Characteristics of indoor and outdoor bioaerosols at Korean high-rise apartment buildings

This study attempted to evaluate the bioaerosol exposure of apartment residents at high-rise apartment buildings in a Korean city. The characteristics associated with the bioaerosol exposure included the apartment floor, seasonal variation, summer survey period (seasonal rain-front period (SRFP) or no rain-front period (NRFP)), and room location inside an apartment. Four most prevalent fungal genera detected in both the indoor and the outdoor air were Cladosporium, Penicillium, Aspergillus, and Alternaria. The outdoor bacterial concentrations were significantly higher in the low-floor apartments than in the high-floor apartments. However, the bacterial and fungal concentrations in the interior air of the apartments were not significantly different between the low- and the high-floor apartments. The current bioaerosol concentrations were comparable to those in other reports, with geometric mean (GM) bacterial values between 10 and 10(3) CFU m(-3) and fungal aerosol concentrations in homes ranging also from 10 to 10(3) CFU m(-3). The indoor and outdoor fungal concentrations and the outdoor bacterial concentrations were usually higher in the summer than in the winter. The indoor and outdoor bioaerosol concentrations were both higher for the SRFP than for the NRFP. The difference in the total bacterial concentrations was not significant among the surveyed five rooms. The GM total fungal and Cladosporium concentrations, however, were significantly higher for the kitchen than for the other rooms.     

Consistent pattern of elevated symptoms in air-conditioned office buildings: a reanalysis of epidemiologic studies.

Published studies of the relation between type of building ventilation system and work-related symptom prevalence in office workers have been contradictory. A reanalysis was performed of six studies meeting specific eligibility criteria, combining published data with unpublished information obtained from study authors. Five eligible studies were from the United Kingdom, and one was from Denmark. Standardized categories of building ventilation type were created to allow comparison of effects across studies. Within each study, prevalence odds ratios (PORs) were calculated for symptoms in each ventilation category relative to a baseline category of naturally ventilated buildings. Air-conditioned buildings were consistently associated with increased prevalence of work-related headache (POR = 1.3-3.1), lethargy (POR = 1.4-5.1), and upper respiratory/mucus membrane symptoms (POR = 1.3-4.8). Humidification was not a necessary factor for the higher symptom prevalence associated with air-conditioning. Mechanical ventilation without air-conditioning was not associated with higher symptom prevalence. The consistent associations found between type of building ventilation and reported symptom prevalence have potentially important public health and economic implications.     

湛江市部分住房室内外空气中氡浓度测定

采用活性炭吸附闪烁法测定了湛江市部分住房室内、外空气中的平衡当量氡浓度。结果表明 ,住房室内、外空气中平衡当量氡浓度平均值分别为 2 5 2 7Bq/m3 和 14 6 8Bq/m3 ,室内空气中平衡当量氡浓度显著高于室外 (P <0 0 1) ;不同装饰材料的住房室内空气中平衡当量氡浓度各有差异 ,其中以花岗岩为装饰材料的住房室内平衡当量氡浓度 (31 18Bq/m3 )为最高 ,水泥地板住房 (14 71Bq/m3 )最低     

全列空调客车内环境的卫生学调查与评价

目的　了解铁路全列空调旅客列车内环境的卫生状况。方法　于 1997年 7月～ 1999年 10月对上海、成都、昆明、哈尔滨、乌鲁木齐、广州等 6个铁路局所属的 10条线路上运行的新型全列空调客车不同车厢的内环境 (不同路况、不同季节 )进行了调查。另在相同试验条件下以普通客车为对照。结果　冬、夏两季全列空调客车车厢内温度、风速均符合GB 96 73 1996 ,夏季湿度超过国家卫生标准。在不同路况下 ,空调客车内四类车厢除餐车平均噪声 [丘陵地区为 (71.2± 4.10 )dB(A)、山区为 (75 .1± 3.2 0 )dB(A) ]超过国家卫生标准外 ,其余车厢均符合卫生标准。振动测试结果均符合ISO 2 6 31/ 1 85标准。而车厢内空气质量测试结果表明 ,空调客车车厢内CO浓度在 3个不同季节(夏、秋、冬季 )其结果均符合国家卫生标准 ,达标率为 10 0 %;夏季硬座和硬卧车厢内CO2 浓度超过国家卫生标准。夏季样品达标率也明显低于普通客车 ,差异有显著性 (P <0 .0 1)。而冬季空调客车的软卧及硬卧车厢CO2 浓度均超过国家卫生标准。车厢内空气中可吸入尘、细菌总数的测定结果均符合国家卫生标准。同时还表明 ,全列空调客车的自然采光和人工照明效果均优于普通客车。结论　夏季车厢内湿度和餐车噪声超过卫生标准 ,车厢内CO2 浓度夏、冬两季     

