冬季自然通风教室室内环境对学习效率的影响

教室作为人员密集型建筑,室内环境的好坏不但影响学生的学习能力,也影响到教师的授课效率。本文通过对某高校冬季自然通风教室室内空气环境、光环境的现场实测,结合现场问卷调查,利用Matlab及Excel等数学工具对数据进行处理,得出室内光照度、PMV值、CO2浓度对学习效率的影响规律。结果表明,CO2浓度较室内光照度、PMV等参数对于学生学习效率的影响更大。针对这种情况,提出了改善措施,如在教室里设置CO2浓度传感器和信号灯、教学楼设置之初考虑当地主导风向以助于自然通风等。     

Long-term impact of water desalination plants on the energy and carbon dioxide balance of Victoria,Australia: a case study from Wonthaggi

In 2007, the state government of Victoria, Australia, announced plans to build a large desalination plant with a capacity of 150 million m³ per year of desalinated water. Currently, the only feasible source for significant expansion of the greenhouse-gas neutral (GGN) energy generation in the state is wind power. A criterion for GGN of a desalination plant has been formulated. In a case of no greenhouse gas contribution from the desalination plant, the criterion is satisfied if the annual growth of the electrical energy generated by GGN sources is around 6–9% for the period 2010–2070. Higher annual growth of 18% for the period 2008–2015, 8% annually for the period 2015–2035 and 6% annual growth thereafter are required if the desalination plant is contributing to the greenhouse-gas balance of the state.     

Indoor air quality in California homes with code-required mechanical ventilation

Data were collected in 70 detached houses built in 2011-2017 in compliance with the mechanical ventilation requirements of California's building energy efficiency standards. Each home was monitored for a 1-week period with windows closed and the central mechanical ventilation system operating. Pollutant measurements included time-resolved fine particulate matter (PM_2.5) indoors and outdoors and formaldehyde and carbon dioxide (CO₂) indoors. Time-integrated measurements were made for formaldehyde, NO₂, and nitrogen oxides (NO_X) indoors and outdoors. Operation of the cooktop, range hood, and other exhaust fans was continuously recorded during the monitoring period. Onetime diagnostic measurements included mechanical airflows and envelope and duct system air leakage. All homes met or were very close to meeting the ventilation requirements. On average, the dwelling unit ventilation fan moved 50% more airflow than the minimum requirement. Pollutant concentrations were similar to or lower than those reported in a 2006-2007 study of California new homes built in 2002-2005. Mean and median indoor concentrations were lower by 44% and 38% for formaldehyde and 44% and 54% for PM_2.5. Ventilation fans were operating in only 26% of homes when first visited, and the control switches in many homes did not have informative labels as required by building standards.     

长沙市某大学教室内外空气品质调查

本文对长沙市某大学校园内三栋教学楼教室内外的空气品质进行了实地测量调查。在室内和室外同时对空气温度(Ta)、相对湿度(RH）、空气流速(V）以及二氧化碳(CO2)、一氧化碳(CO)、二氧化硫(SO2)、二氧化氮(NO2)、可吸入颗粒物(PM10)和甲醛(HCH0)等的浓度参数进行了测量。实地测量时间为2004年3月和4月两个月。测量结果显示CO2和PM10为典型大学教室中污染最为严重的两项指标：CO2的最高和平均浓度分别高达0．3229／0和0．1997％,而中国国家标准为0．100%。造成如此严重污染的主要原因是通风不足以及教室内人员密度过大;教室内PM10的最大和平均浓度分别为0．16mg／m^3和0．13mg／m^3,通过实验分析得出在室内人员密度不是非常大的情况下,室内PM10主要来自室外环境;而人员密度大到一定程度时,室内人员活动与PM10浓度则显示出了一定的正相关性。本文所测的其他污染指标均符合国家标准要求。并且在结论中也提出了一些解决问题的建议。     

Indoor Climate and Indoor Air Quality in Residential Buildings

In buildings which were built within the last 15 to 20 years, or which have been retrofitted, and which do notfeature a mechanical ventilation system, air changes between 0.01 h^?1 and 0.5 h^?1 were measured while windows were closed. In the bedrooms of such buildings, when doors and windows were closed, CO₂ concentrations of up to 4300 ppm were measured whereby the 1500 ppm limit was often exceeded. Simulation calculations and diverse measurements using different door positions with simultaneously closed windows have shown that with the door open more than 10 cm, and a minimal air exchange in the whole of an apartment of 0.1 h^?1, a CO₂ concentration of I500 ppm was not or was only insignifiantly exceeded even after 10 hours. Investigations in a dwelling fined with a mechanical ventilation system have shown that air quality and the indoor climate parameters were in an optimal range.     

