scholarly journals Top-down and bottom-up estimates of anthropogenic methyl bromide emissions from eastern China

2021 ◽  
Author(s):  
Haklim Choi ◽  
Mi-Kyung Park ◽  
Paul J. Fraser ◽  
Hyeri Park ◽  
Sohyeon Geum ◽  
...  
Keyword(s):  
Methyl Bromide ◽  
Eastern China ◽  
Montreal Protocol ◽  
Anthropogenic Sources ◽  
United Nations Environment Programme ◽  
Back Trajectory ◽  
Annual Data ◽  
Bottom Up ◽  
Article 5 ◽  
Pollution Events

Abstract. Methyl bromide (CH3Br) is a potent ozone-depleting substance (ODS) that has both natural and anthropogenic sources. CH3Br has been used mainly for preplant soil fumigation, post-harvest grain and timber fumigation, and structural fumigation. Most non-quarantine/pre-shipment (non-QPS) uses have been phased-out in 2005 for non-Article 5 (developed) countries and in 2015 for Article 5 (developing) countries under the Montreal Protocol on Substances that Deplete the Ozone Layer; some uses have continued under critical use exemptions (CUEs). Under the Protocol, individual nations are required to report annual data on CH3Br production and consumption for quarantine/pre-shipment (QPS) uses, non-QPS uses and CUEs to the United Nations Environment Programme (UNEP). In this study, we analyzed high precision, in situ measurements of atmospheric concentrations of CH3Br obtained at the Gosan station on Jeju island, Korea, from 2008 to 2019. The background concentrations of CH3Br in the atmosphere at Gosan declined from 8.5 ± 0.8 ppt in 2008 to 7.4 ± 0.6 ppt in 2019 at a rate of −0.13 ± 0.02 ppt yr−1. At Gosan, we also observed periods of persistent concentrations (pollution events) elevated above the decreasing background in continental air masses from China. Statistical back trajectory analyses showed that these pollution events predominantly trace back to CH3Br emissions from eastern China. Using an inter-species correlation (ISC) method with the reference trace species CFC-11 (CCl3F), we estimate anthropogenic CH3Br emissions from eastern China at 4.1 ± 1.3 Gg yr−1 in 2008–2019, approximately 2.9 ± 1.3 Gg yr−1 higher than the bottom-up emission estimates reported to UNEP. Possible non-fumigation CH3Br sources – rapeseed production and biomass burning – were assessed and it was found that the discrepancy is more likely due to unreported or incorrectly reported QPS and non-QPS fumigation uses. These largely-unreported anthropogenic emissions of CH3Br are confined to eastern China and account for 30–40 % of anthropogenic global CH3Br emissions. They are likely due to delays in the introduction of CH3Br alternatives, such as sulfuryl fluoride (SO2F2), heat, irradiation and a possible lack of industry awareness of the need for regulation of CH3Br production and use.

scholarly journals Supplementary material to "Top-down and bottom-up estimates of anthropogenic methyl bromide emissions from eastern China"

2021 ◽  
Author(s):  
Haklim Choi ◽  
Mi-Kyung Park ◽  
Paul J. Fraser ◽  
Hyeri Park ◽  
Sohyeon Geum ◽  
...  
Keyword(s):  
Methyl Bromide ◽  
Eastern China ◽  
Top Down ◽  
Bottom Up ◽  
Supplementary Material

scholarly journals Changing trends and emissions of hydrochlorofluorocarbons and their hydrofluorocarbon replacements

2016 ◽  
Author(s):  
Peter G. Simmonds ◽  
Matthew Rigby ◽  
Archibold McCulloch ◽  
Simon O'Doherty ◽  
Dickon Young ◽  
...  
Keyword(s):  
Growth Rates ◽  
Montreal Protocol ◽  
Hfc 134A ◽  
Production And Consumption ◽  
Ozone Depleting Substances ◽  
Phase Out ◽  
Article 5 ◽  
The Impact ◽  
Global Emissions

