We implemented the online coupled WRF-Chem model to reproduce the 2013 January haze event in North China, and evaluated simulated meteorological and chemical fields using multiple observations. The comparisons suggest that temperature and relative humidity (RH) were simulated well (mean biases are–0.2K and 2.7%, respectively), but wind speeds were overestimated (mean bias is 0.5 m?s–1). At the Beijing station, sulfur dioxide (SO2) concentrations were overpredicted and sulfate concentrations were largely underpredicted, which may result from uncertainties in SO2 emissions and missing heterogeneous oxidation in current model. We conducted three parallel experiments to examine the impacts of doubling SO2 emissions and incorporating heterogeneous oxidation of dissolved SO2 by nitrogen dioxide (NO2) on sulfate formation during winter haze. The results suggest that doubling SO2 emissions do not significantly affect sulfate concentrations, but adding heterogeneous oxidation of dissolved SO2 by NO2 substantially improve simulations of sulfate and other inorganic aerosols. Although the enhanced SO2 to sulfate conversion in the HetS (heterogeneous oxidation by NO2) case reduces SO2 concentrations, it is still largely overestimated by the model, indicating the overestimations of SO2 concentrations in the North China Plain (NCP) are mostly due to errors in SO2 emission inventory. 相似文献
Based on the activity level and technical information of coal-fired power-generating units (CFPGU) obtained in China from 2011 to 2015, we, 1) analyzed the time and spatial distribution of SO2 and NOx emission performance of CFPGUs in China; 2) studied the impact of installed capacity, sulfur content of coal combustion, and unit operation starting time on CFPGUs’ pollutant emission performance; and 3) proposed the SO2 and NOx emission performance standards for coal-fired power plants based on the best available control technology. Our results show that: 1) the larger the capacity of a CFPGU, the higher the control level and the faster the improvement; 2) the CFPGUs in the developed eastern regions had significantly lower SO2 and NOx emission performance values than those in other provinces due to better economic and technological development and higher environmental management levels; 3) the SO2 and NOx emission performance of the Chinese thermal power industry was significantly affected by the single-unit capacity, coal sulfur content, and unit operation starting time; and 4) based on the achievability analysis of best available pollution control technology, we believe that the CFPGUs’ SO2 emission performance reference values should be 0.34 g/kWh for active units in general areas, 0.8 g/kWh for active units in high-sulfur coal areas, and 0.13 g/kWh for newly built units and active units in key areas. In addition, the NOx emission performance reference values should be 0.35 g/kWh for active units in general areas and 0.175 g/kWh for new units and active units in key areas. 相似文献
Over the last three decades, ambient concentrations of sulfur dioxide (SO2) air pollution have declined by approximately 80%. This paper tests whether the 1970 Clean Air Act and its subsequent amendments caused this decline. The centerpiece of this legislation is the annual assignment of all counties to SO2 nonattainment or attainment categories. Polluters face stricter regulations in nonattainment counties. There are two primary findings. First, regulators pay little attention to the statutory selection rule in their assignment of the SO2 nonattainment designations. Second, SO2 nonattainment status is associated with modest reductions in SO2 air pollution, but a null hypothesis of zero effect generally cannot be rejected. This finding holds whether the estimated effect is obtained with linear adjustment or propensity score matching. Overall, the evidence suggests that the nonattainment designation played a minor role in the dramatic reduction of SO2 concentrations over the last 30 years. 相似文献
The amount of dry deposition of SO2(g) and HNO3(g) in an urban area in Japan has been estimated by the inferential method. The mean annual dry deposition of SO2(g) (2.91 kgS/ha/year) was close to or less than that in the Clean Air Status and Trends Network (CASTNet) of the U.S. (3.59 kgS/ha/year).
