PROCEEDINGS of the
23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

Effects of changes in operational and residential factors on publichealth and reactions at the vicinity of Noi Bai International Airport
Thulan NGUYEN1; Bachlien TRIEU1; Takashi YANO2; Takashi MORIHARA3;
Yasuhiro HIRAGURI4; Makoto MORINAGA5123

Shimane University, Japan

Kumamoto University, Japan

National Institute of Technology, Ishikawa College, Japan
4

5

Kindai University, Japan

Defense Facilities Environment Improvement Association, Japan

ABSTRACTThe rapid development of air transport resulted in increased levels and wider influential scale of noise due tothe airport operation. The number of flights operated and the housing conditions at residential areas around
Noi Bai International Airport has increased significantly in the past nine years. The exposure noise levels(Lden) at surveyed sites ranged between 48 and 61 dB in 2009, but increased to range between 54 and 76 dB
in 2017. General health indicators such as Body Mass Index (BMI), blood pressure, etc. were investigated in
two surveys conducted in November 2017 and August 2018. Exposure-response relationships established in
the five surveys conducted from 2014 to 2018 were found to be higher than that established in 2009 survey.
Comparisons of respondents with high blood pressure and insomnia ratios at different noise exposure level
ranges showed that there is no significant association between ratios of hypertension and noise exposurelevels (Lden) but a significant exposure-response relationship was found between night-time noise exposurelevels and insomnia. This study results suggested that improvement of residence quality and a restriction onnighttime flight operation should be considered to protect health of resident living around airports in Vietnam.
Keywords: Aircraft noise, Annoyance, Health Effects.

1. INTRODUCTION
An increase of flight operation to meet the growing air travel demand have various negativeenvironmental impacts, particularly noise and air pollution, that affects quality of life and health ofcommunities living near the airport (1). However, the number of studies on this issue is very limited
in developing countries where the aviation transport has the fastest growth rate (2). A socio-acoustic
survey on community response to aircraft noise around Hanoi Noi Bai International Airport (HNBIA),
Vietnam, was conducted in 2009 (3). The operation status of HNBIA was considered to be stablearound the survey period. Since then, the number of operations of the aircraft has gradually increased,
especially after the opening of the new terminal building in December 2014. To assess effects of a
step change of noise exposure levels around HNBIA, step-change surveys were conducted once before
and twice after the operation change happened. As a result, an excess response due to the step-change
were found (4). To clarify whether this excessive reaction decreases over time or continues afterwards,
two follow-up surveys were conducted in 2017 and 2018, which are about 3 years and 4 years after
the step-change. Study results of individual surveys up to 2017 have been reported at previous

1

lan@riko.shimane-u.ac.jp, trieulien0903@gmail.com
yano@gpo.kumamoto-u.ac.jp
3morihara@ishikawa-nct.ac.jp
4hiraguri@arch.kindai.ac.jp
5morinaga@dfeia.or.jp
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Internoise conferences (5).
In parallel with the change in air transport, the period from 2009 up to now has witnessed adramatic change in Vietnam's economy and urbanization. As a result, the housing conditions of theVietnamese people in general as well as the people living around HNBIA also changed. Since noise
annoyance was found to vary through factors other than noise exposure such as housing, neighborhood
environment, socio-demographic variables, and personal and environmental contexts (6, 7). Effect ofnoise change should be investigated using effects of both acoustic and such of non-acoustic variables.
In this paper, the results of socio-acoustic surveys in nine years around HNBIA will be summarizedwith aims to assess effects of changes in operational and residential factors on public health andreactions at the vicinity of HNBIA. The outcomes from this study are expected to contribute toappropriate noise policy for improving the living environment around the airports in developing
countries.

2. METHODS
2.1 Survey sites
HNBIA has two parallel runways in the east-west direction (11L-29R and 11R-29L). Since theoperation direction of the runway is influenced by the wind direction, the use of the flight path toward
the east occupied near 80% of the total movements at HNBIA. As shown in Figure 1, nine surveyedsites (Sites 1-9) were selected around HNBIA in the 2009 survey. Four sites (Sites 1-4) located underthe main landing path, 3 sites (Sites 7-9) located under the main takeoff route, 2 sites (Sites 5-6)
located to the south of the runway. In the surveys from 2014 to 2018, a total of 13 sites (Sites A1 A13), including 7 sites investigated in the 2009 survey, were selected. Particularly, three new sites
A5, A6, A8 located close to the end of the runway of the airport, and two control sites A12 and A13
located in the northeast direction of the airport. The control sites A12 and A13 have almost the sameliving environment as the other sites, but were assumed to be unaffected by aircraft noise.

