Reduction Of SO2 Emissions Research Articles

Sulfur fixation performance of calcium-bearing carbonates in iron ore roasting process: Thermodynamics, phase transition, microstructure evolution, and kinetics

Roasting technology is increasingly used in the beneficiation of refractory iron ores. During the roasting process, the presence of pyrite in some iron ores leads to the formation of SO2, requiring effective sulfur fixation techniques. This study proposed an innovative in-situ sulfur fixation method by pre-oxidation roasting, in which sulfur was fixed during the oxidation roasting process before reduction roasting. The effects of the main iron mineral (hematite), primary gangue mineral (quartz), and common calcium-containing carbonate minerals (calcite and dolomite) on sulfur migration during pyrite roasting were investigated, with particular emphasis on the sulfur fixation capabilities of calcite and dolomite. The study included thermodynamic equilibrium analysis, phase transitions and microstructural evolution in different reaction systems. The results showed that calcite and dolomite effectively reduced SO2 emissions by forming CaSO4 and MgSO4, with calcite exhibiting a stronger sulfur fixation capacity for the same mass. Kinetic analysis indicated that pyrite pyrolysis followed a two-step random nucleation and growth model. Furthermore, the addition of calcite increased the apparent activation energy of SO2 formation and altered the reaction pathway, providing insight into the sulfur fixation mechanism of calcite from a kinetic perspective.

Assessing the effectiveness of SO2, NOx, and NH3 emission reductions in mitigating winter PM2.5 in Taiwan using CMAQ

Abstract. Taiwan experiences higher air pollution in winter when fine particulate matter (PM2.5) levels frequently surpass national standards. This study employs the Community Multiscale Air Quality model to assess the effectiveness of reducing SO2, NOx, and NH3 emissions on PM2.5 secondary inorganic species (i.e., SO42-, NO3-, and NH4+). For sulfate, ∼ 43.7 % is derived from the chemical reactions of local SO2 emission, emphasizing the substantial contribution of regionally transported sulfate. In contrast, nitrate and ammonium are predominantly influenced by local NOx and NH3 emissions. Reducing SO2 emissions decreases sulfate levels, which in turn leads to more NH3 remaining in the gas phase, resulting in lower ammonium concentrations. Similarly, reducing NOx emissions lowers HNO3 formation, impacting nitrate and ammonium concentrations by decreasing the available HNO3 and leaving more NH3 in the gas phase. A significant finding is that reducing NH3 emissions decreases not only ammonium and nitrate but also sulfate by altering cloud droplet pH and SO2 oxidation processes. While the impact of SO2 reduction on PM2.5 is less than that of NOx and NH3, it emphasizes the complexity of regional sensitivities. Most of western Taiwan is NOx-sensitive, so reducing NOx emissions has a more substantial impact on lowering PM2.5 levels. However, given the higher mass emissions of NOx than NH3 in Taiwan, NH3 has a more significant consequence in mitigating PM2.5 per unit mass emission reduction (i.e., 2.43 × 10−5 and 0.85 × 10−5 µg m−3 (t yr−1)−1​​​​​​​ for NH3 and NOx, respectively, under current emission reduction). The cost-effectiveness analysis suggests that NH3 reduction outperforms SO2 and NOx reduction (i.e., USD 0.06 billion yr−1 µg−1 m3, USD 0.1 billion yr−1 µg−1 m3, and USD 1 billion yr−1 µg−1 m3 for NH3, SO2, and NOx, respectively, under the current emission reduction). Nevertheless, the costs of emission reduction vary due to differences in methodology and regional emission sources. Overall, this study considers both the efficiency and costs, highlighting NH3 emissions reduction as a promising strategy for PM2.5 mitigation in the studied environment in Taiwan.

