This paper gives the results of a small environmental, symptomatic, and respiratory function study of byssinosis in a rope factory. An attempt was made to relate the changes in ventilatory function during the working day to the differing dust concentrations within the factory. The tests used included the forced expiratory volume, the forced vital capacity, and, in half the subjects, other derivatives of the forced expiratory spirogram. The inspiratory airways resistance was measured by the interrupter technique.
Measurements were made at the beginning and end of a working shift on either a Monday or a Tuesday in 44 subjects, of whom 22 were in a relatively dusty part of the factory and 14, involved in making wire rope, were exposed to very little dust.
None of the subjects had symptoms of byssinosis, but significant falls were found in the F.E.V.1·0, F.V.C., and other derivatives of the forced expiratory spirogram in those in the dusty parts of the factory. There was some evidence that the peak flow rate, the maximal mid-expiratory flow, and similar indices might be a little more sensitive as measures of the acute changes in ventilatory capacity during the day than the F.E.V.1·0 and F.V.C. There were no significant changes in the airways resistance by the interrupter technique but the results were rather variable.
The fall in ventilatory capacity during the day was not greater in those with symptoms of chronic cough and sputum than in those without, nor did it seem to be related to smoking, but the number of subjects studied was small.