A monitoring-modeling approach to SO42 − and NO3− secondary conversion ratio estimation during haze periods in Beijing, China

SO_4~(2-) and NO_3~- are important chemical components of fine particulate matter(PM_(2.5)),especially during haze periods.This study selected two haze episodes in Beijing,China with similar meteorological conditions.A monitoring-modeling approach was developed to estimate the secondary conversion ratios of sulfur and nitrogen based on monitored and simulated concentrations.Measurements showed that in Episode 1(24th–25th October,2014),the concentrations(proportions)of SO_4~(2-) and NO_3~- reached 35.1μg/m~3(14.9%) and 55.0μg/m~3(22.9%),while they reached 14.4μg/m~3(9.3%) and 59.1μg/m~3(38.1%)in Episode 2(26th–27th October,2017).A modeling system was applied to apportion Beijing's SO_4~(2-) and NO_3~- in primary and secondary SO_4~(2-)/NO_3~- emitted from local and regional sources.Thus,secondary conversion contributions considering the local and regional level were defined.The former primarily focused on Beijing atmospheric oxidation ability and the latter mainly considered the existence form of Beijing SO_4~(2-)/NO_3~- under the regional transport impacts.Finally,secondary oxidation ratios were estimated through combining secondary conversion contribution coefficients for simulated and monitored concentrations.At regional level,sulfur oxidation ratios in polluted(clean)days during two sampling periods were0.57–0.72(0.07–0.52)and 0.74–0.80(0.08–0.61),nitrogen oxidation ratios were 0.20–0.29(0.05–0.15)and 0.34–0.38(0.02–0.29),indicating that atmospheric oxidation was enhanced when considering regional transport through 2014–2017.At the local level,sulfur oxidation ratios were 0.66–0.71(0.04–0.48)in haze(clean)days,while nitrogen oxidation ratios were0.16–0.29(0.02–0.16).The atmospheric oxidation ability markedly increased in PM_(2.5)pollution days,but changed only slightly between the two periods.     

济南市环境、社会、经济协调发展评价

建立了济南市城市环境、社会、经济协调评价指标体系,采用多目标二级决策方法对各指标的权重进行分配;在已有协调度计算方法的基础上,构建了协调度的计算公式;并运用该指标体系和协调度公式对济南市环境、社会经济协调状况进行评判。结果表明济南市的环境、社会经济之间发展是不平衡的,协调状况为中级协调水平;环境综合指数较低,表明环境的建设滞后于社会经济的发展。     

餐饮废物综合利用的探讨

餐饮业残汤剩菜含有较高的脂肪、蛋白质 ,采取加热烘干工艺进行处理 ,做为饲料粗原料 ,然后进行精加工 ,不但解决了环境污染问题 ,同时为饲料原料开发寻找新的来源。餐饮业残汤剩菜的废油再生也可产生可观的经济效益及社会效益。     

地震发生后环境监测工作的思考

分析了地震发生后,可能发生的火灾、有毒有害物泄漏、水源污染等多种次生灾害,及目前现有的震后环境监测手段,提出针对可能的污染状况,应采取的环境监测措施及方法。     

Effects of relative humidity and PM2.5 chemical compositions on visibility impairment in Chengdu, China

To better understand the potential causes of visibility impairment in autumn and winter in Chengdu, relative humidity(RH), visibility, the concentrations of PM_(2.5) and its chemical components were on-line measured continuously in Chengdu from Nov. 2016 to Jan. 2017.Six obvious haze episodes occurred in Chengdu, with the total time of haze episodes accounted for more than 90% of the total observation period, and higher NO_2 concentrations and RH were related to the high particle concentrations in haze episodes. The visibility decreased in a non-linear tendency under different RH conditions with the increase of PM_(2.5) concentrations, which was more sensitive to RH under lower PM_(2.5) concentrations. The threshold concentration of PM_(2.5) got more smaller with the increase of RH. During the entire observation period, organic matter(OM) was the largest contributor(31.12% to extinction coefficient(bext)), followed by NH_4NO_3 and(NH_4)_2SO_4 with 28.03% and 23.01%, respectively.However, with the visibility impairment from Type I(visibility 10 km) to Type IV(visibility ≤ 2 km), the contribution of OM to bextdecreased from 38.12% to 26.77%, while the contribution of NH_4NO_3 and(NH_4)_2SO_4 to bextincreased from 19.09% and 20.20% to 34.29% and 24.35%, respectively, and NH_4NO_3 became the largest contributor to bextat Type IV. The results showed that OM and NH_4NO_3 were the key components of PM_(2.5) for visibility impairment in Chengdu, indicating that the control of precursors emissions of carbonaceous species and NH_4NO_3 could effectively improve the visibility in Chengdu.     

