Reduction Of SO2 Emissions Research Articles

Low-Carbon Clean Technology for Waste Energy Recovery in Power Plants Based on Green Environmental Protection

With the development of biomass power generation technology, biomasswaste has a more excellent recycling value. The article establishes a biomasswaste inventory model based on the material flow analysis method andpredicts raw material waste’s energy utilization potential. The results showthat the amount of biomass waste generated from 2016 to 2020 is on therise. In 2020, biomass waste’s energy utilization can reach 107,802,300 tons,equivalent to 1,955.28PJ of energy. Through biomass energy analysis andemission analysis, the results show that the biomass waste can generate182.02 billion kW·h in 2020, which can replace 35.9% of the region’s totalpower consumption, which is compared with the traditional power generationmethod under the same power generation capacity. Power generation can reduce SO2 emissions by 250,400 tons, NOx emissions by 399,300 tons,and PM10 emissions by 49,700 tons. Reduce direct economic losses by712 million yuan. Therefore, Chinese promotion of the recycling of biomasswaste and the acceleration of the biomass energy industry’s development isof great significance for reducing pollutant emissions and alleviating energypressure.

Wpływ ekologicznych działań badawczo-rozwojowych na emisje SO2 w Chinach – dane z panelowego modelu progowego

Previous studies on the effectiveness of improving sustainable development have acknowledged the importance of domestic research and development (R&D) activities. However, these studies remain general and ambiguous because they assume that all R&D activities are related to energy-saving and sustainable development. The corresponding empirical evidence is scabrous and ambiguous. In this paper, we focus on the effect of green innovation R&D activities on SO2 emission which is an important greenhouse gas affect global climate change and eco-civilization. Considering that there is heterogeneity exists in the innovation activities, the R&D activities are divided into three performers with two purposes. The empirical results based on a Chinese inter-provincial dataset of 2000-2016 suggest that the green innovation R&D activities are crucial for the reduction of the SO2 emission. However, the innovation R&D activities of different purposes and performers show statistically differentiated effects on SO2 emission. The major positive effect of green innovation R&D activities on SO2 emissions reduction is mainly from enterprises and utility-type of R&D activities. A further study based on the panel threshold also indicates that effects of green innovation R&D activities on SO2 emissions are nonlinear, depending on the technology absorptive ability.

Quantifying organic matter and functional groups in particulate matter filter samples from the southeastern United States – Part 2: Spatiotemporal trends

Abstract. Organic species within atmospheric particles vary widely in molecular structure. The variety of molecules that comprise the aerosol make it rich in information about its sources and chemical life cycle but also make particulate organic matter (OM) difficult to characterize and quantify. In Part 1 of this pair of papers, we described a direct method for measuring the composition and concentrations of OM in aerosol samples that is compatible with routine monitoring of air quality. This method uses Fourier transform infrared (FT-IR) spectrometry of filter-based aerosol samples to quantify bonds, or functional groups, that represent the majority of organic composition. Summation of these functional groups gives OM. In this paper, functional group and OM concentrations are directly measured in 8 years of aerosol samples collected at two rural and two urban sites in the Southeastern Aerosol Research and Characterization (SEARCH) network. FT-IR spectrometry with a multivariate calibration is used to quantify the concentrations of aliphatic C−H (aCH), carboxylic acid (COOH), oxalate (oxOCO; representing carboxylates), non-acid and non-oxalate carbonyl (naCO), and alcohol O−H (aCOH) in approximately 3500 filter samples collected every third day from 2009 through 2016. In addition, measurements are made on samples from all days in 2016. To the best of our knowledge, this is the longest time period over which this type of analysis has been applied, and this work also demonstrates the application of a more chemically complete and less destructive method than in prior work using alternate techniques. A decline in the total OM is observed from 2011 to 2016 due to a decrease in the more oxygenated functional groups (carboxylic acid and oxalate) and is attributed to anthropogenic SO2 and/or volatile organic compound (VOC) emissions reductions. The trend in OM composition is consistent with those observed using more time- and labor-intensive analytical techniques. Concurrently, the fractional contributions of aCOH and naCO to OM increased, which might be linked to monoterpene-derived secondary OM, with plausible influences from decreasing NOx and/or increasing O3 concentrations. In addition, this work demonstrates that OM to organic carbon (OM/OC) ratios in the southeastern US (SE US) did not appreciably change over the study time period as a result of these competing functional group contributions to OM. Monthly observations support the sources suggested by these overall trends, including evidence of strong biogenic and photo-oxidation influences. Daily samples from 2016 further elucidate the consistent impact of meteorology and biomass burning events on shorter-term OM variability, including prescribed burning in the winter or spring and wildfires in the autumn, although these sources did not appear to be strong contributors to long-term OM or composition trends in the SE US. These shorter-term and spatial observations reinforce the results of the broader dataset and serve to evaluate the applicability of FT-IR spectrometry measurement to trends analysis on various timescales relevant to routine monitoring of aerosol composition.

