三江平原作物收获期大气颗粒物浓度特征

通过对2013年10月东北三江平原农作物收获期大气颗粒物的在线监测,结合卫星火点数据与后向轨迹模拟,分析了秸秆燃烧和作物收割等农业活动对大气颗粒物质量浓度及粒径分布的影响.结果表明:作物收获前期?中期和后期大气PM2.5的平均质量浓度分别为36.0,158.3,33.8μg/m3;现场观测表明,水稻收割(321.1μg/m3)和秸秆燃烧(2777.1μg/m3)时监测田块内PM2.5的平均浓度分别是收割前和燃烧前平均浓度的2.5倍和11.5倍;卫星火点及后向轨迹分析发现,观测期间PM2.5与该地区卫星火点数量的变化趋势比较一致,且气团轨迹经过火点较集中区域时测得较高的PM2.5浓度值;对不同粒径(<1μm,1~2.5μm,2.5~10μm)大气颗粒物质量浓度的观测表明,收获中期受大面积秸秆燃烧的影响,0~1 μm粒径组分明显增加,而收获后期由于降水过程对0~1μm粒径颗粒物的清除效率较低,故该粒径颗粒物仍维持较高比例.     

烟煤层燃炉颗粒物的生成特征与管理控制

以95台中小型燃烟煤层燃炉(≤70MW)的燃料特性分析数据和颗粒物(PM)排放实测数据为基础,利用统计分析方法,研究了锅炉出力、过量空气系数、燃煤灰分含量对燃烧过程中PM初始排放浓度的影响,分析了燃煤锅炉PM排放现状,讨论了我国中小型燃煤锅炉PM排放管理控制的潜力和可行性。结果表明,在锅炉运行负荷≥80%的条件下,PM初始排放浓度随过量空气系数和燃煤灰分含量的增加略有增大,而与锅炉出力无关;在用烟煤层燃炉PM排放浓度基本上能够满足国家现行污染物排放标准规定的排放限值要求;有96%的锅炉所采用的除尘装置的除尘效率大于80%;与其他国家相比,目前我国对于中小型燃煤锅炉PM的排放控制还处于中等水平,建议在国家层面上适时提高燃煤锅炉颗粒物的排放限制。     

济南冬季典型商业室内环境颗粒物污染特征

2010年1月31日~2月7日,利用宽范围颗粒物分光计(WPS)对济南典型商业室内环境(超市和办公室)的颗粒物数浓度进行了研究.结果显示颗粒物数浓度主要分布在爱根模态(20~100nm),济南室内颗粒物总数浓度(10~2500nm)和国外一些发达国家相当,但质量浓度高一个数量级.超市和办公室颗粒物的日变化和粒径分布研究表明,超市和办公室颗粒物浓度主要受到室外源控制,同时办公室颗粒物浓度还受到打印机使用和吸烟的影响.超市打扫卫生和频繁的顾客流动虽使粗模态颗粒物的体积浓度提升4~7倍,但仅占颗粒物总体积浓度的5%左右.办公室内打印机的使用可使室内30nm左右的颗粒物数浓度显著升高,并且在打印机结束使用后高浓度仍可维持20min左右;吸烟使办公室100nm左右颗粒物升高且可维持6h,吸烟时白天颗粒物体积浓度是无吸烟时的2.5倍,说明即使在受到室外高浓度的颗粒物控制时,这2个室内源的贡献仍不容忽视.     

可再生能源资源的系统评价方法及实例

可再生能源资源评价是可再生能源综合规划的前提,由于能源综合规划各环节之间是相互关联的,因此,能源资源评价不能独立于其它分析过程而单独进行。特别是对可再生能源资源来说,评价内容除了要考虑储量、开采量、生产率等进行一般能源评价所考虑的因素以外,更应注重可再生能源资源的开发技术及市场分析。由于目前对可再生能源的资源评价尚未形成比较系统的评价体系,因此,论文根据可再生能源资源的特性以及它与技术、市场之间的内在联系,从一般系统论的观点出发,对可再生能源资源的系统评价方法进行了研究。最后以秸秆资源为例,对以上选择的评价方法进行了实际应用。     

