Factors affecting wavelength-resolved ultraviolet irradiance indoors and their impacts on indoor photochemistry

We measured wavelength-resolved ultraviolet (UV) irradiance in multiple indoor environments and quantified the effects of variables such as light source, solar angles, cloud cover, window type, and electric light color temperature on indoor photon fluxes. The majority of the 77 windows and window samples investigated completely attenuated sunlight at wavelengths shorter than 320 nm; despite variations among individual windows leading to differences in indoor HONO photolysis rate constants (J_HONO) and local hydroxyl radical (OH) concentrations of up to a factor of 50, wavelength-resolved transmittance was similar between windows in residential and non-residential buildings. We report mathematical relationships that predict indoor solar UV irradiance as a function of solar zenith angle, incident angle of sunlight on windows, and distance from windows and surfaces for direct and diffuse sunlight. Using these relationships, we predict elevated indoor steady-state OH concentrations (0.80–7.4 × 10⁶ molec cm⁻³) under illumination by direct and diffuse sunlight and fluorescent tubes near windows or light sources. However, elevated OH concentrations at 1 m from the source are only predicted under direct sunlight. We predict that reflections from indoor surfaces will have minor contributions to room-averaged indoor UV irradiance. These results may improve parameterization of indoor chemistry models.     

住宅侧窗设计方案探析

在天然光的利用过程中关键是处理好采光口的窗体设计.从窗体不同部分的不同功能定位出发,通过遮阳板、室内反光搁板、百叶窗、窗帘等构配件对直射光的遮挡、反射和漫射光的利用进行了分析,进而对天然采光中最常见的侧窗窗体的设计方法进行了相应的探讨.     

Occupants' operation of lighting and shading systems in office buildings

In most buildings, people operate control devices such as windows, shades, luminaires, radiators and fans to bring about desirable indoor environmental conditions. These control actions have a significant impact on buildings' performance and sustainability (energy use, indoor climate). A better understanding of the logic and patterns of such control-oriented user behaviour can not only facilitate better predictions of buildings' performance, but also support the effective operation of buildings' service systems. This paper describes an extensive empirical study of control-oriented user behaviour (as related to systems for lighting and shading) in a number of office buildings in Austria. The results specifically shed light on the relationships between control actions and environmental conditions inside and outside buildings.     

Shading and lighting operation in office buildings in Austria: A study of user control behavior

Occupants of buildings typically operate devices such as windows, shades, luminaires, radiators, and fans to bring about desirable indoor environmental conditions. These control actions can have a significant impact on buildings’ performance (energy use, indoor climate). A better understanding of control-oriented user behavior can not only facilitate more accurate predictions of buildings’ performance, but also support the effective operation of buildings’ service systems. This paper describes a study of control-oriented user behavior (as related to systems for lighting and shading) in three office buildings in Austria. The results specifically shed light on the relationships between control actions and environmental conditions inside and outside buildings.     

Indoor thermal environmental conditions near glazed facades with shading devices – Part I: Experiments and building thermal model

This paper presents an experimental study of indoor thermal environment near a full-scale glass facade with different types of shading devices under varying climatic conditions in winter. Interior glazing and shading temperature, operative temperature and radiant temperature asymmetry were measured for façade sections with roller shades and venetian blinds at different positions. Interior glass surface temperatures can be high during sunny days with low outdoor temperature. Shading systems significantly improved operative temperature and radiant temperature asymmetry during cold sunny days, depending on their properties and tilt angle. During cloudy days the impact was smaller, however the shading layers could still decrease the amount of heat loss through the façade. A transient building thermal model, which also calculates indoor environmental indices under the presence of solar radiation, was developed and compared with the experimental measurements. Part II of this paper uses this validated model with a transient, two-node thermal comfort model (including transmitted solar radiation) for assessment of indoor environmental conditions with different building envelope and shading properties, façade location and orientation.     

Stable oxygen isotopic fractionation during photolytic O(2) consumption in stream waters