The mean annual dry deposition of HNO3(g) (10.8 kgN/ha/year) was approximately six times larger than that in CASTNet (1.85 kgN/ha/year). The proportions of dry/(dry+wet)
deposition for sulfur and nitrogen were 0.301 and 0.785, respectively. 相似文献
We show that sulphur isotopic composition can be a useful tool to discriminate between various sources of sulphate and a tool
for better understanding of the sulphur cycling and mass balance. Our investigations, carried out in a dam reservoir, demonstrate
differences in sulphur biogeochemistry between different seasons, caused by recharge water supply in spring and intensive
sulphate reduction in summer. In the riverine-affected part of the reservoir δ34S(SO42−) varied from 4.7 to 5.9‰ in spring, and from 4.1 to 4.6‰ in summer. In the lacustrine-affected part δ34S(SO42−) varied from 4.0 to 5.0‰ in spring, and from 4.5 to 5.4‰ in summer. Diurnal variations of δ34S(SO42−) were negligible as compared to seasonal variations. 相似文献
The ambient air particulates pollutants of total suspended particulates (TSP) and PM2.5 were collected by using PS-1 and Wilbur PM2.5 sampler, simultaneously during the year of 2015–2017 at a photoelectric factory in Science Park of central Taiwan. And those of the ambient air atmospheric metallic elements (Cr, Mn, Ni, Cu, Zn, Pb) concentrations which attached on the TSP and PM2.5 were analyzed by using inductively coupled plasma optical emission spectrometer. In addition, identifying anthropogenic and natural pollutants sources were conducted by using the enrichment factor (EF) and principal component analysis (PCA) methods. The results indicated that the average TSP and PM2.5 concentrations were ranked highest in winter season, while summer season was ranked lowest during the year of 2015–2016. In addition, the average highest metallic element concentrations were occurred in winter season for both TSP and PM2.5 during the year of 2015–2016, while the average lowest metallic elements concentrations in TSP and PM2.5 were also occurred in winter season during the year of 2016–2017. Moreover, the EF analysis results showed that the metallic element Zn came from anthropogenic emission source. As for metallic element Mn, the results showed that metallic element Mn was mainly attributed to natural emission in this study. Finally, the PCA results showed that metallic elements Cr, Zn and Pb were the dominant emissions metallic elements in this study. As for PM2.5, the results showed that the metallic elements Cr, Cu and Pb were the dominant emissions metallic elements at this HPB sampling site.
A laboratory modelling for the assessment of damage to marble by the SO2-acidity in the vicinity of stacks has been devised. The modelling is based on the role of metal oxide particulates (also emitted by smoke-stacks) which catalytically convert SO2 to SO3 forming H2SO4 (in presence of water), which has an excessively high selectivity, compared with HNO3, for corroding marble. The requisites of the modelling are: (1) determination of composition of the marble, (2) immersion of samples of marble blocks (after measurement of surface areas) in H2SO4 solutions of known concentrations, maintaining pH and temperature at their initial values, (3) determination of concentrations of Ca and Mg (major components of marble) in the leachate, and thereby evaluating the mass loss of the marble, in terms of mg marble cm–2 day–1, for each level of H2S04 concentration, (4) application of derived data for evaluation of duration (in years) for the decay of 1 cm thickness of marble block by the process of surface corrosion. From the modelling, it was found that the duration for the damage of 1 cm thickness of the marble sample used here by SO2 acidities of 1, 5, 10, 50 and 100 ppm are 83.01, 69.02, 31.24, 8.19 and 4.31 years respectively. 相似文献
Urban energy consumption is one of the most important causes of air pollution. Air pollution-oriented ecological risk assessment is of great significance to the promotion of urban environmental protection. This paper focuses on ecological risk in Xiamen city caused by air pollutant discharge from urban energy consumption. The Long-range Energy Alternatives Planning model was used to establish two scenarios of energy consumption in Xiamen city, and based on different scenarios, we estimated urban energy consumption and discharge quantity of air pollutant (DQAP). A box model and an expert scoring method were used to calculate the air pollution burden (APB) of SO2, NO2, CO, PM10 and PM2.5 and to obtain the probabilities of different air pollution loads. An ecological risk assessment model was developed and utilized to predict Xiamen city’s ecological risks in 2020. The results showed that under an energy-saving scenario, the ecological risks for PM2.5, SO2 and NO2 are high, whereas the ecological risks for CO and PM10 are low. Under a baseline scenario, the ecological risks for PM2.5, SO2 and NO2 are moderate, whereas the ecological risks for CO and PM10 are low. In addition, the APB of SO2, NO2, CO, and PM2.5, but not of PM10, is predicted to rise. In the simulation, energy generation from coal is the main source of air pollution. Although the DQAP from automobiles is not high, it is predicted to rise year-on-year. In summary, the ecological risk due to pollution in Xiamen city is high, and the main pollutants are SO2, NO2 and PM2.5. 相似文献
