentrations of five CFCs have been increasing since 2010 despite bans on their use and production ( Nat. Geosci. 2023, DOI: 10.1038/s41561-023-01147-w ). The researchers think they could be released during the production of other chemicals, such as hydrofluorocarbons (HFCs), which are more ozone-friendly refrigerants. The Montreal Protocol does not ban the use of CFCs as chemical feedstocks. Aside from CFCs, other compounds, such as bromoform, can contribute to ozone depletion, says Susann Tegtmeier, an atmospheric scientist at the University of Saskatchewan. Bromoform is not regulated by the

Abstracts from The Aerosol Society Drug Delivery to the Lungs 33.

Abstracts from The Aerosol Society Drug Delivery to the Lungs 33.

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.

Isothermal (Vapour + Liquid) Equilibrium Measurements and Correlation of the Binary Mixture {3,3,3-Trifluoropropene (HFO-1243zf) + 2,3,3,3-tetrafluoropropene (HFO-1234yf)} at Temperatures from 283.15 K to 323.15 K

The many constrains introduced by the F-gas Regulation and the Kigali Amendment to the Montreal Protocol have resulted in an intense search for alternatives to fluorinated greenhouses gases for air conditioning and refrigeration purposes (Mota-Babiloni A, Makhnatch P, in Int J Refrig 127:101–110, 2021). With respect to the urge of new low-GWP and low-ODP refrigerants, blends composed of hydrofluoroolefins (HFO) are considered promising possible substitutes to hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) for HVAC&R applications (Sovacool et al., in Renew Sustain Energy Rev 141:110759), but thermophysical properties data for these blends are still scarce (Bell et al., in: J Chem Eng Data, 2021). In the present study, the vapor–liquid equilibrium (VLE) for the binary system (HFO-1243zf + HFO-1234yf), for which just one set of data on the VLE is available to date in literature, has been experimentally studied by means of a vapor recirculation apparatus. The measurements have been performed at isothermal conditions in the range of temperatures between 283.15 K and 323.15 K, while the composition of both the phases in equilibrium has been measured by gas-chromatographic analysis. The experimental VLE data have been correlated by two different equations of state (EoS): the Peng-Robinson (PR) EoS combined with Mathias–Copeman (MC) alpha function and van der Waals (vdW) mixing rules, and the Helmoltz EoS with dedicated binary interaction parameters. Correlated results showed a good agreement with the experimental data for the binary system.

"AN ATTEMPT TO IMPROVE ENERGY EFFICIENCY OF VAPOUR COMPRESSION REFRIGERATION ON SYSTEMS WORKING WITH R134a"

"Refrigeration is an industry of high importance in our modern times. It plays also a key role in maritime transport of perishables, where vapour compression refrigeration systems are dominant. These energy systems are indispensable, but they should be wise exploited because their high energy necessity. One of the frequent refrigerant chemical adopted in this system is the hydrofluorocarbon R134a. This refrigerant came to substitute traditional refrigerants, such as chlorofluorocarbons or hydro chlorofluorocarbons – substances being under environmental regulations. In this study, it is approached a single stage vapour compression refrigeration system working with R134a. The aim is to find the conditions in which this system is more energy efficient. In this respect, based on the laws of thermodynamics, are obtained information on Coefficient of Performance and energy destruction trends – when the evaporator temperature increases. Our results indicate that, although the analysis based on the first law of thermodynamics reveals that the performance of the system is higher for high evaporator temperatures, the energy destructions in this system increase together with the evaporator temperature increase. "