Determining the Role of Acidity, Fate and Formation of IEPOX-Derived SOA in CMAQ

Formation of aerosol from biogenic hydrocarbons relies heavily on anthropogenic emissions since they control the availability of species such as sulfate and nitrate, and through them, aerosol acidity (pH). To elucidate the role that acidity and emissions play in regulating Secondary Organic Aerosol (SOA), we utilize the 2013 Southern Oxidant and Aerosol Study (SOAS) dataset to enhance the extensive mechanism of isoprene epoxydiol (IEPOX)-mediated SOA formation implemented in the Community Multiscale Air Quality (CMAQ) model (Pye et al., 2013), which was then used to investigate the impact of potential future emission controls on IEPOX OA. We found that the Henry’s law coefficient for IEPOX was the most impactful parameter that controls aqueous isoprene OA products, and a value of 1.9 × 107 M atm−1 provides the best agreement with measurements. Non-volatile cations (NVCs) were found in higher-than-expected quantities in CMAQ and exerted a significant influence on IEPOX OA by reducing its production by as much as 30% when present. Consistent with previous literature, a strong correlation of isoprene OA with sulfate, and little correlation with acidity or liquid water content, was found. Future reductions in SO2 emissions are found to not affect this correlation and generally act to increase the sensitivity of IEPOX OA to sulfate, even in extreme cases.

Long-term trends of ambient nitrate (NO<sub>3</sub><sup>−</sup>) concentrations across China based on ensemble machine-learning models

