The driving force effect of trade embodied carbon emissions and embodied SO2 emissions transferred in resources-rich areas: A case study of Shanxi province

SDA (Structural Decomposition Analysis) model was applied to analyze the driving factors of embodied carbon and SO2 emissions transferred in Shanxi during 2007–2012 based on the input-output model from the perspectives of region and industry. The results showed that the change of embodied carbon emissions and embodied SO2 emissions of Shanxi and other regions were hindered by the carbon (sulfur) emissions strength effect, but promoted by the intermediate (final) demand scale effect, the intermediate (final) structure effect and the input-output structure effect. The carbon emissions strength effect had a significant contribution to reducing the embodied carbon emissions transferred from industries in Shanxi to other regions. The intermediate (final) demand scale effect was the driving factor to increase the embodied carbon emissions transferred from industries in Shanxi to other regions. The sulfur emissions strength effect was the only factor that reduced the embodied SO2 emissions transferred from Shanxi to other industries. The change of embodied carbon emissions from industries in other regions to Shanxi was hindered by the carbon emissions strength effect, but the input-output structure effect and final demand scale effect both increased the embodied carbon emissions from industries in other regions to Shanxi. The change of the embodied SO2 emissions transferred from industries in other regions to Shanxi was inhibited by the sulfur emissions strength effect, but the input-output structure effect, the intermediate demand structure effect and the final demand scale effect were both the driving force effect of increasing the embodied SO2 emissions transferred from industries in other regions to Shanxi. The corresponding suggestions and measures were put forward.

Optimization of multi variant process parameters to reduce emissions of high sulfur coal during combustion in fluidized bed facility

Pakistan has 185 billion tonnes reserves of coal but unfortunately the quality of 80% of this coal is not good. As the country has a shortage of energy so it is necessary to refine the coal before it can be used to produce electricity. In this sense, this research is very important as it enables indigenous coal to meet the increasing energy demand. This study is focused on the control of sulfur emissions during the combustion of high sulfur Pakistani coal from the Trans Indus Range and the Salt Range. Parameters like Ca/S molar ratios (MRs), limestone particle size, bed temperature, and different percentages of biomass in co-firing with coal have been studied. It is showed that desulfurization of coal was maximum with the fine-sized particles of limestone. Co-firing of moderate quantity biomass exhibited a considerable decrease in SO2 emissions. Results achieved are presented in the form of tables and plots. This study for control of the gaseous emissions from combustion in FBC facility has great potential for new coal based power projects, especially in Pakistan.

Marine gas-phase sulfur emissions during an induced phytoplankton bloom

The oxidation of dimethyl sulfide (DMS; CH3SCH3), emitted from the surface ocean, contributes to the formation of Aitken mode particles and their growth to cloud condensation nuclei (CCN) sizes in remote marine environments. It is not clear whether other, less commonly measured marine-derived, sulfur-containing gases share similar dynamics to DMS and contribute to secondary marine aerosol formation. Here, we present measurements of gas-phase volatile organosulfur molecules taken with a Vocus proton transfer reaction high resolution time-of-flight mass spectrometer during a mesocosm phytoplankton bloom experiment using coastal seawater. We show that DMS, methanethiol (MeSH; CH3SH), and benzothiazole (C7H5NS) account for on average over 90 % of total gas-phase sulfur emissions, with non-DMS sulfur sources representing 36.8 ± 7.7 % of sulfur emissions during the first nine days of the experiment in the pre-bloom phase prior to major biological growth, before declining to 14.5 ± 6.0 % in the latter half of the experiment when DMS dominates during the bloom and decay phases. The molar ratio of DMS to MeSH during the pre-bloom phase (DMS : MeSH = 4.60 ± 0.93) was consistent with the range of previously calculated ambient DMS to MeSH sea-to-air flux ratios. As the experiment progressed, the DMS to MeSH emission ratio increased significantly, reaching 31.8 ± 18.7 during the bloom and decay. Measurements of dimethylsulfoniopropionate (DMSP), heterotrophic bacteria, and enzyme activity in the seawater suggest the DMS : MeSH ratio is a sensitive indicator of the bacterial sulfur demand and the composition and magnitude of available sulfur sources in seawater. The evolving DMS : MeSH ratio and the emission of a new aerosol precursor gas, benzothiazole, have important implications for secondary sulfate formation pathways in coastal marine environments.

