哈尔滨市环境空气质量变化及影响因素分析研究

近年来,大气污染问题已然成为热门话题。大气污染不仅危害中国生态环境和居民健康,甚至可能对其他邻近国家产生影响。哈尔滨地处中国东北部地区,空气质量变化具有区域性特征。本文在参阅了大量参考文献的基础上,结合哈尔滨市2010年-2012年与2012年1～12月份的空气质量数据,对哈尔滨市的大气质量变化规律及影响因素进行了分析。确定了哈尔滨市大气环境质量的级别和首要污染物以及影响空气质量变化的主要影响因素。     

空气相对湿度对煤自燃特性的影响研究

为研究空气相对湿度对煤自燃特性的影响,运用自制空气湿度控制装置和程序升温试验台,通入湿度不同的空气,对砚石台矿煤样进行程序升温,测定不同温度下所产生气体的浓度,分析耗氧速率、CO和CO2产生率、放热强度以及自燃极限参数的变化规律。试验结果表明:低温氧化前期,煤体的耗氧速率、放热强度和CO产生率与空气相对湿度成正比。随着反应的进行,85%或32%的湿度均会对耗氧速率、放热强度和CO产生率产生一定的抑制作用;CO2产生率随空气相对湿度的增大先升高后降低,最小浮煤厚度和下限氧浓度随空气相对湿度的增大先减小后增大,上限漏风强度先增大后减小。增大空气相对湿度对煤低温氧化前期有促进作用,其自燃环境条件更易被满足,自燃危险性升高。     

石灰石-石膏湿法脱硫装置中影响脱硫效率的关键设计参数

本文针对石灰石-石膏湿法脱硫装置阐述了关键参数对工艺性能的影响,介绍了影响脱硫效率的液气比、浆液pH值、钙硫比、固体物停留时间等关键设计参数,并给出这些变量的典型设计范围,为同类型脱硫工程设计提供借鉴和参考。     

气象参数对基于BP神经网络的PM2.5日均值预报模型的影响

建立了基于BP神经网络的PM2.5质量浓度预报模型,对广州市5个监测点2012年6月-2013年5月的PM2.5质量浓度日均值进行预报,分析了总体预报误差、不同风速和降雨量下的预报误差,以及天气预报误差对PM2.5质量浓度预报误差的影响.结果表明,BP神经网络模型对5个站点的PM2.5预报结果稳定,平均相对误差为29.71％.在有利于PM2.5扩散的气象条件下预报误差较大,风速较大时与风速较小时预报误差的差异高达15％,而不同降雨量情况下的预报误差较相近.修正天气预报后,各站点的预报误差平均降低了4.67％.这表明可从空气质量数据质量等方面人手改进模型.     

Zebrafish as a possible bioindicator of organic pollutants with effects on reproduction in drinking waters

Organic contaminants can be detected at low concentrations in drinking water, raising concerns for human health, particularly in reproduction. In this respect, we attempted to use the zebrafish as a bioindicator to detect the possible presence of these substances in drinking water, aiming to define the most relevant parameters to detect these substances, which particularly affect the development and reproduction of zebrafish. To this end, batches of 30 embryos with the chorion intact were cultured in drinking waters from different sources, throughout their full life-cycle up to 5 months, in 20 L tanks. Six replicates were performed in all water groups, with a total of 24 aquariums. Two generations (F0 and F1) were studied and the following parameters were tested: in the F0 generation, survival and abnormality rates evaluated at 5 dpf (days post-fertilization) and at 5 mpf (months post-fertilization), the onset of spawning and the fertility rate from 3 mpf to 5 mpf, and the sex ratio and underdeveloped specimens at 5 mpf. Furthermore, in the F0 offspring (F1), survival and abnormality rates were evaluated at 5 dpf and the hatching rate at 72 hpf. These results revealed that the hatching rate is the most sensitive parameter to distinguish different levels of effects between waters during the early life stages, whereas the rate of underdeveloped specimens is more suitable at later life stages. Regarding adult reproduction, fertility rate was the most sensitive parameter. The possible reversibility or accumulative nature of such effects will be studied in future work.     

