[Experimental data on the effect of ionized air on conditions due to adrenalectomy].
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Adrenalectomy↗
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[Case study of a Legionella epidemic in a rehabilitation clinic].
A series of nosocomial Legionella infections in a rehabilitation center is reported. In a three months period a total of 10 pneumonias with 3 deaths occurred (8 patients, 1 companion, 1 staff member). Serologic analysis proved additional Legionella infections within the nursing staff. The warm-water system was proved to be the source of infection by isolating Legionella pneumophila serogroup 1 subtype Pontiac both in warm-water and patients samples. The air conditioning system could not be ruled out as another (secondary) route of exposure because of shortcomings in construction. Conclusions about prevention and the course of the disease are discussed and standards for warm-water and air conditioning systems are proposed.
Adult↗
An engineering approach to controlling indoor air quality.
Evidence is accumulating that indicates air quality problems in residential and commercial buildings are nearly always associated with inadequacies in building design and methods of operation. Thus, the very systems depended on to control the indoor environment can become indirect sources of contamination if diligence is not exercised at each stage of a building's life: a) planning and design, b) construction and commissioning, c) operation, and d) demolition or renovation. In this paper, an engineering perspective is presented in which the existing building stock is characterized in terms of its environmental performance. Preliminary data indicate that 20 to 30% of the existing buildings have sufficient problems to manifest as sick-building syndrome or building-related illness, while another 10 to 20% may have undetected problems. Thus, only about 50 to 70% of the existing buildings qualify as healthy buildings. Two methods and three mechanisms of control are described to achieve "acceptable" indoor air quality: source control and exposure control. If sources cannot be removed, some level of occupant exposure will result. To control exposures with acceptable values, the primary sensory receptors of the occupants (i.e., thermal, ocular, auditory, and olfactory) cannot be excessively stimulated. The three exposure control mechanisms are conduction, radiation, and convection. To achieve acceptable occupant responses, it is often practical to integrate the mechanisms of radiation and convection in heating, ventilating, and air conditioning systems that are designed to provide acceptable thermal, acoustic, and air quality conditions within occupied spaces.(ABSTRACT TRUNCATED AT 250 WORDS)
Air Conditioning↗
Environmental and human factors influencing thermal comfort of office occupants in hot - humid and hot - arid climates.
The effects of environmental and individual factors on thermal sensation in air-conditioned office environments were analysed for two large, fully compatible thermal comfort field studies in contrasting Australian climates. In the hot - humid location of Townsville, 836 office workers were surveyed; 935 workers participated in hot - arid Kalgoorlie-Boulder. Overall perceived work area temperature and measured indoor operative temperature correlated moderately with thermal sensation for Townsville (T) subjects but only perceived temperature correlated with Kalgoorlie-Boulder (KB) sensation. Multiple regression analyses confirmed that indoor climatic variables (including Predicted Mean Vote) contributed to actual thermal sensation vote (24% T; 15% KB), with operative temperature having more of an effect in T than in KB. Subsequent analyses of individual characteristics showed no linear contributions to thermal sensation. The remaining variances were significantly related to perceived work area temperature (7% additional explained variance in T; 12% in KB). Mann - Whitney analyses (after correction for climatic variables) showed that T subjects with higher job satisfaction had thermal sensations closer to 'neutral'. Males, healthier subjects, non-smokers, respondents with earlier survey times and underweight occupants had lower median thermal sensations in KB. Townsville occupants appeared more adapted to their outdoor climatic conditions than Kalgoorlie-Boulder respondents, perhaps due to limited home air-conditioning. Further research into non-thermal impacts on gender-related thermal acceptability is suggested.
Adolescent↗
Mobile, outdoor continuous-flow isotope-ratio mass spectrometer system for automated high-frequency 13C- and 18O-CO2 analysis for Keeling plot applications.
