Emission Standards For Air Pollutants Research Articles

Process system simulation of coupled pyrolysis disposal of domestic waste in coal-fired boiler and pilot study on dioxin emission

The disposal of domestic waste has become a critical and costly problem. Incineration for power generation is currently the primary domestic waste treatment method. Due to its small capacity and low parameters, domestic waste incineration is generally uneconomical and associated with significant risks to public health and environmental safety. The coal-fired power plants are generally characterized with huge capacity and high parameters, consequently resulting in much higher power generation efficiency with lower cost emission control. This indicates that co-disposal of domestic waste using existing coal-fired units may significantly reduce its treatment costs associated with the improvement of utilization efficiency and environmental risks. Base on this, a highly-flexible coupling of pyrolysis-pretreated solid waste in pulverized coal furnace is proposed in this paper, and field tests and numerical simulations have been carried out separately according to the process route. The results show that after coupling with pulverized coal boiler, domestic waste pyrolysis pretreatment unit can operate self-sustainably without external energy supply and the process route is feasible. Furthermore, the coupled co-combustion of domestic waste pyrolysis products and pulverized coal was simulated by fluent software. Compared with pure pulverized coal combustion, mixing domestic waste pyrolysis products can promote pulverized coal combustion in the furnace and help the pulverized coal boiler to burn stably at low load. The emission concentrations of NOx at the outlet of the furnace are 530 ppm, 545 ppm and 478 ppm respectively when pulverized coal is burned purely and mixed with 100 t/d and 200 t/d domestic waste. the NOx emissions could be reduced to a certain extent by mixing domestic waste. On the basis of previous research, the field test of coupling disposal of domestic waste by pulverized coal boiler was carried out, and the dioxin concentration in flue gas and fly ash was tested emphatically. The results show that when the amount of waste is less than 4 %, the concentration of dioxin in flue gas is 0.0107 ng TEQ/m3, which meets the latest emission standard of air pollutants in Shanghai coal-fired sludge power plant of 0.02 ng TEQ/m3. Low proportion of domestic waste will not increase the production and emission of dioxins. These studies show that it is feasible and promising to treat municipal solid waste with low coupling ratio by using existing coal-fired units.

Non-Thermal Plasma Technology for Further Purification of Flue Gas in the Resource Utilization Process of Waste Mercury Catalyst: A Case Study in Xinjiang, China

This study aims to advance the recycling of mercury-containing waste and promote sustainable development within the polyvinyl chloride (PVC) industry. Our innovative system integrates pre-treatment technology (spraying potassium permanganate and demisting and dust removal) with efficient non-thermal plasma oxidation, resulting in excellent treatment efficiency, low cost, and simple operation. With a processing capacity of 3000 m3/h, the concentration of mercury emissions in flue gas can achieve the target of <0.01 mg/m3, boasting a removal efficiency exceeding 98%, which satisfies the standard “Emission standard of air pollutants for industrial kiln and furnace” (GB 9078-1996). Our results can provide technical support for the comprehensive purification of mercury-containing flue gas during the resource recovery process from mercury-containing waste. The application of our system can contribute to reducing mercury emissions in the PVC industry, lowering occupational exposure risks for workers, and promoting China’s better compliance with “the Minamata Convention on Mercury”.

A novel one-step wet denitration method by hydrodynamic cavitation and chlorine dioxide

Ships have brought substantial economic benefits, and meanwhile, they release exhaust gases, including plenty of nitrogen oxides (NOx). Increasingly stringent air pollutant emission standards (e.g., MARPOL) for ships have been established at home and abroad to reduce the pollution of NOx. In this paper, a promising technology for removing NOx from ship exhaust by hydrodynamic cavitation (HC) and chlorine dioxide (ClO2) was proposed. The mechanism of HC promoting denitration was discussed. The various influencing factors of the HC enhancing ClO2 circulation denitration, such as the pressure difference (∆P) between the inlet and outlet of the HC reactor, solution temperature (10.0 – 55.0 ℃), NO initial concentration (500–1000 ppm), gas flow rate (1.0–1.6 L/min), solution pH (3.00 – 11.00), and ClO2 concentration (0.001–0.100 mmol/L) on denitration effect were studied in the experiments, in which the optimal conditions were established. On the basis of the results of HC enhancing ClO2 circulation denitration, HC enhancing ClO2 non-circulation denitration experiments were carried out. The results showed that the NO and NOx removal efficiencies reached 93% and 90%. We also measured the final anions in solutions after denitration by ion chromatography and discussed the reaction pathways.

