The topography of particle deposition in the human lung.

The effect of varying particle size on the site of deposition of inhaled particles in the human lung was measured in 11 young healthy male subjects. The simultaneous inhalation of two chemically inert, radiolabelled particles, differing in size but in no other respect, controlled for all other variables including airways geometry, breathing pattern and posture. Under conditions of quiet respiration the larger particles (3.5 microns) were preferentially deposited in the upper rather than the lower zones of the lungs as compared with the smaller particles (1.1 microns). Furthermore, the penetrance of the larger particles beyond the mucociliary escalator was greater for 3.5 microns particles in all lung zones and particularly at the apex. These findings may be of significance in the pathogenesis of those diseases induced by the inhalation of particles, vapours or fumes.

Ergonomics and industrial hygiene: a complementary relationship.

This paper examines the nature and scope of ergonomics in relation to the practice of industrial hygiene. It demonstrates that ergonomics is an independent and broadly based discipline, the work of which is complementary to industrial hygiene and not in competition with it. Whereas the industrial hygienist is primarily concerned with the habitability of the working environment and its compatibility with the health and safety of the worker, the ergonomist is primarily concerned with design for human use and the optimization of human performance at work and in adverse environments.

Access systems of heavy construction vehicles: Parameters, problems and pointers.

As part of an investigation of accidents occuring during mounting on and dismounting from heavy construction equipment a study was conducted of operator behaviour during mounting and dismounting. Measurements of access systems of representative vehicles were compared with those from various Standards. In most instances the vehicles did not conform. Recommendations are made for improvements in the safety characteristics of the access. These recommendations are in three classes, namely; changes and developments in procedures and practices, retrofit of existing equipment, and changes in design philosophy. The need for maintaining three point contact at all times during mounting and dismounting is emphasised.

Monocular peripheral vision as a factor in flight safety.

The performance of static visual identification tasks and simulated operational flying tasks, by nine binocular pilots and nine adapted monocular pilots, was measured in a unique operational visual simulator. It was hypothesized that, with head free to move, and adapted monocular pilot would perform as well as a binocular pilot, while an unadapted monocular (simulated by covering an eye) would perform less well. Other hypotheses were advanced. The static primary central task required sequential identification of dial readings. The dynamic primary central task involved simulated aircraft landing operations. During each set of primary tasks, a set of secondary peripheral visual tasks was performed. Results of the primary tasks and times of execution of the secondary tasks were subjected to analysis of variance. Factors included head position (fixed or free), stimulus location in peripheral field, eye state (seeing eye, blind eye), and type of central task (static, dynamic). All hypotheses were validated.

Human response to buffeting in an all-terrain vehicle.

Suitably prepared subjects were exposed to the vibration imposed by driving a personal-type all-terrain vehicle over a heavily plowed track. Acceleration was measured in the Z-axis at the seat of the vehicle, and in the X, Y, and Z axes at the hip and head of the subjects. Acceleration peaks, rates of onset, durations, and frequency ranges were determined and a spectral analysis conducted. Results showed that, for this vehicle under the test circumstances, the subjects respond with a low-frequency (less than 4 Hz) oscillation at approximately 0.5 Gz above nominal, on which are imposed numerous peaks of 1 to 5 G, or higher with rates of onset within the range measured, of 20 to 100 G/s. Although the measurement system did not conform to ISO (International Standards Organization) requirements, the results suggest that continued exposure would exceed the ISO 1-min limit for "health and safety."