PERFORMANCE ANALYSIS OF THE THERMOELECTRIC TEC 12706-BASED COOLING SYSTEM IN COOLER BOX DESIGN

The most widely used refrigeration machine today is a refrigeration machine that operates with a vapor compression cycle (SKU). To operate a vapor compression machine, refrigerant is needed as a working fluid. The most widely used refrigerants are chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) refrigerants. However, their use can damage the ozone layer and has a great potential to increase the effects of global warming. Therefore, a refrigeration system that is environmentally friendly and also has low power is needed, this can be fulfilled by using thermoelectric. This research was conducted to analyze the performance of temperature differences, heat absorbed, cooling capacity and COP in thermoelectric-based cooler boxes, thermoelectric performance with variations in input voltage and with variations in the addition of heatsinks where the method used is experimental by controlling the variable input voltage. From the research results, the calorific value absorbed is proportional to the increase in the applied voltage. Where the greater the voltage applied, the heat absorbed will be higher and the input power that enters the thermoelectric module is directly proportional to the incoming voltage where the greater the voltage. Then the power that goes into the thermoelectric will also be even greater. Whereas the COP value will decrease as the voltage increases and the best thermoelectric performance is with a voltage of 10 V. This can be seen after 60 minutes, the temperature difference value is 6.6 0K, the absorbed calorific value is 19,150 W, and the COP is 0.921. The thermoelectric performance is not only based on the COP value but also based on a review of the electric power consumed and the cooling speed during the 60 minute test. Then for the addition of a copper heatsink the COP value is 0.4832 and the temperature drop in the cooler box is only 3.9 0K, the value is lower than without the additional heatsink due to the gap between the aluminum heatsinks.

The Effects Atmospheric Changes Have on Runoff

Over the last century, the earth has seen unprecedented atmospheric concentrations contaminate our ecosystems due to human activity. Predictions state the introduction of carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons (CFCs), will increase temperatures, and change the amount and location of precipitation causing more runoff. This could potentially result in disturbance events such as floods, to be more frequent and severe. This study aims to perform an assessment of the effects of a range of hypothetical climate changes on runoff in the North-east Pond River watershed, located in Newfoundland.
 To carry this out a watershed runoff model simulates runoff in the basin for current climatic conditions and for hypothetical climatic conditions that represent a range of possible climate changes (Bobba et al., 1997). The hypothetical changes in climate will showcase the effects of a 2oC increase in temperature on the total annual precipitation. This will then be compared to flood forecasting models to analyze how runoff will be affected by various climatic conditions, inducing unusual flooding events (Wijayarathne & Coulibaly, 2020). Previous studies have indicated the runoff sensitivity in watersheds to changes in temperatures which raises concerns as to the adverse effects this may cause in limiting water resources in the semi-arid regions in parts of Canada and the U.S. Thus, there is a need to increase the understanding of the sensitivity of water resources in Canadian watersheds to climate variability and climate change as effects of this magnitude on the North-east Pond River could have significant environmental implications.

An Overview of Stratospheric Ozone and Climate Effects

Anthropogenic Chlorofluorocarbons (CFCs) compelled stratospheric ozone reduction is one of the significant global environmental issues of this era. Ozone acts as a life saviour in the stratosphere whereas the same plays a role as a secondary air pollutant at tropospheric levels. This review encompasses studies involving the science of ozone destruction with an emphasis on chemical processes involved, minimum ozone features, ozone hole area characteristics, various Ozone Depleting Substances (ODSs), consequences of reduced stratospheric ozone levels, and the different executed international commitments to restrain ozone depletion. It has been perceived that the decrease in stratospheric ozone volume gives away extensively to climate change such as through ozone chemistry fluctuations of polar annular modes and its Greenhouse Gas (GHG) features. Different international ozone layer protection agreements have been performing a major role in limiting stratospheric ozone depletion thereby its adverse effects, and specifically Montreal protocol has been a great success to this point.