Feasibility study on the formulation of air non-point source emission standard in China

Emission standards of air pollutants are the legal basis for environmental management. Compared with the point source emission, the non-point source pollution of the air is mostly unorganized, which has the characteristics of large scope, random, hidden and difficult to control. It is difficult to take effective measures to control pollution, and the emission standard of atmospheric non-point source pollution is basically blank. In order to design a scientific and reasonable standard system, we have summarized the characteristics of atmospheric non-point source pollution, summarized the difficulties that dates back to the atmospheric non-point source emission standard in China, analyses the problems in the process of atmospheric non-point source emissions standards, put forward the principles for atmospheric non-point source emission standards. Finally we present the feasibility of typical atmospheric non-point source emission standards in China.

Selective hydrophobic decoration of metal-organic framework for effective removal of ppb-level CH3I from humid streams

Recently, effective removal of toxic gases from humid streams has been an urgent global issue, especially at low concentrations due to increase in air pollutant emission standards. In this work, a series of selectively modified MIL-101 s was prepared by blocking coordinatively unsaturated sites (CUSs) with hydrophobic amine compounds containing –F or long alkyl groups. The nucleophilic quinuclidine (QN) was consecutively encapsulated into the pores of hydrophobic MIL-101 s to remove CH3I by alkylation. The direct correlation between the hydrophobic index (HI) of adsorbents and the CH3I removal performance in a humid environment was systematically investigated for the first time by progressively blocking the CUSs with different amounts of hydrophobic amines including 4-(trifluoromethyl) benzylamine (TFM-BA). Among them, QN@MIL-101-TFM-BA exhibited the unprecedented removal efficiency exceeding 99.999% at 303 K and RH 95% for 11 days, outperforming over 280 times compared to the conventional adsorbents. The strong affinity between QN and CH3I is thoroughly investigated by X-ray photoelectron spectroscopy (XPS) and elemental mapping. MIL-101-TFM-BA showed outstanding removal performance even for HCHO, proving the versatile use of the prepared hydrophobic metal–organic frameworks adsorbents in realistic condition.

A Study on Changes in Air Pollutant Generation Trends after Integrated Permit in Coal-fired Power Plants

Objectives : The Environmental Pollution Facility Act was implemented to effectively reduce pollutants that could be generated in the business establishment, centering on emission facilities, from the Media Act, which had been managed in the aspect of follow-up management. Accordingly, the change in the generation of air pollutants after the integrated permit in coal-fired power plants was examined.Methods : Air pollutant emission standards were analyzed for business establishment that use coal, a solid fuel, as fuel among power plants that have completed integrated permits.Results and Discussion : The standards suggested by the Act on the Integrated Control of Pollutant-Discharging Facilities have numerically higher values than the existing Clean Air Conservation Act Standards, but there is a limit to evaluating only with simple standards because permit standards are given through emission impact analysis. As a result of a comparison through the emission impact analysis, it was found that 10 plants were given stricter permit standards for sulfur oxides and nitrogen oxides by 22% and for dust by 10% at 8 business establishment.Conclusion : The level of pollution on the surrounding location status is evaluated, and permission standards are granted. It was confirmed that the emission impact analysis method under the Act On The Integrated Control of Pollutant-Discharging Facilities can be applied as a more strictly manageable means than the existing standards under the Clean Air Conservation Act.