Synergies quantification and evolution on air pollutant and CO2 emissions driven by different socio-economic effects

Realizing a synergistic reduction of air pollutant and CO2 emissions (APCE) is an important approach to promote a green socio-economic transformation in China, and it can provide a solid foundation for the achievement of clean energy production and climate action under a sustainable development goal framework. The objective of this study is to explore the quantitative relationship and evolution of synergies between APCE in industrial sectors driven by different socio-economic effects from 2007 to 2020 in China. The results indicated that the main sectors of pollutant emissions had consistency, however, large differences in the reduction efficiency of emissions exist among pollutants. The efficiency in reducing CO2 emissions was about 48% lower when compared with reductions of SO2 (95%), NOx (86%), and smoke and dust (83%) emissions from 2007 to 2020. The effects of improved technology were the main contributor to a reduction in pollutant emissions, but the synergies between APCE driving by it were not achieved. While the synergies between APCE driven by structure and final demand effects were significant. The synergies between NOx and CO2 emissions were stronger driven by final demand structure and type effects, with correlation coefficients of 1.06 and 1.13, respectively. Besides, the degree of synergistic reduction between APCE in most industrial sectors was around zero. Therefore, the efficiency of synergistic pollution reduction should be improved with the development of a synergistic governance system for industrial sectors. The structural decomposition analysis based on input-output model combined with the cross-elasticity analysis method to quantitively synergies between APCE from the consumption (demand) perspective, considering the connections between industrial sectors with socio-economic developing, which would contribute to the industrial synergistic reduction and green transformation as the consumption driven gradually increasing.

Can government-led urban expansion simultaneously alleviate pollution and carbon emissions? Staggered difference-in-differences evidence from Chinese firms

The outward expansion of city centers is a typical feature of rapid urbanization in developing countries, leading to complex environmental pollution effects due to evolving urban spatial patterns. This study examines the impact of government-led urban expansion on pollution and carbon emissions by firms, utilizing firm and city-level data. Employing the staggered difference-in-differences (DID) method and taking the county-to-district conversion (CDC) as a quasi-natural experiment, the study finds that CDC reduced SO2 emissions by 80.95% and CO2 emissions by 13.12%. The key to this synergistic emission reduction lies in a series of source control strategies, including enhancing energy efficiency and innovation, industrial restructuring, and production reduction. Furthermore, the study reveals that CDC has a more significant effect on emission reduction for NOEs and small firms. Additionally, large cities, cities with high fiscal self-sufficiency, and cities with high per capita GDP exhibit greater environmental regulatory strength, leading to more effective emissions reduction. This paper seeks to explore potential gaps in research on the environmental impacts of government-led urban expansion, and it may provide empirical support for relevant policies in developing countries.

Research on the impact of manufacturing servitization on environmental pollution: spatial econometric analysis of sulfur dioxide based on 284 prefecture-level cities

Using China’s regional input–output table, the paper constructs indicators of manufacturing servitization, matches manufacturing servitization at the regional level with city data, and uses spatial econometrics to empirically analyze the impact of manufacturing servitization on urban sulfur dioxide (SO2) emissions within the classical Environmental Kuznets Curve (EKC) framework. The results show that manufacturing servitization can reduce SO2 emissions. Producer servitization and consumptive services can both significantly reduce industrial SO2 emissions. Transportation and warehousing servitization, information servitization, leasing, and commercial servitization, technology research and development servitization significantly reduce SO2emissions; technology research and development servitization, in particular, have the largest influence coefficient, while the reduction effect of servitization in the wholesale and retail and finance sectors is not significant. The study also found that servitization reduced the SO2 emissions through technological innovation and industrial structure upgrading.

Assessing the nonlinearity of wintertime PM2.5 formation in response to precursor emission changes in North China with the adjoint method

Abstract While China’s clean air actions implemented since 2013 have been effective in mitigating PM2.5 air pollution, the large emission reductions during the COVID-19 lockdown period in early 2020 did not similarly alleviate PM2.5 pollution in North China, reflecting a distinct nonlinear chemical response of PM2.5 formation to emission changes. Here we apply emission-concentration relationships for PM2.5 diagnosed using the adjoint approach to quantitatively assess how chemical nonlinearity affects PM2.5 over Beijing in February 2020 in response to two emission reduction scenarios: the COVID-19 lockdown and 2013–2017 emission controls. We find that, in the absence of chemical nonlinearity, the COVID-19 lockdown would decrease PM2.5 in Beijing by 17.9 μg m–3, and the 2013–2017 emission controls resulted in a larger decrease of 54.2 μg m–3 because of greater reductions of SO2 and primary aerosol emissions. Chemical nonlinearity offset the decrease for Beijing PM2.5 by 3.4 μg m–3 during the lockdown due to enhanced sensitivity of aerosol nitrate to NO x emissions, but enhanced the efficiency of 2013–2017 emission controls by 11.9 μg m–3 due to the weakened heterogeneous reaction of sulfate. Such nonlinear chemical effects are important to estimate and consider when designing or assessing air pollution control strategies.

