北京地区冬季高校宿舍空气微生物浓度和粒径分布特征

微生物气溶胶对人体健康的危害与其种类、浓度和粒径大小有关。为了研究北京地区冬季高校宿舍空气微生物污染情况以及粒径分布特征,本文采用撞击法对北京某高校学生宿舍空气中的微生物浓度进行测试,并测试室外空气中的微生物浓度作为对照。结果表明,宿舍空气中细菌气溶胶浓度处于清洁状态,有9. 5%的真菌浓度样本超过清洁限值;不同时态的微生物浓度不同,12:00浓度最低,9:00空气中的细菌的含量明显高于18:00;微生物气溶胶集中出现在Ⅳ、Ⅴ级(1. 1～3. 3μm),细菌峰值出现在Ⅴ级,真菌峰值出现在Ⅳ级,真菌可吸入部分所占百分比Rf明显大于细菌气溶胶可吸入部分所占百分比Rb。     

人员密集型场所细菌真菌气溶胶冬季分布特征及健康影响分析

地铁、超市、电子市场、医院挂号大厅等都属于人员数量多且活动多的密集型场所，其室内空气中的细菌真菌污染不容忽视。为了解这些人多场所内的细菌真菌气溶胶浓度及不同粒径段微生物的分布，于2019年冬季首先对四类场所内的细菌和真菌气溶胶进行了现场采样和实验分析，并测试了其它环境参数；然后分析了不同场所内细菌真菌气溶胶的浓度水平及分布特征；最后，评估了不同场所微生物气溶胶的浓度水平及可能产生的健康风险。结果表明：1)细菌气溶胶浓度均值为电子市场>超市>医院>地铁，其中电子城内细菌气溶胶浓度为838 cfu/m³,地铁内细菌为449 cfu/m³;真菌气溶胶浓度均值为超市>电子市场>医院>地铁，其中超市内真菌气溶胶浓度为558 cfu/m³,地铁内真菌为282 cfu/m³;2)细菌气溶胶中值直径为医院>地铁>电子市场>超市，真菌气溶胶中值直径为电子市场>医院>地铁>超市，且场所内细菌、真菌气溶胶中值直径均小于室外细菌真菌气溶胶中值直径；3)...     

北京地区医院建筑冬季室内微生物气溶胶浓度水平及暴露评价

为深入分析不同功能建筑室内微生物气溶胶的污染情况、分布特征及暴露水平。在对学校不同建筑冬季室内外细菌和真菌气溶胶的浓度水平分析的基础上,本文对医院不同功能场所室内细菌和真菌气溶胶的浓度大小、粒径分布和暴露水平进行了研究。结果表明:1)医院各场所冬季室内细菌气溶胶浓度为(82～841) cfu/m~3,真菌为(60～354) cfu/m~3,细菌与真菌浓度比B/F为1.91～5.10。2)医院室内细菌气溶胶的中值直径为(2.33～3.75)μm,真菌为(2.43～2.69)μm。且室内微生物气溶胶的中值直径均小于室外。3)医院室内细菌和真菌气溶胶对医务人员的日均潜在暴露量为(1 406～4 183)cfu/d和(485～1 601) cfu/d,对就诊人员的日均潜在暴露量为(144～1 101) cfu/d和(50～400) cfu/d。4)医院室内微生物气溶胶对医务人员的日均暴露量和潜在暴露量明显高于就诊人员,且测试医院门诊大厅内细菌和真菌气溶胶对医院人群的暴露量均高于呼吸科候诊厅、儿科候诊厅和口腔诊室的暴露量。     

中小学校新风系统节能运行策略分析

随着教育教学的发展,一线城市中小学校的设计建造标准越来越高,尤其是国际学校需要为学生提供环境美好、舒适自在、空气优质的教学环境。近些年,北京曾一度因为室外空气雾霾严重而导致中小学校被动停课,所以教室设置新风系统已成为中小学校设计的基本要求。本文以室外PM2.5浓度、教室内CO₂浓度和PM2.5浓度等参数为计算依据,得出在特定环境下教室人均最小新风量,建立起室外PM2.5浓度与室内空气质量的关系,从而依据室外PM2.5浓度的变化,为运行管理人员提供新风机组节能运行策略。     