(Site 1)(Site 4)(Site 2)(Site 3)(Site 5)(Site 9)(Site 6)(Site 7)(Site 8)Figure 1．Map of all surveyed sites( Site－) : Selected sites of 2009 Survey

Survey sites added since the 2014 survey

2.2 Socio-acoustic and health surveys
In the series of surveys, Vietnamese questionnaires including two standardized annoyancequestions recommended by ICBEN (8, 9) were prepared. Community responses in the vicinity of
HNBIA were collected by the interview method. The percentage of respondents who were highly
annoyed (%HA) was defined as the percentage of respondents who chose 8, 9 or 10 of the 11-point
numerical scale (0-10). At the survey since 2014, the percentage of insomnia (% ISM) was defined by
the frequency of sleep effects as proposed by the International Institute of Sleep (10) was used as anindicator of sleep effect caused by the flight operation during the night time.

3653

In addition to general annoyance and sleep impacts, exposure to high levels of aircraft noise may
adversely affect cardiovascular disease and other health categories (1). Since studies of health effectof aircraft noise has not so far been conducted for residents living near airports in developing countries,
in the survey of 2017, data on the health status of residents such as body mass index (BMI) and bloodpressure based on self-report were collected to evaluate the health effects of aircraft noise around
HNBIA. Furthermore, in the survey in 2018, the blood pressure was measured with a blood pressure
meter (OMRON HEM-6324T). Instead of questions about living conditions and the surrounding
environment, questions about current health status such as BMI, blood pressure and heart rate wereadded.
2.3 Noise measurement
In the surveys until 2017, day-evening-night noise level (Lden) and nighttime equivalent noise level(L night (22:00-6:00) ) were estimated from the field measurement of noise levels. Sound level meters (RION
NL-42, NL-21, NL-22) were set up on the roof of houses selected at each surveyed site. A-weighted
and S-weighted sound pressure levels (L A,S) sampled at 1 s were recorded continuously through 7 days.
The noise data of each day for each site was compared with flight logs to identify the aircraft eventsand then calculate the Lden. Since the day, evening and night periods are different between countries,
depending on the activity pattern of daily life, in this study, they are defined as the periods from 06:00
to 18:00, from 18:00 to 22:00, and from 22:00 to 06:00, respectively.
2.4 Flight operation data and noise estimation
Airport operation data including flight logs and weather conditions were provided by the airport
managers. Although HNBIA is in northern Vietnam which has four seasons, the flight operation at
HNBIA is categorized into winter (late October to late March) and summer (in the remaining period)schedules. Depending on the weather condition, runway used for landing and taking off might varies.
During the surveys conducted in 2014, 2015 and 2017, ADS-B (Automatic Dependent SurveillanceBroadcast) receiver was installed to collect the flight route information. According to the flight logs,
the average arrivals and departures a day in HNBIA were counted.
In the survey of 2018, L den and L night were estimated from a noise contours map created by using
Integrated Noise Model (INM) instead of field measurements. The necessary data for creating thenoise map such as flight logs was provided by the Civil Aviation Authority of Vietnam (CAAV). The
flight route data were referred to the data of 2017 Survey.

3. RESULTS
3.1 Increase in number of flights and noise levels
The number of flights operated and passenger number at HNBIA have increased significantly inthe past nine years. Table 1 shows the average number of daily flights operated by HNBIA during
each survey period. It can be seen that the number of flights observed in 2018 is about three times
higher that of 2009 and 1.7 times higher than that of 2014. It could be seen that the number of flights
increased sharply after the new terminal building was put into operation and has gradually increased
since then. It is worth noting that the most recent number of nighttime flight events increased by 2.5
times and 1.9 times, compared to the September 2014 “before new terminal building opened” survey
and the latest “after the opening” survey for September 2015, respectively. Especially, the recent
number of flight events at night increased sharply and occupied about one-fifth of the total number offlights.
Table 2 shows the noise levels obtained during each survey period. L den measured at the sites whichwere surveyed since 2009 increased from 48 to 61 dB in 2009 and 54 to 66 dB in 2018. Especially,
L night (22:00-6:00) was found to increase about 10 dB higher at Sites A3 and A4. This result is consistent
to the sharp increase of the flight movements during the night time at HNBIA