Abstract. High loadings of nitrate (NO3-) in the aerosol over China significantly exacerbate the air quality and pose a great threat to ecosystem safety through dry–wet deposition. Unfortunately, limited ground-level observation data make it challenging to fully reflect the spatial pattern of NO3- levels across China. Until now, long-term monthly particulate NO3- datasets at a high resolution were still missing, which restricted the assessment of human health and ecosystem safety. Therefore, a unique monthly NO3- dataset at 0.25∘ resolution over China during 2005–2015 was developed by assimilating surface observations, satellite products, meteorological data, land use types and other covariates using an ensemble model combining random forest (RF), gradient-boosting decision tree (GBDT), and extreme gradient-boosting (XGBoost) methods. The new developed product featured an excellent cross-validation R2 value (0.78) and relatively lower root-mean-square error (RMSE: 1.19 µg N m−3) and mean absolute error (MAE: 0.81 µg N m−3). Besides, the dataset also exhibited relatively robust performance at the spatial and temporal scales. Moreover, the dataset displayed good agreement with (R2=0.85, RMSE=0.74 µg N m−3, and MAE=0.55 µg N m−3) some unlearned data collected from previous studies. The spatiotemporal variations in the developed product were also shown. The estimated NO3- concentration showed the highest value in the North China Plain (NCP) (3.55±1.25 µg N m−3); followed by the Yangtze River Delta (YRD) (2.56±1.12 µg N m−3), Pearl River Delta (PRD) (1.68±0.81 µg N m−3), and Sichuan Basin (1.53±0.63 µg N m−3), and the lowest one in the Tibetan Plateau (0.42±0.25 µg N m−3). The higher ambient NO3- concentrations in the NCP, YRD, and PRD were closely linked to the dense anthropogenic emissions. Apart from the intensive human activities, poor terrain condition might be a key factor for the serious NO3- pollution in the Sichuan Basin. The lowest ambient NO3- concentration in the Tibetan Plateau was contributed by the scarce anthropogenic emission and favourable meteorological factors (e.g. high wind speed). In addition, the ambient NO3- concentration showed a marked increasing tendency of 0.10 µgNm-3yr-1 during 2005–2014 (p<0.05), while it decreased sharply from 2014 to 2015 at a rate of −0.40 µgNm-3yr-1 (p<0.05). The ambient NO3- levels in Beijing–Tianjin–Hebei (BTH), YRD, and PRD displayed gradual increases at a rate of 0.20, 0.11, and 0.05 µgNm-3yr-1 (p<0.05) during 2005–2013, respectively. The gradual increases in NO3- concentrations in these regions from 2005 to 2013 were due to the fact that the emission reduction measures during this period focused on the reduction of SO2 emission rather than NOx emission and the rapid increase in energy consumption. Afterwards, the government further strengthened these emission reduction measures and thus caused the dramatic decreases in NO3- concentrations in these regions from 2013 to 2015 (p<0.05). The long-term NO3- dataset over China could greatly deepen the knowledge about the impacts of emission reduction measures on air quality improvement. The monthly particulate NO3- levels over China during 2005–2015 are open access at https://doi.org/10.5281/zenodo.3988307 (Li et al., 2020c).

Examining the Impact and Influencing Channels of Carbon Emission Trading Pilot Markets in China

As China has an important role in global climate change, the Chinese government has set goals to improve its environmental efficiency and performance and launched carbon emission trading pilot markets in 2013, aiming to reduce CO2 emissions. Based on panel data of 30 provinces from 2005 to 2017, this paper uses the difference-in-difference method to study the impact of China’s carbon emission trading pilot markets on carbon emissions and regional green development. The paper also explores possible influencing channels. The main conclusions are as follows: (1) China’s carbon emission trading policy has promoted a reduction in CO2 emissions and carbon emission intensity and has increased green development in the pilot areas. (2) The main path for China’s carbon emission trading policy to achieve carbon emission reduction and regional green development is to promote technology adoption. (3) China’s carbon emission trading policy achieves green development through synergistic SO2 emission reduction. The pilot carbon markets have reduced both the amount of SO2 emissions and SO2 emission intensity.

Developing effective CO2 and SO2 mitigation strategy based on marginal abatement costs of coal-fired power plants in China

This study proposes a novel analysis framework to investigate the CO2 and SO2 emission efficiency, emission reduction potential, and marginal abatement cost (MAC) of 316 coal-fired power plants in China. The comprehensive analysis framework is based on the combined approach of utilizing the directional output distance function (DODF) and parametric linear programming (PLP). The average emission efficiencies of CO2 and SO2 were 0.48 and 0.61, respectively, which indicates that China’s coal-fired power plants have a large potential to reduce CO2 and SO2 emissions, on average by 52% and 39%, respectively. In 2010, the average CO2 and SO2 emissions reduction potential for the 316 investigated power plants were 1,517 kt and 3,773 t, respectively. The average MAC prices for CO2 and SO2 were estimated to be 598 yuan/tonne and 22,401 yuan/tonne, respectively, indicating that the reduction of such emissions is very expensive. Furthermore, I formulated an optimization problem for maximizing CO2 and SO2 emission reductions under the governmental budget constraint. Solving this optimization problem yielded the total cost for the maximum reductions of CO2 and SO2 emissions, the maximum possible reductions for CO2 and SO2 emissions for each allocated budget scale, and the optimal budget allocation for each power plant at a given budget scale. I finally suggest effective mitigation strategies for CO2 and SO2 emissions generated from China’s coal-fired power plants.