空调病房室内浮游细菌浓度与粒径分布特征

为定量评估病房室内空气质量,保障设计及运行管理效果,采用IWL-6型六级撞击式空气微生物采集器对重庆市某综合医院3个内科空调病房进行现场采样,通过培养计数与镜检分析,获得了病房空气细菌气溶胶浓度及粒径分布,发现各科室均有一定的浮游细菌污染,病房空气细菌气溶胶浓度与温度、人员密度呈正相关,与相对湿度呈负相关,与科室类型无显著相关;夏季病房浮游细菌浓度高于冬季,儿科病房最高,浓度为2 865cfu·m~(-3)。细菌气溶胶粒径分布与季节相关,冬季主要分布在Ⅰ级~Ⅲ级,夏季主要在Ⅲ级~Ⅴ级。冬、夏季病房空气细菌气溶胶中值直径大于夏季,但均小于4.7μm。     

青岛市区春、夏季生物气溶胶浓度分布及特征

空气微生物具有重要的生态功能,并且与环境空气质量、空气污染和人体健康密切相关.为了解青岛市空气微生物分布特征和影响因素,采用SAS ISO100空气浮游菌采样仪和Andersen FA-I型6级空气微生物取样器采集空气微生物样品,分析青岛市区街道春季和夏季空气细菌和空气真菌浓度、气溶胶粒径分布以及环境因子对空气微生物浓度的影响.结果表明,青岛市区春季空气细菌和空气真菌浓度分别为596.6、797.4cfu/m3,夏季分别为280.9、250.9cfu/m3;空气细菌气溶胶粒径呈偏态分布,空气真菌气溶胶粒径呈对数正态分布;春季空气细菌、空气真菌气溶胶中值直径分别为4.6和2.2μm,夏季分别为4.1和1.9μm,空气细菌气溶胶中值直径大于空气真菌.     

冬季雾霾期间中学教室室内污染物测量与分析

北方地区中小学教室冬季多采用集中供暖或分体空调,教室长时间密闭,室内空气质量对学生学习效率影响较大。本文以济南某中学教室为例,通过对教室和室外大气中二氧化碳浓度、PM2.5浓度、温度以及相对湿度等连续一周的测试,给出了室内外二氧化碳浓度、PM2.5浓度、温度以及相对湿度等参数的相关性变化规律,为雾霾条件下教室内新风量的确定提供了基础数据。     

新风量对室内空气微生物污染控制的影响研究

对设置新风系统的实际工程进行测试,考察了新风系统对室内空气微生物的控制效果,并模拟了新风量对室内空气微生物污染的影响.测试结果显示,开启新风系统1.5～2.0 h后,教室室内空气中细菌浓度平均降低82.10％,真菌浓度平均降低86.64％.模拟结果显示,随着房间新风量的增大,房间内污染源、排风口及墙壁处气溶胶污染状况均...     

自然通风对教室CO_2浓度的影响模拟研究

分析了重庆市典型气象年风速数据,建立了某高校典型教室室内CO_2扩散的数学模型,采用数值模拟方法分析不同室外风速、不同开窗位置、不同开窗个数、不同教室平面布置时的教室室内CO2浓度变化情况。研究结果表明依据GB/T 18883-2002《室内空气质量标准》,重庆市自然通风能够满足要求的时间占教室全年使用时间的53%。教室自然通风效果受到室外风速、开窗位置、开窗个数、教室平面布置的影响,单一改变某一变量虽然也能够改善室内空气品质,但效率较低。建筑设计阶段应重视建筑平面布局,优化教室气流组织;教室使用阶段应开启正对人员聚集区的窗户,使新风直接进入人员呼吸区,提高通风的有效性。     

浅析西安地区高校教室自然采光设计——以西北工业大学长安校区为例

随着我国对高等教育投入的加大,以及对高校教学环境质量要求的提高,高校教学建筑的室内环境质量开始得到人们更多的关注。该文根据西安地区光气候特征和高校教室具体的使用情况等,结合对西北工业大学长安校区教学楼中典型教室的实地调研和分析,提出了改善高校教室室内自然采光设计的建议,包括优化平面空间设计、优化外窗设计、利用室外折光板、内墙开采光窗等。希望能为高校教室自然采光设计提供有益的参考。     

建筑室内外空气真菌浓度相关性案例测试分析

选取某高校学生办公室进行室内外空气真菌浓度相关性和粒径的研究.结果表明:室内空气真菌浓度变化范围为1 698～4 429 cfu/m3,最大值出现在12:00;室外浓度范围为3 569?29 452 cfu/m3,最大值也出现在12:00.室内外空气真菌浓度比值均小于1,Spearman相关性分析显示室内外空气真菌呈显...     