Modeling study of the impact of SO₂ volcanic passive emissions on the tropospheric sulfur budget

Well constrained volcanic emissions inventories in chemistry transport models are necessary to study the impacts induced by these sources on the tropospheric sulfur composition and on sulfur species concentrations and depositions at the surface. In this paper, the changes induced by the update of the volcanic sulfur emissions inventory are studied using the global chemistry transport model MOCAGE (MOdèle de Chimie Atmosphérique à Grande Échelle). Unlike the previous inventory (Andres and Kasgnoc, 1998), the updated one (Carn et al., 2016, 2017) uses more accurate information and includes contributions from both passive degassing and eruptive emissions. Eruptions are provided as daily total amounts of sulfur dioxide (SO2) emitted by volcanoes in the Carn et al. (2016, 2017) inventories, and degassing emissions are provided as annual averages with the related mean annual uncertainties of those emissions by volcano. Information on plume altitudes is also available and has been used in the model. We chose to analyze the year 2013, for which only a negligible amount of eruptive volcanic SO2 emissions is reported, allowing us to focus the study on the impact of passive degassing emissions on the tropospheric sulfur budget. An evaluation against the Ozone Monitoring Instrument (OMI) SO2 total column and MODIS (Moderate-Resolution Imaging Spectroradiometer) aerosol optical depth (AOD) observations shows the improvements of the model results with the updated inventory. Because the global volcanic SO2 flux changes from 13 Tg yr−1 in Andres and Kasgnoc (1998) to 23.6 Tg yr−1 in Carn et al. (2016, 2017), significant differences appear in the global sulfur budget, mainly in the free troposphere and in the tropics. Even though volcanic SO2 emissions represent 15 % of the total annual sulfur emissions, the volcanic contribution to the tropospheric sulfate aerosol burden is 25 %, which is due to the higher altitude of emissions from volcanoes. Moreover, a sensitivity study on passive degassing emissions, using the annual uncertainties of emissions per volcano, also confirmed the nonlinear link between tropospheric sulfur species content with respect to volcanic SO2 emissions. This study highlights the need for accurate estimates of volcanic sources in chemistry transport models in order to properly simulate tropospheric sulfur species.

The Toba supervolcano eruption caused severe tropical stratospheric ozone depletion

Supervolcano eruptions have occurred throughout Earth’s history and have major environmental impacts. These impacts are mostly associated with the attenuation of visible sunlight by stratospheric sulfate aerosols, which causes cooling and deceleration of the water cycle. Supereruptions have been assumed to cause so-called volcanic winters that act as primary evolutionary factors through ecosystem disruption and famine, however, winter conditions alone may not be sufficient to cause such disruption. Here we use Earth system model simulations to show that stratospheric sulfur emissions from the Toba supereruption 74,000 years ago caused severe stratospheric ozone loss through a radiation attenuation mechanism that only moderately depends on the emission magnitude. The Toba plume strongly inhibited oxygen photolysis, suppressing ozone formation in the tropics, where exceptionally depleted ozone conditions persisted for over a year. This effect, when combined with volcanic winter in the extra-tropics, can account for the impacts of supereruptions on ecosystems and humanity.

