大气微生物的研究──大气细菌粒数中值直径及粒度分布

本文用ＡＮＤＥＲＳＥＮ生物粒子采样器在沈阳市对大气细菌粒数中值直径（ＣＭＤ）及粒度分布进行了一年的观测。结果表明，沈阳市大气细菌年平均粒数中值直径为７．５μｍ。夏季大，为８．１μｍ；冬季小，７．１μｍ。不同地点的大气细菌粒数中值直径变化范围是６．６～９．０μｍ。一天内变化不大，７：ＯＯ时较大，为７．６μｍ；夜间ｌ：００时较小，６．８μｍ。大气细菌粒子的粒度分布是从１～６级粒数百分比逐级减小．     

采样时间对ANDERSEN采样器采样效果的影响

在室内用ANDERSEN生物粒子采样器进行了不同采样时间对采集空气细菌和真菌粒子浓度，粒数中值直径效果的研究，结果表明，在1－12min内，采集的空气细菌和真菌粒子浓度随采样时间的增加而减少，呈明显的负相关关系，相关系数分别为－0．903和－0．688，P值均大于0．05，另外，在采样过程中，空气真菌比细菌耐受采样空气冲击力的能力强，采样时间对空气细菌和真菌粒子的粒度分布和粒数中值直径的影响不明显。     

兰州城区大气粒子态汞的污染状况

通过调查发现在市工业区，粒子态汞浓度高，冬，夏平均值为０．９１和１．００ｎｇ／ｍ＾３，最高达１．９２ｎｇ／ｍ＾３，冬夏季无显著性差异，秋季浓度低，交通频繁区和交通商业混合区冬季平均值０．４５ｎｇ／ｍ＾３，夏季０．４９ｎｇ／ｍ＾３在清洁区大部分在０．１０ｎｇ／ｍ＾３左右，最低０．０７０ｎｇ／ｍ＾３，显示夏季和城区粒子态汞浓度偏高的特征。工业区粒子态汞主要是由人为污染产生的气态汞吸附在同一污染源的粒尘     

广州市区的空气微生物含量

用平皿沉降法测定了广州市区室内外空气微生物含量,市区室外空微生物总量,空气细菌量,真菌量分别为２１７４４．２ＣＦＵ／ｍ＾３、２１１０．６ＦＵ／ｍ＾３、６３３．６ＣＦＵ／ｍ＾３,真菌占总菌量的２．９％,表明空气已受到中度污染,真菌有时占甚大比率。闹市、交通要道的空气质量一般比近郊,清静处的差;室外空气微生物含量显示时间变化的某种特点。室内空气微生物监测结果反出室空气一般尚可。指出应进一步采取得力的环     

沉降法测定大气细菌粒子含量公式的检验

在沈阳市对文献［６］提出的由大气细菌粒子的沉降量计算大气细菌粒子含量的公式进行了检验．结果表明，在同泽小学由公式计算的大气细菌粒子的含量为３３２４个／ｍ３，Ａ·Ｓ采样器测定的大气细菌粒子的含量为３７９２个／ｍ３，二者之间的比值为０．９，ｔ＝０．７８５，Ｐ＞０．０５，两种方法得出的大气细菌粒子的含量没有明显差异，比传统的奥梅梁斯基公式有比较好的准确性和实用性．     

NH_3－N分析中显色后稀释测定误差的探讨

ＮＨ_３－Ｎ分析中显色后稀释测定误差的探讨任晓梅（江苏扬州市环境监测站，扬州２２５）０２）溶液碱度变化影响了纳氏反应平衡，是产生误差的主要原因。稀释５倍时，ｐＨ降低０．５４，误差＜５％；而稀释ＳＯ倍时，与原浓度溶液的ｐＨ值相差１．４，相对误差则高达８?..     

低浓度SO_2检测管的研制

通过对常见的几种检测管法的比较，筛选出灵敏度较高的亚硝基铁氰化钠法；同时筛选出载体为６０—８０目的素陶瓷，指示剂浓度为２０％。玻璃管内径为２．０—２．３ｍｍ，采气速度为０．３（Ｌ／ｍｉｎ），采样体积为１２Ｌ，以此条件进行实验．结果表明，检测管变色长度对应ＳＯ２浓度的相关性很好；变异系数均小于１１０％，检测的重现性较好。检测管的测定值与理论值的平均相对误差为５．０９％（＜±１５％），最大相对误差为７．１３％（＜±２５％），准确度较高．测定结果可靠；与化学法比较，两者无显著性差异；浓度小于０．１５ｍｇ／ｍ３的Ｈ２Ｓ及浓度小于０．０１ｍｇ／ｍ３的ＮＯ２对ＳＯ２检测管无干扰．     

光离子化检测器便携式气相色谱仪快速测定水中苯系物

本文研究了使用光离子化检测器便携式气相色谱仪，在环境温度下手工摇荡的快速顶空法测定水中苯系物（苯、甲苯、乙苯、邻、间、对位的二甲苯及异丙苯）的分析方法。方法的线性范围为０～１８０μｇ／Ｌ，相关系数均在０．９９６以上，方法的变异系数分别为１．０～１４％（１０μｇ／Ｌ），２．９～７．８％（３０μｇ／Ｌ），方法的最低检测限达０．５～１．５μｇ／Ｌ。     