中国CO2集中排放源调查及其分布特征

由于中国经济的快速发展以及对化石能源的过度依赖,大量排放CO2致使面临的环境压力和国际压力越来越大。为减少CO2排放,需详细调查CO2排放源尤其是工业集中点源的现状。在对2004年中国火电、水泥、钢铁、炼油、乙烯、合成氨、环氧乙烷、制氢8类企业生产数据调查的基础上,计算了2004年中国这些企业的CO2排放量,绘制了集中点排放源的全国分布图,同时给出了大规模和高浓度CO2排放源分布图。在此基础上分析了其空间分布特征。2004年8类企业总排放量为29.6315×108t,其中,火电、水泥、钢铁企业总排放量为27.1631×108t,约占91.7%。采用同样的方法,依据统计数据计算了1998～2002年火电、水泥、钢铁三类企业排放量并分析了其增长特征。统计结果表明,3类企业CO2排放量年均增长率达9.7%,到2000年后呈加速增长趋势。     

室内空气中可挥发性有机化合物的研究

分析了室内空气中可挥发性有机物的来源和危害，给出了其监测分析方法和评价标准，最后介绍了降低和消除室内VOC的方法。     

以废热水为热源的二氧化碳热泵热水器分析

提出了以废热水为热源的二氧化碳热泵热水器系统,给出了该系统的工作原理,借助EES计算软件,进行了不同工况下系统的性能分析,为系统的运行提供了参考。     

室内空气质量的管理

根据LEED-CS标准,结合施工现场实际情况,指出工程施工过程中,室内空气质量(IAQ)已成为不容忽视的环境问题。分析室内空气污染物类型及其来源,同时阐述室内污染物的危害。鉴于此提出施工过程中室内空气质量(IAQ)的管理。     

Removing of fulvic acids by ozonation and biological active carbon filtration

It was studied the effect of the content of biodegradable organic carbon (BDOC) after the processes of aeration and ozonation of the fulvic acid (FA) solutions on the efficiency of its adsorption and biofiltration. It was found that the change of free energy of adsorption of the FA oxidation products correlated with the part of biodegradable organic carbon in total organic carbon content. Predicting the effectiveness of NOM solutions ozonation before filtration through BAC is more appropriate by determining the value of the free adsorption energy. It was established that ozonation of FA solutions with high initial BDOC content by ozone doses that are economically and technologically acceptable, leads to a decrease in the BDOC value. Ozonation of FA solutions leads to equalization of the adsorption ability of FA fractions and increases the adsorption energy of FA in most investigated systems with a high initial BDOC content.     

Photocatalytic oxidation of aqueous ammonia in model gray waters

This study investigated the TiO2 photocatalytic degradation of aqueous ammonia (NH4+/NH3) in the presence of surfactants and monosaccharides at pH approximately 10.1. Initial rates of NH4+/NH3 photocatalytic degradation decreased by approximately 50-90% in the presence of anionic, cationic, and nonionic surfactants and monosaccharides. Through correlation analysis, we concluded that scavenging of hydroxyl radical (.OH) by the products of surfactant/monosaccharide photocatalytic degradation, including carbonate and formate, could explain approximately 80% of the variance in initial rates of NH4+/NH3 removal in our system. Addition of a supplemental .OH source (H2O2) enhanced the rate of NH4+/NH3 degradation in the presence of the surfactant Brij 23 lauryl ether (Brij 35), further supporting the idea that .OH scavenging is the mechanism by which surfactants and monosaccharides decreased initial rates of NH4+/NH3 photocatalytic degradation. Despite slowed rates of NH4+/NH3 degradation, both surfactants/monosaccharides and NH4+/NH3 were removed by TiO2 photocatalysis, indicating that this process can effectively remove both carbonaceous and nitrogenous biochemical oxygen demand from gray water.     

