The transformation of outdoor ammonium nitrate aerosols in the indoor environment

Recent studies associate particulate air pollution with adverse health effects; however, the exposure to indoor particles of outdoor origin is not well characterized, particularly for individual chemical species. We conducted a field study in an unoccupied, single-story residence in Clovis, California to provide data and analyses to address issues important for assessing exposure. We used real-time particle monitors both outdoors and indoors to quantify nitrate, sulfate, and carbon particulate matter of particle size 2.5 μm or less in diameter (PM-2.5). The results show that measured indoor ammonium nitrate concentrations were significantly lower than would be expected based solely on penetration and deposition losses. The additional reduction can be attributed to the transformation indoors of ammonium nitrate into ammonia and nitric acid gases, which are subsequently lost by deposition and sorption to indoor surfaces. A mass balance model that accounts for the kinetics of ammonium nitrate evaporation was able to reproduce measured indoor ammonium nitrate and nitric acid concentrations, resulting in a fitted value of the deposition velocity for nitric acid of 0.56 cm s⁻¹. The results indicate that indoor exposure to outdoor ammonium nitrate in Central Valley of California are small, and suggest that exposure assessments based on total particle mass measured outdoors may obscure the actual causal relationships for indoor exposure to particles of outdoor origin.     

光纤化学传感器的实验研究

主要研究对象为基于离子选择性中性载体的无机离子化学传感器，采用以吸光度为主要测量信号的分光光度法为主要分析方法。依据该传感器的特征，可使分析光束与被测溶液分开，甚至对不透明的液体作分光光度分析。为此，在离子选择性中性载体PVC膜的响应特征基础上设计并研制一种新型结构的光吸收池，应用前景广阔。     

荧光化学传感器的制备及其在环境分析监测中的应用

随着荧光分析技术和传感技术的发展,荧光化学传感器已经成为一种重要的连续分析测量装置.它具有很高的选择性和灵敏度,可以实现对pH、溶解氧、含氮化合物、有毒害重金属离子、有机污染物进行实时和在线测定,因此在环境分析监测方面具有广泛的应用前景.简要介绍了荧光化学传感器的原理、制备及分类,综述了近年来荧光化学传感器的发展及其在环境分析监测中的最新研究成果,并探讨了荧光化学传感器在环境分析监测领域的应用前景和发展方向.     

合流制排水系统溢流污染就地调蓄处理控制技术研究

在对高效混合絮凝斜板沉淀工艺进行现场中试的基础上,将化学强化处理工艺与调蓄池相结合,针对上海市某合流制排水系统,进行调蓄/沉淀池的概念设计,提出主要设计参数,利用计算流体力学(CFD)模型对调蓄/沉淀池进行优化设计.试验和模拟结果表明,调蓄/沉淀池与单纯的调蓄池相比具有更好的溢流污染控制效果和效益/造价比.     

PM2.5 chemical source profiles for vehicle exhaust, vegetative burning, geological material, and coal burning in Northwestern Colorado during 1995

PM_2.5 (particles with aerodynamic diameters less than 2.5 μm) chemical source profiles applicable to speciated emissions inventories and receptor model source apportionment are reported for geological material, motor vehicle exhaust, residential coal (RCC) and wood combustion (RWC), forest fires, geothermal hot springs; and coal-fired power generation units from northwestern Colorado during 1995. Fuels and combustion conditions are similar to those of other communities of the inland western US. Coal-fired power station profiles differed substantially between different units using similar coals, with the major difference being lack of selenium in emissions from the only unit that was equipped with a dry limestone sulfur dioxide (SO₂) scrubber. SO₂ abundances relative to fine particle mass emissions in power plant emissions were seven to nine times higher than hydrogen sulfide (H₂S) abundances from geothermal springs, and one to two orders of magnitude higher than SO₂ abundances in RCC emissions, implying that the SO₂ abundance is an important marker for primary particle contributions of non-aged coal-fired power station contributions. The sum of organic and elemental carbon ranged from 1% to 10% of fine particle mass in coal-fired power plant emissions, from 5% to 10% in geological material, >50% in forest fire emissions, >60% in RWC emissions, and >95% in RCC and vehicle exhaust emissions. Water-soluble potassium (K⁺) was most abundant in vegetative burning profiles. K⁺/K ratios ranged from 0.1 in geological material profiles to 0.9 in vegetative burning emissions, confirming previous observations that soluble potassium is a good marker for vegetative burning.     