Confinement of ozone hole mainly in the Antarctic stratosphere to protect the living kingdom on the earth: chemistry behind this Nature’s unique gift

Abstract Man-made activities can release the ozone depleting substances (ODSs) like chlorofluorocarbons (CFCs) and other halocarbons stable in atmosphere and ultimately, they migrate to the stratosphere where they can destroy the ozone layer through the XOx catalytic cycle (X = Cl, Br). The active forms in this catalytic cycle are X and XO that can be arrested in the inactive forms like XONO2 (halogen nitrate, an additive compound of two odd electron molecules XO and NO2) and HX (produced in the reaction of X with CH4) in the stratosphere to prevent the ozone depletion cycle. The catalytically active forms from these inactive species can be regenerated in the reactions on heterogeneous solid surface like polar stratospheric cloud (specially Type II PSC formed at about −85 °C). Formation of such PSC in the stratosphere is only possible in the supercooled stable Antarctic vortex produced in the prolonged winter. In fact, formation of such PSC in the stratosphere is not possible in the other regions of the earth and not even in the Arctic pole where no stable Arctic vortex is generally formed in the winter. Thus nature confines the ozone depletion reactions mainly in the stratosphere of Antarctica pole which is practically inhabited.

Annually Resolved Propagation of CFCs and SF6 in the Global Ocean Over Eight Decades

AbstractOceanic transient tracers, such as chlorofluorocarbons (CFCs) and sulfur‐hexafluoride (SF6), trace the propagation of intermediate‐to‐abyssal water masses in the ocean interior. Their temporal and spatial sparsity, however, has limited their utility in quantifying the global ocean circulation and its decadal variability. The Time‐Correction Method (TCM) presented here is a new approach to leverage the available CFCs and SF6 observations to solve for the Green's functions (GFs) describing the steady‐state transport from the surface to the ocean interior. From the GFs, we reconstruct global tracer concentrations (and associated uncertainties) in the ocean interior at annual resolution (1940–2021). The spatial resolution includes 50 neutral density levels that span the water column along World Ocean Circulation Experiment/Global Ocean Ship‐Based Hydrographic Investigations Program lines. The reconstructed tracer concentrations return a global view of CFCs and SF6 spreading into new regions of the interior ocean, such as the deep north‐western Pacific. For example, they capture the southward spreading and equatorial recirculation of distinct North Atlantic Deep Water components, and the spreading of CFC‐rich Antarctic Bottom Water out of the Southern Ocean and into the North Pacific, East Indian, and West Atlantic. The reconstructed tracer concentrations fit the data in most locations (∼75%), indicating that a steady‐state circulation holds for the most part. Discrepancies between the reconstructed and observed concentrations offer insight into ventilation rate changes on decadal timescales. As an example, we infer decadal changes in Subantartic Mode Water (SAMW) and find an increase in SAMW ventilation from 1992 to 2014, highlighting the skill of the TCM in leveraging the sparse tracer observations.

Levels and distribution profiles of Per- and Polyfluoroalkyl Substances (PFAS) in a high Arctic Svalbard ice core

Per- and polyfluoroalkyl substances (PFAS) are a group of persistent organic contaminants of which some are toxic and bioaccumulative. Several PFAS can be formed from the atmospheric degradation of precursors such as fluorotelomer alcohols (FTOHs) as well as hydrochlorofluorocarbons (HFCs) and other ozone-depleting chlorofluorocarbon (CFC) replacement compounds. Svalbard ice cores have been shown to provide a valuable record of long-range atmospheric transport of contaminants to the Arctic. This study uses a 12.3 m ice core from the remote Lomonosovfonna ice cap on Svalbard to understand the atmospheric deposition of PFAS in the Arctic. A total of 45 PFAS were targeted, of which 26 were detected, using supercritical fluid chromatography (SFC) tandem mass spectrometry (MS/MS) and ultra-performance liquid chromatography (UPLC) MS/MS. C2 to C11 perfluoroalkyl carboxylic acids (PFCAs) were detected continuously in the ice core and their fluxes ranged from 2.5 to 8200 ng m−2 yr−1 (9.51–16,500 pg L−1). Trifluoroacetic acid (TFA) represented 71 % of the total mass of C2 – C11 PFCAs in the ice core and had increasing temporal trends in deposition. The distribution profile of PFCAs suggested that FTOHs were likely the atmospheric precursor to C8 – C11 PFCAs, whereas C2 – C6 PFCAs had alternative sources, such as HFCs and other CFC replacement compounds. Perfluorooctanesulfonic acid (PFOS) was also widely detected in 82 % of ice core subsections, and its isomer profile (81 % linear) indicated an electrochemical fluorination manufacturing source. Comparisons of PFAS concentrations with a marine aerosol proxy showed that marine aerosols were insignificant for the deposition of PFAS on Lomonosovfonna. Comparisons with a melt proxy showed that TFA and PFOS were mobile during meltwater percolation. This indicates that seasonal snowmelt and runoff from post-industrial accumulation on glaciers could be a significant seasonal source of PFAS to ecosystems in Arctic fjords.