Mineralization of organic matter and other chemical effects of chlorination

Selected river waters, estuarine waters and effluents from wastewater treatment plants, collected during various seasons, have been treated with 0.14 mM (10 ppm) chlorine in order to determine the reactive components involved in chlorine decay reactions. Mineralization of organic matter, detected by measuring evolved CO₂, was universal and constituted the most significant decay process observed. In most cases, loss of ammonia, primary organic amines and nitrite occurred, but removal of these components was not complete. Nitrate was usually produced, but the increases were small relative to initial concentrations. Ammonia in secondary effluent retards chlorine decay and suppresses carbon mineralization. After a week, renewed microbial growth began in anaerobic river water treated with monochloramine even though residual monochloramine remained. The onset of growth coincided with accelerated decay of the monochloramine residual, suggesting that reducing agents were being produced biologically. The faster decay of residual chlorine in denitrified secondary effluents, with low ammonia, demonstrates an additional environmental benefit of denitrification.     

几种室内结露的原因分析与防治

本文从结露常见的部位入手,分析原因,并提出相应的防治措施。     

氨氮浓度对活性炭深度处理工艺选择的影响

以北江佛山段原水为处理对象,比较了活性炭吸附（GAC）和臭氧/生物活性炭（O3/BAC）两种深度处理工艺对氨氮的去除效果,并分析了预氯化对其处理效果的影响.结果表明,GAC和O3/BAC工艺均具有一定的耐氨氮冲击负荷能力.低氨氮浓度下,GAC和O3/BAC工艺对氨氮的去除率接近（约40%）,并随着进水氨氮浓度的增大而增加;两者出水中的CHCl3浓度均超标,但O3/BAC的较低;综合考虑处理效果及成本,建议此时优先采用GAC工艺.高氨氮浓度下,O3/BAC工艺去除氨氮的效果显著优于GAC,经消毒后其出水中的CHCl3浓度也低于GAC的,故建议在该种原水水质下优先采用O3/BAC工艺.控制沉淀池出水余氯在合适的范围内,则预氯化对O3/BAC工艺的除污效果无影响.     

Indoor boundary layer chemistry modeling

Ozone (O₃) chemistry is thought to dominate the oxidation of indoor surfaces. We consider the hypothesis that reactions taking place within indoor boundary layers result in greater than anticipated hydroxyl radical (OH) deposition rates. We develop models that account for boundary layer mass‐transfer phenomena, O₃‐terpene chemistry and OH formation, removal, and deposition; we solve these analytically and by applying numerical methods. For an O₃‐limonene system, we find that OH flux to a surface with an O₃ reaction probability of 10^?8 is 4.3 × 10^?5 molec/(cm² s) which is about 10 times greater than predicted by a traditional boundary layer theory. At very low air exchange rates the OH surface flux can be as much as 10% of that for O₃. This effect becomes less pronounced for more O₃‐reactive surfaces. Turbulence intensity does not strongly influence the OH concentration gradient except for surfaces with an O₃ reaction probability >10^?4. Although the O₃ flux dominates OH flux under most conditions, OH flux can be responsible for as much as 10% of total oxidant uptake to otherwise low‐reactivity surfaces. Further, OH chemistry differs from that for ozone; therefore, its deposition is important in understanding the chemical evolution of some indoor surfaces and surface films.     