A series of CeO2 supported V2O5 catalysts with various loadings were prepared with different calcination temperatures by the incipient impregnation. The catalysts were evaluated for low temperature selective catalytic reduction (SCR) of NO with ammonia (NH3). The effects of O2 and SO2 on catalytic activity were also studied. The catalysts were characterized by specific surface areas (SBET) and X-ray diffraction (XRD) methods. The experimental results showed that NO conversion changed significantly with the different V2O5 loading and calcination temperature. With the V2O5 loading increasing from 0 to 10 wt%, NO conversion increased significantly, but decreased at higher loading. The optimum calcination temperature was 400°C. The best catalyst yielded above 80% NO conversion in the reaction temperature range of 160°C–300°C. The formation of CeVO4 on the surface of catalysts caused the decrease of redox ability. 相似文献
Three different types of soil solution samplers (two ceramic cups and PTFE) were tested in the laboratory to validate their use for collecting soil‐water samples and for monitoring the chemical composition of soil solutions. Interactions between porous materials and chemical solutions were examined under different experimental conditions for several major cations (Ca2+, Mg2+, Na+ and K+) and anions (HCO‐3, NO‐3, SO42‐ and Cl‐) and for several minor ions (NH+4, NO‐4, PO43‐and B). The results show that ceramic cups are not inert for bicarbonate, calcium and phosphate ions. Their use is only valid for a limited number of ions such as chloride and nitrate which, however, are the most studied ions in field experiments. PTFE cups have less restrictions although their use in measuring sulphates, phosphates and ammonium presents some problems. Choosing the appropriate type of cup depends on the objectives. In any case, laboratory experiments must be performed before installation. 相似文献
The effects of natural zeolite (clinoptilolite, NZ) and synthetic zeolite (Y, SZ) on salinity and the presence of the harmful salts in the soil were compared on Raphanus sativus L. Nine soil treatments were studied: 1 (control), 2 (NaCl), 3 (Na2SO4), 4 (NZ), 5 (SZ), 6 (NZ?+?NaCl), 7 (SZ?+?NaCl), 8 (NZ?+?Na2SO4), and 9 (SZ?+?Na2SO4). Five radish seeds were planted in each pot. Each treatment was repeated 10 times. After 50 days under equal conditions some parameters consisting of the number of leaves (NL), total leaf area (TLA), total fresh weight (TFW), total dry weight (TDW), root fresh weight (RFW), air fresh weight (AFW), root dry weight (RDW) and air dry weight (ADW) were determined. Results showed that adding either NZ or SZ to salinic soil (treatments NZNaCl, NZNa2SO4, SZNaCl and SZNa2SO4) increased AFW, TFW and TDW. Using both NZ and SZ in normal soil increased the weight of plants by developing AFW. Further NZ was more effective on soil with NaCl than SZ. 相似文献
White lupin is an annual crop that has been used for phytostabilization of acidified multicontaminated (heavy metals and As)
soils from the Aznalcóllar spill-affected area, Southern Spain. One of the most important factors for successful phytostabilization
is monitoring the pollutant bioavailability in the soil. The aim of this work was to determine the best-suited method for
assessing the bioavailability of heavy metals together with As in the Aznalcóllar spill-affected area, by means of a systematic
comparison between different extraction methods (Ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA), CaCl2, NaNO3, BCR, (NH4)2SO4 and rhizo). Both AB-DTPA and the first step of the BCR method were found to be unsuitable for assessing the bioavailability of heavy
metals and As to plants growing in acidic soils. However, CaCl2-extractable As, Cu, and Zn and NaNO3-extractable As and Zn were well correlated with their concentrations in plant organs. Rhizo and (NH4)2SO4, with the highest determination coefficients, were the most recommended simple extraction methods to assess the bioavailability
of As, Cu, Fe, Mn, and Zn in acidified multicontaminated soils using white lupin as an excluder model plant. 相似文献
Porous carbon material facilitates the reaction SO2 + O2 + H2O → H2SO4 in coal-burned flue gas for sulfur resources recovery at mild conditions. It draws a long-term mystery on its heterogeneous catalysis due to the complicated synergic effect between its microstructure and chemical components. To decouple the effects of geometric structure from chemical components, classical molecular dynamics method was used to investigate the static and dynamic characteristics of the reactants (H2O, SO2 and O2) in the confined space truncated by double-layer graphene (DLG). Strong adsorption of SO2 and O2 by the DLG was observed, which results in the filling of the solute molecules into the interior of the DLG and the depletion of H2O. This effect mainly results from the different affinity of the DLG to the species and can be tuned by the separation of the two graphene layers. Such dimension dependence of the static and dynamic properties like distribution profile, molecular cluster, hydrogen bond and diffusion coefficient were also studied. The conclusions drawn in this work could be helpful to the further understanding of the underlying reaction mechanism of desulfurization process in porous carbon materials and other applications of carbon-based catalysts. 相似文献
The degradation of camphor using titanium/ruthenium dioxide (TiO2/RuO2; 70:30) electrodes was investigated in a photoelectrochemical thin-film reactor under near UV light irradiation. Two different
