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At least 19 recordsLinked to original sources
PubMed1992

[Comparison of lung function parameters in healthy non-smokers following exertion in urban environmental air and in air-conditioned inside air].

This study examines the question whether young healthy nonsmokers show differences in parameters of lung function after having been exposed to exercise in city air and to the same exercise in air-conditioned room air. For this purpose 16 young nonsmokers of age 20-39 years (10 men: 26.6 +/- 5.2, 6 women: 22.2 +/- 1.4) exercised maximally once on a bicycle ergometer in city air for 8 minutes and 48 hours later in air-conditioned room air on the same ergometer also for 8 minutes. The forced vital capacity, the forced expiratory volume in 1 second (FEV1) and peak expiratory flow rates were determined before exercise, immediately after, and after the rest of 10, 30, 60, and 120 minutes. The following results were obtained: 1. In city air the continuously recorded concentrations of NO2 showed a mean value (+/- 1 SD) of 71.6 micrograms/m3 (+/- 23.2) and thus about 10 times higher than in air-conditioned room air, where the mean value of NO2 was 7.5 micrograms/m3 (+/- 3.5). 2. 10, 30, 60, and 120 minutes after exercise in city air the mean FEV1 values were about 2.5-3% lower than in room air. Even though these differences were small, they were significant (10 minutes after exercise p = 0.006, 30 minutes p = 0.011, 60 minutes p = 0.025, and 120 minutes p = 0.016). 3. The FEV1 differences were more pronounced in males. The males were, due to conditions beyond our control, exposed to higher NO2 and NO concentrations in city air than females.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1975

Airborne infection in a fully air-conditioned hospital. I. Air transfer between rooms.

Measurements have been made of the extent of air exchange between patient rooms in a fully air-conditioned hospital using a tracer-gas method. When the rooms were ventilated at about six air changes per hour, had an excess airflow through the doorway of about 0.1 m.3/sec. and the temperature difference between rooms and corridor was less than 0.5 degrees C., concentrations of the tracer in rooms close to that in which it was being liberated were 1000-fold less than that in the source room. This ratio fell to about 200-fold in the absence of any excess airflow through the doorways. Considerable dilution took place along the corridors so that the concentration fell by around 10-fold for every 10 m. of corridor.

Air Conditioning↗
PubMedDate not supplied

Human health and air conditioning systems.

In air-conditioned buildings indoor air quality is closely dependent on the efficiency of air-conditioning and humidifier systems since these systems provide a suitable environment for the proliferation of microorganisms. Pollutants released by microorganisms are termed 'bioaerosols' and may be spread in the indoor environment through the air-conditioning system. Moreover, the tightening of the buildings in which central air-conditioning systems are usually located increases the levels of indoor pollutants. Both hypersensitivity and infectious diseases are associated with bioaerosol exposure, whereas the sick building syndrome (a complex of symptoms described among workers in modern office buildings which are hermetically sealed and mechanically ventilated) is very unlikely to have a bioaerosol component.

Aerosols↗
PubMed1988

The effect on airway function of inspired air conditions after isocapnic hyperventilation with dry air.

The magnitude of postexercise or posthyperventilation bronchoconstriction in patients with asthma is related to the temperature and the water content of the inspired air during the exercise or hyperventilation period. Recent studies have suggested that the inspired air conditions during recovery from exercise may also be important in determining the magnitude of postexercise airway narrowing. In the present study, normal subjects (n = 8) and patients with asthma (n = 12) were studied on separate days. On day 1 the subjects performed isocapnic hyperventilation with warm dry air and recovered breathing warm dry air. On the second day, an identical warm dry air challenge was administered, but recovery occurred while they were breathing warm humid air. There was no significant bronchoconstriction in the normal subjects, irrespective of the inspired air conditions during recovery. The patients with asthma showed greater bronchoconstriction during recovery in warm, humid air (maximal decrease in FEV1 31% +/- 17%) than in dry air (maximal decrease in FEV1 19% +/- 20%; p less than 0.05). These results suggest that the inspired air condition during recovery from isocapnic hyperventilation of dry air is also a determinant of the magnitude of the bronchoconstrictor response.