民用燃煤排放细颗粒中金属元素排放特征及单颗粒分析

通过模拟民用煤炭燃烧,采集了5种不同成熟度的典型块煤燃烧排放的单颗粒和PM_2.5样品.利用带能谱仪的透射电镜研究了金属颗粒的单颗粒特征,运用电感耦合等离子体质谱仪和发射光谱仪获得了PM_2.5样品中14种金属元素（包括8种重金属）的浓度特征.结果显示,民用燃煤排放的含金属元素的颗粒物主要有矿物颗粒、部分碳质颗粒、富K颗粒、富S[K]颗粒、富Fe颗粒、富Zn颗粒和富Pb颗粒共7种.5种民用燃煤排放的14种金属元素占PM_2.5的1.29%~15.54%,其中Al、Ca和Na占金属元素总量的57%~80%,是民用燃煤排放的主要的金属元素;V、Cr、Mn、Co、Ni、Cu、Zn和Pb这8种重金属元素占PM_2.5的0.09%~2.53%,其中Zn和Pb占重金属总量的54%~91%,在民用燃煤排放的重金属中占主导.单颗粒分析结果显示Zn和Pb元素主要富集在粒径小于1μm的富Zn和富Pb颗粒中,这些细颗粒能够直接进入人体,对人体健康造成威胁.因此,建议居民应通过使用精煤或天然气等清洁能源来减少重金属的排放.     

Typical atmospheric haze during crop harvest season in northeastern China: A case in the Changchun region

This study presents the mass concentrations of PM_(2.5),O_3,SO_2 and NOxat one urban,one suburban and two rural locations in the Changchun region from September 25 to October 272013. Major chemical components of PM_(2.5)at the four sites were daily sampled and analyzed. Most of daily concentrations of SO_2(7–82 μg/m~3),O_3(27–171 μg/m~3) and NOx(14–213 μg/m~3) were below the limits of the National Ambient Air Quality Standard(NAAQS)in China. However,PM_(2.5)concentrations(143–168 μg/m~3) were 2-fold higher than NAAQS.Higher PM_(2.5)concentrations(~ 150 μg/m~3) were measured during the pre-harvest and harvest at the urban site,while PM_(2.5)concentrations significantly increased from 250 to400 μg m~(-3) at suburban and rural sites with widespread biomass burning. At all sites,PM_(2.5)components were dominated by organic carbon(OC) and followed by soluble component sulfate(SO_4~(2-)),ammonium(NH_4~+) and nitrate(NO_3~-). Compared with rural sites,urban site had a higher mineral contribution and lower potassium(K~+and K) contribution to PM_(2.5).Severe atmospheric haze events that occurred from October 21 to 23 were attributed to strong source emissions(e.g.,biomass burning) and unfavorable air diffusion conditions.Furthermore,coal burning originating from winter heating supply beginning on October 18 increased the atmospheric pollutant emissions. For entire crop harvest period,the Positive Matrix Factorization(PMF) analysis indicated five important emission contributors in the Changchun region,as follows: secondary aerosol(39%),biomass burning(20%),supply heating(18%),soil/road dust(14%) and traffic(9%).     

Characteristics of indoor/outdoor PM2.5 and elemental components in generic urban, roadside and industrial plant areas of Guangzhou City, China

Quantitative information on mass concentrations and other characteristics, such as spatial distribution, seasonal variation, indoor/outdoor （I/O） ratio, correlations and sources, of indoor and outdoor PM2.5 and elemental components in Guangzhou City were provided. Mass concentration of PM2.5 and elemental components were determined by standard weight method and proton-induced X-ray emission （PIXE） method. 18 elements were detected, the results showed positive results. Average indoor and outdoor PM2.5 concentrations in nine sites were in the range of 67.7-74.5μg/m^3 for summer period, and 109.9-123.7 μg/m^3 for winter period, respectively. The sum of 18 elements average concentrations were 5362.6-5533.4 ng/m^3 for summer period, and 8416.8-8900.6 ng/m^3 for winter period, respectively. Average concentrations of PM2.5 and element components showed obvious spatial characteristic, that the concentrations in roadside area and in industrial plant area were higher than those in generic urban area. An obvious seasonal variation characteristic was found for PM2.5 and elemental components, that the concentrations in winter were higher than that in summer. The I/O ratio of PM2.5 and some elemental components presented larger than 1 sometimes. According to indoor/outdoor correlation of PM2.5 and element concentrations, it was found that there were often good relationships between indoor and outdoor concentrations. Enrichment factors were calculated to evaluate anthropogenic versus natural elements sources.     

