The comparison of psychological evaluation between military aircraft noise and civil aircraft noise

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1 The omparison of psyhologial evaluation between military airraft noise and ivil airraft noise Makoto MORINAGA ; Ippei YAMAMOTO ; Hidebumi TSUKIOKA ; Koihi MAKINO 2, Sonoko KUWANO 3, Mitsuo MATSUMOTO 4 Defense Failities Environment Improvement Assoiation, Japan 2 Kobayasi Institute of Physial Researh, Japan 3 Osaka University, Japan 4 Japan Ministry of Defense, Japan ABSTRACT It is reported that ommunity response to military airraft noise is severer than that to ivil airraft noise in some former studies. In the present study, psyhologial experiments were onduted inluding the stimuli of military airraft noise and ivil airraft noise. Partiipants were not informed whether eah noise soure was a military or ivil airraft. It was found that pereived noisiness and subjetive annoyane to airraft noises were almost the same between noises from military and ivil airraft when single-event, A-weighted sound exposure levels were equal. This suggests that partiipants did not distinguish between military and ivil airraft noise. These results imply that overestimation of military airraft noise is aused by not only aousti properties but also non-aousti fators, suh as attitude toward military airraft noise. Keywords: Military airraft noise, Psyhologial evaluation, A-weighted sound exposure level I-INCE Classifiation of Subjets Number(s): , INTRODUCTION It is reported that ommunity response to military airraft noise is severer than that to ivil airraft noise in some former studies. For example, Yokoshima et al. () showed the representative dose response relation for transportation noise in Japan and reported that noise from military airraft reeives the highest annoyane ratings among transportation noise soures, inluding ivil airraft noise. In the ase of military airfields, daily flutuation of flight operations is onsiderable, and the variation in noise level is greater than that in the ase of ivil aviation. These aousti harateristis of military airfields may be one of the reasons for the higher annoyane level of affeted residents. However, it should be onsidered whether non-aousti fators, suh as the attitude toward the noise soure, may ontribute to the negative evaluation of military airraft noise. Guski (2) reported that most itizens have a different mental image of eah noise soure and suggested that a negative attitude toward the noise soure inreased subjetive annoyane. In the present study, a psyhologial experiment was arried out using single event military and ivil airraft noises as stimuli. Our hypothesis was that partiipants who do not know whether noises are from military or ivil airraft will give similar evaluation to the stimuli with the same A-weighted sound exposure levels. 2. METHOD OF PSYCHOLOGICAL EXPERIMENT 2. Stimuli Eighteen kinds of single-event airraft noises were used as stimuli, and two onditions were onsidered (Table ). The airraft noises were reorded outdoors near ivil airports and near military morinaga@dfeia.or.jp Inter-noise 204 Page of 5

2 Page 2 of 5 Inter-noise 204 airfields by two-hannel stereo reording with a data reorder (DA-20, Rion) and measured by two sound level meters (NL-05, Rion). In Condition, the stimuli were presented to the partiipants at the same sound level as was reorded outdoors. In Condition 2, the stimuli were presented after being passed through a filter that simulates the frequeny harateristis of a typial wooden house, as shown in Figure. These single-event airraft noises were presented to the partiipants through an audio interfae (UA-25, Roland), an amplifier (4B SST2, Bryston), and two loudspeakers (IBS, PMC) at the levels shown in Table. The duration of eah stimulus was 45 s. Stimuli ID Airraft type Table Speifiation of stimuli Airraft model Condition (without filter) L A,Smax L AE Condition 2 (with filter) L A,Smax L AE [db] [db] [db] [db] Civil B Civil B Civil B Civil B Civil B Civil B Military F Military F Military F Military F Military F Military F Military F Military F Military E Military E Military KC Military KC Noise redution [db] Frequeny [Hz] Figure Filter for simulating frequeny harateristis of a typial wooden house 2.2 Partiipants The partiipants were 7 women and 8 men aged between 9 and 59 years (average: 42 years), all with normal hearing. Page 2 of 5 Inter-noise 204

3 Inter-noise 204 Page 3 of Proedure A soundproof room at the Kobayasi Institute of Physial Researh, pitured in Figure 2, was used as the loation of the experiment. An indoor ambient noise of less than 30 db and a reverberation time of 0.36 s at 500 Hz were ahieved by plaing plasterboard on the front of the windows and installing sound-absorbing materials in the room. After the presentation of eah stimulus, the partiipant asked to evaluate the stimulus on a 7-point semanti differential sale for 2 pairs of adjetives. The adjetive sales are shown in Table 2. Partiipants were not informed whether noises were from military or ivil airraft. In the experiment, the orders of the adjetive sales were randomized to prevent bias from the order effet. Outside Speaker Speaker m.5 3 Sound-absorbing materials Plasterboard (Front of windows) Experiment room Partiipant PC AMP Control room Speakers Figure 2 Experimental setup. (PC: personal omputer; AMP: amplifier) Table 2 Adjetive pairs Annoying Not annoying Quiet Noisy Powerful Weak Pleasant Unpleasant Pleasing Unpleasing Harsh Mild Loud Soft Sharp Dull Shrill Calm Pure Impure Heavy Light Gentle Hard 3. RESULTS 3. Fator analysis Fator analysis with varimax rotation was onduted on the full set of data, and two fators were extrated for eah ondition. The full loadings are shown in Table 3. For Condition, Fator shows high fator loadings on ertain adjetive pairs, suh as Annoying Not annoying, Quiet Noisy, and Powerful Weak. Fator aounts for 58.3% of the variane under Condition. Fator 2 shows high fator loadings on the adjetive pairs Sharp Dull, Shrill Calm, and Pure Impure. This fator aounts for 4.2% of the variane under Condition. Similarly, Fator shows high fator loadings on many adjetive pairs, suh as Annoying Not annoying, Quiet Noisy, and Powerful Weak under Condition 2. This fator aounted for 59.7% of the variane under Condition 2. Fator 2 shows high fator loadings on the adjetive pairs Pure Impure and Inter-noise 204 Page 3 of 5