A continuous-flow isotope-ratio mass spectrometer (CF-IRMS, custom-made GasBenchII and Delta(plus)Advantage, ThermoFinnigan) was installed on a grassland site and interfaced with a closed-path infrared gas analyser (IRGA). The CF-IRMS and IRGA were housed in an air-conditioned travel van. Air was sampled at 1.5 m above the 0.07-m tall grassland canopy, drawn through a 17-m long PTFE tube at a rate of 0.25 L s(-1), and fed to the IRGA and CF-IRMS in series. The IRMS was interfaced with the IRGA via a stainless steel capillary inserted 0.5 m into the sample air outlet tube of the IRGA (forming an open split), a gas-tight pump, and a sample loop attached to the eight-port Valco valve of the continuous-flow interface. Air was pumped through the 0.25-mL sample loop at 10 mL s(-1) (a flushing frequency of 40 Hz). Air samples were analysed at intervals of approx. 2.8 min. Whole system precision was tested in the field using air mixed from pure CO2 and CO2-free air by means of mass flow controllers. The standard deviation of repeated single measurements was 0.21-0.07 per thousand for delta13C and 0.34-0.14 per thousand for delta18O of CO2 in air with mixing ratios ranging between 200-800 micromol mol(-1). The CO2 peak area measured by the IRMS was proportional to the CO2 mixing ratio (r2 = 1.00), allowing estimation of sample air CO2 mixing ratio from IRMS data. A 1-day long measurement cycle of CO2, delta13C and delta18O of air sampled above the grassland canopy was used to test the system for Keeling plot applications. Delta18O exhibited a clear diurnal cycle (4 per thousand range), but short-term (1-h interval) variability was small (average SD 0.38 per thousand). Yet, the correlation between delta18O and CO2 mixing ratio was relatively weak, and this was true for both the whole data set and 1-h subsets. Conversely, the delta13C of all 541 samples measured during the 25.2-h interval fitted well the Keeling regression (r2 = 0.99), yielding an intercept of -27.40 per thousand (+/-0.07 per thousand SE). Useful Keeling regressions (r2 > 0.9, average r2 = 0.96) also resulted from data collected over 1-h intervals of the 12-h long twilight and dark period. These indicated that 13C content of ecosystem respiration was approx. constant near -27.6 per thousand. The precision of the present system is similar to that of current techniques used in ecosystem studies which employ flask sampling and a laboratory-based CF-IRMS. Sampling (and measurement) frequency is greatly increased relative to systems based on flask sampling, and sampling time (0.025 s per sample) is decreased. These features increase the probability for sampling the entire CO2 range which occurs in a given time window. The system obviates sample storage problems, greatly minimises handling needs, and allows extended campaigns of high frequency sampling and analysis with minimal attendance.
Atmosphere↗
Local airway heat and water vapour losses.
A previously developed time-dependent mathematical model of the heat and water vapour transport in the human respiratory tract for mouth breathing (Daviskas et al., J. Appl. Physiol. 69:362-372, 1990) was applied to calculate the local quantities of heat and water transfer. The results of the heat and water losses agreed with experimental data. The contribution of each airway to the conditioning of inspired air was found to depend on the inspired air conditions and the pattern of breathing as expected. The greater proportion of the total heat and water loss was calculated to occur within the upper airways. However, below the pharynx, the rate of water loss during hyperpnea was calculated at a much faster rate than in the resting state. The rate at which water is returned to the airways may not be adequate to keep the periciliary fluid isotonic. These findings support the proposal that the intrathoracic airways could become significantly dehydrated during hyperpnea. The use of calculated local heat and water transfer rates may help to predict the site of stimuli to exercise-induced asthma.
Asthma↗
Characteristics and health impacts of volatile organic compounds in photocopy centers.
This study investigates the indoor air quality of typical photocopy centers in Taiwan to evaluate the human health risk following inhalation exposure. Both personal and area samplings were conducted at seven photocopy centers in the Tainan area from July 2002 to March 2003, which covered both summer and winter seasons in Taiwan. The benzene, toluene, ethylbenzene, xylenes, and styrene (BTEXS) measurements indicated no difference between personal and area samplings (P>0.05) and found that air conditioning improves indoor air quality. The additive factor at each photocopy center was significantly below 1.0, based on the current BTEXS permissible exposure limits in Taiwan. However, the mean benzene and styrene levels in the current study were 138 and 18 times, respectively, higher than those in another study conducted in the United States. Comparison of mass ratios of BTEXS with those of several chamber studies revealed that the photocopier is not the only volatile organic compound (VOC) source in photocopy centers. The lifetime cancer and noncancer risks for workers exposed to VOCs were also assessed. Results show that all seven centers in this study had a lifetime cancer risk exceeding 1x10(-6) (ranging from 2.5x10(-3) to 8.5x10(-5)). Regarding noncancer risk, levels of toluene, ethylbenzene, xylenes, and styrene were below the reference levels in all photocopy centers; however, the hazard indices for all still exceeded 1.0 (range 26.2-1.8) because of the high level of benzene in the photocopy centers.
