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PubMed1976

An increase of plasma triiodothyronine concentration in man in a cold environment.

In an attempt to study an effect of cold on endocrine function in man, plasma thyroxine (T4), triiodothyronine (T3), TSH, and cortisol concentrations were studied in 24 healthy men who worked in a cold environment (4 to 6C) for 3 h for the culture of mushrooms and 56 healthy men who lived in cold environment in winter. For comparison, similar measurements were made on 47 university employees who lived in rooms with air-conditioning. In 24 adult men, acute exposure to cold for 3 h failed to affect plasma concentrations of T4, T3, and TSH. In 56 adult men, no significant difference was found in the concentrations of T4, TSH, and cortisol between summer and winter. However, plasma T3 concentration increased significantly in winter, suggesting seasonal variation of T3. In contrast, no such seasonal variation was found in 47 university employees who lived in rooms with air-conditioning.

Acclimatization↗
PubMed1997

Fungal colonization of air filters from hospitals.

Air filters of various types, selected on the basis of discoloration, were collected from the primary and secondary filter banks of the heating, ventilating, and air-conditioning systems in seven hospitals in the eastern United States and examined with direct microscopy for fungal colonization. Microscopic observations and culture results showed that filters from five of the hospitals were colonized with fungi including species of Acremonium, Alternaria, Aspergillus, Cladosporium, Epicoccum, Penicillium, and Rhinocladiella, and a Beauveria-like fungus. Several of these commonly airborne species, e.g., Epicoccum purpurescens (syn. E. nigrum) and Rhinocladiella sp., had not been previously reported to colonize (with conidiogenesis) air filters.

Air Conditioning↗
PubMed2004

Assessing the benefit and cost for a voluntary indoor air quality certification scheme in Hong Kong.

A voluntary indoor air quality certification scheme has been proposed in Hong Kong for assessing and evaluating the indoor air quality level in a variety of public places like offices, restaurants and pubs. The scheme intends to promote the public well being, however, its technical and financial practicality has led to serious discussions among the government officials, practitioners and premises owners. Accordingly, this study intends to develop a protocol for examining its financial viability by linking the appropriate dose-response and economic data with the results from indoor micro-environment models. The financial viability of the scheme is evaluated by examining the cost and benefit associated with compliance on the different prescribed indoor particulate (PM10) levels. According to our analysis, the indoor action level of 180 microg/m3 as 8-h mean (with the objective of protecting the health of general public) does not require office owners to improve beyond the base setting. Nevertheless, owners should consider altering the base settings in their air conditioning systems so as to secure more benefit on every dollar they spent. On the contrary, the 20 microg/m3 level as 8-h mean (with the objective of providing comfort) is not considered to be financially viable for office owners as they will incur financial loss on compliance. Subsequent sensitivity analysis indicates that the total net benefit derived have a great dependency on the value-of-life estimates used. If conservative health estimates are adopted, the optimum level determined to be beneficial to both owners and the society will be 55 microg/m3, which can be obtained by operating the air conditioning system with a ventilation rate of 10 l/s, primary filters of 80-85% efficiency and secondary filters efficiency of 60-65% arrestance. This information should be extremely valuable for government officials and policy makers in assessing the financial viability of the voluntary indoor assessment scheme.

Air Pollution, Indoor↗
PubMed2004

Nosocomial invasive aspergillosis in a heart transplant patient acquired during a break in the HEPA air filtration system.

We report a case of nosocomially acquired invasive aspergillosis (IA) in a low-risk heart transplant recipient due to a break in the air conditioning system. A high overload of Aspergillus spores in the intensive care unit room led this patient to acquire IA. Identical environmental and patient isolates allowed our hypothesis to be confirmed and a very precise incubation time to be estimated.

Air Conditioning↗
PubMed2003

Microbiological evaluation of various parameters in ophthalmic operating rooms. The need to establish guidelines.

PURPOSE: Postoperative infections can be caused by a contaminated environment, unsterile equipment, contaminated surfaces, and infected personnel as well as contaminated disinfectants. In order to establish guidelines for microbiological monitoring, a detailed microbiological surveillance was carried out in an ophthalmic hospital. METHOD: Over a period of 21 months, we assessed environmental Bacteria Carrying Particle(BCP) load and surface samples weekly (n = 276); the autoclaving system once a month and repeated whenever the process failed (n = 24); the air conditioning filters for fungal growth once in four months (n = 15), and the disinfectant solution for contamination once in two months (n = 10). Additionally, the personnel involved directly in surgery were screened for potential pathogens such as Staphylococcus aureus and beta haemolytic streptococci. RESULT: On 14 (5.07%) occasions the environment in the operating rooms had a significant risk of airborne infections. Sterilisation of instruments in the autoclaves was unsatisfactory on 4 (16.66%) occasions. Samples from the filters of the air-conditioning units yielded potentially pathogenic fungi on 3 (20%) occasions. Personnel sampling revealed that 5 (8.77%) individuals harboured beta haemolytic Streptococci in the throat and 4 (7.01%) harboured S. aureus in the nasal cavity. The samples of disinfectant in use were not contaminated. CONCLUSION: There is a need to standardise microbiological evaluation protocols for operating rooms.