4 Page 4 of 5 Inter-noise 204 Sharp Dull. This fator aounted for 5.0% of the variane under Condition 2. For both onditions, Fator an be interpreted as indiating pleasantness/power and Fator 2 an be interpreted as indiating a metalli quality. Table3 Fator loadings in eah ondition Condition (Without house filter) Adjetive pair Fator Fator 2 Annoying Not annoying Quiet Noisy Powerful Weak Pleasant Unpleasant Favorable Unfavorable Harsh Mild Loud Soft Sharp Dull Shrill Calm Pure Impure Heavy Light Gentle Hard Condition 2 (With house filter) Adjetive pair Fator Fator 2 Annoying Not annoying Quiet Noisy Favorable Unfavorable Pleasant Unpleasant Powerful Weak Harsh Mild Loud Soft Shrill Calm Gentle Hard Pure Impure Sharp Dull Heavy Light Comparison of Fator sore between military airraft and ivil airraft The linear regressions of L AE against the sore of Fator whih ontains the impression of annoyane and noisiness were examined. A dummy variable for airraft type (ivil or military) was also used in the regression model as an independent variable in order to examine the ontribution of airraft type to the evaluation. Table 4 shows the result of multiple regression analyses on eah ondition. It was found that A-weighted sound exposure level, L AE, was statistially signifiant at the 5% level under both onditions. In ontrast, airraft type was not signifiant under either ondition. The oeffiients of determination of the regression models under Conditions and 2 were moderately high, at 0.78 and 0.75, respetively. It an be said that Fator sore was not affeted by airraft type, with similar sores for similar values of L AE independent of airraft type. Figure 3 shows satterplots of L AE versus the sore of Fator with regression lines aording to airraft type. Table 4 Results of multiple regression analyses Condition : Without house filter Coeffiient 95% onfidene Standardized t-value p-value interval oeffiient Lower Upper Constant L AE Airraft type (Military = ) Condition 2: With house filter Coeffiient 95% onfidene Standardized t-value p-value interval oeffiient Lower Upper Constant L AE Airraft type (Military = ) Page 4 of 5 Inter-noise 204

5 Inter-noise 204 Page 5 of 5 Pleasant.5 Civil airraft Military airraft.5 Civil airraft Military airraft.0.0 r 0.5 a to F 0.0 o f re o-0.5 S r 0.5 a to F 0.0 o f re o-0.5 S Unpleasant L AE of eah stimulus [db] L AE of eah stimulus [db] Condition (Without house filter) Condition 2 (With house filter) Figure 3 Relations between L AE and sore of Fator 4. CONCLUSIONS Partiipants were asked to respond to military and ivil airraft noise stimuli without being given information on the airraft type of the soure. Fator analyses and multiple regression analyses were onduted, with the result that the type of airraft did not signifiantly ontribute to the subjetive evaluation. This result supports the hypothesis that resulting annoyane and pereived noisiness are not affeted by the type of airraft, whih is evidened by the impression being almost the same for stimuli of similar L AE in the present experiment. As desribed in Setion, ommunity responses to military airraft noise, as obtained by soial survey, are more negative than to ivil airraft noise. This may partly be due to the fat that in soial surveys the respondents an identify the noise soure when they answer the questionnaire. Taken together, the results of the present experiment suggest that the reason for the more negative evaluation of military airraft noise in soial surveys is aused by not only aousti properties, suh as large flutuations in flight operations from day to day and high noise levels, but also non-aousti fators, suh as attitude to military airraft noise. ACKNOWLEDGEMENTS The authors would like to thank Prof. Masato Yasuoka, Prof. Akihiro Tamura, Dr. Ihiro Yamada and Prof. Koihi Yoshihisa for their helpful omments on the experiment. REFERENCES. Yokoshima S, Yano T, Morinaga M, Ota A. Representative dose-response urves for individual transportation noises in Japan. Pro INTER-NOISE 202; 9-22 August 202; New York, USA Guski R. Personal and soial variables as o-determinants of noise annoyane. Noise & Health. 999;(3): Inter-noise 204 Page 5 of 5