New method for an occupational dust challenge test.

OBJECTIVES--Specific challenge tests with a suspected allergen in the workplace are standard to confirm the diagnosis of asthma. Facilities for sophisticated exposure tests are available only in a few institutions. A pilot study was carried out that used a novel approach for an occupational dust challenge test with a rotahaler. METHODS--Nine consecutive patients were enrolled in this study. Six of these proved to have asthma to red cedar by challenge tests with plicatic acid. They were challenged with a maximum dosage of 80 mg of red cedar dust and spruce dust (control) with a rotahaler on separate days in a single blinded manner. A positive reaction was defined as a fall in the forced expiratory volume in one second (FEV1) or the peak expiratory flow (PEF) after a challenge test of > or = 20% below the baseline value. RESULTS--Three of the six patients who reacted to plicatic acid also had a positive response to red cedar dust delivered through a rotahaler. All three patients with a negative response to challenge with plicatic acid also showed a negative response to red cedar dust. CONCLUSIONS--This pilot study showed that a positive challenge test with a rotahaler to deliver red cedar dust was specific in the diagnosis of red cedar asthma but a negative response could not rule out the diagnosis. The rotahaler has merits of being easy to operate, safe, inexpensive, and readily available. The usefulness of this method and its reproducibility have to be examined in a series of patients.     

空调隔尘网尘螨过敏原的检测

目的 检测安徽省芜湖地区家庭空调隔尘网灰尘和空调开机前、后室内空气中粉尘螨Ⅰ类过敏原（Derf 1）和屋尘螨Ⅰ类过敏原（Der p 1）浓度,以探讨隔尘网中尘螨过敏原与哮喘发病的关系.方法 分别从哮喘患者和健康居民家庭采集空调隔尘网灰尘样本各30份,同时用粉尘采样器采集哮喘患者和健康居民室内空气粉尘样本,开机前、后各采集30份.ELISA法检测Derf1、Derp 1的浓度,Dot-ELISA检测灰尘提取液过敏原性.结果 健康人群（家庭）组隔尘网灰尘中的过敏原Derf1、Derp 1浓度中位数分别为1.49和1.28 μg/g;哮喘患者（家庭）组隔尘网灰尘中的过敏原Derf1、Derp 1浓度中位数分别为0.73和0.85 μg/g,二者差异有统计学意义（分别为P＜0.01,P＜0.05）.健康人群（家庭）组的空调开机前空气中Derf1、Derp 1浓度中位数分别为4.65和5.90 ng/m3,开机后分别为7.65和7.35 ng/m3.哮喘患者（家庭）组空调开机前空气中Derf1、Derp 1浓度中位数分别为5.05和5.90 ng/m3,开机后分别为7.15和7.10 ng/m3.检测结果显示,打开空调送风情况下,哮喘患者（家庭）组与健康人群（家庭）组的空气中Derf1、Der p 1浓度均比未开空调时高,且差异有统计学意义（P＜0.05）.Dot-ELISA分析显示,灰尘提取液中过敏原能与螨过敏性哮喘患者的IgE产生结合反应.结论 芜湖地区居民空调隔尘网中含有尘螨Ⅰ类过敏原,空调开启送风后空气中尘螨的2个主要过敏原浓度均显著升高,应重视家用空调的清洁与净化,定期清洗、更换隔尘网以防止或减少尘螨孳生.     

Effect of hard metal dust on ventilatory function

The effect of hard metal dust generated in shaping on ventilatory function has been studied, in particular, the relation between levels of exposure to cobalt and changes in ventilatory function. In 15 healthy young men a significant decrease in FVC occurred after a six hour exposure to hard metal dust containing cobalt at a mean concentration of 38 micrograms/m3 (range 14-76 micrograms/m3). No dose-effect relation could be discerned between the decrease in FVC and the hard metal concentration or the cobalt concentration. All the subjects complained of irritation of the airways. On the other hand, in 42 shaping workers exposed to cobalt at an average concentration of 85 micrograms/m3 no significant decreases in ventilatory function were detected after seven hour exposures to hard metal, although in 42 shapers, who had been exposed to cobalt at a mean concentration of 126 micrograms/m3, the FEV1% was significantly decreased compared with matched controls. This finding suggests that hard metal dust containing cobalt at a mean concentration of 126 micrograms/m3 causes chronic bronchial obstruction.     

Effect of hard metal dust on ventilatory function.

The effect of hard metal dust generated in shaping on ventilatory function has been studied, in particular, the relation between levels of exposure to cobalt and changes in ventilatory function. In 15 healthy young men a significant decrease in FVC occurred after a six hour exposure to hard metal dust containing cobalt at a mean concentration of 38 micrograms/m3 (range 14-76 micrograms/m3). No dose-effect relation could be discerned between the decrease in FVC and the hard metal concentration or the cobalt concentration. All the subjects complained of irritation of the airways. On the other hand, in 42 shaping workers exposed to cobalt at an average concentration of 85 micrograms/m3 no significant decreases in ventilatory function were detected after seven hour exposures to hard metal, although in 42 shapers, who had been exposed to cobalt at a mean concentration of 126 micrograms/m3, the FEV1% was significantly decreased compared with matched controls. This finding suggests that hard metal dust containing cobalt at a mean concentration of 126 micrograms/m3 causes chronic bronchial obstruction.     