Disinfection↗
PubMed1985

Nitrous oxide exposure during routine anaesthetic work. Measurement of biologic exposure from urine samples and technical exposure by bag sampling.

Nitrous oxide exposure in a modern hospital during routine anaesthetic work was measured using a technical exposure measurement technique and compared to measurement of biologic exposure from urine samples. The study included different anaesthetic situations and also a study of the efficiency of close scavenging and general air-conditioning in reducing nitrous oxide exposure. Exposure to nitrous oxide varied greatly. The mean nitrous oxide exposure in the total material was 53 ppm corresponding to approximately half the Swedish control limit (100 ppm) for 8 h time-weighted average (TWA). The only anaesthetic situation regularly resulting in 8 h TWA exposure exceeding the control limit was paediatric anaesthesia (92 +/- 67 ppm, mean +/- s.d.). The use of close scavenging significantly reduced the 8 h TWA nitrous oxide exposure in paediatric anaesthesia. The reduction of exposure was not significant during other forms of anaesthesia where low levels were found when anaesthetic equipment with excess gas scavenging was used in theatres with non-recirculating air-conditioning. The correlation between conventional technical exposure measurement and urine headspace nitrous oxide measurement was good. Both theoretical arguments and practical experience indicate that this method can be used for assessing nitrous oxide exposure during routine anaesthetic work.

Air Pollutants, Occupational↗
PubMed2003

[Subjective evaluation of the work environment quality in offices].

BACKGROUND: Exposure to harmful and strenuous factors in offices lead to the sick building syndrome (SBS) with its various symptoms: fatigue, dyspnoea, decreased ability to concentrate, irritation of mucous membranes of eyes as well as of the upper airways. Those symptoms are induced by: unsuitable microclimate, chemical, aerosol and microbiological pollution, noise, vibration, electromagnetic fields, optical radiation, and static electricity. MATERIALS AND METHODS: A questionnaire survey was aimed at collecting information, opinions and personal perception of the work environment quality reported by office workers. The survey covered 229 workers employed in 100 offices. Offices with different density of workers and varied staff movement were equipped with typical office outfit: computers, laser printers, xerographic printers, faxes, scanners, and others. In the majority of offices, various kinds of plastics were used as finishing materials. Offices were located in newly constructed buildings supplied with air conditioning (3 buildings) as well as in old buildings equipped with mechanical or natural ventilation, used for years and frequently modernized (2 buildings). RESULTS AND CONCLUSIONS: The respondents (239) reported frequently experienced fatigue (64%), redness, dry eyes, lacrimation, dyspnoea (62%), decreased ability to concentrate (47%), and irritation of the upper airways (44%). These symptoms were most frequently manifested at the end of the working day (42%). They were predominantly perceived as a result of unsuitable climate parameters (77%), defective ventilation or air conditioning (63%), unfit lighting (62%) and stress (49%).

Environment↗
PubMed2001

Surgeon's occupational exposure to nitrous oxide and sevoflurane during pediatric surgery.

Health hazards from occupational exposure to trace concentrations of anaesthetic gases cannot be definitively excluded. The aim of the study was to determine the surgeon's occupational exposure to nitrous oxide and sevoflurane during pediatric surgical procedures. Twenty young children (age < 10 years) and five teenagers (age > 10 years) underwent elective abdominal surgery under general inhalational anesthesia. The operating room was equipped with modern air conditioning and waste anesthetic gas scavenger. Levels of both nitrous oxide and sevoflurane were determined in the breathing zone of the surgeon and the anesthesiologist during the operative procedures by means of a direct-reading photoacoustic infrared spectrometer. Both the surgeon and the anesthesiologist were exposed to low concentrations of the inhalational agents used. Exposure to sevoflurane and nitrous oxide was clearly higher during surgery in young children than during operative procedures in teenagers. Nonetheless, the concentrations of these agents were well below the threshold limits of 25 ppm for nitrous oxide and 2 ppm for sevoflurane recommended by the National Institute of Occupational Safety and Health. General anesthesia results in operating room air pollution with inhalational anesthetics. Under modern air conditioning, personnel's occupational exposure is low, and inhalational anesthesia is safe from the standpoint of modern workplace laws and health care regulations. Nonetheless, all efforts must be taken to maintain occupational exposure at this low level.