The GEOMON network of Czech catchments provides long‐term insights into altered forest biogeochemistry: From acid atmospheric deposition to climate change

AbstractIn 1994, a network of small catchments (GEOMON) was established in the Czech Republic to determine input–output element fluxes in semi‐natural forest ecosystems recovering from anthropogenic acidification. The network consists from 16 catchments and the primary observations of elements fluxes were complemented by monitoring of biomass stock, element pools in soil and vegetation, and the main water balance components. Over last three decades, reductions of SO2, NOx and NH3 emissions were followed by sulphur (S) and nitrogen (N) deposition reductions of 75% and 30%, respectively. Steeper declines of strong acid anion concentrations compared to cations (Ca, Mg, Na, K, NH4) in precipitation resulted in precipitation pH increase from 4.5 to 5.2 in bulk precipitation and from 4.0 to 5.1 in spruce throughfall. Stream chemistry responded to changes in deposition: S leaching declined. However at majority of catchments soils acted as a net source of S to runoff, delaying recovery. Stream pH increased at acidic streams (pH < 6) and aluminium concentration decreased. Stream nitrate (NO3) concentration declined by 60%, considerably more than N deposition. Stream NO3 concentration was tightly positively related to stream total dissolved nitrogen to total phosphorus (P) ratio, suggesting the role of P availability on N retention. Trends in dissolved organic carbon fluxes responded to both acidification recovery and to runoff temporal variation. An exceptional drought occurred between 2014 and 2019. Over this recent period, streamflow decreased by ≈ 40% on average compared to 1990s, due to the increases of soil evaporation and vegetation transpiration by ≈ 30% and declines in precipitation by ≈ 15% on average across the elevational gradient. Sharp decreases of stream runoff at catchments <650 m a.s.l. corresponded to areas of recent forest decline caused by bark beetle infestation on drought stressed spruce forests. Understanding of the interactions among legacies of acidification and eutrophication, drought effects on the water cycle and forest disturbance dynamics is requisite for effective management of forested ecosystems under anthropogenic influence.

Sulfur Contamination and Environmental Effects: A Case Study of Current SO2 Industrial Emission by Biomonitoring and Regional Post-mining hot-spots

The presence of sulfur in the environment is an important macroelement for plant growth but becomes harmful in excessive amounts. The previous century saw rising levels of high SO2 concentrations (stemming from fossil fuel combustion) and wet deposition from acid rain, causing the intensification of forest die-back. Air pollution can be controlled or measured by biomonitoring. Despite recent reductions in SO2 emissions, urban and industrial areas are still at risk from high sulfur contamination. Open-cast lignite and sulfur borehole mining play a pivotal role in the regional scale of ecosystem contamination and acid mine drainage. Consequently, these aspects are unique for assessing the impact of extreme S contamination on soil properties changes, the vegetation effect, and biogeochemical cycles. We presented i) current SO2 pollution based on S concentration in pine needles, and ii) a comprehensive study of soil properties, as well as plant reactions to excessive sulfur concentration in the restored forest ecosystem of a former sulfur mine.