城市污水二级处理出水用于地下回灌的深度处理技术研究

采用混凝沉降-砂滤-活性炭吸附-消毒工艺,对模拟城市污水处理厂二级处理工艺的SBR中试系统的出水进行了深度处理实验研究。实验结果表明,深度处理后的出水所检测的浊度、pH、COD、NH3-N、细菌总数等5项指标已经达到了《生活饮用水卫生标准》（GB5749—2006）。     

Vertical distributions of wintertime atmospheric nitrogenous compounds and the corresponding OH radicals production in Leshan, southwest China

Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations were operated from 02 to 21 December 2018 in Leshan, southwest China, to measure HONO, NO₂ and aerosol extinction vertical distributions, and these were the first MAX-DOAS measurement results in Sichuan Basin. During the measurement period, characteristic ranges for surface concentration were found to be 0.26–4.58 km^?1 and averaged at 0.93 km^?1 for aerosol extinction, 0.49 to 35.2 ppb and averaged at 4.57 ppb for NO₂ and 0.03 to 7.38 ppb and averaged at 1.05 ppb for HONO. Moreover, vertical profiles of aerosol, NO₂ and HONO were retrieved from MAX-DOAS measurements using the Heidelberg Profile (HEIPRO) algorithm. By analysing the vertical gradients of pollutants and meteorological information, we found that aerosol and HONO are strongly localised, while NO₂ is mainly transmitted from the north direction (city center direction). Nitrogen oxides such as HONO and NO₂ are important for the production of hydroxyl radical (OH) and oxidative capacity in the troposphere. In this study, the averaged value of OH production rate from HONO is about 0.63 ppb/hr and maximum value of ratio between OH production from HONO and from (HONO+O₃) is > 93% before12:00 in Leshan. In addition, combustion emission contributes to 26% for the source of HONO in Leshan, and we found that more NO₂ being converted to HONO under the conditions with high aerosol extinction coefficient and high relative humidity is also a dominant factor for the secondary produce of HONO.     

Role of secondary aerosols in haze formation in summer in the Megacity Beijing

A field experiment from 18 August to 8 September 2006 in Beijing, China, was carried out. A hazy day was defined as visibility < l0 km and RH (relative humidity) < 90%. Four haze episodes, which accounted for ~ 60% of the time during the whole campaign, were characterized by increases of SNA (sulfate, nitrate, and ammonium) and SOA (secondary organic aerosol) concentrations. The average values with standard deviation of SO₄^2 −, NO₃⁻, NH₄⁺ and SOA were 49.8 (± 31.6), 31.4 (± 22.3), 25.8 (± 16.6) and 8.9 (± 4.1) μg/m³, respectively, during the haze episodes, which were 4.3, 3.4, 4.1, and 1.7 times those in the non-haze days. The SO₄^2 −, NO₃⁻, NH₄⁺, and SOA accounted for 15.8%, 8.8%, 7.3%, and 6.0% of the total mass concentration of PM₁₀ during the non-haze days. The respective contributions of SNA species to PM₁₀ rose to about 27.2%, 15.9%, and 13.9% during the haze days, while the contributions of SOA maintained the same level with a slight decrease to about 4.9%. The observed mass concentrations of SNA and SOA increased with the increase of PM₁₀ mass concentration, however, the rate of increase of SNA was much faster than that of the SOA. The SOR (sulfur oxidation ratio) and NOR (nitrogen oxidation ratio) increased from non-haze days to hazy days, and increased with the increase of RH. High concentrations of aerosols and water vapor favored the conversion of SO₂ to SO₄^2 − and NO₂ to NO₃⁻, which accelerated the accumulation of the aerosols and resulted in the formation of haze in Beijing.     

Potential of secondary aerosol formation from Chinese gasoline engine exhaust

Light-duty gasoline vehicles have drawn public attention in China due to their significant primary emissions of particulate matter and volatile organic compounds(VOCs). However,little information on secondary aerosol formation from exhaust for Chinese vehicles and fuel conditions is available. In this study, chamber experiments were conducted to quantify the potential of secondary aerosol formation from the exhaust of a port fuel injection gasoline engine. The engine and fuel used are common in the Chinese market, and the fuel satisfies the China V gasoline fuel standard. Substantial secondary aerosol formation was observed during a 4–5 hr simulation, which was estimated to represent more than 10 days of equivalent atmospheric photo-oxidation in Beijing. As a consequence, the extreme case secondary organic aerosol(SOA) production was 426 ± 85 mg/kg-fuel, with high levels of precursors and OH exposure. The low hygroscopicity of the aerosols formed inside the chamber suggests that SOA was the dominant chemical composition. Fourteen percent of SOA measured in the chamber experiments could be explained through the oxidation of speciated single-ring aromatics. Unspeciated precursors, such as intermediate-volatility organic compounds and semi-volatile organic compounds, might be significant for SOA formation from gasoline VOCs. We concluded that reductions of emissions of aerosol precursor gases from vehicles are essential to mediate pollution in China.     