Emissions of BTEXs, NMHC, PAHs, and PCDD/Fs from Co-processing of Oil-based Drilling Cuttings in Brick Kilns

Oil-based drilling cuttings (OBDC) produced from shale gas development is a hazardous waste that have high calorific values and should be disposed of properly. Burning bricks with OBDC is a promising co-disposal method; however, organic pollutants emitted during this process have not received sufficient attention. In this study, the composition and combustion characteristics of OBDC were determined, and the emissions of typical organic pollutants when burning bricks with the addition of OBDC were investigated; these included benzene series compounds (BTEXs), non-methane total hydrocarbons (NMHC), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). The results showed that OBDC comprised large amounts of alkanes and aromatic hydrocarbons, and combusted mainly in the temperature range of 145–450 °C with an ignition temperature of 145 °C. The co-processing 10% OBDC increased the concentrations of toluene, NMHC, and PAHs in the flue gases by ∼1000%, ∼500%, and 200%, respectively, compared to the control experiment; however, their emission concentrations were within the limits set by the Integrated emission standards of air pollutants of Chongqing. It is worth noting that 26.443 ng/Nm3 PCDD/Fs with a total toxicity of 0.709 ng I-TEQ/Nm3 was generated from the co-processing 10% OBDC, which was ascribed to the high content of chlorine and aromatic hydrocarbons in the OBDC-promoted PCDD/Fs formed during the burning and cooling processes. Though PCDD/Fs in flue gas exceeded the 0.5 ng I-TEQ/Nm3 limit prescribed in the Pollution control standard for hazardous wastes incineration of China, the realistic emission of PCDD/Fs is expected to meet with this emission limit after desulfurization treatment as PCDD/Fs can be absorbed by gypsum. It is recommended that a lower amount of OBDC is added to reduce PCDD/F formation at the source and to take more efficient air pollution control system in order to reach a stricter emission limit of 0.1 ng I-TEQ/Nm3 in EU and USA. Cycling flue gas may also be an effective method to reduce other organic pollutants. Under these conditions, co-processing OBDC in brick kilns can be achieved without serious environmental pollution, making it a potential method for disposal and utilization.

Characteristics and control measures of odor emissions from crematoriums in Beijing, China

The promulgation and implementation of the national and Beijing municipal standards for air pollutants emitted from crematoriums has effectively alleviated the problem of “black smoke” in crematoriums, but noticeable odor in crematoriums remains. We determined the level of odor emissions in crematoriums by monitoring the odor concentrations of cremators, incinerators, and cremation workshops in five crematoriums in Beijing. Subsequently, we analyzed the major contributing factors to the odor level and proposed control measures. A high odor concentration in crematoriums was observed; two different mechanisms were proposed to explain this finding. First, poor ventilation conditions in workshops and inadequate airtightness of equipment resulted in dimensionless concentrations of unorganized odor emissions in the workshops ranging from 97 to 732, with an average of 504, which is much higher than the standard level of 20. Second, the postprocessing facilities used in cremation sites produce poor odor removal, which, coupled with fuel usage and unregulated operations, led to high concentrations of organized odor emissions ranging from 231 to 1303 (910 on average) for cremators and incinerators. The odor emissions of cremators and incinerators meet the Integrated Emission Standards of Air Pollutants (DB11-501-2017), which are suitable for industries containing industrial kilns but not for crematoriums. The odor emissions in crematoriums are lower than those emitted from industries, such as fiber manufacturing and activated carbon processing. However, the unique geographical locations of crematoriums, high population density, and high exposure risk to local residents necessitate strengthening the management and control of odor emissions from crematoriums. To further address the problem of odor emissions from crematoriums in Beijing, further clarification and tightening of industry standards for the concentration limits of organized and unorganized odor emissions is recommended. Crematoriums will thus be prompted to increase odor control in workshops and adopt and improve deodorization facilities, including the installation and application of treatment facilities, such as adsorption and biological control.