Aerosol radiative forcings induced by substantial changes in anthropogenic emissions in China from 2008 to 2016

Abstract. Anthropogenic emissions in China play an important role in altering the global radiation budget. Over the past decade, the strong clean-air policies in China have resulted in substantial reductions of anthropogenic emissions of sulfur dioxide (SO2) and primary particulate matter, and air quality in China has consequently improved. However, the resultant aerosol radiative forcings have been poorly understood. In this study, we used an advanced global climate model integrated with the latest localized emission inventory to quantify the aerosol radiative forcings by the changes of anthropogenic emissions in China between 2008 and 2016. By comparing with multiple observation datasets, our simulations reproduced the considerable reductions of sulfate and black carbon (BC) mass loadings reasonably well over eastern China (the key region subject to stringent emission controls) during the period and accordingly showed a clear decline in both aerosol optical depth and absorption aerosol optical depth. The results revealed a regional annual mean positive direct radiative forcing (DRF) of +0.29 W m−2 at the top of the atmosphere (TOA) due to the reduction of SO2 emissions. This positive aerosol radiative forcing was comprised of diminished sulfate scattering (+0.58 W m−2), enhanced nitrate radiative effects (−0.29 W m−2), and could be completely offset by the concurrent reduction of BC emissions that induced a negative BC DRF of −0.33 W m−2. Despite the small net aerosol DRF (−0.05 W m−2) at the TOA, aerosol–radiation interactions could explain the surface brightening in China over the past decade. The overall reductions in aerosol burdens and associated optical effects mainly from BC and sulfate enhanced the regional annual mean downward solar radiation flux at the surface by +1.0 W m−2 between 2008 and 2016. The enhancement was in general agreement with a long-term observational record of surface energy fluxes in China. We also estimated that aerosol effects on cloud radiative forcings may have played a dominant role in the net aerosol radiative forcings at the TOA in China and over the northern Pacific Ocean during the study period. This study will facilitate more informed assessment of climate responses to projected emissions in the future as well as to sudden changes in human activities (e.g., the COVID-19 lockdown).

The Impact of Green R&D Activities on SO2 Emissions: Evidence from China

Prior research on the effectiveness of improving environmental performance has acknowledged the importance of domestic research and development (R&D) activities. However, these studies remain general and ambiguous because they assume that all R&D operations are associated with environmental performance. The corresponding empirical evidence is inexact and ambiguous. In this study, we focus on the effect of green R&D activities on SO2 emission. Considering that heterogeneity exists in green R&D activities, we divide them into two groups for two purposes. The empirical results, explored based on China’s interprovincial data between 2000 and 2016, suggest that green R&D activities critically influence the reduction of SO2 emissions. However, the R&D activities of different purposes show statistically differentiated effects on SO2 emissions. Primarily, utility-type R&D activities show the most significant positive impact on SO2 emissions reduction. Subsequent research based on the panel threshold also indicates that the impact of green R&D activities on SO2 emissions shows nonlinear characteristics, depending on the technology’s absorptive ability.

Reducing the energy efficiency design index for ships through a post-combustion carbon capture process

This paper discusses the possibility to reduce the energy efficiency design index for ships through a post-combustion carbon capture process. The post-combustion carbon capture process, successfully implemented in the electricity generation sector, allows reduction of CO2 emissions of existing units using fossil fuels with relative simplicity. An assessment of implementing an amine-based carbon capture system onboard of the ship is presented. The analysis covers the energy requirements of the entire system including SO2 removal, carbon capture and CO2 compression. Simulations, conducted for different ambient conditions, revealed that the highest CO2 emission, translating into a reduction of the EEDI, is possible in tropical conditions. The energy efficiency reduction is possible also in arctic conditions to a lesser extent. The post-combustion carbon capture process seems to be a promising technology as the method to reduce the EEDI for ships. An additional advantage is the possibility to retrofit existing constructions as the implementation requires no significant changes in the ship propulsion system. Finally, the nature of the amine-based carbon capture process, aimed to remove acidic exhaust gas components, supports SO2 emission reduction, making the exhaust gas practically sulfur-free.