A comparison of chemical MSW compositional data between China and Denmark

Chemical waste compositions are important for municipal solid waste management, as they determine the pollution potentials from different waste strategies. A representative dataset for chemical characteristics of individual waste fractions is frequently required to assess chemical waste composition, but it is usually reported in developed countries and not in developing countries. In this study, a dataset for Chinese waste was established through careful data screening and assessment, named as CN dataset. Meanwhile, a dataset for Danish waste (DK dataset) was also summarized based on previous studies. In order to quantitatively evaluate the reliabilities of CN and DK datasets, the chemical waste compositions in four Chinese cities were estimated by utilizing both of them, respectively. It is indicated that the usage of CN datasets led to significantly lower discrepancies from the actual values based on laboratory analysis in most cases. Within the datasets, the moisture contents of food waste, paper, textiles, and plastics, the carbon content of food waste, as well as the oxygen content of plastics would induce significant divergences, which should be paid special attention when gathering the information. In addition, the fractional waste compositions in China showed similar features with other developing countries but differ significantly with developed countries. Thus the above-mentioned conclusions could also be true in other developing countries.     

香料生产废水的生化处理研究

某合成洋茉莉醛香料厂的生产废水中含有香料、香料副产品、降解物以及原辅材料,具有CODcr浓度高、水质波动大以及水中污染物成分复杂等特点,属于典型的高浓度难降解有机废水,而该厂现有的废水处理工艺不仅流程长、费用高且出水难以达到GB8978—1996一级排放标准。本文采用活性污泥法及MBR工艺研究了洋茉莉醛香料废水的处理效果及其影响因素,并结合GC—MS对降解产物进行了分析。试验结果表明：采用本文方法对洋茉莉醛香料废水有较好的降解作用,可经较少的步骤处理实现达标排放。     

化学法除磷的试验研究

探讨了含磷废水在添加不同药剂、不同试验条件下的的处理效率;研究表明:石灰法除磷在〔Ca2+/TP〕(摩尔比)为2:1时,pH值控制在10.0左右,TP的去除率达到96%以上;三氯化铁除磷时控制〔Fe3+/TP〕为2:1,pH值为7.0,TP的去除率能达到96%;硫酸亚铁与活性污泥协同除磷效果优于三氯化铁。     

基于物料衡算法的复杂化工过程产排污量核算软件的开发及应用

物料衡算法是污染源普查技术规定的污染物排放量核算的一种重要方法,但对于复杂的化工过程,物料衡算法的难度和计算工作量均很大,难以为基层环境监察人员掌握和运用,同时运用物料衡算进行污染物排放量核算的可靠性,也很难保证。结合排污量核定实践,综合进行物料衡算的技巧和一般方法,科学地模化物质转化转移过程,以此为基础,应用Visual Basic高级计算机语言编制了针对复杂化工过程的物料衡算计算软件,并以沈阳某制药有限公司的脑复康生产过程为原型,利用实测资料对计算模型进行了验证,应用该软件计算某制药厂VC生产线等4条生产线的产排污量核算。该软件应用简便,可以方便快捷地进行复杂化工过程的物料衡算,并可以分析生产过程中的主要产污环节,为提高清洁生产水平提供科学依据。     

化肥污染与防治

随着农业发展,化肥的用量越来越大,大量化肥进入环境中,必然对环境造成污染。本文着重探讨化肥对水、空气、土壤及人畜的污染及危害,提出防治化肥污染的措施。