Adult↗
PubMed1992

[Legionella and other bacteria in air humidifiers and cooling systems of air conditioning units--a survey].

Air humidifiers using cold water and cooling towers of air-conditioning systems provide the best settings for the growth of bacteria. Hence, we investigated 90 water samples for humidifiers and 15 water samples from cooling towers of hospitals, authorities, schools, and factories. The colony forming units/ml at 20 degrees C and 36 degrees C, the biological activity of added biocidal substances, and the occurrence of legionella were determined. About 90 percent of the samples showed no activity of the biocidal substance added, suggesting the uselessness of such substances. Furthermore, they exercised neither an influence on the CFU of the water samples nor on the occurrence of legionella. Legionella were isolated in 7 per cent of the humidifiers investigated, in 3 per cent of air conditioned buildings, respectively. 13 per cent of the cooling towers contained legionella. The risk of infection by air conditioning systems, humidifiers, cooling towers, and other emitters of infections agents should be controlled by the public health service.

Air Conditioning↗
PubMed1989

[Hygienic evaluation of substrata of contamination of ventilation and air conditioning systems].

Modern ventilation and air conditioning systems are complex technological objects in environment which can be sources of health-hazardous factors, including biological ones. Ventilation and air conditioning contact systems with water and partial air recirculation have construction prerequisites for environmental accumulation and dispersal of organic substances of microorganism and anthropogenic origin. Pollution substrates of inner surfaces of the above systems contain specific antigens causing immune response in persons working in air-conditioned premises.

Air Conditioning↗
PubMed1978

Effect of central air conditioning and meteorologic factors on indoor spore counts.

We have studied the effect of residential central air conditioning on indoor spore counts. The air of 6 pairs of homes (air-conditioned and non-air-conditioned) was sampled volumetrically 4 times daily for 3 consecutive days at 2-hr intervals in the kitchens, bedrooms, and basements with an Anderson sampler. Nearly simultaneous samples were taken outdoors at the same intervals. The total spore count was significantly lower (p less than 0.05) in the kitchens and bedrooms of air-conditined as compared to non-air-conditioned homes. Logarithmic conversion of the total spore count showed significant reduction in all indoor locations of air-conditioned homes. Multiple regression analysis revealed the lower relative humidity of air-conditioned homes to be associated with the lower spore counts. There was no difference in the percent concentration of the major genera within both types of homes. Since reducing the influx of outdoor spores decreases the total spore count without altering the relative concentration of the genera whereas filtration preferentially removes the larger spores, we conclude that the major mechanism in reducing spore counts in air-conditioned homes is the closed windows, although the lower relative humidity and perhaps filtration are also associated with lower spore counts.

Air Conditioning↗
PubMed1992

Air-conditioning and mortality in hot weather.

A cohort of 72,740 persons for whom information on household air-conditioning was available was monitored for mortality via the National Death Index from April 1980 through December 1985. A total of 2,275 deaths occurred among the members of this cohort. The basic question addressed was whether persons in households with air-conditioning experienced lower death rates during hot weather than persons in households without air-conditioning. This question was examined for both central and room air-conditioning. The analysis was based on a state-by-state approach, that cross-tabulated deaths by air-conditioning status (yes or no) and average temperature during the month of death (less than 21.2 degrees C (less than 70 degrees F) or greater than or equal to 21.2 degrees C (greater than or equal to 70 degrees F)). The Mantel-Haenszel and sign tests were used to summarize the data. For central air-conditioning versus no air-conditioning, statistically significant benefits (p less than 0.05, Mantel-Haenszel test) were observed for the overall total, for females, for persons not in the labor force, and for persons living in fewer than six rooms. These groups had more exposure to air-conditioning. The relative risk for the total group was 0.58, implying that in hot weather, the death rate for persons who had central air-conditioning was 42 percent lower than the rate for persons who did not have air-conditioning, after confounding variables had been controlled for. For room air-conditioning versus no air-conditioning, the odds ratio for the total group was 0.96, which was not significantly different from 1.0, suggesting that no real benefit was derived from room air-conditioning. Some reasons for the lack of a demonstrable benefit for room air-conditioning are given.