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Table 1 – Average numbers of aircraft noise events
SurveysTime period

Day (6:00-18:00)

Evening (18:0022:00)

Night (22:00-6:00)

All day

Operation modes

8/20099/20142-3/2015

9/2015

11/20178/2018

Arrival

50

84

104

100

125

141

Departure

51

90

109

107

139

123

Total

101

174

213

207

264

264

Arrival

23

32

43

39

48

12

Departure

14

16

27

22

35

13

Total

38

48

70

61

83

25

Arrival

9

9

16

14

39

77

Departure

10

21

26

25

37

94

Total

19

30

42

39

76

171

Arrival

82

125

163

153

211

230

Departure

75

127

162

154

211

230

Total

157

252

325

307

422

460

Table 2 – Changes of noise exposure levels: Lnight (22:00-6:00) and (Lden)
Site

Lden

Lnight(22:00-6:00)

8/2009 9/2014 3/2015 9/2015 11/2017 8/2018 8/2009 9/2014 3/2015 9/2015 11/2017 8/2018

A1

55

55

55

53

55

53

47

45

46

45

47

44

A2

56

55

56

54

54

56

49

45

48

46

47

47

A3

61

62

64

62

62

61

51

53

56

55

54

52

A4

56

54

56

57

63

61

44

46

48

48

55

53

A5

-

61

61

68

76

71

-

51

53

59

69

63

A6

-

65

64

64

53

64

-

50

57

56

44

56

A7

57

66

62

62

65

64

48

55

56

55

57

56

A8

-

66

66

65

66

66

-

58

58

58

59

57

A9

61

63

60

63

65

66

54

55

53

56

58

57

A10

-

60

58

59

60

60

-

52

52

53

53

50

A11

52

60

57

59

59

58

45

52

50

52

52

49

A12

-

45

45

49

38

41

-

36

38

39

30

-

A13

-

47

44

51

38

40

-

36

38

44

29

-

3.2 Changes in Residential Factors
In this study, residential factors such as length of residence, total floor area of the house, evaluation
on sound insulation, location of the bedroom, air-conditioner installation are considered to be factors
related to respondents’ reaction to noise. The average data of these factors obtained from the survey
sites, including 9 sites of the survey in 2009, and 13 sites of the other surveys are summarized in Table
3. The short length of residence was assumed to increase the respondents’ negative reaction to aircraft
noise due to insufficient time to adapt to the living environment near the airport. The respondents
living in larger houses with good insulation ability, bedroom not facing the road, and air-conditioner

3655

installed were assumed to be less affected by noise than those living in smaller houses, with bad
insulation ability, bedroom facing the road, and air-conditioner uninstalled. The survey result showsthat more houses were installed air-conditioner after 2015. Within more than 2 years, corresponding
to the positive change in the economy, the living amenities of the residents around HNBIA has been
improved, including increased use of air conditioners. The percentage of the length of residence thatis less than 5 years has decreased in the recent surveys.
Table 3 – Changes of residential factor through the surveys from 2009 to 2018
Residential factors (%)

8/2009 9/2014 3/2015 9/2015 11/2017 8/2018

Length of residence <=5 years

12.5

14.8

10.3

11.0

8.8

6.2

Floor area <=100m2

79.2

40.6

71.4

67.7

51.1

-

Bad sound insulation

32.1

33.0

31.0

38.9

32.4

-

Bedroom facing road

30.6

-

35.3

31.0

44.2

-

-

-

71.5

71.2

50.1

-

Air-conditioner uninstalled

3.3 Changes in Sleep Effects and General Annoyance
As shown in Table 4, there is a dramatic increase of %ISM at Site A5, which increased from 17%
in September 2015 to 43.8% in November 2017. This result is consistent with a 10 dB increase in thenighttime noise level measured at Site A5. However, the same trends were not found with the generalannoyance defined by %HA. Despite a slight increase in L den between 2015 and 2017, %HA decreasedat Sites A7 and A9, which located under the take-off path of aircrafts. A decrease in %HA was seen inall sites under the landing path, except for site A3.
Table 4 – Percentage of highly annoyed (%HA) and percentage of insomnia (%ISM)
%HA

