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室内外空气污染物相关性研究

Correlation between Outdoor and Indoor Air Pollutants

【作者】 文远高

【导师】 连之伟;

【作者基本信息】 上海交通大学 , 制冷及低温工程, 2008, 博士

【摘要】 室内空间是人们停留时间最长的一种环境场所,因此室内空气品质对人的健康和工作状况有直接影响。通常情况下,室内外环境是相互作用、相互联系的,这二者之间的定量关系如何是一个值得研究的问题,特别是室内外污染物的相互影响需要研究。本文采用理论与实验相结合的方法,在分析影响室内空气品质(IAQ)各主要因素基础上,对建筑物室内外环境中与人体健康密切相关的几种污染物——甲醛、CO、CO2和颗粒物以及空调运行排放的废热进行了研究。首先,利用系统工程的原理,建立起反映IAQ系统问题要素间层次关系的递阶结构模型。该模型表明影响IAQ因素之间存在着5个层次关系。其次,通过测量上海某校园内一个办公室和一个公寓建筑室内外颗粒物PM10、PM2.5、PM1的浓度,研究了室内外PM10、PM2.5、PM1的浓度及其室内外浓度比值(I/O)随时间变化的规律以及相关性。结果表明:对公寓和办公室而言,室外颗粒物是室内颗粒物的主要来源。在城市没有工业污染源的情况下,室内外颗粒物浓度都随时间变化而变化,并且变化趋势一致。颗粒物从室外向室内输运过程中,细颗粒物穿透能力强,I/O比值随粒径的减少而增大。室内外颗粒物浓度密切相关,并且这种相关性随粒径的减少而增强。对上海中心城区的三个空调商场室内外空气污染物进行了测试分析。结果表明:若人流密度中等以下,且除了顾客购物外,没有其它明显的室内污染源的商场,其室内颗粒物PM10、PM2.5、PM1浓度比室外浓度低,且I/O比值小于1。若人流密度大,且商场内有餐饮等室内污染源的商场,其室内颗粒物PM10、PM2.5、PM1浓度比室外浓度高,且I/O比值大于1,说明这样的商场颗粒物污染较室外严重,室内污染源对室内颗粒物浓度贡献大。在这样的地方,除了人的活动产生颗粒物外,应对餐厅等产生的颗粒物加以控制,以改进室内环境质量。对武汉市区8个商场室内外HCHO、CO和CO2浓度以及其中三个商场的颗粒物浓度进行了测试研究。结果表明:商场楼层不同,CO2及甲醛(HCHO)浓度不一样。由于商场面积大,每个楼层商品不同,即使同一楼层,不同柜台(商品区)的CO2及甲醛(HCHO)浓度也有差异,这些问题在进行空调设计时应加以考虑。商品不同,其构成的成分不一样,所散发有害物的特性不同。对于除了顾客以外没有室内污染源并且人流密度中等的商场,空调运行季节其室内颗粒物TSP、PM10、PM2.5、PM1浓度比室外浓度值低得多;而在空调不运行季节,室内颗粒物TSP、PM10、PM2.5、PM1浓度等于甚至高于室外浓度,特别是有室内污染源的情况更是如此。对上海市夏季不同种类的空调客车车辆内环境质量进行了测试。测试指标包括温度、湿度、CO、CO2和甲醛等指标。测试车辆种类有空调公共汽车、地铁和轻轨。测试分析表明:通常情况下,不同种类车辆的室内温湿度一般满足人体热舒适的要求,但正午时分,由于太阳辐射强,公共汽车车厢内温度较高,甚至远高于人体舒适温度。地铁和轻轨车厢内空气品质较好,空调公汽的空气品质很差。公汽内CO2浓度高达3223ppm以上,CO高达18ppm,甲醛浓度也较高。对空调公交汽车的空气品质有待改进。最后研究了空调的使用所排放的废热对室外环境的影响。空调在改善室内热环境的同时,也向室外排放大量的热量。空调运行排放的废热所引起的热污染是一种广义的空气污染。本文提出了计算由此引起气温上升的模型,并采用这种模型计算了武汉市的温升值。在逆温情况下计算的温升值为2.56℃,正常温度情况下计算的温升值为0.2℃。可见大气处于稳定时,家用空调器排放的热量引起的热污染尤为严重。本文的研究成果有助于合理寻求改善室内空气品质的对策和措施,有助于建筑环境的合理规划。