Aged↗
PubMed1975

[Transfer of organisms during exchange of heat and moisture in air conditioning installations (author's transl)].

With the exhaust air from ventilation and air conditioning installations escaping into the open, the heat content is also lost which fresh air from outside obtains at considerable expense of energy and technical equipment. The heat content, on the other hand, consists of about equal proportions of sensible heat and latent heat which is associated with the moisture content of the air. In order to regain the heat content of the escaping air so as to be able to use it again - and this is becoming increasingly important with rising energy costs - heat exchangers are necessary which remove the heat content from the exhaust air and transfer it to the fresh air from outside. With the high proportion of latent heat, this energy exchange is only effective if the latent heat can also be regained. For this purpose it is essential to have exchange surfaces which store and transfer both heat and moisture. To achieve this they must come into contact with the exhaust air stream and the fresh air stream alternately. Technically, this is done in a simple way by resolving rotor-like storage material. But a rigid separation of the air streams is no longer possible. Even if it is known that there are very highly developed sealing elements between the fixed and moving parts, the question whether particles from the exhaust air can get into the newly introduced outside air through the rotating storage material still gains in importance in certain types of usuage. For example, this is of importance for hospitals, especially in the operation areas in which air conditioning is desirable for 24 hours daily on hygienic grounds, but also in schools and offices where the present normal practice, for economic reasons, of recirculating air is to be avoided to stop the transference of infections pathogens and odours. In various places, experiments have been carried out earlier with heat exchangers consisting of asbestos board and with rotating storage material coated with lithium chloride and a particularly high degree of exchange achieved. The experiments are published and had the result that nothing was transferred which could give rise to objection. Yet these experiments have been criticised from various points of view.

Air Conditioning↗
PubMed1985

The effect of ipratropium bromide (Atrovent) on the air conditioning capacity of the nose.

The air conditioning capacity of the nose was assessed by a method which permits measurements in both nasal cavities without blockage of the passage between the nasopharynx and oropharynx. By this method the degree of warming of the air and its humidification during the passage through the nasal cavity can be calculated. The effect of intranasal application of ipratropium bromide (Atrovent) on the air conditioning capacity of the nasal mucosa was evaluated in a group of normal subjects and a group of patients with vasomotor rhinitis. In this short term trial Atrovent was found not to have any effect on this capacity.

Adult↗
PubMedDate not supplied

Measurements of the air conditioning capacity of the nose during normal and pathological conditions and pharmacological influence.

A simple method is introduced for measuring the air conditioning capacity of the nose. A flow of 8 1/min dry air is introduced by a catheter into the nasopharynx, while 5 1/min is sucked out from the investigated nasal cavity through a psychrometer. The additional 3 1/min passes down into the pharynx, thus reducing the intermingling with expiratory air. By using CO2 as a tracer, this error was found to be maximally 15% and often about 1%. The three different enthalpy factors: increase in enthalpy of dry air, vaporization, and increase in enthalpy of water vapour, were calculated separately and the vaporization was found to be the dominant factor. The calculated total supply of humidity showed that the method presented causes at least a slight stress on the humidifying capacity. Pharmacological studies have shown that subcutaneously injected atropine decreased the total enthalpy and that of water vapour, while nasal administration of oximetazoline also decreased the total enthalpy. Nasal administration of homatropine or pilocarpine had no effect on the air conditioning. In comparison with normal subjects, those with vasomotor rhinitis had an increased enthalpy of the air, while the same enthalpy factor was reduced in cases with atrophic rhinitis. Laryngectomized patients had no significant difference in the air conditioning capacity of the nose in relation to normal subjects, while patients operated with partial maxillectomy had a considerable reduction in vaporization and total enthalpy.

