Sudden temperature changes and respiratory symptoms--an experimental approach

BACKGROUND

Exposure to air-conditioning systems and allergic phenotypes are consistent risk factors to develop indoor air quality (IAQ) respiratory complaints. The aim of this study was to compare the role of allergic rhinitis on respiratory complaints in individuals exposed to sudden temperature changes.

METHODS

To address this question, a case-control challenge study was performed in a laboratory of thermal comfort evaluation with twin isolated chambers set at 14 degrees C/57.2 degrees F (cold) and 26 degrees C/78.8 degrees F (hot) temperatures. A groups of 32 patients with persistent allergic rhinitis (rhinitis group) and 16 control subjects (control group) were exposed for 30 minutes, three times alternately in the chambers. Symptoms were reported using an analog visual scale and nasal and pulmonary peak flow measurements were taken during baseline at hot and cold temperatures and after the challenge.

RESULTS

The rhinitis group reported increased itching and stinging eyes when compared with the baseline during exposure to hot and cold temperatures and they also reported increased breathlessness during hot air exposure. In addition, there was a significant decrease in expiratory flow rates in this group during exposure to hot and cold temperatures that persisted for 24 hours after challenge.

CONCLUSION

This study suggests that individuals with allergic rhinitis have a lower threshold than controls to develop respiratory and ocular symptoms after air-conditioning-induced sudden temperature changes.

Persistent allergic rhinitis and indoor air quality perception--an experimental approach

In order to compare patterns of indoor air perception, including perceptions of temperature, air movement, indoor air quality (IAQ), mental concentration, and comfort, 33 subjects either with persistent allergic rhinitis or controls were exposed to different temperatures and constant relative humidity in an experimental office environment. Results were obtained by means of a self-administered visual analogue scale, analyzed using mean score comparisons and principal component analysis. At 14 degrees C, the rhinitis group reported higher scores for sensations of air dryness than controls. At 18 degrees C, in the rhinitis group, there was a correlation between dry, stagnant air, and difficult mental concentration. This group also correlated heat, dry air, and poor IAQ, in contrast to the control group, which correlated comfort, easy mental concentration, and freshness. At 22 degrees C, the rhinitis group correlated heat, dryness, stagnant air, and overall discomfort. This group also correlated non-dry air, freshness, and comfort, whereas the control group correlated heat, humidity, good indoor air, freshness, and comfort. This study suggests that the rhinitis group perceives indoor temperatures of 14 degrees C as dryer than controls do, and that at 18 and 22 degrees C this group positively correlates different adverse perceptions of IAQ. By means of a self-administered questionnaire in an experimental condition, the present study compares subjective patterns of indoor air perception from individuals with respiratory allergy (allergic rhinitis) to control individuals. It reports different patterns of perception of indoor air quality (IAQ) between the two groups, suggesting that allergic individuals could have different IAQ perception.

A REVIEW OF AIR DISTRIBUTION PATTERNS IN SURGERY ROOMS UNDER INFECTION CONTROL FOCUS

The problem of airborne contamination in surgical infections still raises discussion. The success of the aseptic methods and the use of medicines for the combat of infections are making most surgeons contempt the danger of the aerial particles course. A detailed knowledge of the characteristics of the contamination sources and of the ventilation system performance used at surgery rooms is necessary to guarantee that the ventilation system supplies the pollutant control in ventilation rates that assure the health and the comfort of the occupants. There are many configurations of air distribution systems and a wide range of potential conditions inside a surgery room that are influenced by their performance. In the same way, it is evident the lack of information in the literature regarding which characteristics of the systems of air treatment have stronger influence on the amount of particles in suspension. This paper provides a review of the distribution patterns and air movement at surgery rooms, describing the importance of airborne particles in the infection process, making a comparative analysis of the efficiency of microbiological control of the main airflow systems, identifying and demonstrating the control strategies that can reduce the risks of airborne contamination in surgical infections.

Association of air-conditioning with respiratory symptoms in office workers in tropical climate

To evaluate the association of heating, ventilation and air-conditioning systems (HVAC) and respiratory symptoms in a tropical city, self-administered questionnaires were given to 2000 individuals working in air-conditioned office buildings and to 500 control workers in naturally ventilated buildings. Reported symptoms from the two populations were analyzed using chi-square tests, univariate and multiple logistic regressions models. Symptoms were the outcome variable and the odds ratios were adjusted by gender, age, accumulated work time, smoking habits and atopic background. There was a 79.8% response rate and there was a positive association of nasal symptoms (odds ratio, OR = 1.59, 95% confidence interval, CI = 1.11-2.28), naso-ocular symptoms (OR = 1.58, 95% CI = 1.05-2.38), persistent cough (OR = 3.04, 95% CI = 2.00-4.63) sinusitis symptoms (OR = 1.85, 95% CI = 1.27-2.71) and building-related worsening of the symptoms (OR = 4.92, 95% CI = 2.93-8.27) with working in air-conditioned buildings. In conclusion, our study suggests that artificial air-conditioning is a matter of concern for respiratory symptoms in cities with hot and humid climate.

PRACTICAL IMPLICATIONS

This study suggests that indoor air-related respiratory symptoms are a matter of concern in places with hot and humid climate. The regression models were adjusted by confounders that could be used in further reanalysis of indoor air quality related symptoms and ventilation systems with expanded variety of climatic conditions.