Air Quality Index Prediction

Falling back past few years rapid progress in Air pollution has become a life-threatening concern in many nations throughout the world due to human activity, industrialisation, and urbanisation.. As a result of these activities, sulphur oxides, carbon dioxide (CO2), nitrogen oxides, carbon monoxide (CO), chlorofluorocarbons (CFC), lead, mercury, and other pollutants be emitted into atmosphere. Simultaneously, estimating quality of air is a tough undertaking because of evolution, variability, also unreasonable unpredictability over pollution and particle region and time. In this project we compare the two Algorithms of machine learning in predicting Index of Air Quality and its predominant. Support vector machine (SVM) exists as prominent machine learning method beneficial to forecasting pollutant plus particle levels and predicting the air quality index (AQI), and Random Forest Regression is another. We'll be working with data from India's Open Government Data Platform. This website displays Air Quality Index readings from around India, including Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), and Particulate Matter (PM) are examples of contaminants (PM10 and PM2.5), Carbon Monoxide (CO), and others. The output of the project is the predict of Air Quality index using two different algorithms and the comparison of models using various error metrics.

Concentrations and emissions of trichlorotrifluoroethane (CFC-113) from eastern china inferred from atmospheric observations

Trichlorotrifluoroethane (C2Cl3F3, CFC-113) is a long-lived ozone-depleting substance (ODS) regulated under the Montreal Protocol and a potent greenhouse gas (GHG). Production and consumption of chlorofluorocarbons (CFCs) were phased out after 2007 in China, while unexpected increases in CCl3F (CFC-11) emissions from eastern China after 2012 were inferred from atmospheric observations. However, atmospheric concentrations and emissions of CFC-113 in China over the past few years are unclear. In this study, we conducted hourly observation of atmospheric CFC-113 concentrations in 2021 in eastern China, explored the potential CFC-113 emission sources using a dispersion model, and estimated the CFC-113 emissions using an interspecies correlation method. Results show that pollution events of CFC-113 were observed frequently, and the concentrations were higher than those of global background stations with similar latitudes. The dominant potential emission regions of CFC-113 were located in the eastern-central Yangtze River Delta region and Shandong province. The estimated mean CFC-113 emission from eastern China in 2021 was 0.88 ± 0.19 Gg/yr (5350 ± 1155 CO2-equivalent Gg/yr), which was higher than 0 Gg/yr (0 CO2-equivalent Gg/yr) in 2008−2021, as reported by bottom-up studies that considered CFC-113 to be phased out in China after 2007. Therefore, substantial CFC-113 emissions still existed in eastern China in 2021, which are of importance to protecting the ozone layer and mitigating the effects of climate change.

Retrieval of atmospheric CFC-11 and CFC-12 from high-resolution FTIR observations at Hefei and comparisons with other independent datasets

