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An experiment that was carried out to find the acceptability of heat flow to the seat contact surface occurring in a vehicle cabin environment and the acceptable cabin temperature range when heated/cooled seat were operated is discussed. Results show that for drivers and passengers in vehicle cabins providing optimal seat temperature could extend the conventional 80% acceptable range of air temperature by 9.3 degrees Celsius downwards and by 6.4 degrees Celsius upwards.

This study managed to create thermal comfort conditions at three temperatures (24°C‐T24, 26°C‐T26, and 28°C‐T28) by adjusting clothing and air velocity. Thirty‐six subjects (18 males and 18 females) were exposed to each of the three conditions for 4.5 h in a design balanced for order of presentation of conditions. During each exposure, they rated the physical environment, their comfort, the intensity of acute subclinical health symptoms, and their mental load, and they performed a number of cognitive tasks. Their physiological reactions were monitored. The subjects rated T24 to be comfortably cool, T26 to be comfortably neutral, and T28 to be comfortably warm. Their self‐estimated performance did not differ between conditions but 12 of 14 objective metrics of cognitive performance decreased significantly at the elevated temperatures: compared with T24, their average cognitive performance decreased by 10% at T26 and by 6% at T28. At the elevated temperatures, their parasympathetic nervous system activity (as indicated by PNN50) and their arterial blood oxygen saturation level (SpO2) were both lower, which would be expected to result in reduced cognitive performance. The subjects also rated their acute subclinical health symptoms as more intense and their workload as higher at the elevated temperatures. These results suggest that where cognitive performance is the priority, it is wise to ensure a comfortably cool environment. The present study also supports the use of fans or natural ventilation to reduce the need for mechanical cooling. [ABSTRACT FROM AUTHOR]

A study on the effects of energy intake at breakfast on school performance was conducted among 10-year-old children. The results revealed that voluntary physical endurance and the performance of creativity test are significantly better among subjects who took breakfast which meet 20% of the recommended daily energy intake compared to those who received less than 10% of the recommended values. It was also found that error rate in an addition task is negatively correlated, while the rate of working in a number checking task was positively correlated with energy intake from the low-energy breakfast. Less number of children complained of feeling bad and hungry during the morning classes when they took high energy breakfast.

Heat stress has a negative effect on driver vigilance in a moving vehicle. The overall signals missed is 50% higher and the response time 22% longer at 27 degrees celsius than at 21 degrees celsius. These effects are more evident at speeds below 60 km/h in city traffic and among individuals below 40 years of age. The individuals respond to the heat stress by raising their level of arousal. The attentional field also alters from the peripheral signals at higher temperatures. Only women commit overt driving errors and this is greater at 27 degrees centigrade.

Humans emit carbon dioxide (CO 2) as a product of their metabolism. No measurements of CO 2 emission rates (CERs) of elderly sleeping people have yet been reported. This study performed such measurements and examined the possible mechanisms impacting CERs. Sixteen participants (8 males) aged ≥65 years old slept alone for a whole night under each of the four conditions in a 2 × 2 design: air temperatures of 27 °C and 30 °C and ventilation rates of 5 m3/h per person and 28 m3/h per person (resulting in an average indoor CO 2 concentration of about 1200 ppm and 760 ppm, respectively). Physiological responses were recorded during sleep. Indoor parameters including CO 2 concentration were continuously measured during and after sleep period. The CERs were calculated using a mass-balance model. The results show that the average CER was 9.0 ± 1.6 L/h per person. It was ca. 20% higher for males than for females, probably due to higher body mass, body surface area, and longer time awake during sleep. Compared with 27 °C, the CER was about 10% higher at 30 °C probably due to longer time awake and higher heart rate and skin temperature at this condition. No significant differences in CERs were observed between the two ventilation rates. The CERs measured in the present study for elderly are slightly lower than recently reported for young adults and 10–12 year old children. They all provide information required for estimating ventilation rates in bedrooms assuming that the ventilation is achieved with clean outdoor air. • The CO 2 emission rate of elderly subjects during sleep was 9.0 ± 1.6 L/h per person. • Males emitted more CO 2 due to higher body mass and surface area, and longer awake time. • Raised indoor temperature increased the CO 2 emission rate while sleeping. [ABSTRACT FROM AUTHOR]

Sleep is essential for the health of elderly people, but few studies have made connection between their sleep quality and their bedroom environment. This study performed field measurements in Shanghai, China, to investigate the bedroom thermal environment and ventilation and their associations with the sleep quality of elderly subjects in summer. Forty-five elderly subjects participated in this study for six consecutive days. Their bedroom air temperature, relative humidity and CO 2 concentration were measured continuously and their sleep quality was objectively measured using a wrist-worn sleep tracker. Wrist skin temperature was measured continuously at night. Each morning after waking up the subjects assessed their sleep quality, recalled their thermal sensation, and recorded their bed covering, sleepwear and cooling/ventilation arrangements during that night. The results show that higher air temperature and CO 2 concentration were both negatively correlated with objective sleep quality. Air temperature was the key factor influencing objective sleep quality. When air temperature increased by 1 °C, sleep efficiency (SE) decreased by 0.7%, duration of Rapid Eye Movement (REM) sleep decreased by 2.1min, and time awake increased by 2.3min. The sleep quality of elderly subjects was more negatively affected by heat exposure than has been previously reported for younger subjects. As CO 2 concentration increased by 100 ppm, the Total Sleep Time (TST) decreased by 11min. The combined effects of air temperature, relative humidity and CO 2 concentration were analyzed: TST and duration of REM sleep were reduced at higher air temperature, relative humidity and CO 2 concentration. [Display omitted] • The elderly subjects preferred to open doors/windows at night in summer. • Their sleep quality decreased with increased air temperature and CO 2 concentration. • Thermal environment and CO 2 concentration interactively affected sleep quality. • Wrist skin temperature could be a good marker of thermal sensation and sleep quality. [ABSTRACT FROM AUTHOR]