Energy Effectiveness or Economic Profitability? A Case Study of Thermal Modernization of a School Building

Thermal refurbishment of buildings results in certain energy, financial, and environmental effects. Such investments are financially supported in Poland after meeting the legally defined conditions of thermal protection and energy consumption. This paper presents a complex thermal modernization of a school building, performed by following Polish regulations. A detailed description of the studied object was given, and the calculation procedure was described. Then an optimal variant of an investment and an ex-post analysis were described. Simple payback time (SPBT) of modernization measures was from 15.8 years (insulation of the ceiling under the unheated attic) to 87 years for insulation of the wooden external wall, with 35.6 years for the whole project, which is shorter than the predicted lifespan of the whole building (50–70 years). Annual calculated heating demand decreased from 464.78 to 168.73 GJ, resulting in the primary energy consumption indicator (EP) of 484.44 and 129.46 kWh/m2, respectively. Thermal refurbishment with the replacement of an old boiler into a new wood-pellet one resulted in a significant reduction of SO2 and dust emissions from 451 to 27.5 kg and from 399 to 13 kg, respectively.

Revealing the sulfur dioxide emission reductions in China by assimilating surface observations in WRF-Chem

Abstract. The anthropogenic emission of sulfur dioxide (SO2) over China has significantly declined as a consequence of the clean air actions. In this study, we have developed a new emission inversion system based on a four-dimensional local ensemble transform Kalman filter (4D-LETKF) and the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) to dynamically update the SO2 emission grid by grid over China by assimilating the ground-based hourly SO2 observations. Sensitivity tests for the assimilation system have been conducted firstly to tune four system parameters: ensemble size, horizontal and temporal localization lengths, and perturbation size. Our results reveal that the same random perturbation factors used throughout the whole model grids with assimilating observations within about 180 km can efficiently optimize the SO2 emission, whereas the ensemble size has only little effect. The temporal localization by assimilating only the subsequent hourly observations can reveal the diurnal variation of the SO2 emission, which is better than updating the magnitude of SO2 emission every 12 h by assimilating all the observations within the 12 h window. The inverted SO2 emission over China in November 2016 has declined by an average of 49.4 % since 2010, which is well in agreement with the bottom-up estimation of 48.0 %. Larger reductions of SO2 emission are found over the a priori higher source regions such as the Yangtze River Delta (YRD). The simulated SO2 surface mass concentrations using two distinguished chemical reaction mechanisms are both much more comparable to the observations with the newly inverted SO2 emission than those with the a priori emission. These indicate that the newly developed emission inversion system can efficiently update the SO2 emissions based on the routine surface SO2 observations. The reduced SO2 emission induces the sulfate and PM2.5 surface concentrations to decrease by up to 10 µg m−3 over central China.

Efforts to Reduce SO2 Emission in Paiton Coal-Fired Power Plant

Several breakthrough methods are needed to reduce the exhaust emissions of coal combustion in the boiler in order to meet the environmental quality standard requirements. The implementation of coal mixing is one of the short-term programs to reduce SO2 emissions, which is carried out by mixing several types of coal which have different calorific values and sulfur content to obtain the right coal mixture so that coal combustion will produce low SO2 emissions. Supply of coal with low sulfur content is getting smaller due to limited reserves, which causes the coal switching method will no longer be effective. Installation of flue gas desulfurization (FGD) facilities is an effective way to reduce SO2 emissions. Considering the condition and location of the Paiton 1-2 coal-fired power plant, the seawater desulfurization system is the most appropriate to be implemented because it is close to abundant seawater sources and the system has high reliability and effective economic value. By implementing flue gas desulphurization, SO removal efficiencies will be more than 95%.