不同气候区城市公共建筑内微生物浓度对比分析

为研究不同气候区公共建筑室内微生物污染状况,选取昆明和南京分别代表温和地区和夏热冬冷地区,对医院和办公楼2类公共建筑内的微生物浓度进行了测量和分析。结果表明:温和气候区内医院细菌和真菌平均浓度分别为520、316 cfu/m³,办公楼细菌和真菌平均浓度分别为369、520 cfu/m³,均高于夏热冬冷气候区对应类型公共建筑;2个气候区室内细菌、真菌粒径分布相似,峰值均出现在粒径范围Ⅳ级(2.1~3.3μm)和Ⅴ级(1.1~2.1μm);2个气候区公共建筑室内相对湿度和空气真菌浓度存在确定关系,除此之外,仅在昆明医院内发现温度和微生物浓度之间存在显著相关性。     

Size-resolved emission rates of airborne bacteria and fungi in an occupied classroom

The role of human occupancy as a source of indoor biological aerosols is poorly understood. Size-resolved concentrations of total and biological particles in indoor air were quantified in a classroom under occupied and vacant conditions. Per-occupant emission rates were estimated through a mass-balance modeling approach, and the microbial diversity of indoor and outdoor air during occupancy was determined via rDNA gene sequence analysis. Significant increases of total particle mass and bacterial genome concentrations were observed during the occupied period compared to the vacant case. These increases varied in magnitude with the particle size and ranged from 3 to 68 times for total mass, 12-2700 times for bacterial genomes, and 1.5-5.2 times for fungal genomes. Emission rates per person-hour because of occupancy were 31 mg, 37 × 10(6) genome copies, and 7.3 × 10(6) genome copies for total particle mass, bacteria, and fungi, respectively. Of the bacterial emissions, ～18% are from taxa that are closely associated with the human skin microbiome. This analysis provides size-resolved, per person-hour emission rates for these biological particles and illustrates the extent to which being in an occupied room results in exposure to bacteria that are associated with previous or current human occupants. PRACTICAL IMPLICATIONS: Presented here are the first size-resolved, per person emission rate estimates of bacterial and fungal genomes for a common occupied indoor space. The marked differences observed between total particle and bacterial size distributions suggest that size-dependent aerosol models that use total particles as a surrogate for microbial particles incorrectly assess the fate of and human exposure to airborne bacteria. The strong signal of human microbiota in airborne particulate matter in an occupied setting demonstrates that the aerosol route can be a source of exposure to microorganisms emitted from the skin, hair, nostrils, and mouths of other occupants.     

混合通风空调房间中粒子谱的空间变化

根据成都市夏季室外颗粒物浓度的实测结果,利用数值流体力学方法对混合通风空调房间的粒子进行了模拟,分析了室内粒子的空间演化及其与室外粒子的浓度关系。结果表明,室内粒子浓度对室外粒子浓度具有直接的依赖性,其中进风携带的小粒子浓度在室内下降较为明显。因此,在研究室内空气品质的同时,应考虑室外背景粒子浓度变化的影响。     

Chemical characterization of indoor and outdoor fine particulate matter in an occupied apartment in Rome,Italy

The daily concentration and chemical composition of PM_2.5 was determined in indoor and outdoor 24‐h samples simultaneously collected for a total of 5 weeks during a winter and a summer period in an apartment sited in Rome, Italy. The use of a specifically developed very quiet sampler (<35 dB) allowed the execution of the study while the family living in the apartment led its normal life. The indoor concentration of PM_2.5 showed a small seasonal variation, while outdoor values were much higher during the winter study. Outdoor sources were found to contribute significantly to indoor PM concentration especially during the summer, when the apartment was naturally ventilated by opening the windows. During the winter the infiltration of outdoor PM components was lower and mostly regulated by the particle dimensions. Organics displayed In/Out ratios higher than unity during both periods; their indoor production increased significantly during the weekends, where the family stayed mostly at home. PM components were grouped into macrosources (soil, sea, secondary inorganics, traffic, organics). During the summer the main contributions to outdoor PM_2.5 came from soil (30%), secondary inorganics (29%) and organics (22%). Organics dominated both indoor PM_2.5 during the summer (60%) and outdoor and indoor PM_2.5 during the winter (51% and 66%, respectively).     