应用EPIC模型计算黄土塬区作物生产潜力的初步尝试

黄土高原地区土壤侵蚀强烈,土地现实生产力水平低,研究该地区作物生产潜力可以为有效提高作物产量及合理进行农业生产规划提供依据。论文介绍了EPIC(侵蚀-生产力影响计算模型)的特点、组成部分及应用步骤,对部分作物参数进行了修订。以黄土塬区冬小麦和春玉米为例,对EPIC模型的适用性进行了分析和验证,表明EPIC在黄土高原地区作物生产潜力模拟研究中具有较好的适用性。结果显示,冬小麦产量模拟值与实测值之间多年平均误差为7.78%;春玉米多年平均误差为9.60%。冬小麦水分胁迫天数多年平均为9.9天,最少为1.7天(1993年),最多为23.1天(1995年);春玉米水分胁迫天数多年平均为13.4天,最少为1.1天(1993年),最多为44.2天(1995年),与各年作物生育期降水情况基本一致。此模型经修正后在正常年份模拟值较为精确,在干旱年份对作物、土壤等参数的修正方法需要进一步探讨。     

以稻草为碳源和生物膜载体去除水中的硝酸盐

采用室内试验装置,研究了以农业废弃物稻草为反硝化碳源和反应介质的生物反应器对于污水中硝酸盐的去除效果及其影响因素.结果表明,以稻草为反硝化碳源和生物膜载体的反应器启动时间短,对污水中硝酸盐氮的去除效果好,且试验过程中未发现亚硝酸盐累积;进水硝酸盐浓度对装置的处理效果有一定影响,浓度过高会导致硝酸盐的去除率下降;装置对进水DO和ｐH变化有一定抗性,DO在1.0～3.5 mg/L,pH在6.5～8.5之间变化时,反应器硝酸盐的去除率变化很小,缓冲能力较强;反应器稳定性强,装置运行84 ｄ后,出水硝酸盐开始升高,硝酸盐去除率逐步降低,但去除率仍在50%以上.     

Characteristics, evolution, and regional differences of biomass burning particles in the Sichuan Basin, China

The Sichuan Basin has experienced serious air pollution from fine particulate matter (PM_2.5) in the past few years with biomass burning has been identified as a major source of PM_2.5 in this region. We used single particle aerosol mass spectrometer to investigate the characteristics of biomass burning particles in three interacting cities representing different types of urban environment in the Sichuan Basin. A total of 739,794, 279,610, and 380,636 biomass burning particles were detected at Ya'an, Guang'an, and Chengdu, which represented 42%, 69%, and 61%, respectively, of the total number of particles. We analyzed the chemical composition, transportation, and evolution of biomass burning particles. The contribution of K-elemental carbon and K-secondary inorganic particles was highest in Ya'an (36%) and Guang'an (47%), respectively, reflecting the important role of fresh biomass burning particles and long-distance transport in these two cities. Air masses originating from different directions corresponded to different levels of PM_2.5 and the contributions of polluted clusters increased significantly on polluted days. Fresh and secondary inorganic biomass burning particles increased pollution at Ya'an and Guang'an, respectively, but dominated different stages of pollution in Chengdu. K-nitrate particles were formed by photochemical reactions, whereas K-sulfate particles were formed by both photochemical and liquid-phase reactions. Investigation of the degree of particle aging showed that there were more fresh particles at Ya'an and more aged particles at Guang'an. These results are useful in helping our understanding of the characteristics of biomass burning particles and evaluating their role in PM_2.5 pollution in the Sichuan Basin.