Prevalence of irritative symptoms in a nonproblem air-conditioned office building

Objectives: To assess the prevalence of work-related complaints and symptoms in employees in an air-conditioned office building (Building AC) in a mild climatic area (Italy). No discomfort had previously been reported. Methods: A total of 198 employees in Building AC and 281 controls working in three naturally ventilated buildings (Building NV) answered a questionnaire investigating work-related complaints and symptoms. Results: A significantly higher percentage of workers in Building AC reported a lack of comfort in the working environment as compared with the controls (30.6% versus 18.9%). The most common complaints were strong lighting, high temperature, and dry, dusty, and/or stuffy air. The prevalence of ocular, upper airway, and cutaneous symptoms was significantly higher (29.8% versus 14.9%, 25.3% versus 9.6%, and 14.1% versus 3.6%, respectively). No significant difference was observed in respiratory or general symptoms. Logistic regression analysis showed that working with video display units and photocopiers influenced ocular symptoms; upper airway and cutaneous symptoms were influenced by female gender and working in the air-conditioned building. Conclusions: In an apparently healthy air-conditioned office building, complaints and symptoms are reported more often than in a naturally ventilated edifice, but the prevalence is lower than that usually observed in sick buildings. Symptoms are influenced by individual and work-related characteristics. Received: 17 September 1997 / Accepted: 26 February 1998     

Indoor air particles in office buildings with suspected indoor air problems in the Helsinki area

Objectives

Airborne particle concentrations can be used as quality indicators of indoor environments. The previous lack of reference data has limited the use of particle measurements in office environments. The aim of this study was to describe the concentrations of airborne particles (≥ 0.5 μm and ≥ 5.0 μm) in 122 Finnish office buildings with suspected indoor air problems.

Materials and Methods

The database consisted of indoor air and supply air particle samples collected in 2001–2006 from the Helsinki area. The particle concentrations (≥ 0.5 μm and ≥ 5.0 μm) were measured in the indoor air (528 samples from 122 office rooms) and in the supply air (384 samples from 105 office rooms) with an optical particle counter. Airborne particle concentrations ≥ 0.5 μm were categorized according to the efficiency of supply air filtration and health survey data.

Results

The mean concentrations in the indoor air equaled 1900 particles/l and in the supply air 1300 particles/l. The efficiency of supply air filtration decreased the fine particles counts in both the indoor and supply air. The counts of large particles, ≥ 5.0 μm, were low in the indoor air. Airborne counts of ≥ 0.5 μm particles (geometric mean) were statistically higher in the offices whose occupants had work-related symptoms (eye and/or upper respiratory symptoms or upper respiratory infections) than in the offices whose occupants had no such symptoms. However, the symptoms may also be linked to other indoor air problems or particle characteristics not studied in this work.

Conclusions

This study indicates typical airborne particle levels (≥ 0.5 μm and ≥ 5.0 μm) in Finnish office buildings with suspected indoor air problems. The results can be used to evaluate the quality of indoor environment, possible indoor air problems, and the need for additional investigations.     

Investigation of atmospheric, mechanical and other pressure effects influencing the levels of radon and radon progeny in buildings.

Real-time data measurement and analysis have identified a number of influences affecting the variability and accumulation of radon and its progeny in indoor air. Observed cycles in radon concentrations were shown to be related to the influence of air-conditioning and water-heated central heating systems. The cyclical pattern, related to operation of the air-condition system, showed radon levels almost four times lower during the period when the system was switched On than when it was Off. When the heating system was switched On the radon and radon progeny levels were 40% lower than when it was switched Off. Under both regimes, it was possible to establish the over-riding influence of meteorological factors by separating the recurring cyclical component from the relevant data set. The general or trend level of indoor radon was determined substantially by the prevailing atmospheric conditions.     

Modeling seasonal variation in indoor radon concentrations

Radon, a well-established risk factor for human lung cancer, is present at low concentrations in most homes. Consequently, many countries have established national guidelines for residential radon concentrations. In this article, we evaluate two models for describing seasonal variation in residential radon concentrations based on the data from a large case-control study conducted in Winnipeg, Canada. In this study, radon levels in homes were monitored during two successive 6-month periods, with integrated annual radon concentrations obtained using CR-39 alpha-track detectors. Significant differences were noted among measurements taken during different seasons of the year. Using the model introduced by Pinel et al. (1995) to describe temporal variation in residential radon levels in southwest England using seasonal adjustment factors, reasonable predictions of annual average radon concentrations were obtained from the 6-month integrated radon measurements. However, a simple multiplicative model was found to provide better predictions than the seasonal adjustment model. Although model coefficients vary somewhat from one geographic location to another, the concordance with respect discriminating between results above and below 150 Bq/m(3) in Winnipeg was in the range 85-90% using seasonal adjustment models with coefficients derived from data in either Winnipeg or southwest England.     