Thermo-Chemical Treatment for Carcass Disposal and the Application of Treated Carcass as Compost

A mechanized thermo-chemical treatment system was developed to treat the undecomposed carcass and remediate livestock burial sites. Animal carcasses were thus processed via crushing, mixing, and treatment with quicklime treatment, heat treatment (200–500 °C), and mixing with sawdust. The machinery was applied to two sites where 16,000 chickens and 418 pigs had previously been buried in fiber-reinforced plastic storage bins. No dioxins were detected in the gas discharged during processing, and the concentration of total volatile organic compound, toluene, ethylbenzene, xylene, and styrene were 430.3, 139.0, 18.3, 21.4, and 10.4 μg/m3, respectively, which were below the air pollutant emission standards issued by the Korean Ministry of Environment. Korean standards stipulating the use of treated carcasses as compost (C, N, and P content, heavy metal concentration, Escherichia coli, and Salmonella) were met, but the germination index value was less than 70, not satisfying the criteria. Plant height, leaf length, leaf width, and dry weight of lettuce grown in soil amended with treated carcass product were significantly lower than those grown in low nutrient soil due to the poor germination index of the treated carcass. These results indicate that a composting process is required before the use of the treated carcass as a fertilizer. The addition of zeolite retarded the elution of ammonia from the carcasses and its efficiency was about 87.9%. It is expected that the mechanized thermo-chemical treatment process developed in this study could replace other technologies for the remediation of livestock burial sites.

Study on Fuel Specificity and Harmful Air Pollutants Factor of Agglomerated Wood Charcoal

This study selected three types of agglomerated wood charcoal (Agglomerated wood charcoal with charcoal powder, Carbonized wood briquette, Ignition-type of perforated charcoal) that are in circulation in Korea among fuel-type wood products and analyzed the fuel characteristics, harmful substance content, and emissions of air pollutants generated by combustion. The first results showed that charcoal-grilled carbon, which is the raw material of charcoal, produced higher CO than saw-billed carbon. The second result is that the emission standards of air pollutants generated by the combustion of molded wood coal are not up to the emission standards of nitrogen oxides and sulfur oxides in the entire product, compared with the emission criteria of the atmospheric environment preservation method (based on 2019, carbon monoxide: 200 ppm, nitrogen oxides, 150 ppm sulfur oxides: 100 ppm), but the carbon dioxide moulding and carbon dioxide levels were not up. Based on the analysis of combustion gas generated during combustion derived from this study, future research is needed for comparing with the emission standards of pellets, which are wood products for fuel, among the existing biomass burning standards and for reducing carbon monoxide generated during incomplete combustion of agglomerated wood charcoal.

Emission Status and Standards of Volatile Organic Compounds from Chinese and Foreign Bulk Petroleum Terminals

Chinese emission standard of air pollutants for bulk gasoline terminals (GB 20950-2007) stipulate standards for vapor emissions during gasoline storage and receiving in bulk gasoline terminals. However, the standards are not applicable to crude oil, aviation kerosene, naphtha, and other kinds of oil. We assess emission standards or directives for vapor processing equipment in terminals in the United States (US) and European Union (EU), and analyze the emission status of vapor processing equipment in three typical cities in China. We further propose revisions to GB 20950-2007. We made the following observations. ① US and EU standards include scope not only for gasoline, but also crude oil and other organic liquids. ② The emission limits of non-methane hydrocarbons defined in GB 20950-2007 are i) 0.5, 1.8, and 8.9 times those defined in Subpart XX, Subpart R, and Subpart Y in the US federal regulations, ii) 1.8 and 3.1 times those defined in Rule 462 and Rule 1142 in southern California law, and iii) 0.7 and 500 times those defined in EU and German directives, respectively. The vapor leakage limit for general areas of China is 0.5 times that defined in Subpart XX of the US standards, whereas the limits for some other specific areas of China, are 0.7 and 2.0 times those defined by Rule 462 and Rule 1142 in southern California law. ③ The numerical range of P5th-P95th of NMHC emissions from the inlet and outlet of vapor processing equipment in three typical cities of China were 115-811 g·m-3 and 0.1-20.0 g·m-3, respectively. The proportion of NMHC emission concentrations less than or equal to 10 g·m-3 at the outlet of vapor processing equipment was>85%. We suggest that the scope of application of GB 20950-2007 should be extended to crude oil, gasoline (including ethanol gasoline), aviation kerosene, and naphtha. The emission concentration limit of NMHC from vapor processing equipment should be tighten from 25 g·m-3 to 20 g·m-3, with a emission limit of 10 g·m-3 added for particular cases.

