Tape recordings were made of ca 1500 takeoffs at Arlanda Airport by means of an automatically operating recording device. Type of aircraft and destination as well as temperature, air humidity and wind velocity, and direction were registered. Correlation analyses of peak sound levels in dBA and meteorological factors were made. Sound level showed no significant covariation with humidity and temperature, but a positive correlation to the wind velocity from the aircraft towards the measuring station was found. The mean values measured verify theoretical calculation of the sound level from standard noise contours according to ISO Recommendation No. 507 and NASA CR-767 and also show that calculations are more accurate than occasional measurements. Parts of the data were also analyzed as to the difference among dBA, PNdB, EPNdB, and dBD. High correlations among these different units were found.
Annoyance reactions to motor vehicle noise have been studied in Sweden and Italy. Every possible care has been taken to assure that the interview forms used to measure reactions have been translated adequately. Exposure factors have been stratified strictly. Nevertheless a difference in exposure could be detected when check measurements were carried out. Despite a higher noise level in Italian homes, annoyance reactions were fewer. This investigation stresses the importance of investigating possible differences in reactions in order to make valid comparisons between results of annoyance studies carried out in different countries.
Abstract Annoyance reactions to motor vehicle noise have been studied in Sweden and Italy. Every possible care has been taken to assure that the interview forms used to measure reactions have been translated adequately. Exposure factors have been stratified strictly. Nevertheless a difference in exposure could be detected when check measurements were carried out. Despite a higher noise level in Italian homes, annoyance reactions were fewer. This investigation stresses the importance of investigating possible differences in reactions in order to make valid comparisons between results of annoyance studies carried out in different countries.
Data are given from investigations into the production of radioactive test aerosols and studies of lung clearance in the rabbit. Lung clearance was measured using a specially developed profile scanning technique. This technique made it possible to follow the clearance rate from repeated measurements of the lung activity in a single animal. Furthermore, the animal could be re-exposed. Heterodisperse radioactive aerosols were used initially; more recently, monodisperse aerosols have been used. Monodisperse radioactive aerosols in the particle range 1–10 micro have hitherto been produced mainly by a modified LaMer method for lung clearance studies. Monodisperse radioactively tagged plastic aerosols have also been produced by the spinning disk technique, and methods for iodinating (with 131I) latex particles are in progress.