Life cycle and sustainability assessments of biorefineries producing glucaric acid, sorbitol or levulinic acid annexed to a sugar mill

To advance the ‘green’ economy agenda aimed at mitigating environmental impacts, a holistic approach assessing sugarcane biorefineries is vital in establishing their sustainability (economic, environment and social matters). This study evaluates the environmental impact of six (bio)energy self-sufficient biorefineries (S1–S6), annexed to a sugar mill and using sugarcane residues to produce sorbitol, glucaric acid and levulinic acid, along with electricity. Different pretreatment technologies, i.e. SO2-steam explosion and dilute acid, were investigated for sorbitol and glucaric acid production (S1–S4). Scenario S5 investigated levulinic acid and furfural production via the Biofine process, whereas S6 added the manufacture of gamma valerolactone to S5. Life cycle assessments evaluated using SimaPro PhD 8.5.2.0 and together with inventory data from previous Aspen Plus® v 8.6 models on economic and social impacts were used to evaluate the scenarios’ sustainability. Results revealed that dilute acid pretreatment applied in S2 and S4 exhibited 23%–92% lower environmental impacts across most impact categories, compared to S1 and S3 via SO2-steam explosion, mainly due to reduced SO2 emissions. Regarding the scenarios’ sustainability based on a combination of eight socio-economic and environmental indicators, S4 producing glucaric acid via dilute acid pretreatment was the most favourable as it had the least environmental burdens despite being marginally profitable and creating 49 jobs. It was followed by S5, the levulinic acid and furfural biorefinery whilst S6, despite attractive socio-economic outcomes was the least desirable due to high environmental loads from gamma valerolactone production, associated with the manufacture, transportation and use of n-butyl acetate solvent and hydrogen from natural gas.

Sulfur dioxide (SO2) emission reduction and its spatial spillover effect in high-tech industries: based on panel data from 30 provinces in China.

Industrial sulfur dioxide (SO2) has become an important source of environmental pollution in China, and the regional SO2 emission reduction capacity is a comprehensive reflection of cleaner production capacity, environmental regulation, and economic development. It is obvious that high-tech industries play a crucial role in promoting the cleaner production capacity of the whole industry. Simultaneously, only considering the regional emission and the development of high-tech industry in isolation may deviate from actual economic characteristics. Therefore, by using the panel data of 30 provinces in China from 2005 to 2016, this paper adopts spatial autoregression model (SAR), spatial error model (SEM), and spatial Durbin model (SDM) to analyze the effect of the high-tech industry development on SO2 emission reduction under the spatial adjacency matrix (W1), geographic distance matrix (W2), and economic distance matrix (W3). In addition, this paper selects three indicators, which is SO2 removal rate, SO2 emission, and SO2 removal quantity, as explanatory variables, and R&D investment and number of enterprises in high-tech industry are selected to represent the industrial development level. The major conclusions are as follows: (1) The ability of SO2 emission reduction in the local province is significantly affected by the surrounding provinces, showing the agglomeration characteristics of "high-high" or "low-low." (2) The R&D investment of high-tech industry has a negative impact on SO2 removal rate and SO2 removal quantity, but a positive effect on the SO2 emissions for the local province, and has a positive effect on the emission reduction of surrounding provinces. (3) The expansion of high-tech industry has significantly improved the SO2 emission reduction capacity of the local province and its surrounding provinces. The robustness test supports the empirical conclusions of this paper. Finally, this paper puts forward some policy suggestions for government in environmental governance, such as "joint prevention and control" and the promotion of cleaner production.

The nonlinear response of fine particulate matter pollution to ammonia emission reductions in North China

Recent Chinese air pollution actions have significantly lowered the levels of fine particulate matter (PM2.5) in North China via controlling emissions of sulfur dioxide (SO2) and nitrogen oxides (NO x ) together with primary aerosols, while the emissions of another precursor, ammonia (NH3), have not yet been regulated. This raises a question that how effective the NH3 emission controls can be on the mitigation of PM2.5 pollution along with the reduction of SO2 and NO x emissions. Here we use a regional air quality model to investigate this issue focusing on the PM2.5 pollution in North China for January and July 2015. We find that the efficiency of the PM2.5 reduction is highly sensitive to the NH3 emission and its reduction intensity. Reductions in the population-weighted PM2.5 concentration (PWC) in the Beijing–Tianjin–Hebei region are only 1.4–3.8 μg m−3 (1.1%–2.9% of PM2.5) with 20%–40% NH3 emission reductions, but could reach 8.1–26.7 μg m−3 (6.2%–21%) with 60%–100% NH3 emission reductions in January 2015. Besides, the 2015–2017 emission changes (mainly reduction in SO2 emissions) could lower the PM2.5 control efficiency driven by the NH3 reduction by up to 30% for high NH3 emission conditions, while lead to no change or increase in the efficiency when NH3 emissions become low. NO x emission reductions may enhance the wintertime PM2.5 pollution due to the weakened titration effect and can be offset by simultaneously controlling NH3 emissions. Our results emphasize the need to jointly consider NH3 with SO2 and NO x emission controls when designing PM2.5 pollution mitigation strategies.