Indoor emissions of total and fluorescent supermicron particles during HOMEChem

Inhalation of particulate matter is associated with adverse health outcomes. The fluorescent portion of supermicron particulate matter has been used as a proxy for bioaerosols. The sources and emission rates of fluorescent particles in residential environments are not well-understood. Using an ultraviolet aerodynamic particle sizer (UVAPS), emissions of total and fluorescent supermicron particles from common human activities were investigated during the HOMEChem campaign, a test-house investigation of the chemistry of indoor environments. Human occupancy and activities, including cooking and mopping, were found to be considerable sources of indoor supermicron fluorescent particles, which enhanced the indoor particle concentrations by two orders of magnitude above baseline levels. The estimated total (fluorescent) mass emission rates for the activities tested were in the range of 4-30 (1-11) mg per person meal for cooking and 0.1-4.9 (0.05-4.7) mg/h for occupancy and mopping. Model calculations indicate that, once released, the dominant fate of coarse particles (2.5-10 micrometer in diameter) was deposition onto indoor surfaces, allowing for the possibility of subsequent resuspension and consequent exposures over durations much longer than the ventilation time scale. Indoor coarse particle deposition would also contribute to soiling of indoor surfaces.     

Relationships Between Indoor and Outdoor Contaminants in Mechanically Ventilated Buildings

Abstract It is shown that comparing measured indoor and outdoor contaminant concentrations can be misleading if the concentrations vary with time and if the averaging periods are too short. In this article an alternative methodology aimed at estimating the internal source and sink effects in mechanically ventilated buildings is described. The methodology is based on both the results from continuous measurements, and calculations under transient conditions. The relative importance of indoor sources and outdoor sources is established by a comparison of the measured indoor concentration and a calculated indoor concentration of a compound. Furthermore, dynamic calculations are used to investigate how the indoor concentrations of contaminants originating outdoors and contaminants emitted from indoor sources are influenced by temporal reductions of the airflow rate. Reducing the outdoor airflow rate during periods with high outdoor concentrations can significantly reduce the indoor levels of pollutants for situations in which the outdoor sources are more important than the indoor sources.     

室内空气中氨含量两种化学测定方法的比较

GB/T18204.25-2000《公共场所空气中氨测定方法》中给出的氨的化学检测方法为靛酚蓝试剂比色法和纳氏试剂比色法.两种方法各有优点和局限性,现就两法的标准曲线的相关系数、灵敏度、检出限、测量范围等特性进行了比对实验,认为靛酚蓝试剂比色法为测量室内空气最佳方法,同时对两法的优缺点进行了探讨.     

Outdoor Air Contaminants and Indoor Air Quality under Transient Conditions

The indoor concentrations of contaminants originating from outdoor sources have been measured and calculated under transient conditions. The results show that contaminants that are supplied to an office building via the ventilation system can reach considerably high concentration levels. The indoor/outdoor concentration ratio and time lag are dependent on the air change rate. In buildings with low air change rates the indoor concentration variations are smoothed out compared to buildings with high air change rates. The results from the theoretical model are compared to the results from both laboratory and field measurements and the model is verified for well mixed conditions in a 20 m³ test chamber. The model can be used to simulate different control strategies for reduction of indoor contaminant concentrations related to outdoor sources. One such control strategy is based on reduction of the outdoor air change rate during periods with peak outdoor contaminant concentrations.     

Predictive Models Based on Personal,Indoor and Outdoor Air Pollution Exposure

Portable air pollution samplers were used to measure sulphur dioxide (SO₂), nitrogen dioxide (NO₂) and respirable suspended particulates (RSP) in a study of a group of nineteen asthmatics during two periods in the winter and summer respectively. One sampler was carried by each subject, one was placed in the home indoors, and one outdoors by the home. In addition, similar pollutants were measured at a central stationary site within a 15 km radius during the same time periods. Samplers were not placed, however, in other indoor spaces where subjects spent part(s) of the day. We used the data from all the sampling sites to develop predictive models for personal exposure. With 330 person-days of exposure data, multiple regression of these “fixed site” measures of pollution against the personal exposure measures revealed a predictive relationship whose power increased proportionally to the time the subjects spent indoors. This relationship was limited, however, since samplers were not placed at other indoor spaces, thus leaving the predictive model incomplete. A pollution index in which these indoor and outdoor pollutant measures were weighted by the time spent at home indoors and outdoors was predictive of personal exposure for NO₂ and RSP (R = 0.78,0.44 respectively); the SO₂ levels were too low to be used in the comparative analysis (R = 0.19).