Effects on eyes and nose in humans after experimental exposure to airborne office dust

To test sensory irritation symptoms and physiological effects on humans caused by airborne office dust, ten subjects were exposed to both clean air and airborne non-industrial office dust for 3 h in a climate chamber. The average dust concentration in exposure sessions was 394 micrograms/m3 total suspended dust (TSD). Tear film break-up time, foam formation in the eye canthus, conjunctival epithelial damage, nasal volume, and nasal minimal cross-sectional area were assessed. Tear film break-up time decreased significantly after dust exposure and nasal volume showed a tendency to decrease. In a questionnaire investigation, significant effects were found from the questions: "facial skin humidity", "throat irritation", "feeling needs of coughing", "dry nose", "concentration difficulty", and "headache". Additionally, the intensity of the questions "facial skin humidity", "dry nose", "body skin temperature", "sluggishness", and "sleepiness" worsened over time. A correlation analysis showed that perceived "air quality" was significantly correlated with "dry eyes", "eye irritation", "facial skin irritation", "nose irritation", and "feeling stressed by chamber occupancy" for subacute responses, and with "odor intensity" for acute responses. This supports that the perceived air quality may be a function of odor and irritation symptoms. A number of localized symptoms of irritation (e.g. dry nose, throat irritation, coughing) and of general symptoms (e.g. sluggishness, sleepiness, headache, ability to concentration) were mutually correlated acutely and subacutely. These results indicate that non-industrial office dust may cause physiological changes and sensory symptoms in eyes and nose and that these effects have different time courses.     

Eye trigeminal sensitivity, tear film stability and conjunctival epithelium damage in 182 non-allergic, non-smoking Danes

The population distributions of CO(2)-induced irritation sensitivity in the eyes (COI), tear film stability (break-up time, BUT), and epithelium damage (ED) and the relation of these to basic potential confounders were assessed in an age- and gender-stratified random sample of citizens in Aarhus County, Denmark. One hundred eighty-two non-allergic, non-smoking persons participated. A general health questionnaire and an indoor air questionnaire was filled out before the measurements. The BUT was non-normally distributed, as was COI at 16% CO(2) and single ED-scores. However, COI average for all levels was normally distributed and the total score for ED was only marginally deviating. BUT decreased, the threshold to CO(2) increased, and irritation intensity at CO(2) eye exposure decreased with increasing age. ED was increased among women. There were no internal relations between the three measures, but reduced BUT was seen among subjects rating high levels of exposure to dust, electrostatic fields, and dry air. ED decreased by perceived unpleasant odors and increased with experiences of high temperatures. CO(2) sensitivity increased by perceived draught, dry air, and noise exposure prior to measurements. Selection bias cannot be excluded and the results may therefore not be truly representative of the general population. However, the results may be used as reference data for future use of measurements of break-up time, epithelium defects, and CO(2) sensitivity of the eyes in the indoor air. PRACTICAL IMPLICATIONS: The most direct implication is that results can be used as reference level for measurements in problem buildings and for individual measurements. The reference can also be used in research and the other results as basis for future hypotheses and for support of existing hypotheses.