Safety and kinetic parameters analysis for 1,1,-Di(tert-butylperoxy) cyclohexane mixed with monoammonium phosphate

Runaway reactions by organic peroxides have occurred throughout the world. In this study, we used 1,1,-Di(tert-butylperoxy) cyclohexane (CH) 70 mass% as the main material, which was extensively employed as initiator for styrene in polymerization. Fire extinguishers are the first fire-fighting apparatus when fires occur. If a fire extinguisher has sat idle for a long time, which would cause the extinguishing agent to damp, it cannot achieve the desired effect and be properly handled at the start of the accident, thereby causing more casualties and property losses. CH 70 mass% was employed to mixed with monoammonium phosphate (MAP) for understanding the phenomenon by applying differential scanning calorimetry (DSC). Safety parameters also were carried out for more deeply understanding the basic characteristics for preventing an accident from occurring, in terms of applying CH 70 mass% as the initiator in the manufacturing process.     

Study of the explosion parameters of vapor–liquid diethyl ether/air mixtures

The knowledge of the vapor–liquid two-phase diethyl ether (DEE)/air mixtures (mist) on the explosion parameters was an important basis of accident prevention. Two sets of vapor–liquid two-phase DEE/air mixtures of various concentrations were obtained with Sauter mean diameters of 12.89 and 22.90 μm. Experiments were conducted on vapor–liquid two-phase DEE/air mixtures of various concentrations at an ignition energy of 40.32 J and at an initial room temperature and pressure of 21 °C and 0.10 MPa, respectively. The effects of the concentration and particle size of DEE on the explosion pressure, the explosion temperature, and the lower and upper flammability limits were analyzed. Finally, a series of experiments was conducted on vapor–liquid two-phase DEE/air mixtures of various concentrations at various ignition energies. The minimum ignition energies were determined, and the results were discussed. The results were also compared against our previous work on the explosion characteristics of vapor–liquid two-phase n-hexane/air mixtures.     

长江三角洲地区城市臭氧污染特征与影响因素分析

为研究长三角地区城市O3污染特征及其影响因素,对长三角地区25个城市2013年国家环境监测点位和国家气象台数据进行了统计分析.结果表明:除淮安外,其余24个城市均存在不同程度的O3日超标现象,超标率在1.6%~15.1%之间,平均为5.8%,低于珠三角地区(8.9%)和京津冀地区(9.7%).5—8月是长三角地区O3污染最为严重的月份,而这一时期颗粒物污染相对较轻,因此,O3与颗粒物污染在时间上呈相反的态势.从空间分布看,长三角地区O3污染呈现较为明显的连片分布特征,上海及周边城市O3污染较重.机动车数量影响城市O3污染:各城市民用汽车保有量与各城市NO2年均浓度、O3超标天数有显著的相关性,相关系数分别为0.672和0.564;每日O3小时浓度高峰值与车流量高峰基本吻合.高温、长时间日照容易出现O3浓度的高值;随着相对湿度、风速的增加,O3超标频率和浓度均值都表现为先升后降的规律.     

兰州市大气重污染气象成因分析

兰州市曾经是全国乃至全世界空气污染最严重的城市之一,重度空气污染特征明显.根据兰州市环境保护局公布的大气污染数据及气象局的气象观测数据,采用时间序列法和相关统计方法对兰州市2002—2011年空气污染指数(Air Pollution Index,API)大于200的大气重污染特征进行研究,并探析了其气象学成因.结果表明,静稳型重污染发生天数约占重污染发生总天数的77%,而沙尘型重污染只占23%.静稳型重污染是兰州市最主要的大气重污染类型,它往往存在PM10、SO2和NO2三种污染物同步累积的过程,持续时间长,主要发生在冬季;而沙尘型重污染持续时间短,由于外来高浓度沙尘输送的影响,PM10浓度会急剧升高,而SO2和NO2浓度则会明显下降(SO2、NO2浓度明显低于静稳型重污染),几乎都发生在春季.对它们的成因分析表明:静稳型重污染的气象学成因主要是风速小,稳定能量大,大气环境稳定度大,不利于湍流扩散,本地源污染物持续积累造成;沙尘型重污染气象学成因主要是春季气候干燥,相对湿度低,造成大风沙尘天气,给兰州市输送大量沙尘颗粒形成大气重污染.此研究结果可为兰州市大气重污染的防治提供科学依据.