Non-Specific Symptoms In Office Workers: A Review And Summary Of The Epidemiologic Literature

Epidemiologic research into the causes of non-specific symptoms among office workers has produced a variety of conflicting findings which are difficult to synthesize. This paper first discusses methodologic issues important in the interpretation of epidemiologic studies, and then reviews the findings of 32 studies of 37 factors potentially related to office worker symptoms. Among environmental factors assessed, there were generally consistent findings associating increased symptoms with air-conditioning, carpets, more workers in a space, VDT use, and ventilation rates at or below 10 liters/second/person. Studies with particularly strong designs found decreased symptoms associated with low ventilation rate, short-term humidification, negative ionization, and improved office cleaning, although studies reviewed showed little consistency of findings for humidification and ionization. Relatively strong studies associated high temperature and low relative humidity with increased symptoms, whereas less strong studies were not consistent. Among personal factors assessed, there were generally consistent findings associating increased symptoms with female gender, job stress/dissatisfaction, and allergies/asthma. For other environmental or personal factors assessed, findings were too inconsistent or sparse for current interpretation, and there were no findings from strong studies. Overall evidence suggested that work related symptoms among office workers were relatively common, and that some of these symptoms represented preventable physiologic effects of environmental exposures or conditions. Future research on this problem should include blind experimental and case-control studies, using improved measurements of both environmental exposures and health outcomes     

Perceived Air Quality,Sick Building Syndrome (SBS) Symptoms and Productivity in an Office with Two Different Pollution Loads

Abstract Perceived air quality, Sick Building Syndrome (SBS) symptoms and productivity were studied in an existing office in which the air pollution level could be modified by introducing or removing a pollution source. This reversible intervention allowed the space to be classified as either non-low-polluting or low-polluting, as specified in the new European design criteria for the indoor environment CEN CR 1752 (1998). The pollution source was a 20-year-old used carpet which was introduced on a rack behind a screen so that it was invisible to the occupants. Five groups of six female subjects each were exposed to the conditions in the office twice, once with the pollution source present and once with the pollution source absent, each exposure being 265 min in the afternoon, one group at a time. They assessed the perceived air quality and SBS symptoms while performing simulated office work. The subject-rated acceptability of the perceived air quality in the office corresponded to 22% dissatisfied when the pollution source was present, and to 15% dissatisfied when the pollution source was absent. In the former condition there was a significantly increased prevalence of headaches (P= 0.04) and significantly lower levels of reported effort (P=0.02) during the text typing and calculation tasks, both of which required a sustained level of concentration. In the text typing task, subjects worked significantly more slowly when the pollution source was present in the office (P=0.003), typing 6.5% less text than when the pollution source was absent from the office. Reducing the pollution load on indoor air proved to be an effective means of improving the comfort, health and productivity of building occupants.     

Prevalence and risk factors associated with nonspecific building‐related symptoms in office employees in Japan: relationships between work environment,Indoor Air Quality,and occupational stress

A nationwide cross‐sectional study of 3335 employees was conducted in 320 offices in Japan to estimate the prevalence of building‐related symptoms (BRSs) and determine the risk factors related to work environment, Indoor Air Quality, and occupational stress. Data were collected through self‐administered questionnaires. The prevalences of general symptoms, eye irritation, and upper respiratory symptoms were 14.4%, 12.1%, and 8.9%, respectively. Multiple logistic regression analyses revealed that eye irritation was significantly associated with carpeting [odds ratio (OR), 1.73; 95% confidence interval (CI), 1.24–2.41], coldness perception (OR, 1.28; 95% CI, 1.13–1.45), and air dryness perception (OR, 1.61; 95% CI, 1.42–1.82). General symptoms were significantly associated with unpleasant odors (OR, 1.37; 95% CI, 1.13–1.65), amount of work (OR, 1.24; 95% CI, 1.06–1.45), and interpersonal conflicts (OR, 1.44; 95% CI, 1.23–1.69). Upper respiratory symptoms were significantly associated with crowded workspaces (OR, 1.36; 95% CI, 1.13–1.63), air dryness perception (OR, 2.07; 95% CI, 1.79–2.38), and reported dustiness on the floor (OR, 1.39; 95% CI, 1.16–1.67). Although psychosocial support is important to reduce and control BRSs, maintaining appropriate air‐conditioning and a clean and uncrowded workspace is of equal importance.     