Modeling study of the impact of SO₂ volcanic passive emissions on the tropospheric sulfur budget

The contribution of volcanic emissions is argued as non-linear on the sulfur species burden. Thus, well constraining volcanic emissions inventories is necessary to better study the impacts induced by these pollution sources on the troposheric sulfur composition, as well as on sulfur species concentrations and depositions at the global surface. In this paper, the changes induced by the update of the volcanic sulfur emissions inventory on the global chemistry-transport model MOCAGE (MOdèle de Chimie Atmosphérique à Grande Échelle) are studied. Unlike the current inventory [Andres and Kasgnoc (1998)], the new inventory [Carn et al. (2016, 2017)] includes contributions from both passive degassing and eruptive emissions with more accu- rate information. Eruptions are provided as daily total amounts of sulfur dioxide (SO2) emitted by volcanoes, while degassing are provided as annual averages with annual uncertainties by volcanoes. Information on plumes altitudes is also available and has been used in the model. The choice is made to look at the year 2013, when a neglieable amount of eruptive volcanic SO2 emissions is referenced, allowing us to focus the study on the impact of passive degassing emissions on the tropospheric sulfur budget. A validation against GOME-2 SO2 total column and MODIS AOD observations shows the improvements of the model results with the new inventory. Because the global volcanic SO2 flux changes from 13 Tg.yr−1 in the current inventory to 23.6 Tg.yr−1 in the new inventory, the updated inventory shows significant differences in the global sulfur budget, mainly in the free troposphere and in the tropics. Even though volcanic SO2 emissions represent 15 % of the total annual sulfur emissions, the volcanic contribution to the tropospheric sulfate aerosol burden is 27 %. Moreover, a sensitivity study on passive degassing emissions, using the annual uncertainties of emissions per volcanoes, also confirmed the non-linear link between tropospheric sulfur species and volcanic emissions. This study highlights the necessity of using accurate estimates of volcanic sources in chemistry-transport models in order to properly simulate tropospheric sulfur species.

Effects of global ship emissions on European air pollution levels

Ship emissions constitute a large, and so far poorly regulated, source of air pollution. Emissions are mainly clustered along major ship routes both in open seas and close to densely populated shorelines. Major air pollutants emitted include sulfur dioxide, NOx, and primary particles. Sulfur and NOx are both major contributors to the formation of secondary fine particles (PM2.5) and to acidification and eutrophication. In addition, NOx is a major precursor for ground-level ozone. In this paper, we quantify the contributions from international shipping to European air pollution levels and depositions. This study is based on global and regional model calculations. The model runs are made with meteorology and emission data representative of the year 2017 after the tightening of the SECA (sulfur emission control area) regulations in 2015 but before the global sulfur cap that came into force in 2020. The ship emissions have been derived using ship positioning data. We have also made model runs reducing sulfur emissions by 80 % corresponding to the 2020 requirements. This study is based on model sensitivity studies perturbing emissions from different sea areas: the northern European SECA in the North Sea and the Baltic Sea, the Mediterranean Sea and the Black Sea, the Atlantic Ocean close to Europe, shipping in the rest of the world, and finally all global ship emissions together. Sensitivity studies have also been made setting lower bounds on the effects of ship plumes on ozone formation. Both global- and regional-scale calculations show that for PM2.5 and depositions of oxidised nitrogen and sulfur, the effects of ship emissions are much larger when emissions occur close to the shore than at open seas. In many coastal countries, calculations show that shipping is responsible for 10 % or more of the controllable PM2.5 concentrations and depositions of oxidised nitrogen and sulfur. With few exceptions, the results from the global and regional calculations are similar. Our calculations show that substantial reductions in the contributions from ship emissions to PM2.5 concentrations and to depositions of sulfur can be expected in European coastal regions as a result of the implementation of a 0.5 % worldwide limit of the sulfur content in marine fuels from 2020. For countries bordering the North Sea and Baltic Sea SECA, low sulfur emissions have already resulted in marked reductions in PM2.5 from shipping before 2020. For ozone, the lifetime in the atmosphere is much longer than for PM2.5, and the potential for ozone formation is much larger in otherwise pristine environments. We calculate considerable contributions from open sea shipping. As a result, we find that the largest contributions to ozone in several regions and countries in Europe are from sea areas well outside European waters.