electrolytes (Na2SO4 and NaCl) were used in this work. Camphor degradation was monitored by solvent extraction methods and gas chromatography
(GC) analysis. Comparative studies between photoelectrochemical, electrochemical, photolytic, and heterogeneous photocatalytical
process were carried out. When NaCl was used, the degradation efficiency of camphor was improved, probably on account of electrochemical
generation of active chlorine species and their photochemical conversion to chlorine radicals. Under these conditions camphor
was completely mineralized at reaction times of 30 min. 相似文献
Numerous studies had focused on the association between air pollution and health outcomes in recent years. However, little evidence is available on associations between air pollutants and premature rupture of membranes (PROM). Therefore, we performed time-series analysis to evaluate the association between PROM and air pollution. The daily average concentrations of PM2.5, SO2 and NO2 were 54.58 μg/m3, 13.06 μg/m3 and 46.09 μg/m3, respectively, and daily maximum 8-h average O3 concentration was 95.67 μg/m3. The strongest effects of SO2, NO2 and O3 were found in lag4, lag06 and lag09, and an increase of 10 μg/m3 in SO2, NO2 and O3 was corresponding to increase in incidence of PROM of 8.74% (95% CI 2.12–15.79%), 3.09% (95% CI 0.64–5.59%) and 1.68% (95% CI 0.28–3.09%), respectively. There were no significant effects of PM2.5 on PROM. Season-specific analyses found that the effects of PM2.5, SO2 and O3 on PROM were more obvious in cold season, but the statistically significant effect of NO2 was observed in warm season. We also found the modifying effects by maternal age on PROM, and we found that the effects of SO2 and NO2 on PROM were higher among younger mothers (<?35 years) than advanced age mothers (≥?35 years); however,?≥?35 years group were more vulnerable to O3 than?<?35 years group. This study indicates that air pollution exposure is an important risk factor for PROM and we wish this study could provide evidence to local government to take rigid approaches to control emissions of air pollutants.
Pulmonary mast cell degranulation is a well-characterized response to diesel exhaust exposure. A primary constituent of fossil fuel combustion is sulfur dioxide (SO2). SO2 was shown to induce mast cell degranulation in an immortalized cell line secondary to induction of intracellular oxidative stress; however, it is not known whether SO2-induced oxidative stress directly triggers the activation of cardiac mast cells. Accordingly, this study sought to determine whether Na2SO3 induces degranulation of cardiac mast cells, and furthermore whether cardiac mast cell activation may be prevented by inhibition of oxidative stress. To this end, cardiac mast cells were isolated from epicardial surface of the heart and incubated with increasing concentrations of Na2SO3 (0, 0.5, or 5 mM). Antioxidant compounds targeting different mechanisms of free radical generation, including ebselen, diphenyleneiodonium (DPI), or α-tocopherol, were incubated with 5 mM of Na2SO3 in order to determine their efficacy in preventing mast cell degranulation. Na2SO3 induced a significant concentration-dependent histamine release from cardiac mast cells ranging from 8.87% to 18.86%, which was prevented by ebselen. No effect was observed with DPI and α-tocopherol under these conditions. In conclusion, these findings indicate that SO2 is capable of producing cardiac mast cell degranulation in vitro; however, the variable effectiveness of the three antioxidants evaluated is indicative of a multifactorial mechanism mediating SO2-induced cardiac mast cell degranulation. The particular effectiveness of ebselen in preventing mast cell degranulation may be related to its multiple mechanisms of preventing oxidative stress. 相似文献
An attempt has been made to present the data relating to full scale application of evaporation‐incineration technology for containment of wastewater emanating from H‐acid (mono sodium salt of 1 amino‐8‐hydroxynapthalene 3,6‐disulphonic acid) production with recourse to zero wastewater discharge. The wastewater is acidic with high concentrations of COD and total dissolved salts and BOD/COD ratio of 0.11. NOx, SOx, SPM and CO from stack emissions are within the standards stipulated by the statutory bodies. 相似文献
Daily PM2.5, PM2.5–10 and TSP have been collected by Universal and PS‐1 sampler simultaneously at a site within Taichung between February and March 1999. The filters were analyzed by atomic absorption spectrophotometry for the elemental analysis of Ca, Fe, Mn, Pb, Cu, Zn and Cr. In general, the concentration of these metallic elements are higher in fine particles than in coarse particles. On average, PM10 accounted for 67% of the TSP at daytime, while at nighttime PM10 accounted for only 44% of the TSP. For PM2.5, PM2.5–10 and TSP concentrations, there were no significant differences between day and night period. The averaged concentrations of metallic elements in PM2.5 at daytime were all higher than that at nighttime. Ca, Fe and Zn have large and variable PM2.5 concentrations at both daytime and nighttime. For the daytime Zn and Pb account for the largest portion of the heavy metal elements. For the nighttime, Zn and Cr make the largest portion of the heavy metal elements. The concentrations of Mn were higher on fine particulates. The trace metals Cu and Cr in Taichung are probably due to particulates emitted by Taichung Fire Power Plants transported into the sampling area by the prevailing northwesterly wind. 相似文献