Influence of local air velocity from air conditioner evaluated by salivary and skin biomarkers

Abstract

-The purpose of this paper is to reveal both the psychosomatic and the physical effects of local air velocity from an air conditioner using biomarkers which can be collected noninvasively. Salivary α-amylase activity (SAA) and salivary cortisol were used as the indexes of psychosomatic effects. The total protein (TP) collected from stratum corneum was used as an index of the physical condition of dry skin. A continuous experiment over a 5 days period in summer was conducted using 8 healthy young male adults for 2 -types of airflow conditioners, a whole ceiling-type air conditioner (without local air velocity) and a normal-type air conditioner (with local air velocity). The subjects felt cool, windy, dry and uncomfortable when under the normal-type air conditioner as determined in a subjective evaluation.The SAA under the normal-type air conditioner fluctuated more widely than with the whole ceiling-type air conditioner. The level of salivary cortisol decreased more in a day under the normal-type air conditioner than with the whole ceiling-type air conditioner. These results showed that reducing local air velocity may provide more healthy psychosomatic conditions over the long-term. Moreover, the TP of a drying-exposed skin area showed a significant change during this experiment whereas the TP of drying-protected area was relatively unchanged. It was indicated that one week's exposure to local air velocity conditions possibly influences the drying of facial skin. Thus, air movement at low velocity can be provides more comfortable conditions not only psychosomatically but also physically.

Noninvasive Evaluation of the Chronic Influence of Local Air Velocity from an Air Conditioner Using Salivary Cortisol and Skin Caspase-14 as Biomarkers of Psychosomatic and Environmental Stress

“…The whole ceiling-type air conditioning unit (S28FLV, 2.8 kW cooling capacity; Daikin Industries, Osaka, Japan) comprised a blower tube and a three-dimensional knit fabric (1.77 m × 0.89 m × 2 sheets; 3.2 m 2 ; Asahi Kasei Fibers Co., Tokyo, Japan) which covered the ceiling and through which air flowed. 3,4 The unit was installed in the evaluation room for the experimental assessment and provided uniform temperature and relative humidity by generating parallel airflow (Fig. 1A).…”

“…3 Furthermore, by measuring salivary cortisol and total skin protein levels, 1 week's exposure to local air flow has been shown to have a drying effect on facial skin. 4 Quantitative measurements of air velocity, with a resolution accuracy < 0.1 m/s, and the hydration index of skin have not, however, been measured simultaneously in these previous experiments.…”

“…1,2 In order to improve airflow conditions in confined spaces, a low-cost whole ceiling-type air conditioner has been proposed previously by the authors of the present study. 3,4 The airflow from this novel air conditioner is dispersed from the whole ceiling by using a three-M Yamaguchi, H Nishimiya Effect of air velocity on salivary cortisol and skin caspase-14 dimensional knit fabric at the outlet. Air velocity from the whole ceiling-type air conditioner is low (< 0.2 m/s) and similar to that used in laboratory and factory 'clean rooms'.…”