Abdomen↗
PubMed1986

A theoretical model of localized heat and water vapor transport in the human respiratory tract.

A steady-state, one-dimensional theoretical model of human respiratory heat and water vapor transport is developed. Local mass transfer coefficients measured in a cast replica of the upper respiratory tract are incorporated into the model along with heat transfer coefficients determined from the Chilton-Colburn analogy and from data in the literature. The model agrees well with reported experimental measurements and predicts that the two most important parameters of the human air-conditioning process are: the blood temperature distribution along the airway walls, and the total cross-sectional area and perimeter of the nasal cavity. The model also shows that the larynx and pharynx can actually gain water over a respiratory cycle and are the regions of the respiratory tract most subject to drying. With slight modification, the model can be used to investigate respiratory heat and water vapor transport in high stress environments, pollutant gas uptake in the respiratory tract, and the connection between respiratory air-conditioning and the function of the mucociliary escalator.

Body Temperature Regulation↗
PubMed1983

Measurement of IgG antibody and airborne antigen to control an industrial outbreak of hypersensitivity pneumonitis.

An outbreak of hypersensitivity pneumonitis in a textile plant was attributed on epidemiological grounds to a chilled water air-conditioning system where a slime was growing in the chilled water sump and on demister vanes. All of the patients and about 80% of their asymptomatic co-workers had strongly positive precipitin tests to extracts of the slime. An adaptation of a radioiodinated staphylococcal protein A solid-phase radioimmunoassay was applied to monitor antigen and specific antibody. To control the outbreak, a variety of cleaning and water treatment measures were taken between 1977 and 1979 to reduce the amount of antigen in the water and in the air. The amount of slime in the water was greatly reduced though the antigen content per gram of slime did not change. Airborne antigen in the affected work areas decreased progressively.

Air Conditioning↗
PubMed2001

[A new application for the human whole blood test: development of an assay to assess the health risk of air-borne microbial contaminations].

The pathogenic properties of environmental microorganisms as well as pyrogens as fragments of those bacteria (especially endotoxins) for humans is increasingly recognised. Various clinical syndromes are described after contact with airborne microbial contaminants via the respiratory tract: Sick-building-syndrome, humidifier lung (a form of hypersensitive pneumonitis), "Monday sickness" etc. Air-conditioning and ventilation systems intensify this problem as well as storage of compost within the household which represents a considerable source of airborne pollutants. In 1995 a new method for the detection of pyrogenic (fever-inducing) hazardous substances was described by Hartung and Wendel. This whole blood assay utilises the natural reaction of the immune system in order to detect a broad spectrum of pyrogens very sensitively in the relevant species. Injectable drugs are the main area of application in which this innovative test has already proven effective and is currently validated for inclusion into European Pharmacopoeia. In co-operation with the FU Berlin we could demonstrate in ventilation systems in animal stables that the whole blood pyrogen test can also detect airborne environmental microorganisms very sensitively. The filtration technique for collection of these germs is an established method for air-conditioning and ventilation systems. In co-operation with the FU Berlin (Institut für Tier-und Umwelthygiene) and the filter producer Sartorius this method is currently developed for the detection of airborne contaminations.

Air Microbiology↗
PubMedDate not supplied

Neurological symptoms of the sick building syndrome: analysis of a questionnaire.

Sick building syndrome (SBS) is an excess of work-related irritations of the skin and mucous membranes and of symptoms such as headache and fatigue in those working in modern air-conditioned buildings. We aimed to analyse the neurological symptoms, especially headache, in workers with potential SBS. The most frequent symptoms were headache and dry eyes. Sex was a major factor of difference: women report more symptoms than men. A positive correlation emerged between the number of symptoms and the asthenia scale score. Only 11 (8.2% of the whole sample) and 37 (27.4%) workers met all the IHS criteria for migraine and tension-type headache respectively. At least one symptom of SBS was present in 92.6% of workers. A negative correlation emerges between air conditioning and headache during working hours. No correlation emerges between the workplace comfort indicator and SBS and asthenic symptoms while a negative correlation was found between migraine and tension-type headache and comfort in the workplace. SBS symptoms are very frequent among all workers but headache is the primary symptom.

Adult↗
PubMed2000

Occupational exposure to inhaled anaesthetics: a follow-up study on anaesthetists of an eastern European university hospital.