Abstract. Synthetic halogenated organic chlorofluorocarbons (CFCs) play an important role in stratospheric ozone depletion and contribute significantly to the greenhouse effect. In this work, the mid-infrared solar spectra measured by ground-based high-resolution Fourier transform infrared spectroscopy (FTIR) were used to retrieve atmospheric CFC-11 (CCl3F) and CFC-12 (CCl2F2) at Hefei, China. The CFC-11 columns observed from January 2017 to December 2020 and CFC-12 columns from September 2015 to December 2020 show a similar annual decreasing trend and seasonal cycle, with an annual rate of -0.47±0.06 % yr−1 and -0.68±0.03 % yr−1, respectively. So the decline rate of CFC-11 is significantly lower than that of CFC-12. CFC-11 total columns were higher in summer, and CFC-12 total columns were higher in summer and autumn. Both CFC-11 and CFC-12 total columns reached the lowest in spring. Further, FTIR data of NDACC (Network for the Detection of Atmospheric Composition Change) candidate station Hefei were compared with the ACE-FTS (Atmospheric Chemistry Experiment Fourier transform spectrometer) satellite data, WACCM (Whole Atmosphere Community Climate Model) data, and the data from other NDACC-IRWG (InfraRed Working Group) stations (St. Petersburg, Jungfraujoch, and Réunion). The mean relative difference between the vertical profiles observed by FTIR and ACE-FTS is -5.6±3.3 % and 4.8±0.9 % for CFC-11 and CFC-12 for an altitude of 5.5 to 17.5 km, respectively. The results demonstrate that our FTIR data agree relatively well with the ACE-FTS satellite data. The annual decreasing rate of CFC-11 measured from ACE-FTS and calculated by WACCM is -1.15±0.22 % yr−1 and -1.68±0.18 % yr−1, respectively. The interannual decreasing rates of atmospheric CFC-11 obtained from ACE-FTS and WACCM data are higher than that from FTIR observations. Also, the annual decreasing rate of CFC-12 from ACE-FTS and WACCM is -0.85±0.15 % yr−1 and -0.81±0.05 % yr−1, respectively, close to the corresponding values from the FTIR measurements. The total columns of CFC-11 and CFC-12 at the Hefei and St. Petersburg stations are significantly higher than those at the Jungfraujoch and Réunion (Maïdo) stations, and the two values reached the maximum in local summer or autumn and the minimum in local spring or winter at the four stations. The seasonal variability at the three stations in the Northern Hemisphere is higher than that at the station in the Southern Hemisphere.

Selectivity and Sensitivity: The Electron Capture Detector (ECD), Its Unique Inventor James Lovelock (1919–2022), and GAIA

The electron capture detector (ECD) is among the original classical detectors for gas chromatography (GC). It is highly selective and sensitive for electron-absorbing compounds, especially those containing halogens. The ECD was developed in the 1960s by James Lovelock (1919–2022), who passed away earlier this year. The ECD is among the early detectors that is used in a relatively unmodified form today. The ECD was crucial in the discovery of chlorofluorocarbons (CFCs) in the upper atmosphere, ultimately leading to the international agreements limiting their use and reducing the ozone hole. In this installment, we review the ECD and its principles of operation and discuss the general tradeoffs in detection between selectivity, ease of use, and sensitivity. We also look at the unique life and work of Lovelock, both inventor of the ECD and one of the earliest scientists to bring attention to climate change through GAIA, which explained his theory that the Earth acts as a massive living organism.

Exploring the Fe doped borazine system as a promising CFC adsorbent: A DFT study

Adsorption of ozone-depleting chlorofluorocarbons (CFC) over Fe-doped borazine is of major global environmental concern. The first-principles conceptual density functional theory with the B3LYP/LANL2DZ/6-31G* level of theory is used to investigate the nature of CFCs including fluoro, chlorofluoro and hydrofluoro/chloro carbons (CH2FCl, CHF2Cl, CF2Cl2, CF2ClBr, and CF3Cl) adsorption on Fe doped borazine system. Maximum hardness and minimum electrophilicity principles were used to compute global reactivity parameters. According to our calculations, the embedded iron metal atom interacts rather weakly with the fluorine atom in CFC molecules. The adsorption energy, LUMO, HOMO, and density of states (DOS) were calculated using the optimal parameters. All the calculations and analyses denoted that the adsorption of the CFCmolecule on the Fe-doped borazine system occurred due to chemical adsorption and van der Waals interactions.