Use of temporal/seasonal- and size-dependent bioaerosol data to characterize the contribution of outdoor fungi to residential exposures

With the use of published temporal/seasonal and particle size distribution of outdoor bioaerosol data and meteorological information in the subtropical climate, we characterized the airborne fungal concentration indoor/outdoor/personal exposure relationships in a wind-induced naturally ventilated residence. We applied a size-dependent indoor/outdoor ratio model coupled with a compartmental lung model based on a hygroscopic growth factor as a function of relative humidity on aerodynamic diameter and concentration of fungal spores. The higher indoor airborne fungal concentrations occurred in early morning and late afternoon in which median values were 699.29 and 626.20 CFU m(-3) in summer as well as 138.71 and 99.01 CFU m(-3) in winter, respectively, at 2 am and 8 pm. In the absence of indoor sources, summer has higher mean indoor/outdoor ratios of airborne fungal concentration (0.29-0.58) than that in winter (0.12-0.16). Lung region of extrathoracic (ET) has higher fungal concentration lung/indoor ratios (0.7-0.8) than that in bronchial (BB; 0.41-0.60), bronchiolar (bb; 0.12-0.40), and alveolar-interstitial (AI); 0.01-0.24) regions. The highest airborne fungal deposition dose (95th-percentile is 4600 CFU) occurred in 11 pm-5 am in region AI in that the 95th-percentile fungal deposition rate was 0.22 CFU s(-1).     

长江流域住宅分体式空调全年使用特性分析

为了明晰长江流域住宅居民采用分体式空调供暖供冷的行为特性,选取了4个典型城市的19户住户(均为新建住宅小区,家庭结构相似,采用一级能效房间空调器),对其空调房间全年温湿度和耗电量进行了连续一年的监测.结果 显示:住户采用空调供暖多集中在12月,夏季供冷集中在7月中下旬至8月中上旬,空调开启比例高于50％,且多发生在20...     

Profiles and seasonal distribution of airborne fungi in indoor and outdoor environments at a French hospital

A one-year prospective survey of fungal air contamination was conducted in outdoor air and inside two haematological units of a French hospital. Air was sampled with a portable Air System Impactor. During this period of survey, the mean viable fungal load was 122.1 cfu/m³ in outdoor air samples, and 4.1 and 3.9 cfu/m³ in samples from adult and pediatric haematology units, respectively. In outdoor samples, Cladosporium was the dominant genus (55%) while in the clinical units, Penicillium sp. (23 to 25%), Aspergillus sp. (15 to 23%) and Bjerkandera adusta (11 to 13%) were the most frequently recovered airborne fungi. The outdoor fungal load was far higher in autumn (168 cfu/m³), spring (110 cfu/m³) and summer (138 cfu/m³) than in winter (49 cfu/m³). In indoor air, fungal concentrations were significantly lower in winter (2.7 to 3.1 cfu/m³) than in summer (4.2 to 5.0 cfu/m³) in both haematology units. In the outdoor environment, Penicillium sp. and Aspergillus sp. were more abundant in winter while the levels of Cladosporium were lowest during this season. In the haematological units, the presence of Aspergillus sp. was stable during the year (close to 20%), Bjerkandera sp. was particularly abundant in winter (close to 30%); levels of Penicillium sp. were highest in autumn while levels of Cladosporium sp. were highest in spring and summer.     

农村保温墙体的热湿性能分析

通过建立非保温墙体和XPS保温墙体模型,应用COMSOL Multiphysics软件模拟墙体的热湿变化规律,分析农村保温墙体的热湿性能.结果表明:水泥砂浆与混凝土交界面、混凝土与水泥抹灰交界面分别受室外、室内温度影响大于相对湿度影响.潜热净吸热量密度在非保温墙体和XPS保温墙体内分别占净吸热量密度的21.7％和14....     

Characterizing airborne fungal and bacterial concentrations and emission rates in six occupied children's classrooms

Baseline information on size‐resolved bacterial, fungal, and particulate matter (PM) indoor air concentrations and emission rates is presented for six school classrooms sampled in four countries. Human occupancy resulted in significantly elevated airborne bacterial (81 times on average), fungal (15 times), and PM mass (nine times) concentrations as compared to vacant conditions. Occupied indoor/outdoor (I/O) ratios consistently exceeded vacant I/O ratios. Regarding size distributions, average room‐occupied bacterial, fungal, and PM geometric mean particle sizes were similar to one another while geometric means estimated for bacteria, fungi, and PM mass during vacant sampling were consistently lower than when occupied. Occupancy also resulted in elevated indoor bacterial‐to‐PM mass‐based and number‐based ratios above corresponding outdoor levels. Mean emission rates due to human occupancy were 14 million cells/person/h for bacteria, 14 million spore equivalents/person/h for fungi, and 22 mg/person/h for PM mass. Across all locations, indoor emissions contributed 83 ± 27% (bacteria), 66 ± 19% (fungi), and 83 ± 24% (PM mass) of the average indoor air concentrations during occupied times.