Oxygen (O(2)) is required for life in higher organisms, however, processes such as respiration, the oxidation of reduced inorganic species, and the photolytic breakdown of dissolved organic matter (DOM) decrease the O(2) concentrations in aquatic systems. Filtered, inoculated, and sterile samples of stream waters from Ontario, Canada, were incubated in natural sunlight to examine the effects of photolysis of DOM, respiration, and abiotic reactions on O(2) consumption and delta(18)O of dissolved oxygen (delta(18)O-O(2)). Oxygen consumption rates in the light were up to an order of magnitude greater than in the dark, suggesting light-mediated processes controlled O(2) consumption. Rates of O(2) loss were the same for each treatment (i.e. filtered, inoculated, and sterile) indicating that photolysis was the dominant O(2) consuming process over respiration in these incubations. O(2) consumption rates were different between streams, even when normalized to the change in dissolved organic carbon (DOC), signifying that DOM photolability varied among streams. During DOM breakdown to CO(2), the lighter (16)O isotopomer was preferentially consumed. Fractionation factors observed for photolysis, respiration, and abiotic reactions ranged between 0.988 and 0.995, and were similar in both the light and in the dark incubations in all streams. These fractionation factors are not a function of O(2) consumption rates, and are outside the range published for respiration (0.975-0.982). In current models of O(2) and delta(18)O-O(2), photolysis and respiration are not considered separately and the isotopic fractionation during respiration that is measured in the dark is used in the light. In these incubations, DOM degradation and abiotic reactions are important O(2) consuming and delta(18)O-O(2) fractionating processes. Current models of O(2) and delta(18)O-O(2) incorporate photolysis of DOM and other abiotic processes into the respiratory component of O(2) consumption, thereby overestimating respiration and underestimating photosynthesis to respiration ratios. Consequently, photolysis and abiotic reactions should be considered separately, particularly in shallow aquatic systems with high DOC.     

Comparative monitoring of natural,hybrid and mechanical ventilation systems in urban canyons

A number of field and indoor experimental procedures were performed in three typical apartment buildings located in two street canyons characterized by different urban features, during summer period 2002 in Athens. Natural, mechanical and hybrid ventilation measurements were performed based on the tracer gas method on a circular basis within the 24-h period. The indoor exchange rates are estimated using both single and multi-zone approaches based on the mass balance of two tracer gases (N₂O and SF₆). The experiments pointed out that, in spite of the canyon effect, appreciable ventilation rates can be obtained with natural ventilation, especially when cross ventilation with two or more windows is measured. In the presence of cross ventilation and with sufficient ambient wind speeds, natural ventilation is shown to be more effective, with regard to ACH, in comparison with hybrid. However, when only single-sided ventilation is possible or under calm conditions hybrid ventilation has a slight advantage over natural. A comparative analysis is made for the total air change rates estimated with the single and multi-zone methodologies. The multi-zone approach, in spite of its better theoretical basis, has been found more sensitive to the accuracy of the measured concentrations, especially when a single tracer is used.     

Thermal analysis of super insulated windows (numerical and experimental investigations)

Windows are crucial for people's experience of the indoor climate, especially in the Nordic countries with cold climate and short days during the winter. This paper reports the first results from an ongoing research project focused on an improved integration of windows with the indoor air climate and people's perception of the windows. The thermal performance of a well-insulated window has been investigated both numerically and experimentally in a full scale test room. The window under consideration is a low-emissive triple-glazing window with two closed spaces filled with the inert gas krypton. An oxidised metal with low emissivity factor coats one pane in each space. Experimental and numerical investigations on the thermal performance of the window have been conducted for different winter cases. Temperature data obtained by direct temperature measurement using thermocouples and through numerical analysis are presented. The heat transfer through a window construction depends on three mechanisms i.e., conduction, convection and radiation. In this paper the convection-conducting mechanisms have been closely investigated. The numerical predictions agree well with the results from the measurements.     

外窗遮阳对室内温度的影响

建筑遮阳系数对建筑能耗和室内热环境均有影响,而室内空气温度作为影响热舒适的主要因素与窗户遮阳存在必然联系.采用DOE-2软件计算方法分析遮阳系数变化时室内温度降低的分布情况,说明夏季设置外遮阳对室内热环境改善的效果.     

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.     

Improvement of thermal environment and reduction of energy consumption for cooling and heating by retrofitting windows

Various techniques for creating a comfortable thermal environment and saving energy have been proposed and employed in residential buildings in many countries, including Japan. For these techniques to be introduced, existing houses should be renovated. Among the techniques available, installation of additional inner windows is effective in creating a comfortable and energy-efficient living environment. In the present research, the effect of additional inner windows on the thermal environment and energy saving was investigated by measuring indoor windows on the thermal environment and energy saving was investigated by measuring indoor concrete building. Air temperatures, the humidity, the global solar radiation on horizontal and vertical surfaces, radiant temperatures, and the electricity consumption of air-conditioners were measured. A comparison of these values before and after the installation of inner windows showed that the thermal environment and energy saving had improved. Results obtained from a thermal model agreed well with measured results by changing the value of solar transmittance and heat transmission coefficient of the glazing following renovation. Furthermore, in a questionnaire survey conducted in summer, more than half of the occupants answered ‘‘comfortable’’ to a question on the overall thermal comfort.     

