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Two independent field intervention experiments involving a total of about 190 pupils were carried out in winter and early spring of 2005 in five pairs of mechanically ventilated classrooms that received 100% outdoor air. Each pair of classrooms was located in a different school. Electrostatic air cleaners were installed in classrooms and either operated or disabled to modify particle concentrations while the performance of schoolwork was measured. In one school, the used supply-air filters in a ventilation system without recirculation were also replaced with new ones to modify classroom air quality, while the filters in use in other schools were not changed. The conditions were established for one week at a time in a blind crossover design with repeated measures on ten-to-twelve-year-old children. Pupils performed six exercises exemplifying different aspects of schoolwork as part of normal lessons and indicated their environmental perceptions and the intensity of any symptoms. A sensory panel of adults judged the air quality in the classrooms soon after the pupils left. Operating the electrostatic air cleaners considerably reduced the concentration of particles in the classrooms. The effect was greater the lower the outdoor air supply rate. There were no consistent effects of this reduction on the performance of schoolwork, on the children's perception of the classroom environment, on symptom intensity, or on air quality as perceived by the sensory panel. This suggests there are no short-term (acute) effects of particle removal outside the pollen season. When new filters were installed, the effects were inconsistent, although this is believed to be due to sequential and unbalanced presentation of filter conditions and to the fact that the used filters retained very little dust. [ABSTRACT FROM AUTHOR]

Ninety-nine young-adult subjects of both genders were randomly assigned to four groups. One group performed simulated office work for two hours in a set of poor environmental conditions, with overhead fluorescent lighting, recorded traffic noise from a busy street, 27°C (80.6°F) operative temperature, supply air polluted by emissions from linoleum, recorded open office noise, and almost no daylight. The realistic annual cost of improving each of the six conditions was estimated and expressed as a percentage of the total sum of the cost of improving conditions. The modifications included improved lighting, barely audible traffic noise, operative temperature of 22°C (71.6°F), clean air, quiet, and a daylit view out. A second group briefly experienced all 12 conditions and individually selected the improvements they preferred, up to a 50% budget. A third group of subjects was randomly paired with each of the subjects from the second group, and each pair was exposed to the conditions selected by the second-group subjects. A fourth group was exposed to fully-improved (100% budget) conditions. Significant improvements in subjective assessment occurred at higher budget/individual choice levels, and the self-reported performance of office tasks improved, although measured performance could not be shown to differ significantly between treatment groups. [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]

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]

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]

Examines the effect of energy intake at breakfast on the test performance of 10-year-old children in school. Visual analogue scales; Voluntary physical endurance; Statistical analysis; Positive correlation with the rate of working in a number checking task; Estimation of energy intake by dietary recall.

A total of 83 drivers, 51 males and 32 females, aged 25-65, were recruited to drive an apparently unmodified passenger car for 1 h over at least four laps of a predetermined route on public roads, which included seven sets of traffic lights and sections limited to 50, 70, 90 and 110km/h. They were randomly assigned to one of two thermal conditions (21 or27°C), and drove only during die hours of daylight. A computer initiated unprepared signals to which drivers would normally be alert. Drivers responded by pressing a foot-switch and reporting verbally. Signals were selected at random from 21 possible signals, and were presented for up to 3min, with a random delay of 30-180 s after each response or failure to respond. The negative effect of heat stress on vigilance was statistically significant. At 27°C, the overall proportion of missed signals was 50% higher and response times were 22% longer than they were at 21°C. These effects of heat were significant and proportionally greater in the second half-hour, for subjects <40 years and for speeds below 60km/h (i.e. in city traffic). The latter finding suggests that heat may have increased arousal, and there was some indication of a redistribution of attention away from the most peripheral signals at the higher temperature. Overt driving errors were observed significantly more often at 27°C than at 21°C for women only. [ABSTRACT FROM PUBLISHER]