Current situation and prospect of air pollutant emission standards for ships

The emission limits and measurement methods of pollutants from ship engines (China’s first and second stages) implemented on July 1, 2018 (GB15097-2016) marked the initial establishment of China’s ship air pollutant emission standard system. Based on the study of the development of China’s ship air pollutant emission standards, this paper analyzes the applicable ships and the types of pollutants controlled by China’s ship air pollutant emission standards system, and puts forward some suggestions to improve China’s ship air pollutant emission standards system.

An overview of the development history and technical progress of China’s coal-fired power industry

As the main power source of China, coal-fired power industry has achieved a great progress in installed capacity, manufacturing technologies, thermal efficiency, as well as pollutant control during the past century. With the fast development of renewable energies, coal-fired power industry is experiencing a strategic transformation. To specify the development of coal-fired power industry, its development history is reviewed and the technical progresses on aspects of thermal efficiency, pollutants control and peaking shaving capacity are discussed. It is concluded that the role of China’s coal-fired power source would be transformed from the dominant position to a base position in power source structure. Considering the sustainable development of coal-fired power industry in energy conservation, emission control, and utilization of renewable energies, it is suggested that the national average thermal efficiency should be improved by continual up-gradation of units by using advanced technologies and eliminating outdated capacity. Moreover, the emission standard of air pollutants should not be stricter any more in coal-fired power industry. Furthermore, the huge amount of combined heat and power (CHP) coal-fired units should be operated in a decoupled way, so as to release more than 350 GW regulation capacity for the grid to accept more renewable energy power.

Technology-forcing or Technology-following? -Evolution of air pollutant emission standards in the United States-

Technology-forcing or Technology-following? -Evolution of air pollutant emission standards in the United States-

Clean synthesis gas production from municipal solid waste via catalytic gasification and reforming technology

In this paper, the municipal solid waste was used as raw material to produce clean synthesis gas via catalytic gasification and reforming technology and gas purification unit. Nickel based catalysts with different Ce content were prepared by impregnation, then the effects of operating parameters including the oxygen addition, steam addition and Ni-based catalysts’ component on synthesis gas generation characteristics were studied. The results indicated that the increasing of oxygen injection and steam supply can improve the carbon conversion efficiency and cold gas efficiency. The addition of metal additives in Ni-based catalyst can promote the decomposition of tar and increase synthesis gas yield. At the temperature of 850 °C, equivalence ratio = 0.06, steam/carbon ratio = 3.6, the clean synthesis gas was produced with hydrogen concentration of 36.78 vol.% and carbon monoxide concentration of 15.29 vol.% via catalytic gasification and reforming process. The cold gas efficiency and carbon conversion rate were 70.17% and 87.17%, respectively. The yield of syngas was up to 0.679 m3/kg and the tar content was reduced to 17.76 g/Nm3. After the purification of the gas purification unit, the phenolic compounds were completely removed. The content of SO2 and NOX gas can meet the emission standard of air pollutants, and the average removal efficiency of heavy metal Cr, Pb, Zn, Cu and Hg was above 50%.

Advanced exergoenvironmental evaluation for a coal-fired power plant of near-zero air pollutant emission

Advanced exergy and exergoenvironmental analyses based on life cycle assessment (LCA) are conducted to an SCPP with and without dust, SO2 and NOX mitigation controls. The analyses show that environmental impacts of components are mainly caused by exergy destruction while combustion chamber (COM) still has great potential to reduce pollutant environmental impact reduced by 99.5% by near-zero air pollutant emission standards. Avoidable environmental impact within each component is endogenous other than most regenerative feedwater heaters. COM has the largest environmental impact of exergy destruction but lower avoidable part compared with superheat transfer (SH) including boiling process. Reheat transfer (RH) shows similar avoidable environmental impact but less exergy destruction in contrast with COM. Turbines play well in exergy efficiency and over 50% of environmental impact within intermediate-pressure turbine (IP) can be avoided. Air preheater (APH) displays a higher avoidable environmental impact than condenser (CND) albeit lower exergy destruction. Pumps and fans have small environmental impacts with over 45% can be avoided. Most environmental impact related to pollutant formation is avoidable and endogenous except for wet flue gas desulfurization (WFGD) which imposes a negative environmental impact on other components. The specific environmental impact of electricity generation is higher than European.