Abstract. High frequency, in situ global observations of HCFC-22 (CHClF2), HCFC-141b (CH3CCl2F), HCFC-142b (CH3CClF2) and HCFC-124 (CHClFCF3) and their main HFC replacements HFC-134a (CH2FCF3), HFC-125 (CHF2CF3), HFC-143a (CH3CF3), and HFC-32 (CH2F2) have been used to determine their changing global growth rates and emissions in response to the Montreal Protocol and its recent amendments. The 2007 adjustment to the Montreal Protocol required the accelerated phase-out of HCFCs with global production and consumption capped in 2013, to mitigate their environmental impact as both ozone depleting substances and important greenhouse gases. We find that this change has coincided with a reduction in global emissions of the four HCFCs with aggregated global emissions in 2015 of 444 ± 75 Gg/yr, in CO2 equivalent units (CO2 e) 0.75 ± 0.1 Gt/yr, compared with 483 ± 70 Gg/yr (0.82 ± 0.1 Gt/yr CO2 e) in 2010. (All quoted uncertainties in this paper are 1 sigma). About 80 % of the total HCFC atmospheric burden in 2015 is HCFC-22, where global HCFC emissions appear to have been relatively constant in spite of the 2013 cap on global production and consumption. We attribute this to a probable increase in production and consumption of HCFC-22 in Montreal Protocol Article 5 (developing) countries and the continuing release of HCFC-22 from the large banks which dominate HCFC global emissions. Conversely, the four HFCs all show increasing annual growth rates with aggregated global HFCs emissions in 2015 of 329 ± 70 Gg/yr (0.65 ± 0.12 Gt/yr CO2 e) compared to 2010 with 240 ± 50 Gg/yr (0.47 ± 0.08 Gt/yr CO2 e). As HCFCs are replaced by HFCs we investigate the impact of the shift to refrigerant blends which have lower global warming potentials (GWPs). We also note that emissions of HFC-125 and HFC-32 appear to have increased more rapidly during the 2011–2015 5-yr period compared to 2006–2010.

scholarly journals Methods for management of soilborne plant pathogens

2017 ◽  
Vol 32 (1) ◽  
pp. 9-24 ◽  
Author(s):  
Milica Mihajlovic ◽  
Emil Rekanovic ◽  
Jovana Hrustic ◽  
Mila Grahovac ◽  
Brankica Tanovic
Keyword(s):  
Methyl Bromide ◽  
Agricultural Production ◽  
Plant Pathogens ◽  
Current Knowledge ◽  
Montreal Protocol ◽  
Economic Losses ◽  
Simultaneous Application ◽  
Soilborne Disease ◽  
Single Chemical ◽  
Soil Disinfection

Soilborne pathogens cause significant economic losses in agricultural production all over the world. These species can survive for many years in the absence of a host plant by forming persistent structures such as microsclerotia, sclerotia, chlamydospores or oospores. Consequently, soilborne diseases are particularly difficult to predict, detect, diagnose and successfully control. Over the past 30 years, a fumigant, methyl bromide, has been widely used for their control in many crops. In 1992, methyl bromide was listed as an ozone-depleting substance under the Montreal Protocol ? an international treaty to protect the ozone layer. During the phaseout of methyl bromide, problems generated in agricultural production made it clear that dependence on a single method or a single chemical should be avoided. The objective of this review paper was to summarize the current knowledge about different methods of soilborne disease control including: crop rotation, steam soil disinfection, soil amendments, hydroponics and soilless growing systems, soil solarization, grafting, biological control and use of natural compounds, and chemical control. Positive and negative aspects of all available methods were reviewed. Benefits, achieved by simultaneous application of several methods based on different mechanisms of actions, are discussed.

scholarly journals Carbonaceous aerosols in China: top-down constraints on primary sources and estimation of secondary contribution

2011 ◽  
Vol 11 (10) ◽  
pp. 28219-28272 ◽  
Author(s):  
T.-M. Fu ◽  
J. J. Cao ◽  
X. Y. Zhang ◽  
S. C. Lee ◽  
Q. Zhang ◽  
...  
Keyword(s):  
Eastern China ◽  
Western China ◽  
Spatiotemporal Variability ◽  
Anthropogenic Source ◽  
Carbonaceous Aerosols ◽  
Top Down ◽  
Bottom Up ◽  
Secondary Sources ◽  
Secondary Formation ◽  
Emission Estimate