食用油烟气浓度的分析方法研究

以３种常见食用油的蒸馏抽提冷凝物为标准品，用紫外分光光度法研究食用油烟气浓度的分析方法。结果表明油烟标准品和样品的最大吸收波长均为２６４ｎｍ；标准管油烟含量为０￣１００μｇ围时，吸光度与油烟量间呈良好的线性关系（相关系数ｒ为０．９９４￣０．９９９）；该法测油烟含量的准确度即变异系数（ＣＶ％）为１．３％￣８．５％（Ｘ＝３．９％），回收率为９０．８３％￣１０６．６９％（９９．４％），检测下限０．１μｇ     

硝化细菌富集培养方法研究

探讨利用提高基质－氨氮浓度的方式富集硝化细菌的可行性，结果表明，温度为３０℃，ｐＨ为６．５～８．０，溶解氧（ＤＯ）的质量浓度高于２ｍｇ／Ｌ时，经过１２～１３周的富集培养，污泥中硝化细菌浓度是未经富集污泥中硝化细菌浓度的１２．５～２０．０倍。     

Assessment of microbiological indoor air quality in an Italian office building equipped with an HVAC system

The purpose of this study was to evaluate the level and composition of bacteria and fungi in the indoor air of an Italian office building equipped with a heating, ventilation and air conditioning (HVAC) system. Airborne bacteria and fungi were collected in three open-space offices during different seasons. The microbial levels in the outdoor air, supply air diffusers, fan coil air flow and air treatment unit humidification water tank were used to evaluate the influence of the HVAC system on indoor air quality (IAQ). A medium–low level of bacterial contamination (50–500 CFU/m³) was found in indoor air. Staphylococcus and Micrococcus were the most commonly found genera, probably due to human presence. A high fungal concentration was measured due to a flood that occurred during the winter. The indoor seasonal distribution of fungal genera was related to the fungal outdoor distribution. Significant seasonal and daily variation in airborne microorganisms was found, underlining a relationship with the frequency of HVAC system switching on/off. The results of this monitoring highlight the role of the HVAC system on IAQ and could be useful to better characterise bacterial and fungal population in the indoor air of office buildings.     

室内空气中颗粒状污染物的PTV测量

针对室内空气中颗粒状污染物流动特性的测量搭建了PTV测量系统,该系统由白光照明、CCD摄像头采集图像及四轨迹像点匹配算法软件构成.测量结果表明,该PTV系统具有测量室内空气中可吸入颗粒扩散与流动的速度分布、浓度分布等特性.     

乌鲁木齐大气微生物污染研究

采用网格布点用自然沉降法同步采样，调查和研究乌鲁木齐建成区大气微生物浓度分布、污染现状及微生物污染类型特征．结果表明：乌鲁木齐市大气微生物以细菌为主导，占微生物总数的７９．５％，真菌约占２０．５％．建成区大气微生物达５级中污染水平．大气微生物污染分布与环境条件和环境质量都有一定关系。     

Increased levels of bacterial markers and CO2 in occupied school rooms

Our group previously demonstrated that carbon dioxide (CO2) levels in heavily occupied schools correlate with the levels of airborne bacterial markers. Since CO2 is derived from the room occupants, it was hypothesized that in schools, bacterial markers may be primarily increased in indoor air because of the presence of children; directly from skin microflora or indirectly, by stirring up dust from carpets and other sources. The purpose of this project was to test the hypothesis. Muramic acid (Mur) is found in almost all bacteria whereas 3-hydroxy fatty acids (3-OH FAs) are found only in Gram-negative bacteria. Thus Mur and 3-OH FA serve as markers to assess bacterial levels in indoor air (pmol m(-3)). In our previous school studies, airborne dust was collected only from occupied rooms. However, in the present study, additional dust samples were collected from the same rooms each weekend when unoccupied. Samples were also collected from outside air. The levels of dust, Mur and C10:0, C12:0, C14:0, and C16:0 3-OH FAs were each much higher (range 5-50 fold) in occupied rooms than in unoccupied school rooms. Levels in outdoor air were much lower than that of indoor air from occupied classrooms and higher than the levels in the same rooms when unoccupied. The mean CO2 concentrations were around 420 parts per million (ppm) in unoccupied rooms and outside air; and they ranged from 1017 to 1736 ppm in occupied rooms, regularly exceeding 800-1000 ppm, which are the maximum levels indicative of adequate indoor ventilation. This indicates that the children were responsible for the increased levels of bacterial markers. However, the concentration of Mur in dust was also 6 fold higher in occupied rooms (115.5 versus 18.2 pmole mg(-1)). This further suggests that airborne dust present in occupied and unoccupied rooms is quite distinct. In conclusion in unoccupied rooms, the dust was of environmental origin but the children were the primary source in occupied rooms.     