The impact of China’s booming tech sector on environmental sustainability: An analysis through comprehensive CS-ARDL approach

China’s rapid technological advancement and the growth of its tech sector have raised concerns about their impact on environmental sustainability. The current analysis aims to contribute to the existing literature by offering a fresh perspective on China’s environmental sustainability, as the existing literature tends to overlook the role of the size of the technological market, which is closely connected with several Sustainable Development Goals (SDGs)—SDG 7, SDG 9, SDG 11, SDG 12 and SDG 13. China can make significant strides towards achieving these goals by harnessing the potential of the technological market and aligning it with environmental sustainability objectives. This study also investigates the roles of urbanization and economic growth and examines the existence of the inverted N-shaped Environmental Kuznets Curve hypothesis in 31 Chinese provinces from 2004 to 2021. Robust tests are employed to analyse the data, including the Cointegrated Structural Auto Regressive Distributed Lag approach (CS-ARDL) and the Augmented Mean Group(AMG) method. The results indicate that economic growth, urbanization, and the size of the technological market can reduce SO2 emissions, demonstrating a positive environmental impact through China’s inverted N-shaped Environmental Kuznets Curve. Additionally, the Dumitrescu-Hurlin Granger causality test showed evidence of bidirectional causality between the size of the technological market and SO2 emissions. Based on the findings, the study proposes sustainable development policies for China, in line with the SDG targets. In this context, the country’s rapid economic growth and strategies for industrial competitiveness need reassessment. The objective should be to redesign these strategies to increase the proportion of high-tech activities in overall manufacturing and promote the adoption of renewable energy in the country’s total energy consumption. Consequently, Chinese policymakers should prioritize the implementation of regulations that uphold fundamental principles to enhance environmental quality while maintaining rapid economic growth and a competitive advantage in the industrial sector.

Anthropogenic and biogenic pollutants in a forested environment: SPRUCE-22 campaign overview

The SPRUCE-22 field campaign was conducted during July 2022 on a remote mountainous forested site in Greece to assess interactions of biogenic and anthropogenic pollutants in the Eastern Mediterranean. Particle chemical composition and size distributions along with concentrations of organic and inorganic gases were measured at high temporal resolution, while samples were collected and analyzed off-line. PM1 had a surprisingly high average concentration of 13 μg m−3 consisting primarily of organics (57%), followed by sulfate (30%), ammonium (9%), and black carbon (2%). Nitrates (both inorganic and organic) were less than 1% of the PM1 despite the relatively high NOx emissions in the Balkans. The PM2.5 concentrations at this remote site were similar and even higher than those in major cities across Greece including Athens, indicating the importance of regional transport for summertime pollution in the Eastern Mediterranean. The relatively constant average diurnal profiles of major anthropogenic pollutants are consistent with only minimal effects from local sources. Sulfates are not any more the dominant component of fine PM in Greece due to the reduction of SO2 emissions of coal-burning powerplants. The organic aerosol (OA) was quite oxidized with an average oxygen to carbon ratio (O:C) equal to 0.83. The average concentration of isoprene was 0.6 ppb, of monoterpenes 0.5 ppb, while the biogenic secondary organic aerosol factor (obtained through source apportionment analysis) was estimated to contribute 22% of the OA. Additional biogenic secondary organic aerosol (SOA) may be part of the two oxygenated OA (OOA) factors that were also identified. Radiocarbon analysis indicated that the non-fossil carbon was approximately equal to the sum of the biogenic and the more oxidized oxygenated OA, implying that the less oxidized OOA in this study was mostly associated to anthropogenic fossil fuel combustion. The biogenic SOA was quite aged (O:C equal to 0.63) and was also mostly transported to the site. Nearby new particle formation events occurred during 20 % of the days, with an average SO2 concentration of 0.3 ppb. The oxidative potential of the PM per unit of mass was quite high. The source attribution of the fine PM and the interactions among its anthropogenic and biogenic components are also discussed.