Simultaneous harmless ionization of CFC and resource utilization of waste solar panel through one-pot hydrothermal treatment

Chlorofluorocarbons (CFCs), which possess the characteristics of high volatility and destroy ozone layer, are hardly disposed of through traditional methods. With a tightly closed reaction environment and high-temperature water medium, CFCs can react and generate inorganic Cl- and F- under subcritical water conditions, which is very useful to enhance leaching and enrich rare metals. Therefore, in the current study, CFCs and photovoltaic wastes containing gallium arsenide (GaAs) were co-processed for mineralization and enhanced leaching simultaneously. Based on frontier orbital theory and bond energy theory, possible decomposition pathways of CFCs were speculated. Enhanced leaching process was studied in detail. When experimental conditions were 300 °C and 8.8 MPa, the mineralization rates of organofluorine and organochlorine in CFCs were 83.68% and 93.37%, respectively. Leaching agent generated by the hydrothermal treatment of CFCs leached GaAs effectively, and the leaching rates of gallium and arsenic were 95.74% and 99.89%, respectively. Converting CFCs into leaching agent will not only avoid ozone layer depletion but also save the cost of hazardous waste treatment and realize economic benefits. Environmental impact assessment indicated that the proposed Ga recycling route allows remarkable reduction of total environmental impacts compared with published processes.

Bayesian assessment of chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC) and halon banks suggest large reservoirs still present in old equipment

Abstract. Halocarbons contained in equipment such as air conditioners, fire extinguishers, and foams continue to be emitted after production has ceased. These “banks” within equipment and applications are thus potential sources of future emissions, and must be carefully accounted for in order to differentiate nascent and potentially illegal production from legal banked emissions. Here, we build on a probabilistic Bayesian model, previously developed to quantify chlorofluorocarbon (CFC-11, CFC-12, and CFC-113) banks and their emissions. We extend this model to a suite of banked chemicals regulated under the Montreal Protocol (hydrochlorofluorocarbon, HCFC-22, HCFC-141b, and HCFC-142b, halon 1211 and halon 1301, and CFC-114 and CFC-115) along with CFC-11, CFC-12, and CFC-113 in order to quantify a fuller range of ozone-depleting substance (ODS) banks by chemical and equipment type. We show that if atmospheric lifetime and prior assumptions are accurate, banks are most likely larger than previous international assessments suggest, and that total production has probably been higher than reported. We identify that banks of greatest climate-relevance, as determined by global warming potential weighting, are largely concentrated in CFC-11 foams and CFC-12 and HCFC-22 non-hermetic refrigeration. Halons, CFC-11, and CFC-12 banks dominate the banks weighted by ozone depletion potential (ODP). Thus, we identify and quantify the uncertainties in substantial banks whose future emissions will contribute to future global warming and delay ozone-hole recovery if left unrecovered.

Chloro Fluro Carbon Gas Leak Monitoring System in Internet of Things-Based Air Conditioner

Refrigerant leaks have a major impact on system operating performance, increasing power consumption, damage to components, and worse, global warming. This study aims to use a monitoring system based on the Internet of Things (IoT) to track Chloro Fluro Carbon gas in the air conditioning system. Using NodeMCU as a microcontroller-based control tool that has been assisted by a Wi-Fi module. The sensitivity level of refrigerant leakage is very high based on the sensitivity of the sensor used, namely MQ135. In experimenting, the refrigerant leak starts with the closest distance to the inaccessibility of the sensor readings to determine the acceleration of the sensor in detecting leaks. The voltage required for the MQ135 sensor is 5 Volt DC. This system uses an android application, namely blynk which has features for monitoring and warning users that the AC unit has detected a leak. The results of measuring the sensitivity level of the sensor are very high for alcohol, benzene, and NH3 gases. It can detect small leaks at a distance of 20 cm, at a moderate level of leakage it can detect further at 80 cm, and at a maximum detection level at a distance of 160 cm in closed rooms or low winds. Because the leakage distance is quite far, it will be affected by the wind, the sensor reading will be hampered because the refrigerant cannot hit the sensor.