Monitoring of Particle Mass and Number in Urban Air

Measurements of aerosol particles in the air of an urban area in the UK have been made. Ambient air was sampled and the particulates measured after passing through a size selective PM₁₀ inlet. Particle mass was measured using a Tapered Element Oscillating Microbalance (TEOM). Particle number and size distributions were obtained using an Electrical Aerosol Analyser (EAA) and an Aerodynamic Particle Sizer (APS). Measurements were also made of local meteorological parameters. Fine particle number concentrations were found to show better temporal agreement, including diurnal variation, with particle mass concentrations than the coarser particle number concentrations.     

空气扰动对净化器去除香烟源颗粒物性能的影响

空气净化器可有效改善雾霾天气下室内空气质量,颗粒物去除效果与洁净空气量(CADR)是衡量其性能的主要参数。在典型室内环境下,以香烟源颗粒物为目标,开展空气扰动对净化器去除颗粒物效果和CADR的影响实验与评价分析。结果显示,在室内空气扰动下,净化器对粒径≥5μm的颗粒物去除率为75.6%,在无空气扰动情况下的去除率为46.6%。空气净化器对粒径0.3μm^5μm的颗粒物有较好的去除效果,而对于粒径10μm的较大颗粒物,空气扰动造成CADR增加。空气扰动在一定程度上提升了空气净化器的净化能力,同时在性能方面也存在影响。     

Monitoring of bioaerosol inhalation risks in different environments using a six-stage Andersen sampler and the PCR-DGGE method

Increasing evidences show that inhalation of indoor bioaerosols has caused numerous adverse health effects and diseases. However, the bioaerosol size distribution, composition, and concentration level, representing different inhalation risks, could vary with different living environments. The six-stage Andersen sampler is designed to simulate the sampling of different human lung regions. Here, the sampler was used in investigating the bioaerosol exposure in six different environments (student dorm, hospital, laboratory, hotel room, dining hall, and outdoor environment) in Beijing. During the sampling, the Andersen sampler was operated for 30 min for each sample, and three independent experiments were performed for each of the environments. The air samples collected onto each of the six stages of the sampler were incubated on agar plates directly at 26 °C, and the colony forming units (CFU) were manually counted and statistically corrected. In addition, the developed CFUs were washed off the agar plates and subjected to polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) for diversity analysis. Results revealed that for most environments investigated, the culturable bacterial aerosol concentrations were higher than those of culturable fungal aerosols. The culturable bacterial and fungal aerosol fractions, concentration, size distribution, and diversity were shown to vary significantly with the sampling environments. PCR-DGGE analysis indicated that different environments had different culturable bacterial aerosol compositions as revealed by distinct gel band patterns. For most environments tested, larger (>3 μm) culturable bacterial aerosols with a skewed size distribution were shown to prevail, accounting for more than 60 %, while for culturable fungal aerosols with a normal size distribution, those 2.1–4.7 μm dominated, accounting for 20–40 %. Alternaria, Cladosporium, Chaetomium, and Aspergillus were found abundant in most environments studied here. Viable microbial load per unit of particulate matter was also shown to vary significantly with the sampling environments. The results from this study suggested that different environments even with similar levels of total microbial cuturable aerosol concentrations could present different inhalation risks due to different bioaerosol particle size distribution and composition. This work fills literature gaps regarding bioaerosol size and composition-based exposure risks in different human dwellings in contrast to a vast body of total bioaerosol levels.     

家庭室内空气中细菌浓度分布之分析

对家庭室内空气的细菌浓度,在不同时间段的分布进行了研究分析。采用平皿沉降法,测得结果：清晨７：００为强污染时,晚１９：００为弱污染时。并对居室清扫方式提出建议,以促进生存空间的环境质量的改善。     

Large particles are responsible for elevated bacterial marker levels in school air upon occupation

Muramic acid (Mur) is found in bacterial peptidoglycan (PG) whereas 3-hydroxy fatty acids (3-OH FAs) are found in Gram-negative bacterial lipopolysaccharide (LPS). Thus Mur and 3-OH FAs serve as markers to assess bacterial levels in indoor air. An initial survey, in a school, demonstrated that the levels of dust, PG and LPS (pmol m(-3)) were each much higher in occupied rooms than in the same rooms when unoccupied. In each instance, the Mur content of dust was increased and the hydroxy fatty acid distribution changed similarly suggesting an alteration in the bacterial population. Here, findings are compared with results from two additional schools. Follow-up aerosol monitoring by particle size was also performed for the first time for all 3 schools. The particle size distribution was shown to be quite different in occupied versus unoccupied schoolrooms. Within individual classrooms, concentrations of airborne particles [greater-than-or-equal]0.8 [micro sign]m in diameter, and CO(2) were correlated. This suggests that the increased levels of larger particles are responsible for elevation of bacterial markers during occupation. Release of culturable and non-culturable bacteria or bacterial aggregates from children (e.g. from flaking skin) might explain this phenomenon.