A study of indoor carbon dioxide levels and sick leave among office workers

Background  

A previous observational study detected a strong positive relationship between sick leave absences and carbon dioxide (CO₂) concentrations in office buildings in the Boston area. The authors speculated that the observed association was due to a causal effect associated with low dilution ventilation, perhaps increased airborne transmission of respiratory infections. This study was undertaken to explore this association.     

Sanitary assessment of radon hazards in residential buildings

The authors have constructed models including that of dose-effect of the content of decay products, that of the volumetric activity of radon in the apartments, and that of biological human responses. They have found specific features of female reproduction dysfunction, perinatal, general, and cancer morbidity and mortality. The maximum ineffective radon concentration upon chronic exposure has been established by using dosage simulation of the frequency of genetic disorders (small malformations).     

Airborne microbial contaminants in indoor environments. Naturally ventilated and air-conditioned homes

The atmospheric burden of viable particulates in the interiors of condominium homes with central air conditioning was compared with that of the typically more open-type of naturally ventilated Hawaiian homes. Andersen microbial air samplers were used to enumerate the numbers and kinds of respirable fungi and bacteria inside the residences. The results were compared with that obtained outside the homes to evaluate the impact of the air conditioning systems on indoor air quality. There were no significant differences in microbial air contaminants between the outdoors and the air inside naturally ventilated residences. The air inside air conditioned homes were found to have fewer fungi, including a significantly smaller number of Cladosporium sp., but had a significantly greater number of Aspergillus sp. when compared to the outdoors. The total number of bacteria and the number of Gram positive (+) cocci were significantly larger inside air-conditioned residences than outside. A preliminary health status survey revealed occupants of centrally air-conditioned homes had more complaints of eye irritation, sneezing, nasal congestion, and cough.     

Exposure to varying levels of contaminants and symptoms among workers in two office buildings.

OBJECTIVES: We hypothesized that exposure to contaminants would be associated with symptoms reported by office workers. METHODS: In two mechanically ventilated office buildings in. Montreal, the outdoor air supply was manipulated for 6 weeks, while symptoms were reported and environmental parameters were measured at multiple sites. RESULTS: Contaminant concentrations varied considerably, in part related to experimental changes in outdoor air supply. Eye symptoms were reported with higher dust and with higher concentrations of nitrogen dioxide. Mucosal symptoms were increased with higher TVOCs, higher nitrogen dioxide, and higher total contaminant load. Systemic symptoms were associated with higher dust levels. CONCLUSIONS: Symptoms reported by the workers were associated with increased concentrations of several contaminants and a summary measure of all contaminants.     

Radon and radon daughter measurements in solar buildings

Measurements of radon and radon daughters in 11 buildings in five states, using active or passive solar heating, showed no significant excess in concentrations over the levels measured in buildings with conventional heating systems. Radon levels in two buildings using rock storage in their active solar systems exceeded the U.S. Nuclear Regulatory Commission's limit of 3 pCi/l. for continuous exposure in uncontrolled areas. In the remainder of the buildings, radon concentrations were found to be at levels considered to be normal. It appears that the slightly elevated indoor radon concentrations result from the local geological formations and from the tightening of the buildings rather than as a result of the solar heating technology.     

室内空气中氡污染防治的研究进展

随着居民生活水平的不断提高,人们环保意识的加强,室内空气中氡的对人体健康的影响已成为人们关注的热点。作者介绍了近几年国内居室内空气中氡气的主要污染来源和状况、阐述了氡对人体健康的危害;并针对室内氡污染的来源,本文总结了国家制定的相应标准和规范,提出了有效、具体的防氡污染措施和治理方法;以达到创造健康室内环境的目的。     

Long term measurements of indoor radon equilibrium factor

To provide detailed information for bronchial dose estimates, aerosol particle size distributions, and radon gas concentration, measurements were made in six residential homes and three laboratory rooms in different office buildings in the city of Ottawa. In the literature, most particle size distribution measurements are taken with samplers operating for a few days at most. In this study, the particle size samplers collected the samples from 77 to 162 d. The equilibrium factor determined from the long-term measurements ranged from 0.6 to almost 1 with an average of 0.75. Even though radon concentrations were quite different between residential setting and office buildings, the average equilibrium factor was similar in the two different indoor environments. The results suggest that at least in some basements, if they were occupied, the radon dose would be about twice as high as normally estimated from the conventional F(eq) value of 0.4.