Role of secondary aerosols in haze formation in summer in the Megacity Beijing

A field experiment from 18 August to 8 September 2006 in Beijing, China, was carried out. A hazy day was defined as visibility 10 km and RH(relative humidity) 90%. Four haze episodes, which accounted for ~ 60% of the time during the whole campaign, were characterized by increases of SNA(sulfate, nitrate, and ammonium) and SOA(secondary organic aerosol) concentrations. The average values with standard deviation of SO2-+4, NO-3, NH4 and SOA were 49.8(± 31.6), 31.4(±22.3), 25.8(±16.6) and 8.9(±4.1) μg/m3, respectively, during the haze episodes, which were 4.3, 3.4, 4.1, and 1.7 times those in the non-haze days. The SO2-4,NO-3, NH+4, and SOA accounted for 15.8%, 8.8%, 7.3%, and 6.0% of the total mass concentration of PM10 during the non-haze days. The respective contributions of SNA species to PM10 rose to about27.2%, 15.9%, and 13.9% during the haze days, while the contributions of SOA maintained the same level with a slight decrease to about 4.9%. The observed mass concentrations of SNA and SOA increased with the increase of PM10 mass concentration, however, the rate of increase of SNA was much faster than that of the SOA. The SOR(sulfur oxidation ratio) and NOR(nitrogen oxidation ratio) increased from non-haze days to hazy days, and increased with the increase of RH. High concentrations of aerosols and water vapor favored the conversion of SO2 to SO2-4and NO2 to NO-3, which accelerated the accumulation of the aerosols and resulted in the formation of haze in Beijing.     

反硝化除磷工艺中二次曝气作用分析

反硝化除磷工艺是根据反硝化除磷菌开发的新工艺．结合试验重点探讨了二次曝气在该工艺中的作用：吹脱反硝化产生的附着于活性污泥上的氮气;缺氧段硝酸盐不足时提供O2作为二级电子受体使DPB污泥充分吸磷：p（COD）／p（N）,p（COD）／p（P）比值偏高时,再生活性污泥。指出二次曝气在反硝化除磷工艺中具有重要作用。     

老爷岭次生林主要树种分布格局及动态的研究

在帽儿山林场老爷岭生态站内设置次生林的典型样地,并对样地内的几种天然次生林的数据进行调查.研究用方差均值比率法研究老爷岭次生林群落主要树种的分布格局及其动态,并且做出相关的数据分析.主要选择当地典型的次生林类型进行调查,类型包括白桦林、蒙古栎林、硬阔叶林等.分析表明影响种群分布格局的因子大致归纳分为两类:第一:物种本身的生物学特性,第二:由于环境条件引起的生物学特征.并且对各林分主要树种分布格局及其动态的分析,揭示林分的未来发展趋势.     

活性污泥法对松香废水的二级处理试验

采用活性污泥对经炉渣吸附后的松香废水进行二级生化处理。试验过程中对污泥进行驯化培菌;试验结果表明,经驯化的污泥对松香废水进行二级处理,COD_(Cr)、BOD_5的去除率分别达到65.5％和82.3％,色度由724倍降低到135倍,为开发松香废水治理的实用技术提供了途径。     

Chemical characteristics and source apportionment of PM2.5 between heavily polluted days and other days in Zhengzhou, China

PM_(2.5) samples were collected in Zhengzhou during 3 years of observation, and chemical characteristics and source contribution were analyzed. Approximately 96% of the daily PM_(2.5) concentrations and annual average values exceeded the Chinese National Ambient Air Quality Daily and Annual Standards, indicating serious PM_(2.5) pollution. The average concentration of water-soluble inorganic ions was 2.4 times higher in heavily polluted days(daily PM32.5 concentrations 250 μg/mand visibility 3 km) than that in other days, with sulfate, nitrate, and ammonium as major ions. According to the ratio of NO-3/SO2-4,stationary sources are still the dominant source of PM_(2.5) and vehicle emission could not be ignored. The ratio of secondary organic carbon to organic carbon indicated that photochemical reactivity in heavily polluted days was more intense than in other days.Crustal elements were the most abundant elements, accounting for more than 60% of 23 elements. Chemical Mass Balance results indicated that the contributions of major sources(i.e., nitrate, sulfate, biomass, carbon and refractory material, coal combustion, soil dust,vehicle, and industry) of PM_(2.5) were 13%, 16%, 12%, 2%, 14%, 8%, 7%, and 8% in heavily polluted days and 20%, 18%, 9%, 2%, 27%, 14%, 15%, and 9% in other days, respectively.Extensive combustion activities were the main sources of polycyclic aromatic hydrocarbons during the episode(Jan 1-9, 2015) and the total benzo[a]pyrene equivalency concentrations in heavily polluted days present significant health threat. Because of the effect of regional transport, the pollution level of PM_(2.5) in the study area was aggravated.     