Current Status and Atmospheric Mercury Emissions Associated with Large-Scale Gold Smelting Industry in China

ABSTRACTMercury, being bound with metal concentrate, is released to atmosphere in the smelting process, and has adverse effects on surrounding ambient air quality and public health. In this study, based on literature and field investigations, onsite measurements of mercury emissions to the atmosphere for four large-scale gold smelters were estimated. Almost all of the atmospheric mercury released from the roasting pretreatment process occurred before acid plants. All the concentrations of mercury emitted from the four tested gold smelters were much lower than the emission standard of air pollutants for GB 9078–1996 Grade II level areas of 1000 µg m–3. The speciation of Hgp took up the largest proportions for the total mercury concentrations. Because of using high mercury oxidation efficiency of double-conversion double absorption (DCDA) technology, the proportions of Hg2+ in the exhaust flue gas was higher than Hg0. Average emission factors of atmospheric mercury for these four tested gold smelters were calculated to be 1.7 kg of Hg per ton gold produced, and the national total amount of mercury emitted from large-scale gold smelting industry in the year of 2014 was estimated to 639.9 kg. However, mercury emission factors obtained from present study were much lower than that in previous research. Thus, with the exact emission factor obtaining from more specific field-test data and the detailed activity data information about gold smelting industry, an accurate inventory of mercury emissions to the atmosphere from large-scale gold smelters in China can be updated in the future.

Low-Temperature Selective Catalytic Reduction with NH<sub>3</sub> over MnO<sub>x</sub>-CeO<sub>2</sub> Catalysts Supported on Nano Tetragonal Zirconia

The MnOx-CeO2/t-ZrO2 catalyst was prepared by impregnation with nano t-ZrO2 as the support. The influence of active component and reaction temperature on denitration performance of catalyst was investigated. The results showed that denitration efficiency improved as active component increased and reaction temperature rose. The denitration efficiency of 2.5% MnOx-CeO2/t-ZrO2 at 100°C was 68.1% while 15% MnOx-CeO2/t-ZrO2 was 97.4%. The results of XRD, BET and H2-TPR showed that surface structure of loaded catalyst was good for oxidation-reduction and denigration. NH3-TPD test demonstrated that NH3 was mainly adsorbed at Lewis acid sites on the surface of catalysts and became coordination NH3. Intermediate product NH2NO generated from reactions between coordination NH3 and NO which finally changed into N2 and H2O.NOx are potentially harmful to humans as a kind of primary pollutants. And NOx are the main cause of many environment problems, such as acid rain, surface ozone pollution and Particulate Matter 2.5[1]. The emission of NOx was 2337.8 tons in China in 2011 and that was 2275.4 tons[2]. The environmental situation is grim although the emission of NOx had begun decreasing. Emission standard of air pollutants for thermal power plants which came into effect on January 1, 2012 require the emission concentration of NOx under 100mg·m-3. The task is arduous.Selective catalytic reduction (SCR) of NOx with NH3 is the most promising method to remove NOx and catalysts with high activity play a decisive part in low temperature SCR technology. Many researches about metal oxide as SCR catalyst support have been reported recently, such as TiO2[3], Al2O3[4], activated carbon[5] and molecular sieve[6]. Zirconium oxide has attracted considerable attention recently as a catalyst support because of its special characteristics. Takahashi et al.[7] investigated the influence of the various compositions of TiO2 and ZrO2 on the NOx removal ability over a sulfur-treated NSR catalyst and came to a conclusion that ZrO2 support suppressed the solid phase reaction with potassium. Reddy et al.[8, 9] investigated structural characteristics of nanosized ceria-silica, ceria-titania, and ceria-zirconia mixed oxide catalysts and found these mixed oxides exhibit better redox properties than pure CeO2. YAN Zhi-yong et al.[10] reported that the existence of ZrO2 in catalysts can raise its specific area and enhance the dispersion of CeO2 on catalysts which results in high activity of the catalysts. CeO2/TiO2-ZrO2 catalyst has strong tolerance to water vapor and sulfur dioxide.It is well known that ZrO2 exists mainly in three polymorphs with monoclinic (m-ZrO2), tetragonal (t-ZrO2) and (c-ZrO2) cubic structures[11]. ZrO2 polymorphs have different amphoteric character of its surface hydroxyl groups. The crystalline phase of ZrO2 has a great effect on the structure, activity and selectivity of catalysts. Therefore, it is valuable to investigate the effects of nanocrystalline zirconia polymorphs on catalytic properties of MnOx-CeO2/t-ZrO2 Catalysts which few researchers have concerned about. In this study, we try to investigate catalytic activity and microstructure of SCR catalysts with manganese oxide and cerium oxide supported on t-ZrO2.