%ISM

8/20099/20143/20159/2015

11/20178/20189/20143/20159/2015

11/20178/2018

A1

6.5

8.2

5.7

2.0

0.0

20.0

1.4

1.1

0.0

0.0

20.0

A2

11.5

9.1

35.8

28.9

14.3

20.0

0.0

6.9

3.1

4.2

20.0

A3

57.0

59.1

71.1

65.3

95.7

60.0

17.0

20.2

21.9

2.2

22.2

A4

68.4

48.2

83.3

92.0

77.8

60.0

17.5

26.5

22.4

19.1

20.0

A5

-

47.7

73.9

96.0

91.7

90.0

8.9

33.7

17.0

43.8

40.0

A6

-

70.8

63.8

84.0

83.0

60.0

4.6

7.5

20.0

17.0

10.0

A7

8.3

44.1

12.4

60.6

10.4

20.0

5.4

17.5

9.0

0.0

10.0

A8

-

58.2

55.1

68.5

33.3

80.0

33.3

1.0

7.4

8.3

10.0

A9

20.0

28.4

37.8

56.0

53.2

10.0

6.7

5.6

24.0

10.6

10.0

A10

-

10.1

10.3

28.0

34.0

0.0

6.1

5.1

12.1

10.4

10.0

A11

4.7

9.0

5.5

11.2

12.0

40.0

0.0

4.2

5.1

0.0

30.0

A12

-

0.0

0.0

2.0

0.0

9.1

0.0

0.0

1.0

0.0

-

A13

-

0.0

0.0

3.2

0.0

0.0

6.3

1.4

1.0

0.0

-

Figure 2 shows a comparison of (a) Lden - %HA and (b) L night(22:00-6:00) - %ISM relationships
established by using data obtained from all the surveys. The L den - %HA relationships of the follow-

3656

up survey in 2017 and 2018, which were conducted about 3 and 4 years after the step-change, arelower than that of the 2015 surveys which were carried out immediately after the change within therange of L den over 60 dB, but higher than the exposure-response relationship established for the 2009
and 2014 surveys and the curved presented in EU position paper (11). In other words, the excess
response due to the step change seems to decrease with time, but still remains higher than the reaction
before the terminal is completed at the same noise exposure level. However, considering the L night(22:006:00) - %ISM relationships, the relationship obtained by the 2017 survey data is lower, while that of
the 2018 survey is higher than the relationships obtained in the previous survey. This result indicatesthat causal structure of insomnia might be different from that of annoyance. This discrepancy should
be explained not only by the amount of noise exposure but also by other various non-acoustical factors.
100

50
Aug-1840

Sep-15%Insomnia%Highly Annoyed

Aug-18

Nov-1780

Mar-1560

Sep-14Aug-0940

EU

20

Nov-17
Sep-1530

Mar-15
Sep-14

20
10

0
35

45

55
65
Lden (dB)

0

75

25

35

(a) %Highly Annoyed (%HA)

45
55
Lnight (dB)65(b) %Insomnia (%ISM)

Figure 2 – Comparison of the relationships synthesized from the data ofeach survey from 2009 to 2018

40

40

20

20

∆%ISM

60

∆%HA

60

0

-20

0

-20

-40

-40
-10

-5

0

(2nd-1st)(4th-1st)線形 ((2nd-1st))Line
線形 ((4th-1st))
Line

5

∆Lden

10

15

(3rd-1st)(5th-1st)線形 ((3rd-1st))Line
線形 ((5th-1st))
Line

20

-10

-5

0

(2nd-1st)(4th-1st)線形 ((2nd-1st))Line
線形 ((4th-1st))Line

5∆Lnight

10

15

20

(3rd-1st)(5th-1st)線形 ((3rd-1st))Line
線形 ((5th-1st))Line

Figure 3 – Comparing relationships between the changes in noise levels and the change in highly
annoyance and insomnia (△Lden - △%HA and △L night(22:00-6:00) - △%ISM)