Adult↗
[Interaction between the temperature of the surroundings, performance and level of feed for growing pigs].
Investigations of the performance of growing pigs in the live weight range of 30 to 60 kg kept individually and in groups with ad libitum and rationed feeding were carried out in two air-conditioned rooms. The air temperature in the individual experiments was 20 degrees C, 10 degrees C and 5 degrees C, the relative atmospheric moisture in all experiments was between 70 and 80%. A diminished growth of 24 g per day per degrees C below 20 degrees could be ascertained for pigs kept individually. The diminishing of the growth can be compensated by an increase of the feed intake of 1.3 g per kg live weight, day and degrees C resp. the intake of metabolisable energy of 4 kcal per kg live weight, day and degrees C until the capacity of feed consumption is reached.
Animal Feed↗
Assessment of whole body and regional evaporative heat loss coefficients in very premature infants using a thermal mannequin: influence of air velocity.
In human adults, experimental assessment of the evaporative heat loss coefficient (h(e)) requires a fully wetted skin surface area implying exposure to severe heat stress. For ethical reasons, this type of experimental situation is impossible to perform on neonates. The aim of the present study was to assess h(e) values in clinical situations for the body as a whole and for the different body segments, in particular, in natural and forced convection and using an anthropomorphic, sweating, thermal mannequin to represent a very small premature neonate (body mass 900 g). Skin hydration (i.e., simulated sweating) was performed by two electronic pumping systems, providing a steady adjustable flow of water to the mannequin surface. Experiments were carried out in a closed-incubator heated to air temperatures of 33 degrees C and 36 degrees C, with air velocities (Va) ranging from 0.01 to 0.7 m s(-1), and with four levels of air relative humidity (40, 50, 60, and 80%). For the body as a whole, h(e)=7 W m(-2) mb(-1) in natural convection, whereas in forced convection h(e) was 11.7, 12.4, and 14.1 W m(-2) mb(-1) for air velocities of 0.2, 0.4, and 0.7 m s(-1), respectively. As far as local h(e) is concerned, our results showed that the relative values of regional water loss in forced convection differ greatly from those observed under still air conditions. Thus, increasing air velocity enhances the heterogeneity in regional skin cooling, which may contribute to the neonate's thermal discomfort.
Computer Simulation↗
Reduced nocturnal asthma by improved nasal breathing.
The nose and not the mouth should be used for breathing as the nose has better air conditioning capacity. When air is inhaled through the mouth it may dry and cool the respiratory mucosa, which can lead to bronchoconstriction in sensitive patients with asthma. By dilating the nostrils you can increase nasal breathing in most subjects. The aim of this study was to investigate whether sleeping with dilated nostrils reduces nocturnal asthma. At the Asthma and Allergy Research Centre, Gothenburg, 15 out-patients with nocturnal asthma were selected. Every other night for 10 nights the test subjects slept with the nasal dilator Nozovent which has been shown to increase the nasal air-flow and decrease the need for mouthbreathing. Every morning the patients self-reported on a form whether they had woken with asthma during the night or if they had had to take asthma medication. When sleeping with the nasal dilator the patients woke up with asthma on 17 of 75 nights as compared with 32 of 75 when sleeping without the device (p < 0.01). Reduced nocturnal asthma was observed by 12 patients and less need for asthma medication at night by 7. None of the patients noted any side-effects due to the device. In conclusion, the easy-to-use and cheap medical device, Nozovent, which mechanically dilates the nostrils and improves nasal breathing, can reduce nocturnal asthma.
Adult↗
[Pollution of operating rooms. Measurements made during five anesthesias].