Characterizing multi-pollutant emission impacts of sulfur reduction strategies from coal power plants

Fuel combustion for electricity generation emits a mix of health- and climate-relevant air emissions, with the potential for technology or fuel switching to impact multiple emissions together. While there has been extensive research on the co-benefits of climate policies on air quality improvements, few studies have quantified the effect of air pollution controls on carbon emissions. Here we evaluate three multi-pollutant emission reduction strategies, focused on sulfur dioxide (SO2) controls in the electricity sector. Traditional ‘add-on’ pollution controls like flue gas desulfurization (FGD) reduce SO2 emissions from coal combustion but increase emissions of nitrogen oxides (NO X ), volatile organic compounds (VOCs), fine particulate matter (PM2.5), and carbon dioxide (CO2) due to heat efficiency loss. Fuel switching from coal to natural gas and renewables potentially reduces all pollutants. We identified 135 electricity generation units (EGUs) without SO2 controls in the contiguous US in 2017 and quantified the unit-level emission changes using pollution control efficiencies, emission rates, fuel heat input, and electricity load. A cost-benefit analysis is conducted, considering pollution control costs, fuel costs, capital and operation and maintenance (O&M) costs, the monetized health benefits from avoided multi-pollutant, and the social cost of carbon as the benefit for carbon reduction. We find that add-on SO2 controls result in an average annual net benefit of $179.3 million (95% CI: $137.5-$221.0 million) per EGU, fuel switching from coal to natural gas, $432.7 million (95% CI: $366.4-$498.9 million) per EGU; and fuel switching from coal to renewable energy sources, $537.9 million (95% CI: $457.1-$618.9 million) per EGU. Our results highlight multi-pollutant emission reduction strategy as a cost-effective way to synergistically control air pollution and mitigate climate change.

Can carbon emission trading policy enhance the synergistic emission reduction of carbon dioxide and air pollutants? A comparative study considering different pollutants

Exploring the synergistic control of carbon dioxide and pollutants is significant to the dual carbon target. This study first evaluates the effect of CET on the synergistic emission reduction of carbon dioxide and different pollutants. Moreover, this study investigates the mechanisms of synergistic emission reduction through the pathways of technology progress and structure adjustment. Technology progress is categorized into technology research and development, technology introduction, reverse technology spillover and technology purchase. Structure adjustment contains industrial structure and energy structure. Finally, the impact of CET on the synergistic emission reduction in the surrounding regions is analyzed. The results indicate that the CET could promote the synergistic emission reduction of carbon dioxide and pollutants, including air pollutants (SO2, PM2.5), wastewater and solid waste. The synergistic emission reduction of CO2 and SO2 could be enhanced through reverse technology spillover, technology purchase and industrial structure adjustment. The synergistic emission reduction of CO2 and PM2.5 could be enhanced through R&D and reverse technology spillover. The synergistic emission reduction of carbon dioxide and ammonia nitrogen could be enhanced by increasing R&D, technology purchase and energy structure adjustment. The CET could improve the synergistic emission reduction effect of carbon dioxide and air pollutants in the surrounding regions.

Is green place-based policy effective in mitigating pollution? Firm-level evidence from China

The green place-based policy is crucial for balancing economic competitiveness and environmental protection. However, there is scarce literature examining its impact on environmental pollution and the underlying mechanisms at the micro level. This paper treats China's National Demonstration Eco-Industrial Parks (EIP) as a quasi-natural experiment and systematically evaluates its effect on pollution using a difference-in-differences (DID) approach. With data from Chinese industrial firms and counties, this research reveals that the EIP leads to a significant reduction of 54.36% in firms’ sulfur dioxide (SO2) emissions. Moreover, increasing R&D investment, reducing SO2 emission intensity, implementing production process pollution control, and dynamic adjustments of firm entry and exit are significant influencing mechanisms. Heterogeneity tests indicate a stronger SO2 reduction effect of the EIP program on firms in eastern regions, capital-intensive industries, and non-state-owned enterprises. This study suggests that the Chinese government should support the establishment of EIP, conduct a coordinate system, strategically plan the industrial chain, establish a pollution monitoring and early warning system, enhance information disclosure, and give greater emphasis to the construction of EIPs in central and western China.