二级处理出水中肠道病毒的PCR检测研究

建立了二级处理出水中肠道病毒的巢式PCR检测方法。在2006年7月至2007年2月期间分别用第一次PCR和巢式PCR方法对西安市北石桥污水净化中心的二级处理出水中的肠道病毒进行了检测,两种检测方法的阳性率分别为12．5％和87．5％。另外,还对二级处理出水中的肠道病毒含量和温度、pH值等理化指标的关系作了分析。     

再生铝生产过程中二噁英成因及全过程污染控制技术

介绍了再生铝生产工艺、二噁英生成机理,原物料铝渣中含有未完全破坏的PCDD/Fs和"熔炉"中形成的以及"从头合成(DeNovo)"二噁英形成的3种途径。有针对性地采用源头减污、过程控制及末端治理等全过程污染控制技术进行二噁英减排,从再生铝生产及治污工艺设备入手,提出再生铝二噁英污染控制最佳可行技术,为业内人士及环境管理部门二噁英控制与管理提供技术依据。     

广州市报废机动车回收企业二次污染现状及污染防治对策

界定机动车维修、报废过程中产生的固体废物、废水、土壤污染为机动车二次污染,并通过实地调查、监测分析广州市12家定点报废汽车回收公司,开展机动车二次污染现状研究。研究表明,报废机动车回收过程中对资源化金属的回收利用成效较好,但对用途不大的部件随意渠道转移,对危险废物和严控废物未能较好处理;大多没有完善废水处理设施,废水直接排放;土壤多项特征污染物超标严重。针对广州市机动车二次污染现状,提出了加强法规建设、环境监控、行业管理、清洁生产等防治措施。     

炼油废水反硝化脱氮新工艺研究

用水解酸化－好氧工艺模拟炼油废水生化处理系统，在二沉池中加入软性纤维填料后，不但使泥水分离效果更好，而且可起到反硝化脱氮的功能，改进了脱氮工艺的传统方式，弥补了由于原工艺中构筑物的原因造成废水无法回流脱氮的缺陷。二沉池中反硝化工艺研究表明，当供给适量C源、DO＜1mg/L、温度在25℃-40℃时，NOx-N降解率可达75％－90％。出水COD、oiL等各污染指标均达到国家和DB44／56－92地方排放标准。     

关于我国废干电池再生利用技术研究的几点思考

对我国废干电池再生利用技术研究提出了几点看法，认为我国废干电池再生利用技术既要注意环境无害化、资源化，还要考虑产业化和适应性问题，使我们的技术既有高的技术含量又符合我国国情。     

Biogenic volatile organic compound emission patterns and secondary pollutant formation potentials of dominant greening trees in Chengdu, southwest China

Integral to the urban ecosystem, greening trees provide many ecological benefits, but the active biogenic volatile organic compounds (BVOCs) they release contribute to the production of ozone and secondary organic aerosols, which harm ambient air quality. It is, therefore, necessary to understand the BVOC emission characteristics of dominant greening tree species and their relative contribution to secondary pollutants in various urban contexts. Consequently, this study utilized a dynamic enclosure system to collect BVOC samples of seven dominant greening tree species in urban Chengdu, Southwest China. Gas chromatography/mass spectrometry was used to analyze the BVOC components and standardized BVOC emission rates of each tree species were then calculated to assess their relative potential to form secondary pollutants. We found obvious differences in the composition of BVOCs emitted by each species. Ficus virens displayed a high isoprene emission rate at 31.472 μgC/(gdw (g dry weight)•hr), while Cinnamomum camphora emitted high volumes of D-Limonene at 93.574 μgC/(gdw•hr). In terms of the BVOC emission rates by leaf area, C. camphora had the highest emission rate of total BVOCs at 13,782.59 μgC/(m²•hr), followed by Cedrus deodara with 5466.86 μgC/(m²•hr). Ginkgo biloba and Osmanthus fragrans mainly emitted oxygenated VOCs with lower overall emission rates. The high BVOC emitters like F. virens, C. camphora, and Magnolia grandiflora have high potential for significantly contributing to environmental secondary pollutants, so should be cautiously considered for future planting. This study provides important implications for improving urban greening efforts for subtropical Chinese urban contexts, like Chengdu.