Abstract. We simulate elemental carbon (EC) and organic carbon (OC) aerosols in China and compare model results to surface measurements at Chinese rural and background sites, with the goal of deriving "top-down" emission estimates of EC and OC, as well as better quantifying the secondary sources of OC. We include in the model state-of-the-science Chinese "bottom-up" emission inventories for EC (1.92 Tg C yr−1) and OC (3.95 Tg C yr−1), as well as updated secondary OC formation pathways. The average simulated annual mean EC concentration at rural and background site is 1.1 μg C m−3, 56% lower than the observed 2.5 μg C m−3. The average simulated annual mean OC concentration at rural and background sites is 3.4 μg C m−3, 76% lower than the observed 14 μg C m−3. Multiple regression to fit surface monthly mean EC observations at rural and background sites yields best estimate of Chinese EC source of 3.05 ± 0.78 Tg C yr−1. Based on the top-down EC emission estimate and observed seasonal primary OC/EC ratios, we estimate Chinese OC total emissions to be 6.67 ± 1.30 Tg C yr−1. Using these top-down estimates, the simulated average annual mean EC concentration at rural and background sites significantly improved to 1.9 μg C m−3. However, the model still significantly underestimates observed OC in all seasons (simulated average annual mean OC at rural and background sites is 5.4 μg C m−3), with little skill in capturing the spatiotemporal variability. Secondary formation accounts for 21% of Chinese annual mean surface OC in the model, with isoprene being the most important precursor. In summer, as high as 62% of the observed surface OC may be due to secondary formation in eastern China. Our analysis points to three shortcomings in the current bottom-up inventories of Chinese carbonaceous aerosols: (1) the anthropogenic source is severely underestimated, particularly for OC; (2) there is a missing source in western China, likely associated with the use of biofuels or other low-quality fuels for heating; and (3) sources in fall are not well represented, either because the seasonal shifting of emissions and/or secondary formation are poorly captured or because specific fall emission events are missing. More regional measurements with better spatiotemporal coverage are needed to resolve these shortcomings.

scholarly journals Emissions of Carbon Tetrachloride (CCl<sub>4</sub>) from Europe

2016 ◽  
Author(s):  
Francesco Graziosi ◽  
Jgor Arduini ◽  
Paolo Bonasoni ◽  
Francesco Furlani ◽  
Umberto Giostra ◽  
...  
Keyword(s):  
Carbon Tetrachloride ◽  
Large Scale ◽  
Stratospheric Ozone ◽  
Montreal Protocol ◽  
Scale Production ◽  
Top Down ◽  
Significant Discrepancy ◽  
Bottom Up ◽  
Atmospheric Observations ◽  
Global Emissions

Abstract. Carbon tetrachloride (CCl4) is a long-lived radiatively-active compound able to destroy stratospheric ozone. Due to its inclusion in the Montreal Protocol on Substances that Deplete the Ozone Layer, the last two decades have seen a sharp decrease in its large scale emissive use with a consequent decline of its atmospheric mole fractions. However, the Montreal Protocol restrictions do not apply to the use of carbon tetrachloride as feedstock for the production of other chemicals, implying the risk of fugitive emissions from the industry sector. The occurrence of such unintended emissions is suggested by a significant discrepancy between global emissions as derived by reported production and feedstock usage (bottom-up emissions), and those based on atmospheric observations (top-down emissions). In order to better constrain the atmospheric budget of carbon tetrachloride, several studies based on a combination of atmospheric observations and inverse modelling have been conducted in recent years in various regions of the world. This study is focused on the European scale and based on long-term high-frequency observations at three European sites, combined with a Bayesian inversion methodology. We estimated that average European emissions for 2006–2014 were 2.3 (± 0.8) Gg yr−1, with an average decreasing trend of 7.3 % per year. Our analysis identified France as the main source of emissions over the whole study period, with an average contribution to total European emissions of 25 %. The inversion was also able to allow the localisation of emission "hot-spots" in the domain, with major source areas in Southern France, Central England (UK) and Benelux (Belgium, The Netherlands, Luxembourg), where most of industrial scale production of basic organic chemicals are located. According to our results, European emissions correspond to 4.0 % of global emissions for 2006–2012. Together with other regional studies, our results allow a better constraint of the global budget of carbon tetrachloride and a better quantification of the gap between top-down and bottom-up estimates.

scholarly journals Pollution events observed during CARIBIC flights in the upper troposphere between South China and the Philippines

2010 ◽  
Vol 10 (4) ◽  
pp. 1649-1660 ◽  
Author(s):  
S. C. Lai ◽  
A. K. Baker ◽  
T. J. Schuck ◽  
P. van Velthoven ◽  
D. E. Oram ◽  
...  
Keyword(s):  
South China ◽  
Source Region ◽  
Sampling Period ◽  
The Philippines ◽  
Substantial Contribution ◽  
Back Trajectory ◽  
Upper Troposphere ◽  
Chemical Tracers ◽  
Back Trajectory Analysis ◽  
Pollution Events

Abstract. A strong pollution episode in the upper troposphere between South China and the Philippines was observed during CARIBIC flights in April 2007. Five pollution events were observed, where enhancements in aerosol and trace gas concentrations including CO, CO2, CH4, non-methane hydrocarbons (NMHCs) and halocarbons were observed along the flight tracks during four sequential flights. The importance of the contribution of biomass/biofuel burning was investigated using chemical tracers, emission factor analysis, back-trajectory analysis and satellite images. The Indochinese peninsula was identified as the probable source region of biomass/biofuel burning. However, enhancements in the urban/industrial tracer C2Cl4 during the events also indicate a substantial contribution from urban anthropogenic emissions. An estimation of the contribution of fossil fuel versus biomass/biofuel to the CO enhancement was made, indicating a biomass/biofuel burning contribution of ~54 to ~92% of the observed CO enhancements. Biomass/biofuel burning was found to be the most important source category during the sampling period.