The purpose of this study is to measure amounts of anaesthetic vapours present in operating rooms and anaesthetic places without any gas scavenging system except air conditioning with fifteen air changes per hour. Nitrous oxide, halothane and isoflurane were measured. Halothane and isoflurane concentration is slightly higher than the French standard for anaesthetic places and lower for operating rooms. Nitrous oxide concentration is five to eight times greater than recommended standard. Although no international agreement exists concerning an acceptable pollution standard, it seems that only nitrous oxide pollution is disquieting. It would seem sensible to avoid needles contamination by use of waste gas scavenging devices.
Abdomen↗
HIV infection risk to nonhealth-care workers.
As has been summarized above, the risk of casual contact transmission of HIV virus is remote. A review of these data should provide reassurance to both workers and management. No evidence exists for direct contact spread through shaking hands and nonsexual touching. There is also no evidence for indirect spread through contact with shared inanimate objects such as typewriters, telephones, computers, water fountains, rest rooms, dining facilities, exercise equipment, bathing facilities, spas, saunas, and swimming pools. In addition, there is no evidence to suggest the airborne spread of HIV, thus there should be no potential risk of transmission through air-conditioning units, air-handling systems, or by sharing the same office space with an infected individual. The fear of AIDS may lead to irrational beliefs and biased perceptions of risk. This, unfortunately, can sometimes lead to discriminatory and inhumane treatment of persons with AIDS. The best way to manage this potential problem in the workplace is through effective educational interventions.
Adult↗
[The effect of a weak magnetic alternating field on immunobiologic reactions].
UNLABELLED: The influence of a 10 Hz, 0.5 mT (millitesla) alternating magnetic field (rectangular function) on immunologic parameters was investigated. In four chambers, each containing 15 mice, the following electroclimatic conditions existed: conventionally air conditioned laboratory (L), screening of the ambient atmospheric electric fields (F), Faradayscreening plus the above mentioned magnetic field (F + M) and the magnetic field only (M). After 14 days of acclimatizing without magnetic field influence the mice were exposed to the field in the chambers F + M and M for 1, 3, 7 and 21 days, respectively. At the end of the exposure immunological reactions were examined. METHODS: Plaquetest (hemolysis in gel) according to Jerne et al. and determination of the hemagglutination titer. The different groups (L, F, F + M and M) were compared using the Student-t test or variance analysis. RESULTS: After 7 days of field exposure the plaquecount and the hemagglutination titer (converted into the logarithm of base 2) increased significantly in comparison to the controls (L and F, respectively) in some experiments. In experiments carried out with 3 and 21 days of exposure the same tendency (increase of immunological reaction) was detected.
Analysis of Variance↗
Influence of in-tunnel environment to in-bus air quality and thermal condition in Hong Kong.
In this study, the potential exposure of bus commuters to significant air parameters (CO(2), CO and RSP) and thermal environment (air temperature and relative humidity) when buses traveled through tunnels in Hong Kong was investigated. It was found that air-conditioned buses provided a better commuting environment than non-air-conditioned buses. The blate increasing trend was found on air-conditioned buses as the in-bus air parameters concentration levels rose slowly throughout the traveling process. In contrast, the in-bus environment varied rapidly on non-air-conditioned buses as it depended on the out-bus environment. The measured in-bus CO concentration was 2.9 ppm on air-conditioned buses, while it was 4.6 ppm (even reaching the highest level at 12.0 ppm) on non-air-conditioned buses. Considering the in-bus thermal environment, air-conditioned buses provided thermally comfortable cabins (about 24 degrees C and 59% of relative humidity). However, on non-air-conditioned buses, the thermal environment varied with the out-bus environment. The mean in-bus air temperature was about 34 degrees C and 66% of relative humidity, and the in-bus air temperature varied between 29 and 38 degrees C. Also, the lower-deck to upper-deck air parameters concentration ratios indicated that the vertical dispersion of air pollutants in tunnels influenced non-air-conditioned buses as higher air parameters concentration levels were obtained on the lower-deck cabins.
Air Conditioning↗
Alterations in health examination items and skin symptoms from exposure to ultra-low humidity.