空气湿度对ICU的影响

概述了ICU的重要性,阐述了医院内空气湿度对ICU内工作人员、空气质量、危重症患者及设备的影响,呼吁提升CU的建设水平。     

工作场所空气中乙酐测定方法的改进

目的对工作场所空气中乙酐的测定对象和定量方法进行改进,提高方法的适用性。方法采集在活性炭管中的乙酐易与微量水分反应,生成乙酸和乙酐混合物,经丙酮解吸后,解吸液中乙酐和乙酸经DB-FFAP毛细管柱分离,以气相色谱(FID)测定,合并换算成空气中乙酐浓度。结果乙酐最低检出浓度为0.2 mg/m~3,解吸效率为92.0%~94.1%,相对标准偏差为1.8%~7.3%,加标回收率为101%。结论改进后的方法适用于工作场所空气中乙酐的测定。     

湿式填料在中央空调中除尘的效果观察

目的 在呼吸性传染病高发时期，改造全空气中央空调系统．实现净化、消毒功能．减少二次污染，以切断病毒的传播途径。方法 以除尘为立足点，利用湿式填料除尘器作为空气粉尘过滤和消毒的功能段。结果 通常情况下，湿式填料除尘器对1μm粉尘除尘效率可以达到25％～40％，5μm颗粒的除尘效率为75％～98％．压力损失范围在30～130Pa。结论 湿式填料除尘器具备净化、消毒、加湿、蒸发冷却等功能，可以替代传统空调中的初效过滤器，对阻止传染病利用空调系统蔓延、改善空气品质和节省能源消耗具有重要作用。     

纳米光催化空气净化器净化效果的实验研究

目的研究纳米光催化空气净化器在空气试验室和现场两种环境中对空气中甲醛、总挥发性有机物(TVOC)的净化效率，了解其净化效果。方法按照国家标准《空气净化器》(GB／T18801—2002)的步骤进行实验。根据实验结果计算空气净化器的洁净空气量和净化效果。结果纳米光催化空气净化器对空气试验室和现场空气中甲醛及TVOC的净化效率分别为(21．0％，16．7％)和(46．8％，39．2％)．3h在两种环境中对甲醛和TVOC的去除率分别达到54．1％，90．5％(扣除自然衰减影响)和43．8％，72．0％。结论纳米光催化空气净化器对室内装修产生的主要污染物甲醛和TVOC均有一定的净化作用，但对TVOC的净化效率远高于甲醛。     

工作场所空气中尿素粉尘测定

目的 建立工作场所空气中尿紊粉尘的检测方法.方法 工作场所空气中的尿素粉尘经测尘滤膜采集、水洗脱后,酸性条件下,尿素与对二甲氨基苯甲醛(PDAB)反应生成黄色化合物,在440 nm波长下比色测定.结果 方法在0～200.00 ms/L有良好线性关系,检出限为5.68 ms/L,空气中最低检出质量浓度为0.47 ms/m3(以采样体积300 L计算),精密度为1.04%～1.77%,洗脱效率为102.9%-115.2%.结论 该方法各项指标均符合WS/T 73-1996<工作场所空气中毒物检测方法的研究规范>要求,适用于工作场所空气中尿素粉尘的测定.     

Cotton dust sampling efficiency of the vertical elutriator.

A theoretical model of the vertical elutriator air sampler based upon the phenomenon of flow separation at the inlet was developed at SRRC. The model's equations were simulated by a computer program (VELUT). The model was calibrated by comparison of available experimental results to isokinetic sampling efficiencies calculated by the model. The calibrated model was used to predict integral efficiencies for a systematic assortment of size distributions of cotton dust. Rather than cutting off cleanly at 15 micrometers, the computer model exhibited a 50% differential efficiency at approximately 20 micrometers. Furthermore, the model predicted substantial non-zero collection efficiencies in the aerodynamic size range of individual cotton fibers. Program VELUT represents an objective method whereby the isokinetic sampling efficiency of the vertical elutriator can be explicitly calculated for any known or postulated ambient dust distribution presented to the sampler at its inlet plane.     

Quantification of house dust mite allergens in ambient air

The house dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae are important sources of indoor allergens. In sensitized patients, house dust mites induce and exacerbate diseases like asthma bronchiale, rhinitis, and conjunctivitis. The most significant exposure of persons occurs overnight in bed and to a lesser extent, during the daytime while performing activities like vacuum cleaning or bed making. In general, house dust mite antigens are quantified in samples of reservoir dust of carpets or beds. Yet, assessing allergens in ambient air would better represent human exposures because inhalation is the main route of uptake, and a close correlation between levels of floor and air antigens has not yet been proved. Unfortunately, because of extremely low airborne particle concentrations, analyses are difficult to perform and depend on sophisticated sampling strategies, as well as on sensitive immunometric detection assays. Using monoclonal immunoassays, house dust mite antigens, quantified in undisturbed conditions in ambient air, are found at pg/m3 levels. The disturbance of reservoir dust by vacuum cleaning or bed making increases the airborne allergen levels up to ng/m3 concentrations. In this review, we discuss the current knowledge regarding the analysis of airborne house dust mites in both undisturbed and disturbed ambient air. The advantages and disadvantages of different sampling strategies are outlined.