【Abstract】 People generally spend most of their time indoors. Indoor air quality (IAQ) is directly related to human health and working efficiency. Usually, there is interaction and interrelation between indoor and outdoor environmental parameters. Therefore, the quantitative relation between them is worthy of being studied, especially correlation between outdoor and indoor air pollutants.The theoretical analysis and site measurement are together combined in this research. After discussing the relationship between some dominant factors affecting IAQ, several pollutants (HCHO、CO、CO2 and particulate matter, PM), which closely relate to human health in indoor and outdoor environments of buildings, and waste heat rejected by air conditioning were investigated. First, based the principle of system engineering, the interpretative structural modeling (ISM) that related to the relationship among the factors affecting indoor air quality (IAQ) in buildings is established, which indicates that there are five layers among these factors.Second, the particulate matter concentrations in an office and residential room were measured. Then indoor and outdoor particle concentrations and their ratios (I/O) were analysed. For buildings that without any indoor sources and with low human activity, the indoor particulate matters mainly come from the outdoor particulate matters. So for the buildings near roadside without industrial pollution sources, the indoor particulate matter in fact primarily comes from the traffic emissions. Both the concentration of indoor and outdoor particulates of the apartment room and office room vary with time, and tendency of their variation is similar. The I/O ratio increases as the size of particles decreases, which indicates that the fine particles penetrate through the building envelopes more easily. The concentration of indoor particles is closely correlated with that of outdoor particles, and the correlation increases as particle size reduces. The concentration of indoor particle is correlated with environmental parameters to some extent. For the apartment, the concentration of indoor particle is positively correlated with the indoor/outdoor temperature; and it is negatively correlated with the indoor/outdoor humidity and wind speed.Through the survey of three shopping malls in Shanghai, results demonstrated that different floors at the shopping malls have different concentrations of CO2, HCHO and PM (PM10, PM2.5, PM1). Moreover, owing to big area of shopping malls and different merchandises for sale at each floor, there was difference on concentration of CO2, HCHO and PM (PM10, PM2.5, PM1) even at the same floor. These problems should be taken into consideration when designing an air conditioning system. In two shopping malls without indoor sources besides the consumers and where occupant density is under middle level, the indoor concentrations of PM10、PM2.5、PM1are lower than outdoor concentrations, and the I/O ratios below unity. In one shopping mall with indoor sources like cooking and where occupant density is under high level, the indoor concentrations of PM10、PM2.5、PM1 are higher than outdoor concentrations, and the I/O ratios above unity. It implies that the pollution from particulate matter in this shopping mall is much serious indoors than outdoors. In this environment, except human activity, the airborne particulate matter from cooking and combustion should be controlled in order to improve indoor air quality.The survey results of eight shopping malls in Wuhan demonstrated that different floors at the shopping malls have different concentrations of CO2, HCHO and PM (PM10, PM2.5, and PM1). Moreover, due to big area of shopping malls and different merchandises for sale at each floor, there were differences in concentration of CO2, HCHO and PM (PM10, PM2.5, and PM1) even at the same floor. These problems should be taken into consideration when designing an air conditioning system. Different merchandises emitted different harmful pollutants due to their different composition. During operation of air conditioning systems at the shopping malls without indoor sources besides the customers and where occupant density is under middle level, the indoor concentrations of TSP, PM10、PM2.5、PM1 are lower than outdoor concentrations. During the non-operation of air conditioning system in the floor of a shopping mall with indoor sources like cooking and where occupant density is under high level, the indoor concentrations of TSP, PM10、PM2.5、PM1 are equal to or higher than outdoor concentrations, and the indoor/outdoor (I/O) ratios equal to or above unity. It implies that the pollution from particulate matter at this situation is much more serious indoors than outdoors and the indoor source has much contribution to the concentration of indoor particulate matter. In this environment, except human activity, the airborne particulate matter from cooking and combustion should be controlled in order to improve indoor air quality.The measurement results of the inside microenvironment parameters for different types of air conditioned vehicles in Shanghai demonstrate that the inside temperature and humidity can usually meet human thermal comfort in most time, but around sunny noon the temperature inside bus is high, even far higher than human comfort zone temperature due to strong sunny radiation. There is a remarkable difference between the inside air environment parameters of different types of air-conditioned urban transit vehicles. Usually, there is good air quality inside the light rail and subway carriages. Poor air quality inside air-conditioned bus exists, which CO2 concentration may be high to 3223ppm, CO concentration high to 18ppm sometimes, and HCHO concentration is high. Therefore, the thermal comfort and air quality inside air-conditioned bus need to be improved.Finally, the influence of air conditioners utilization on urban thermal environment is studied. The urban heat island effect is essentially a kind of thermal pollution caused by artificial activity. Air conditioning units used in buildings release a great deal of heat into outdoors while they improve the indoor thermal environment. Therefore, this will cause a rise in the outside air temperature and strengthen the urban heat island effect. The model for calculating the rise in atmospheric temperature caused by domestic air conditioners is proposed and used to determine the rise in the outside air temperature in Wuhan. The results demonstrate that the rise in atmospheric temperature is 2.56℃under inversion conditions and 0.2℃under normal conditions, which indicates that thermal pollution is serious when the atmosphere is stable. To a certain extent, the rise of atmospheric temperature can be verified by the rise of lowest atmospheric temperature of Wuhan over recent years. The study is helpful to seek for methods to improve indoor air quality and and layout of building and environment.

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