BACKGROUND: Although no dose-response relationship for the health risks associated with the occupational exposure to inhaled anaesthetics exists, public health authorities recommend threshold values. The aim of the present study was to assess if and to what extent these threshold values are exceeded in an eastern European university hospital before and after measures had been taken to reduce occupational exposure. METHODS: At nine workplaces occupational exposure of anaesthetists to nitrous oxide and halothane or isoflurane was measured by means of photoacoustic infrared spectrometry. The measurements were carried out in 1996 and were repeated in 1997 after the installation of active scavenging devices at five workplaces and an air-conditioning system at one workplace. RESULTS: Occupational exposure to nitrous oxide and halothane or isoflurane was lower in 1997 compared to 1996. In 1997 most of the nitrous oxide values still exceeded the threshold value of 100 ppm, whereas most of the halothane and isoflurane values were already below the threshold values of 5 ppm and 10 ppm in 1996. CONCLUSION: The measures taken were effective in reducing waste gas exposure. Nevertheless, further efforts are necessary, especially for nitrous oxide, to reach western European standards. These efforts comprise structural measures such as active scavenging devices and air-conditioning systems at all workplaces, the use of total intravenous anaesthesia, low-flow anaesthesia and an appropriate working technique.

Anesthesiology↗
PubMed2000

Occupational exposure to nitrous oxide and desflurane during ear-nose-throat-surgery.

PURPOSE: To determine occupational exposure of the anesthesiologist and surgeon to nitrous oxide and desflurane during general anesthesia for ear-nose-throat (ENT) surgery in children and adults. METHODS: An observational clinical trial was performed in ten children (C) and ten adults (A). Tracheas were intubated, in adults, with cuffed tubes and in children with uncuffed tubes. The operating room was equipped with modern air conditioning and waste anesthetic gas scavengers. Gas samples were obtained during the operative procedure every 90 sec from the breathing zone of subjects. Time-weighted averages (TWA) over the time of exposure were calculated for nitrous oxide and desflurane. RESULTS: Nitrous oxide TWAs for anesthesiologists were 0.41 +/- 0.23 ppm (A) and 1.20 +/- 0.32 ppm (C, P < 0.0001), and 2.24 +/- 1.93 ppm (A) and 5.30 +/- 0.60 ppm (C, P = 0.0001) for the surgeon who worked close to the patient's airway and thus had higher exposure (P < 0.05 [A], P < 0.0001 [C]). With regard to desflurane, the anesthesiologists' TWAs were 0.02 +/- 0.03 ppm for both adults and children. The surgeon was exposed to 0.21 +/- 0.24 ppm desflurane (A) and 0.30 +/- 0.14 ppm (C, P: n.s.). Although the surgeon's exposure was greater (P < 0.05 [A], P < 0.0001 [C]), the threshold limits of 25 ppm for nitrous oxide and 2 ppm for desflurane recommended by the National Institute of Occupational Safety and Health were not exceeded. CONCLUSIONS: Under modern air conditioning, occupational exposure to inhalational anesthetics is low, and inhalational anesthesia is safe from the standpoint of modern workplace laws and health-care regulations.

Adult↗
PubMed2002

Evaluating the potential efficacy of three antifungal sealants of duct liner and galvanized steel as used in HVAC systems.

Current recommendations for remediation of fiberglass duct materials contaminated with fungi specify complete removal, which can be extremely expensive, but in-place duct cleaning may not provide adequate protection from regrowth of fungal contamination. Therefore, a common practice in the duct-cleaning industry is the postcleaning use of antifungal surface coatings with the implication that they may contain or limit regrowth. However, even the proper use of these products has generally been discouraged because little research has been conducted on the effectiveness of most products as used in heating, ventilating, and air-conditioning (HVAC) systems. Three different coatings were evaluated on fiberglass duct liner (FGDL). Two of the three coatings were able to limit growth in the 3-month study; the third did not. One of the coatings that was able to limit growth was further evaluated in a comparison of FGDL or galvanized steel (GS) under conditions that mimicked their use in HVAC systems. The results showed that both moderately soiled and heavily soiled uncoated FGDL and GS duct material can support fungal growth, but that GS duct material was more readily cleaned. The use of an antifungal coating helped limit, but did not fully contain, regrowth on FGDL. No regrowth was detected on the coated GS.

Air Conditioning↗
PubMed2006

Idle emissions from heavy-duty diesel vehicles: review and recent data.