Seawater source heat pump system based on capillary heat exchanger for seepage in submarine tunnel: a case study

Abstract The discharge of seepage water from undersea tunnel structures, often treated as wastewater, inherently carries a substantial reservoir of untapped low-grade thermal energy. Unfortunately, comprehensive investigations into harnessing this latent potential remain notably limited. This study introduced an innovative strategy through the design of an undersea tunnel seepage seawater source heat pump system. Distinguished by the integration of a capillary front-end heat exchanger, this system aimed to effectively exploit the frequently disregarded low-grade thermal energy present in the seepage water of undersea tunnel structures. The seawater seepage from the tunnel is transported to the car park at the tunnel entrance, and a seawater energy pool is constructed by storing seawater in its underground space. The use of capillary network placed in the energy pool in the front heat exchanger, water source heat pump units, circulating water pumps and fan coil end device composed of underground undersea tunnel seepage seawater source heat pump system for the building heating and cooling. Furthermore, a comparative assessment was conducted, contrasting this novel system with the traditional air-conditioning setup that utilizes chillers and gas boilers as cooling and heating sources. The aim was to evaluate its capacity for energy conservation and emission reduction. The findings from the study strongly affirmed the viability of the proposed seepage seawater source heat pump system within undersea tunnels. It boasted the potential to achieve annual savings of 53.55 tce, highlighting a noteworthy energy-saving rate of 21.2%. Concurrently, reductions in CO2, SO2, and particulate emissions amounted to 132.28 t/a, 1.07 t/a, and 0.54 t/a, respectively. This study not only stands as a reference for the strategic utilization of seepage seawater from undersea tunnel structures, prioritizing energy conservation and emission reduction, but also pioneers innovative approaches toward resource optimization and environmental sustainability, meeting the inherent needs of carbon peaking and carbon neutrality goals.

Environmental regulation and manufacturing employment: Evidence from China's Eleventh Five-Year Plan

This paper employs a difference-in-difference-in-differences (DDD) identification strategy to investigate the impact of environmental regulation on employment in the manufacturing sector in China, using the country's Eleventh Five-Year Plan (FYP) as a quasi-experiment. Our results indicate that the 11th FYP had a significant negative impact on firm employment, with every 10% increase in SO2 reduction targets resulting in a 3.1% decrease in employment for firms in high-pollution industries. This corresponds to a reduction of approximately 9 people per firm. Our findings indicate that firms primarily reduce SO2 emissions by reducing production levels and transitioning to cleaner energy sources. Additionally, we show that political promotion incentives played a role in driving the decline in employment. Heterogeneous tests reveal that the impact was more significant for private firms, SMEs and trade-exposed firms.

Hydrogen peroxide serves as pivotal fountainhead for aerosol aqueous sulfate formation from a global perspective

Traditional atmospheric chemistry posits that sulfur dioxide (SO2) can be oxidized to sulfate (SO42–) through aqueous-phase reactions in clouds and gas-phase oxidation. Despite adequate knowledge of traditional mechanisms, several studies have highlighted the potential for SO2 oxidation within aerosol water. Given the widespread presence of tropospheric aerosols, SO42− production through aqueous-phase oxidation in aerosol water could have a pervasive global impact. Here, we quantify the potential contributions of aerosol aqueous pathways to global sulfate formation based on the GEOS-Chem simulations and subsequent theoretical calculations. Hydrogen peroxide (H2O2) oxidation significantly influences continental regions both horizontally and vertically. Over the past two decades, shifts in the formation pathways within typical cities reveal an intriguing trend: despite reductions in SO2 emissions, the increased atmospheric oxidation capacities, like rising H2O2 levels, prevent a steady decline in SO42− concentrations. Abating oxidants would facilitate the benefit of SO2 reduction and the positive feedback in sulfate mitigation.

