Respiratory effects of experimental exposure to office dust

The aim of this experiment was to test if healthy persons respond to exposures to normal office dust with objective or subjective effects in a dose-related way. If they did, the importance of their personal characteristics should be investigated. This paper presents the results related to respiratory effects caused by exposures to office dust. The experiment compared the responses of 24 healthy non-sensitive adult subjects with no known hyperreactivity to exposure to normal office dust in the air at 136 and 390 microg/m3 with their responses in clean air. The exposure duration was 5.25 h in a climate chamber under controlled conditions. The dust had no major identifiable specific reactive compounds. There were no direct effects of dust exposures on nasal lavages or rhinometry. The overall indications of the experiment are that healthy subjects without any hypersensitive reactions seem to respond to exposure to house dust without specific reactive components. The only effect indicated was on eosinophil cationic protein in nasal lavages and peak flow. A delayed effect on peak expiratory flow was observed the day after the exposure. Other effects were seen but in opposite direction of expectations. Several deviations from the original design of the experiment prevent any definitive conclusions from being made from these findings before they have been confirmed in future experiments to come.

Reflecting the exploratory status of the study its major implication is to point at possible future hypotheses. The study implies that office dust may have an effect on occupants' lung function even at concentrations found in normal indoor environments. The influences of a multitude of response modifying variables were tested but no consistent pattern was found. The study does therefore not identify a specific risk group but suggests that among normal non-sensitized subjects most of the traditional risk factors can be rejected as single responsible risk factor.