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The association between changes in noise levels (△ Lden and △ L night(22:00-6:00) ) and the change inhighly annoyance (△ %HA) and insomnia (△ %ISM) were compared in Figure 3. The data of the survey
conducted in 2014 (1st ) was considered as a base of the comparisons. The difference in data of thesurveys conducted in Mar 2015, Sep 2015, 2017, and 2018 compared with the data of the 2014 survey
were (2 nd -1 st ), (3rd -1st ), (4th-1 st ), (5 th-1 st ), respectively. Regarding the relationships of △ Lden and△ %HA, the slope of the regression line for the (2 nd –1 st ) Survey is steepest. It could be observed thatthe slope is decreasing with the recent surveys. Accordingly, the lowest slope is found with the dataof the most recent survey compared to the first survey. In other words, the change of annoyancecorresponding to the noise level has become less excessive in the follow-up surveys than the survey
conducted shortly after the change. This trend could not be seen clearly with the changes in △L night(22:00-6:00) and △ %ISM. A significant association was found between ISM and L night(22:00-6:00)(Table 6). An increase in noise level due to the increase in the number of flight movements at night
has been shown to have an adverse effect on the quality of sleep and the health of residents living near
the airport. According to the results of logistic regression analysis shown in Table 5, the residential
factors such as sound insulation, location of the bedroom, the use of air-conditioner had significant
effect on the rates of annoyance and insomnia.
Table 5 – Multiple logistic regressions for annoyance and insomnia
Annoyance
Odds

95% CI

95% CI

Ratio

Lower

Upper

<.0001

1.217

1.190

1.244

4.650

0.031

1.452

1.035

2.037

0.108

2.920

0.088

0.831

0.672

1.028

-0.8280.101

67.120<.0001

0.437

0.358

0.533

-0.303

0.106

8.140

0.004

0.739

0.600

0.910

-0.6230.114

30.150<.0001

0.536

0.429

0.670

Intercept-5.8020.721

64.840<.0001

Lnight(22:00-6:00)

0.083

0.013

43.250<.0001

1.087

1.060

1.114

Live<5years

0.162

0.246

0.440

0.509

1.176

0.726

1.906

S<100m2

0.020

0.147

0.020

0.892

1.020

0.765

1.361

Sound insulation-0.5140.136

14.270<.0001

0.598

0.458

0.781

-0.4960.138

12.860<.0001

0.609

0.464

0.799

-0.7600.172

19.550<.0001

0.467

0.334

0.655

Term

Estimate

Std Error

Intercept-11.4280.692

273.020<.0001

Lden

0.196

0.011

307.390

Live<5years

0.373

0.173

S<100m2-0.185

Sound insulation
Bedroom
direction
Air conditioner

ChiSquare Prob>ChiSq

Insomnia

Bedroom
direction
Air conditioner

3.4 Health Effects
In this study, hypertension was defined as if the systolic and diastolic blood pressure were higher
than 120 and 80 mmHg, respectively. A comparison was made to examine the relationship between
L den and % hypertension (Table 6). Comparisons of respondents with high blood pressure at different
noise exposure level ranges showed that there is no significant association between ratios ofhypertension and noise exposure levels (Lden ) .

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Table 6 – Comparison of high blood pressure ratios at different noise level ranges of the 2017-2018 surveys
Noise level ranges Lden (dB)
<50

50-55

55-60

60-65

65-70

>70

%

57

47

41

20

71

100

Response number

21/37

27/58

9/22

5/25

5/7

12/12

%

55

50

66.7

72.5

45

70

Response number

11/20

5/10

20/30

29/40

9/20

7/10

11/20178/2018p value
0.677
0.681

4. CONCLUSIONSIn this study, it seems that the excess response due to the step-change decreases over time, but the
response is still high compared with those obtained before the opening of the new terminal at the endof 2014 at the same noise level. An increase in the number of flights operated at night negatively
affects the quality of sleep. It should be considered to protect the living environment in the vicinities
around the airports in Vietnam by improving the residence quality and restricting night operation andformulating policy regarding aircraft noise.

ACKNOWLEDGEMENTS
This study was financially supported by Grant-in-Aid for Research Activity Start-up by Japan
Society for Promotion of Science (No. 17H06875). We acknowledge gratefully the staffs of Civil
Aviation Authority of Vietnam (CAAV), Noi Bai International Airport (NIA), and all the lecturers andstudents of National University of Civil Engineering (NUCE) and Hanoi University of Mining andGeology (HUMG) for supporting social survey and noise measurement.

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