Assessment of air quality benefits from the national pollution control policy of thermal power plants in China: A numerical simulation

In 2010, an emission inventory of air pollutants in China was created using the Chinese Bulletin of the Environment, the INTEX-B program, the First National Pollution Source Census, the National Generator Set Manual, and domestic and international research studies. Two emission scenarios, the standard failed emission scenario (S1) and the standard successful emission scenario (S2), were constructed based upon the Instructions for the Preparation of Emission Standards for Air Pollutants from Thermal Power Plants (second draft). The Fifth-Generation NCAR/Penn State Mesoscale Model (MM5) and the U.S. EPA Models-3 Community Multiscale Air Quality (CMAQ) model were applied to China to study the air quality benefits from Emission Standards for Air Pollutants from Thermal Power Plants GB13223-2011. The performance of MM5 and CMAQ was evaluated with meteorological data from Global Surface Data from the National Climatic Data Center (NCDC) and the daily Air Pollution Index (API) reported by Chinese local governments. The results showed that the implementation of the new standards could reduce the concentration of air pollutants and acid deposition in China by varying degrees. The new standards could reduce NO2 pollution in China. By 2020, for the scenario S2, the area with an NO2 concentration higher than the second-level emission standard, and the average NO2 concentration in 31 selected provinces would be reduced by 55.2% and 24.3%, respectively. The new standards could further reduce the concentration of declining SO2 in China. By 2020, for S2, the area with an SO2 concentration higher than the second-level emission standard and the average SO2 concentration in the 31 selected provinces would be reduced by 40.0% and 31.6%, respectively. The new standards could also reduce PM2.5 pollution in China. By 2020, for S2, the area with a PM2.5 concentration higher than the second-level emission standard and the average concentration of PM2.5 in the 31 selected provinces would be reduced by 17.2% and 14.7%, respectively. The new standard could reduce nitrogen deposition pollution in China. By 2020, for S2, the area with a nitrogen deposition concentration >2.0 tons·km−2 and the total nitrogen deposition in China would be reduced by 28.6% and 16.8%, respectively. The new standards could reduce sulfur deposition pollution in China. By 2020, for S2, the area with a sulfur deposition >1.5 tons·km−2 and the total sulfur deposition in China would be reduced by 55.3% and 21.0%, respectively.

Risk Analysis of Environmental Pollution by Secondary Hydrogen Chloride from Leakage of Phosphorus Trichloride

This study aims to analyse the influence of the pollution of hydrogen chloride which is the side effect of the leakage accident of a 50m3 phosphorus trichloride tank. When the leakage source intensity is 1.06kg/s with the leakage time of 30 minutes, and the distance is about 2700m away from the highest allowable concentration (0.05mg/m3) in air of residential areas, which goes beyond about the distance of 700m over the "Comprehensive emission standard of air pollutants" (GB16297-1996) table 2 (100mg/m3, new sources of pollution emission limits), however, the mean value of hydrogen chloride concentration beyond 400m is less than the that of IDLH (immediately dangerous to life or health concentration), and no half lethal concentration (LC50) appears. The scope and extent of pollution can be significantly reduced by timely using fire water to eliminate smoke to change hydrogen chloride into hydrochloric acid fog and make them drop in a lower position.