[Effect of air pollution in MTTp (convenient calculation) of children]

A convenient formula (MTTp = 0.1FVC/2Vp) was derived according to the linear character of each 10% FVC portion on the FVC-t curve proposed by Jordanoglou. It was used to examine 765 healthy school children at the age of 8-13 in the lightly and heavily polluted, and controlled areas in the living quarters in a steel corporation. The results showed that the small airways were more severely affected than the larger ones. MTT45-55% at the middle lung volume had both higher sensitivity and accuracy, and could be considered as a good index for tests on the function of small airways in air pollution while MTT20-30% and MTT70-80% at high and low lung volumes had greater variability and less accuracy.