Heavy-duty diesel vehicle idling consumes fuel and reduces atmospheric quality, but its restriction cannot simply be proscribed, because cab heat or air-conditioning provides essential driver comfort. A comprehensive tailpipe emissions database to describe idling impacts is not yet available. This paper presents a substantial data set that incorporates results from the West Virginia University transient engine test cell, the E-55/59 Study and the Gasoline/Diesel PM Split Study. It covered 75 heavy-duty diesel engines and trucks, which were divided into two groups: vehicles with mechanical fuel injection (MFI) and vehicles with electronic fuel injection (EFI). Idle emissions of CO, hydrocarbon (HC), oxides of nitrogen (NOx), particulate matter (PM), and carbon dioxide (CO2) have been reported. Idle CO2 emissions allowed the projection of fuel consumption during idling. Test-to-test variations were observed for repeat idle tests on the same vehicle because of measurement variation, accessory loads, and ambient conditions. Vehicles fitted with EFI, on average, emitted approximately 20 g/hr of CO, 6 g/hr of HC, 86 g/hr of NOx, 1 g/hr of PM, and 4636 g/hr of CO2 during idle. MFI equipped vehicles emitted approximately 35 g/hr of CO, 23 g/hr of HC, 48 g/hr of NOx, 4 g/hr of PM, and 4484 g/hr of CO2, on average, during idle. Vehicles with EFI emitted less idle CO, HC, and PM, which could be attributed to the efficient combustion and superior fuel atomization in EFI systems. Idle NOx, however, increased with EFI, which corresponds with the advancing of timing to improve idle combustion. Fuel injection management did not have any effect on CO2 and, hence, fuel consumption. Use of air conditioning without increasing engine speed increased idle CO2, NOx, PM, HC, and fuel consumption by 25% on average. When the engine speed was elevated from 600 to 1100 revolutions per minute, CO2 and NOx emissions and fuel consumption increased by >150%, whereas PM and HC emissions increased by approximately 100% and 70%, respectively. Six Detroit Diesel Corp. (DDC) Series 60 engines in engine test cell were found to emit less CO, NOx, and PM emissions and consumed fuel at only 75% of the level found in the chassis dynamometer data. This is because fan and compressor loads were absent in the engine test cell.

Air Pollutants↗
PubMed2000

A comparison of sampling media for environmental viable fungi collected in a hospital environment.

Quantitative evaluation of fungal exposure is often conducted by analysis of the composition of microbes in air samples and calculation of the concentrations afterward. The collecting medium that favors the growth for most saprophytic fungi is considered to be the ideal choice in most circumstances. Currently, the culture medium most frequently adopted in environmental sampling for airborne fungi is MEA (malt extract agar) recommended by the ACGIH for its suitability for most fungal growth. DG18 (dichloran glycerol-18), developed in 1980, is suggested for growth at lower water activity (a(w)=0.95) specifically and is not as commonly used in general studies. This investigation collected airborne viable fungi using a single stage/N6 Andersen impactor with MEA and DG18 agar plates attached simultaneously to the same set of samplers. The sampling locations were at 17 sites within a central air-conditioned hospital. After incubation and morphological identification, concentrations of airborne fungi and bacteria were expressed as CFU/m(3) (colony forming units/m(3)). There are 405 DG18 plates and 378 plates available for statistical analysis. Results show that the airborne fungal concentrations, shown by geometric mean (GM), are higher from the DG18 plates than from the MEA plates. The total fungal concentrations is 68.6 vs 12.94 CFU/m(3), and for Aspergillus spp., the concentration is 1.58 vs 0.72 CFU/m(3); for Penicillium spp., 3.37 vs 0.71; and for yeast, 5.09 vs 0.49 CFU/m(3). In addition, the number of different genera present is greater on the DG18 plates than on the MEA plates, on average, 2.85 types vs 1.72. This study suggests that in a hospital environment with 24-h, central air conditioning, DG18 plates appear to be more effective in collecting more fungal colonies in terms of both quantity and types of genera. Such a finding is presumed to be attributed to the characteristic of DG18 in slowing colony growth so that the dominating genus will not over occupy the culture plate surface before the less competitive genus can fully develop. Future studies on related biological mechanisms are essential to conclude whether the above results sustain when sampling is conducted in other environments.

Air Pollutants↗
PubMed1981

Investigation and control of an outbreaks of legionnaires' disease in a district general hospital.

Between December, 1979, and July, 1980, 12 cases of legionnaires' disease were recognised in a district general hospital. 11 of the patients probably acquired their infection within the hospital. Epidemiological and environmental studies indicated that the plumbing system and possibly also the air-conditioning cooling-tower exhaust in the new building of the hospital were the sources of infection. Chlorination of the cold-water supply and raising the hot-water temperature appeared to terminate the outbreak.

Adult↗