Subjective perceptions,symptom intensity and performance: a comparison of two independent studies,both changing similarly the pollution load in an office

The present paper shows that introducing or removing the same pollution source in an office in two independent investigations, one in Denmark and one in Sweden, using similar experimental methodology, resulted in similar and repeatable effects on subjective assessments of perceived air quality, intensity of sick building syndrome symptoms and performance of office work. Removing the pollution source improved the perceived air quality, decreased the perceived dryness of air and the severity of headaches, and increased typing performance. These effects were observed separately in each experiment and were all significant (P < or = 0.05) after combining the data from both studies, indicating the advantages of pollution source strength control for health, comfort, and productivity.     

Effect of age, gender, economic group and tenure on thermal comfort: A field study in residential buildings in hot and dry climate with seasonal variations

Energy consumption in Indian residential buildings is one of the highest and is increasing phenomenally. Indian standards specify comfort temperatures between 23 and 26 °C for all types of buildings across the nation. However, thermal comfort research in India is very limited. A field study in naturally ventilated apartments was done in 2008, during the summer and monsoon seasons in Hyderabad in composite climate. This survey involved over 100 subjects, giving 3962 datasets. They were analysed under different groups: age, gender, economic group and tenure. Age, gender and tenure correlated weakly with thermal comfort. However, thermal acceptance of women, older subjects and owner-subjects was higher. Economic level of the subjects showed significant effect on the thermal sensation, preference, acceptance and neutrality. The comfort band for lowest economic group was found to be 27.3-33.1 °C with the neutral temperature at 30.2 °C. This is way above the standard. This finding has far reaching energy implications on building and HVAC systems design and practice. Occupants’ responses for other environmental parameters often depended on their thermal sensation, often resulting in a near normal distribution. The subjects displayed acoustic and olfactory obliviousness due to habituation, resulting in higher satisfaction and acceptance.     

A Study of Human Reactions to Emissions from Building Materials in Climate Chambers. Part II: VOC Measurements,Mouse Bioassay,and Decipol Evaluation in the 1–2 mg/m3 TVOC Range

Monitoring of human reactions to the emission of formaldehyde and volatile organic compounds (VOC) from four commonly used building materials was carried out. The building materials were: a painted gypsum board, a rubber floor, a nylon carpet, and a particle board with an acid-curing paint. The exposures were performed in climate chambers. The air quality was quantified on the decipol scale by a trained panel, measurements of formaldehyde and VOC being performed simultaneously. The irritating potency of the materials was measured by a mouse bioassay. The VOC measurements showed several malodorants and irritants. Some abundant VOC identified in the head-space analyses were absent in the climate chamber air. The rubber floor and the nylon carpet exhibited a marked increase in decipols compatible with a number of odorous VOC identified in the air. A high formaldehyde concentration (minimum 743μg/m³) was measured for the particle board coated with an acid-curing paint. This was not reflected by a corresponding relatively high decipol value but a long-lasting irritating potency was observed in the mouse bioassay. TVOC sampled on Tenax and expressed in mass per volume as well as in molar concentration, and decipol evaluation both have limitations and should be used with caution as indicators of (perceived) indoor air quality. Eye irritation expressed by means of the eye index reflecting the tear film quality index (comprised of break-up time, foam formation, thickness of the precorneal lipid layer of the tear film, and epithelial damage) was found to be insensitive to formaldehyde and a VOC mixture but sensitive to TVOC concentrations of 1–2 mg/m³. Lipophilic VOC may be the cause of reduced tear film quality by destabilization of the lipid multilayer of the tear film.     

Gaseous formaldehyde removal: A laminated plate fabricated with activated carbon,polyimide, and copper foil with adjustable surface temperature and capable of in situ thermal regeneration

Formaldehyde is one of the most common indoor air pollutants in Chinese residences. This study introduces a novel laminated plate with adjustable surface temperature to remove gaseous formaldehyde. The plate is fabricated with activated carbon, polyimide, and copper foil via thermal compression. The plate can be regenerated in situ by applying a direct current to the copper foil. Adsorption‐regeneration cycle tests were conducted to evaluate the plate's formaldehyde removal performance. The overall removal efficiency of the fabricated laminated plate with glue mass fraction of 25% and thickness of 1.5 mm was about 30% at the face velocity of 0.8‐1.2 m/s. The pressure drop was about 5 Pa. Its removal ability can be regenerated in situ in 8 minutes by increasing the surface temperature to 80°C. The fabricated laminated plate showed good durability after 52 cycles of adsorption‐regeneration tests. The results indicate that the proposed laminated plate can enhance the purifying efficiency and enlarge the life span of ordinary, cheap sorbents. It makes cheap materials with low performance suitable for air purification.