Atropine↗
PubMed1989

[Bacteriologic investigation of the hospital air-conditioning water].

We have isolated a pathogenic strain of LDB from the water of the hospital cooling-water storage tank for air-conditioning system. At the same time, other bacteria were also isolated with Pseudomonas and Flavobacterium being predominant, most of these organisms in the water of air-conditioning system were resistant to antibacterial drugs. A proposal to improve architectural design and to sterilize air-conditioning water was suggested.

Air Conditioning↗
PubMed1990

Air-conditioning and health: effect on pulse and blood pressure of young healthy Nigerians.

Blood pressure and pulse of 32 young healthy Nigerian volunteers were determined after they had been in an air-conditioned room from between 60 and 90 minutes. The same determinations were made at the same time of another day with air-conditioning switched off for the same period. The mean systolic blood pressure (SBP) was 115.3 +/- 11.5 mmHg under air-conditioner (AC) and 108.5 +/- 10.1 mmHg without air-conditioning. This difference was statistically significant (p less than 001). Similarly, diastolic blood pressure (DBP) was higher in AC, 69.4 +/- 8.9 mmHg, than without AC, 66.5 +/- 9.1 mmHg (p less than 025), while mean blood pressure was also higher in AC, 84.9 +/- 9.1 mmHg, than without, 79.9 +/- 7.7 mmHg (less than 005). There was no significant different in pulse rate. These differences in the BP of normal young subjects are not thought to be of clinical significance but the result suggests that study of the effect of AC on BP and pulse in older subjects and hypertensive subjects is desirable.

Adult↗
PubMedDate not supplied

High prevalence of sick building syndrome in a new air-conditioned building in Italy.

This study, which was conducted in central Italy, included (a) 525 office workers employed in an air-conditioned building that had fan coil units in every room (building B) and (b) 281 subjects who worked in three naturally ventilated buildings (building A) that were operated by the same public administration. The prevalence of work-related symptoms was assessed by a questionnaire that was administered by an occupational medicine specialist. The most frequent complaints of employees in building B were dry air, strong lighting, and high temperature. Employees who worked in this building experienced a statistically higher prevalence of symptoms that were characteristic of the sick building syndrome. This is the first time that this syndrome has been reported in Italy. Excessive illumination, a low relative humidity, and fiberglass on floors and furniture might have contributed to the symptoms. Inadequate maintenance of the building's air-conditioning plant and the employees' lack of information regarding self-regulation of the fan coil units may also have contributed to the prevalence of symptoms.

Air Conditioning↗
PubMed1990

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.

Air Conditioning↗
PubMed1992

Air-conditioned environments do not prevent deterioration of human semen quality during the summer.

OBJECTIVE: To determine if air conditioning might mitigate summer reductions in semen quality. DESIGN: Prospective study of semen quality in summer and winter. SETTING: Normal human volunteers were studied in the setting of a fertility laboratory. PATIENTS, PARTICIPANTS: Two groups of volunteers were selected from the vicinity of New Orleans: 64 men who worked indoors during the summer in air-conditioned environments and 76 others who worked outdoors. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Parameters of manual semen analysis were examined for seasonal and group differences. RESULTS: Remarkably similar reductions in semen quality during summer as compared with winter were observed in both indoor and outdoor workers, respectively, with regard to the following parameters of semen quality: 19% and 19% in sperm concentration, 25% and 27% in total sperm per ejaculate, 17% and 20% in motile sperm concentration, 13% and 15% in percent sperm with normal morphology, and 23% and 23% in concentration of morphologically normal motile sperm. CONCLUSIONS: These findings do not support the hypothesis that the heat of the summer is detrimental to male reproductive capacity. The available evidence suggests instead a possible role of photoperiod in causing the seasonal changes in semen quality.

Adolescent↗