Decoupling dynamics: Evaluating the relationship between ship emissions and socioeconomic progress in the Yangtze River Basin from 2007 to 2022

To investigate the decoupling relationship between inland ship emissions and regional socioeconomic development in the Yangtze River Basin, this study constructed an emissions inventory for inland ships from 2007 to 2022, based on inland shipping freight statistics and ship carbon pollution emission intensity. Additionally, the Petri-Tapio decoupling model was employed to analyze the relationship between ship carbon pollution emissions and per capita GDP. The study concluded that CO2 emissions from inland ships in the Yangtze River Basin increased from 2.418 million tons in 2007 to 10.801 million tons in 2022. In 2021, the emissions of NOx and SOx from inland ships in the Yangtze River Basin accounted for 2.27% and 0.0021%, respectively, of China's anthropogenic emissions. Despite a year-on-year increasing trend in ship emissions within the basin, significant reductions in PM and SO2 emissions were observed post-2018 due to the implementation of emission reduction policies. Furthermore, we found that economically developed areas such as Shanghai, Jiangsu, and Zhejiang had higher emissions compared to other regions, with regional ship emissions positively correlating with the level of economic activity. Decoupling analysis results indicated that most provinces in the Yangtze River Basin have not effectively decoupled ship carbon pollution emissions from GDP growth. The findings of this study provide support for the Chinese government to formulate stricter ship emission control policies while promoting the growth of the Yangtze River shipping economy.

Time to say goodbye? The impact of environmental regulation on foreign divestment

Time to say goodbye? The impact of environmental regulation on foreign divestment

Investigating the impact of control strategies on the sulfur dioxide emissions of South Korean industrial facilities using an aircraft mass balance approach

We present top-down SO2 emission estimates from four large point sources, including two power plants, a steel mill, and a petrochemical industrial facility in Taean, South Korea. The airborne observations were conducted over two years, with three intensive observations in Fall 2019, Fall 2020, and Spring 2021. During this period, an active policy implementation to reduce air pollutant emissions from large industrial point sources in the region had been exercised, in addition to activity disruptions from the global COVID-19 pandemic. We quantify the observed SO2 emission reduction over the time period resulting from the policy implementation. The Continuous Emission Monitoring System (CEMS) datasets from the coal power plants were 1) validated by comparing them with emissions calculated using a top-down airborne mass balance method and 2) compared with the annual bottom-up national SO2 emission inventory. The comparisons illustrate that the policy implementation resulted in a 35% reduction in SO2 emissions from increased implementation of SO2 reduction technologies such as scrubbers. Finally, the COVID-19 pandemic did not cause a meaningful disruption in SO2 emissions from industrial sectors, such as steel mills and petrochemical manufacturing facilities.

The effect of additives on the co-pelletization of sewage sludge and extraction residue on combustion behavior and off-gas emission reduction

Co-combustion of biomass and sludge is a promising method for waste treatment and power generation. In this study, additives such as ammonium dihydrogen phosphate (ADP), calcium oxide (CaO), attapulgite (AT), and their combinations were added into the co-pelletization of semi-dry sludge (with approximately 50% water content) and extraction residue from vegetable oil processing. The objective of the studies was to examine the pelletization behavior, reduce off-gas emissions during the combustion, and investigate the mechanisms influenced by these additives through the thermogravimetric analysis and the tube furnace combustion experiment. The results of the analysis of variance (ANOVA) indicated an increase in pellet density due to the addition of additives. During the combustion, the addition of AT and compound additives generated more complex compounds with high melting temperatures, thereby mitigating the high slagging tendency. Meanwhile, additives facilitated the conversion of ultrafine particles (PM0.1) to fine particles, leading to a reduction in PM0.1 emissions by 15.60–42.40%. The additives exhibited efficacy in reducing SO2 emissions, with a reduction range of 5.00–23.20%. However, the addition of ADP additives resulted in a 12.00% increase in NO emissions. Consequently, adding additives to pellets could address the slagging issue and reduce the emission of air pollutants during combustion.

Does target-based performance evaluation system reduce pollution emissions? Firm-level evidence from China

This paper sheds light on the effectiveness of a concrete target-based performance evaluation system (TPES) for localities in enhancing local environmental enforcement in China. We conduct a difference-in-differences (DID) specification and exploit unique firm-level data to investigate the effects of the TPES on SO2 emission reduction through the Two control Zones (TCZ) policy. The results suggest that the TPES significantly reduces SO2 emissions of firms located at the TCZ cities, both in extensive and intensive margins. We also find that the treatment effects vary largely across enterprise sizes, ownership types, and local economic development. Our findings further verify how the long-standing distortions in the decentralized implementation of nationwide environmental regulations in China are remedied with a proper performance evaluation system.

How does fiscal transparency reduce SO2 emissions? Treating at the source

How does fiscal transparency reduce SO2 emissions? Treating at the source