OBJECTIVES: Several lines of evidence have shown that insufficient humidity could result in health problems but no studies have been performed in ultra-low humidity (ULH) environments. The aims of this study are to investigate the health examination items alterations and skin symptoms of workers exposed to ULH environment based on a longitudinal study design. METHODS: Twelve male ULH (RH = 1.5%) workers and 12 age-sex-matched reference workers were selected. The examination items in blood and urine as well as the skin problems were compared between ULH workers and controls, and between ULH workers in 2000 and 2003. Biochemistry analysis of blood and urine were implemented from annual health examinations. Information on skin symptoms and diseases were obtained from a structured questionnaire in 2000 and 2003. RESULTS: The alterations in mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and total cholesterol in blood analysis and only sediment-WBC in urine analysis were found significantly different in 2000. These changes were almost fully recovered in 2003 although a consistently significant elevation in the urine specific gravity was found during the 3-year follow-up period. Skin disorders, however, showed an earlier elevated itching symptom in lower limb and pretibial that developed to physician-diagnosed contact dermatitis. CONCLUSIONS: Long-term ULH exposure could cause progressive pathological changes in the skin and urine concentration elevation. Because low humidity condition occurs frequently in air-conditioned buildings, the findings of this study suggest the population long-term exposed to low humidity should be cautious about health manifestations living in a low humidity environment. While the indoor environment is equipped with an air-conditioner, continuous monitoring on the humidity is recommended.
Air Conditioning↗
Effectiveness of personal protection measures against mosquito bites for malaria prophylaxis in travelers.
BACKGROUND: To determine the effectiveness of personal protection measures (PPM) against mosquito bites in travelers as tools of malaria prevention. METHODS: Two step questionnaire survey conducted in European tourists who visited East Africa: cross-sectional evaluation during the return flight with follow-up 12 weeks after return home. Among 100,336 tourists participating in a malaria survey, 89,617 had answered all questions relating to PPM and to malaria occurrence. The main outcome measure was the occurrence of malaria. RESULTS: Only 2% of tourists visiting East Africa regularly take all four of the most important PPM. Regular use of PPM resulted in a small, but significant reduction of malaria incidence when travelers were interviewed 12 weeks after returning home. Air-conditioned rooms and clothing which covered arms and legs were effective, whereas repellants, insecticides, coils, etc. showed no significant effect. CONCLUSIONS: In general, advice relating to all possible PPM in travelers should be concentrated on those who are at greatest risk of bites, and thus of malaria. For those at low and intermediate risk, preference should be given to convenient measures with proven effectiveness, such as using air-conditioned rooms and appropriate clothing.
Adolescent↗
Indoor and outdoor air quality investigation at schools in Hong Kong.
Five classrooms in Hong Kong (HK), air-conditioned or ceiling fans ventilated, were chosen for investigation of indoor and outdoor air quality. Parameters such as temperature, relative humidity (RH), carbon dioxide (CO2), sulphur dioxide (SO2), nitric oxide (NO), nitrogen dioxide (NO2), respirable particulate matter (PM10), formaldehyde (HCHO), and total bacteria counts were monitored indoors and outdoors simultaneously. The average respirable particulate matter concentrations were higher than the HK Objective, and the maximum indoor PM10 level exceeded 1000 microg/m3. Indoor CO2 concentrations often exceeded 1000 microl/l in air-conditioning and ceiling fan classrooms, indicating inadequate ventilation. Maximum indoor CO2 level reached 5900 microl/l during class at the classroom with cooling tower ventilation. Increasing the rate of ventilation or implementation of breaks between classes is recommended to alleviate the high CO2 level. Other pollution parameters measured in this study complied with the standards. The two most important classroom air quality problems in Hong Kong were PM10 and CO2 levels.
Air Pollution↗
Effect of ventilation systems on prevalence of symptoms associated with "sick buildings" in Brazilian commercial establishments.
In this questionnaire study, the authors compared the prevalence of certain symptoms and signs associated with Sick Building Syndrome and perceptions relative to environmental discomfort of employees in a central-air-conditioned dropping center and in natural-ventilation commercial shops located on the streets of Niteroi, Rio de Janeiro, Brazil. There was a statistically significant higher prevalence of symptoms (e.g., water and itching of eyes, sore throat, nose irritation, difficulty breathing, skin irritation, sneezing) that were characteristic of Sick Building Syndrome in the air-conditioned building than in the naturally ventilated stores. The results indicated that there exists a continuing need for further research in Brazilian work environments.
Adult↗