Biofumigation: Opportunities and Challenges for Control of Soilborne Diseases in Nursery Production

2018 ◽  
Vol 19 (4) ◽  
pp. 332-337 ◽  
Author(s):  
Fulya Baysal-Gurel ◽  
Prabha Liyanapathiranage ◽  
Jill Mullican
Keyword(s):  
Cover Crops ◽  
Methyl Bromide ◽  
Montreal Protocol ◽  
Phytophthora Nicotianae ◽  
Soilborne Diseases ◽  
Soilborne Disease ◽  
Flower Production ◽  
Row Crop ◽  
Nursery Production ◽  
Brassicaceae Family

Soilborne diseases reduce crop performance, increase costs to the nursery producers, and can cause potential ecological damage to the natural environment. In particular, soilborne diseases caused by Phytophthora nicotianae and Rhizoctonia solani are the most economically important problems of southeastern U.S. nursery producers. Methyl bromide was widely used as a standard treatment in many parts of the world until the implementation of the Montreal Protocol. Since then, many chemical and nonchemical soilborne disease management methods have been tested but are not yet providing effective and consistent results like methyl bromide. Cover crops that belong to the Brassicaceae family can be incorporated into the soil to control soilborne diseases, and this process is widely known as biofumigation. Glucosinolates that are available inside Brassicaceae plant cells can be hydrolyzed into isothiocyanates, and these compounds are proven to be highly biocidal to many microorganisms (including fungi, oomycetes, nematodes, and bacteria), insects, and germinating weed seeds. The use of biofumigant cover crops is a newer area of research in woody ornamental nursery production that has been previously explored most extensively in row crop, vegetable, fruit, and flower production. This review article compiles previous research observations in biofumigation while emphasizing the potential of biofumigation to control diseases in nursery production caused by soilborne pathogens.

scholarly journals Classification of clouds sampled at the puy de Dôme (France) based on 10 yr of monitoring of their physicochemical properties

2014 ◽  
Vol 14 (3) ◽  
pp. 1485-1506 ◽  
Author(s):  
L. Deguillaume ◽  
T. Charbouillot ◽  
M. Joly ◽  
M. Vaïtilingom ◽  
M. Parazols ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Chemical Composition ◽  
Inorganic Compounds ◽  
Average Concentration ◽  
Anthropogenic Sources ◽  
Back Trajectory ◽  
Data Set ◽  
Air Masses ◽  
High Concentrations ◽  
Inorganic Constituents

Abstract. Long-term monitoring of the chemical composition of clouds (73 cloud events representing 199 individual samples) sampled at the puy de Dôme (pdD) station (France) was performed between 2001 and 2011. Physicochemical parameters, as well as the concentrations of the major organic and inorganic constituents, were measured and analyzed by multicomponent statistical analysis. Along with the corresponding back-trajectory plots, this allowed for distinguishing four different categories of air masses reaching the summit of the pdD: polluted, continental, marine and highly marine. The statistical analysis led to the determination of criteria (concentrations of inorganic compounds, pH) that differentiate each category of air masses. Highly marine clouds exhibited high concentrations of Na+ and Cl−; the marine category presented lower concentration of ions but more elevated pH. Finally, the two remaining clusters were classified as "continental" and "polluted"; these clusters had the second-highest and highest levels of NH4+, NO3−, and SO24−, respectively. This unique data set of cloud chemical composition is then discussed as a function of this classification. Total organic carbon (TOC) is significantly higher in polluted air masses than in the other categories, which suggests additional anthropogenic sources. Concentrations of carboxylic acids and carbonyls represent around 10% of the organic matter in all categories of air masses and are studied for their relative importance. Iron concentrations are significantly higher for polluted air masses and iron is mainly present in its oxidation state (+II) in all categories of air masses. Finally, H2O2 concentrations are much more varied in marine and highly marine clouds than in polluted clouds, which are characterized by the lowest average concentration of H2O2. This data set provides concentration ranges of main inorganic and organic compounds for modeling purposes on multiphase cloud chemistry.

ECONOMICS OF THE “CRITICAL USE” OF METHYL BROMIDE UNDER THE MONTREAL PROTOCOL

2005 ◽  
Vol 23 (3) ◽  
pp. 376-393 ◽  
Author(s):  
STEPHEN J. DECANIO ◽  
CATHERINE S. NORMAN
Keyword(s):  
Methyl Bromide ◽  
Montreal Protocol
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