Green and efficient sulfur dioxide removal using hydrogen peroxide in rotating packed bed reactor: Modeling and experimental study

In order to reduce SO2 emissions and achieve green utilization of sulfur resources, a desulfurization method of SO2 removal using hydrogen peroxide (H2O2) in rotating packed bed (RPB) is proposed. It can not only achieve the efficient removal of SO2, but also lead to the effective utilization of sulfur resources. A mathematic model was first developed to describe the reaction and mass transfer process between H2O2 and SO2 in RPB. The influences of different operating conditions including RPB rotating speed, H2O2 mass fraction, gas–liquid volumetric flow rate ratio, gas flux, and inlet SO2 concentration on desulfurization performance were studied. Under the optimized conditions, it turned out that the desulfurization efficiency was above 99% and the outlet SO2 concentration was ultra-low, below 35 mg/m3. The validity of the model was confirmed by the fact that most of the predicted desulfurization efficiency agreed well with the experimental result with a deviation within 5%. The height of mass transfer unit HTU for RPB is calculated to be 1.60–2.07 cm, which is one order of magnitude lower than that of conventional reactors, indicating the investment of the desulfurization reactor can be greatly reduced by using RPB.

Investigation of Effect on Environmental Performance of Using LNG as Fuel for Engines in Seaport Tugboats

Decarbonization of ship power plants and reduction of harmful emissions has become a priority in the technological development of maritime transport, including ships operating in seaports. Engines fueled by diesel without using secondary emission reduction technologies cannot meet MARPOL 73/78 Tier III regulations. The MEPC.203 (62) EEDI directive of the IMO also stipulates a standard for CO2 emissions. This study presents the results of research on ecological parameters when a CAT 3516C diesel engine is replaced by a dual-fuel (diesel-liquefied natural gas) powered Wartsila 9L20DF engine on an existing seaport tugboat. CO2, SO2 and NOx emission reductions were estimated using data from the actual engine load cycle, the fuel consumption of the KLASCO-3 tugboat, and engine-prototype experimental data. Emission analysis was performed to verify the efficiency of the dual-fuel engine in reducing CO2, SO2 and NOx emissions of seaport tugboats. The study found that replacing a diesel engine with a dual-fuel-powered engine led to a reduction in annual emissions of 10% for CO2, 91% for SO2, and 65% for NOx. Based on today’s fuel price market data an economic impact assessment was conducted based on the estimated annual fuel consumption of the existing KLASCO-3 seaport tugboat when a diesel-powered engine is replaced by a dual-fuel (diesel-natural gas)-powered engine. The study showed that a 33% fuel costs savings can be achieved each year. Based on the approved methodology, an ecological impact assessment was conducted for the entire fleet of tugboats operating in the Baltic Sea ports if the fuel type was changed from diesel to natural gas. The results of the assessment showed that replacing diesel fuel with natural gas achieved 78% environmental impact in terms of NOx emissions according to MARPOL 73/78 Tier III regulations. The research concludes that new-generation engines on the market powered by environmentally friendly fuels such as LNG can modernise a large number of existing seaport tugboats, significantly reducing their emissions in ECA regions such as the Baltic Sea.