Untersuchungen zum Raumklima und zur Fensterlüftung in Schulen

Investigations on indoor environmental conditions and natural ventilation in school buildings. There are more than 40,000 school buildings in Germany. Most of them are awaiting retrofitting. Retrofitting is not only intended to improve the energetic standards, but first of all to improve indoor environmental conditions for pupils and teachers. As most of German schools are not equipped with mechanical ventilation systems, natural ventilation controlled by the occupants opening the windows is the main way to maintain healthy and comfortable conditions in the classrooms. For that purpose the influence of window opening behaviour of the occupants on the indoor environment was measured in two German schools. Temperature and carbon dioxide concentration of the indoor air as well as the outdoor climate conditions were measured. In one school the frequency of window opening was recorded. Besides high CO₂‐concentrations especially during winter, some of the investigated classrooms are additionally to cold in winter or to hot in summer. Some classrooms do not have a shading device or the shading device is insufficient or it constricts the ventilation of the room. Windows are used as controls in some degree during lessons and during the breaks. But windows get closed after lessons and stay closed until next morning. There is no night or early morning ventilation in summer. A significant weak to moderate positive correlation between total open window ratio and indoor temperature has been found. Correlation between total open window ratio and outdoor temperature is not significant in most cases or show a weak correlation coefficient.     

On the estimation of characteristic indoor air quality parameters using analytical and numerical methods

Indoor exposure to air contaminants penetrating from the outdoor environment depends on a number of key processes and parameters such as the ventilation rate, the geometric characteristics of the indoor environment, the outdoor concentration and the indoor removal mechanisms. In this study two alternative methods are used, an analytical and a numerical one, in order to study the time lag and the reduction of the variances of the indoor concentrations, and to estimate the deposition rate of the air contaminants in the indoor environment employing both indoor and outdoor measurements of air contaminants. The analytical method is based on a solution of the mass balance equation involving an outdoor concentration pulse which varies sinusoidally with the time, while the numerical method involves the application of the MIAQ indoor air quality model assuming a triangular pulse. The ratio of the fluctuation of the indoor concentrations to the outdoor ones and the time lag were estimated for different values of the deposition velocity, the ventilation rate and the duration of the outdoor pulse. Results have showed that the time lag between the indoor and outdoor concentrations is inversely proportional to the deposition and ventilation rates, while is proportional to the duration of the outdoor pulse. The decrease of the ventilation and the deposition rate results in a rapid decrement of the variance ratio of indoor to outdoor concentrations and to an increment of the variance ratio, respectively. The methods presented here can be applied for gaseous species as well as for particulate matter. The nomograms and theoretical relationships that resulted from the simulation results and the analytical methods respectively were used in order to study indoor air phenomena. In particular they were used for the estimation of SO2 deposition rate. Implications of the studied parameters to exposure studies were estimated by calculating the ratio of the indoor exposure to the exposure outdoors. Limitations of the methods were explored by testing various scenarios which are usually met in the indoor environment. Strong indoor emissions, intense chemistry and varying ventilation rates (opening and closing of the windows) were found to radically influence the time lag and fluctuation ratios.     

Assessment of indoor HONO formation mechanisms based on in situ measurements and modeling

The photolysis of HONO has been found to be the oxidation driver through OH formation in the indoor air measurement campaign SURFin, an extensive campaign carried out in July 2012 in a classroom in Marseille. In this study, the INCA‐Indoor model is used to evaluate different HONO formation mechanisms that have been used previously in indoor air quality models. In order to avoid biases in the results due to the uncertainty in rate constants, those parameters were adjusted to fit one representative day of the SURFin campaign. Then, the mechanisms have been tested with the optimized parameters against other experiments carried out during the SURFin campaign. Based on the observations and these findings, we propose a new mechanism incorporating sorption of NO₂ onto surfaces with possible saturation of these surfaces. This mechanism is able to better reproduce the experimental profiles over a large range of conditions.     

