Day-to-day changes in ventilatory function in relation to the environment: Part I. Spirometric values

Abstract

Measurements of forced expiratory volume at 1 second, forced vital capacity, and maximum midexpiratory flow have been made on four normal subjects employed in central London on each working day for five years. For three of the subjects, MMF was highest on days with low concentrations of smoke and sulphur dioxide, and it decreased at successively higher concentrations, but it was not clear whether this was an effect of pollution or of other associated factors. Respiratory infections were found to have pronounced effects on these spirometric measurements, and analysis of the results for the complete series revealed small seasonal variations and long-term changes, some of which were large and in the opposite direction from those expected with increasing age. Some immediate but transient effects of pollution on the spirometric values were seen following exercise in periods of high pollution. In addition to small direct effects, the role of pollution in affecting the course of respiratory infections and thus indirectly further affecting ventilatory function was considered.