Two independent field intervention experiments were carried out in school classrooms in late summer (in 2004 and 2005). The air temperature was manipulated by either operating or idling split cooling units installed for the purpose. In one of these experiments, the outdoor air supply rate was also manipulated. The conditions were established for one week at a time in a blind crossover design with repeated measures on two classes of 10- to 12-year-old children. Six to eight exercises exemplifying different aspects of schoolwork (numerical and language-based) were performed as part of normal lessons. Pupils indicated their environmental perceptions and the intensity of any symptoms on visual analogue scales. Their thermal sensation changed from slightly too warm to neutral and the performance of two numerical and two language-based tests was significantly improved when the temperature was reduced from 25°C to 20°C (77°F to 68°F). When the outdoor air supply rate was increased from 5.2 to 9.6 L/s (11.0 to 20.3 cfm) per person, their performance of four numerical exercises improved significantly, confirming the results of previously reported experiments in the same series. The above improvements were mainly in terms of the speed at which tasks were performed, with negligible effects on error rate. Most school classrooms worldwide experience raised air temperatures during increased thermal loads, e.g., in warm weather; these results show that providing some means of avoiding elevated temperatures would improve educational attainment. [ABSTRACT FROM AUTHOR]

Two independent field intervention experiments were carried out in mechanically ventilated classrooms receiving 100% outdoor air. Outdoor air supply rate and filter condition were manipulated to modify indoor air quality, and the performance of schoolwork was measured. The conditions were established for one week at a time in a blind crossover design with repeated measures on 10- to 12-year-old children in two classes. Seven exercises exemplifying different aspects of schoolwork (numerical or language-based) were performed as part of normal lessons by pupils who also marked visual analogue scales to indicate their environmental perceptions and the intensity of any symptoms. The children indicated that the air was fresher but otherwise perceived little difference when the outdoor air supply rate increased from 3.0 to 8.5 L/s (6.4–18 cfm) per person, while the speed at which they performed two numerical and two language-based tasks improved significantly. A significant effect of ventilation rate was observed in 70% of all the statistical tests for an effect on work rate, but there were no significant effects on errors. The effects were probably due to improved air quality in the classrooms as judged by a sensory panel of adults blind to conditions, as perceived by children, and as indicated by the reduction in the average CO2 concentration from 1300 to 900 ppm, taking this as a marker of reduced bioeffluent concentration. It was not possible to test the effect of replacing a soiled filter with a new one because very little dust had been retained by the ‘used’ filter and because of an incompletely balanced design. The unbalanced design also made it impossible to test for an interaction between filter condition and ventilation rate. These results indicate the importance of improving indoor air quality and ventilation in classrooms. [ABSTRACT FROM AUTHOR]

Thirty subjects (17 female) were exposed for five hours in a climate chamber at 22 °C (71.6°F) to clean air at 5%, 15%, 25%, and 35% RH. A comparable group was similarly exposed to air polluted by carpet and linoleum to the 35% RH condition and to 18°C, 22°C, and 26°C (64.4 °F, 71.6°F, and 78.8°F) at an absolute humidity equal to 15% RH at 22°C (71.6°F). They performed simulated office work to ensure that they kept their eyes open and reported sick building syndrome (SBS) symptom intensity on visual-analogue scales. Nine objective tests of eye, nose, and skin function were applied. Subjective discomfort, though significantly increased by low humidity, was slight even at 5% RH. More rapid blink rates were observed at 5% than at 35% RH (P < 0.05), and tear film quality as indicated by the Mucous Ferning Test deteriorated (P < 0.05) at low humidity (5%, 15%) and at the highest air temperature 18 °C, 22°C > 26°C (78.8°F). Low humidity was found to have reduced the rate of performance of three office tasks by 3%-7%. [ABSTRACT FROM AUTHOR]

The case for using symptom intensity feedback testing (SIFT) procedures to determine which of the available practical measures will be effective in improving the design or management of a problem building is presented. Instantaneous symptom intensity is estimated by the occupants using visual analogue scales which have been validated against objective measures of symptom intensity. Intervention experiments are carried out in all or in parts of the actual building. The use of control groups and, where possible, placebo groups, ensures that occupants' reports are unbiased by long-standing griev ances. A number of practical conclusions are then drawn from a review of the scientific literature concerning thermal conditions, artificial humidification, dust, sick building syndrome, sensations of dryness and the benefits and cur rently available means of providing individual control of the microclimate. [ABSTRACT FROM PUBLISHER]