Formation and emission of hydrogen chloride in indoor air

To improve our understanding of chlorine chemistry indoors, reactive chlorine species such as hydrogen chloride (HCl) must be analyzed using fast time‐response measurement techniques. Although well studied outdoors, sources of HCl indoors are unknown. In this study, mixing ratios of gaseous HCl were measured at 0.5 Hz in the indoor environment using a cavity ring‐down spectroscopy (CRDS) instrument. The CRDS measurement rate provides a major advance in observational capability compared to other established techniques. Measurements of HCl were performed during three types of household activities: (a) floor exposure to bleach, (b) chlorinated and nonchlorinated detergent use in household dishwashers, and (c) cooking events. Surface application of bleach resulted in a reproducible increase of 0.1 ppbv in the affected room. Emissions of HCl from automated dishwashers were observed only when chlorinated detergents were used, with additional HCl emitted during the drying cycle. Increased mixing ratios of HCl were also observed during meal preparation on an electric element stovetop. These observations of HCl derived from household activities indicate either direct emission or secondary production of HCl via chlorine atoms is possible. Calculations of photolysis rate constants of chlorine atom precursors provide evidence that photolysis may contribute to indoor HCl levels.     

高原寒冷地区太阳辐射对室内热环境影响

以拉萨地区某多层办公建筑为研究对象,对供暖期测试日(全天晴朗、晴转阴)逐时太阳辐射强度模拟计算,对测试日室外温度、风速进行实测。分析太阳辐射对测试房间(分别选取南向房间2间,北向房间2间,其中1间南向测试房间不供暖)室内温湿度的影响。结合实测结果,对拉萨地区供暖系统、建筑的优化设计提出建议。     

Real-time characterization of aerosol particle composition,sources and influences of increased ventilation and humidity in an office

Most of human exposure to atmospheric pollutants occurs indoors, and the components of outdoor aerosols may have been changed in the way before reaching indoor spaces. Here we conducted real-time online measurements of mass concentrations and chemical composition of black carbon and the non-refractory species in PM_2.5 in an occupied office for approximately one month. The open-close windows and controlled dampness experiments were also performed. Our results show that indoor aerosol species primarily originate from outdoors with indoor/outdoor ratio of these species typically less than unity except for certain organic aerosol (OA) factors. All aerosol species went through filtration upon transport indoors. Ammonium nitrate and fossil fuel OA underwent evaporation or particle-to-gas partitioning, while less oxidized secondary OA (SOA) underwent secondary formation and cooking OA might have indoor sources. With higher particulate matter (PM) mass concentration outdoors than in the office, elevated natural ventilation increased PM exposure indoors and this increased exposure was prolonged when outdoor PM was scavenged. We found that increasing humidity in the office led to higher indoor PM mass concentration particularly more oxidized SOA. Overall, our results highlight that indoor exposure of occupants is substantially different from outdoor in terms of mass concentrations and chemical species.     

轻型钢结构大空间建筑空调设计两题一例

结合工程实践，探讨了大空间建筑空调设计的一些特点。主张推广使用直接蒸发系统，简化室内气流组织设计，使空调系统与大空间建筑自身更加协调。对一具体工程的技术经济比较表明上述观点是可行的。     

谈西安地区教学建筑的遮阳设计

合适的遮阳设计可以改善建筑的室内热环境．但窗口设置遮阳之后,对房间的采光和通风产生不利的影响。本文以西安地区为例,结合当地的气候特．董及高校教室的具体情况,详细论速了教学建筑南向及西向的遮阳设计,提出了适合该地区的遮阳措施。     

Photochemical induced changes of in vitro estrogenic activity of steroid hormones

Steroid estrogens are endocrine disrupting contaminants frequently detected in natural waters. Because these estrogens can elicit significant biological responses in aquatic organisms, it is important to study their rates and pathways of degradation in natural waters and to identify whether the transformation products retain biological activity. Photochemical kinetics experiments were conducted under simulated solar light for the hormones 17β-estradiol (E2), 17α-ethinylestradiol (EE2), estrone (E1), equilin (EQ), and equilenin (EQN) under direct and indirect photolysis conditions. All of these hormones were susceptible to direct photodegradation, with half-lives ranging from 40 min for E1 to about 8 h for E2 and EE2. Indirect photolysis experiments with added Suwannee River fulvic acid (SRFA) lead to faster degradation rates for E2, EE2, and EQ. Added SRFA caused slower photodegradation rates for E1 and EQN, indicating that it acts primarily as an inner filter for these analytes. The well-established yeast estrogen screen (YES) was used to measure the estrogenicity of the analytes and their photoproducts. Results of YES assay experiments show that only the direct photolysis of E1 gave estrogenic products. Lumiestrone, the major E1 direct photolysis product, was isolated and characterized. It formed in 53% yield and exhibited moderate estrogenic activity. When photolysed in the presence of perinaphthenone, a potent synthetic sensitizer, E1 degraded via an indirect photolysis pathway and did not produce lumiestrone or any other active products. These results suggest that under typical natural water conditions photochemical reactions of E2, EE2, EQ, and EQN are expected to produce inactive products while E1 will give the estrogenic product lumiestrone in moderate yield.