noise3

°“√»÷°…“§«“¡‡ªìπ‰ª‰¥â„π°“√µ√«®«—¥„π√–¬– —ÈπÊ ”À√—∫°“√µ√«®«—¥‡ ’¬ß „π ¿“«–·«¥≈âÕ¡„π‡¢µ°√ÿß‡∑æ¡À“π§√Feasibility Study of Short-term Method for Environmental NoiseMeasurement in Bangkok

N.Chansombat*, T.Suksa-ard*,

W.Auesongtham*, T.Norach*, P.Sukasem*,

M.S.Tabucanon*, H.Tanaka*, P.Areephol**,

S.Bualert**, C.Yachoosri**, R.Watananukulkit**

∫∑§—¥¬àÕ„πªí®®ÿ∫—πªí≠À“‡ ’¬ß√∫°«π„πª√–‡∑»‰∑¬

‰¥â‡ªìπªí≠À“ ”§—≠·≈–∑«’§«“¡√ÿπ·√ß‡™àπ‡¥’¬«°—∫

ªí≠À“ ‘Ë ß·«¥≈âÕ¡Õ◊Ëπ ‚¥¬‡©æ“–Õ¬à“ß¬‘Ë ß„π

°√ÿß‡∑æ¡À“π§√ ÷Ëß‡ªìπ»Ÿπ¬å°≈“ß§«“¡‡®√‘≠∑“ß

¥â“π‡»√…∞°‘®·≈–°“√æ—≤π“ —ß§¡ ¡’‚§√ß°“√‡°‘¥¢÷Èπ

‡ªìπ®”π«π¡“° ‡™àπ ‚§√ß°“√∑“ß¥à«π ∂ππ«ß·À«π

√Õ∫πÕ° √–∫∫¢π àß¡«≈™π·≈–‚§√ß°“√ π“¡∫‘π

π“π“™“µ‘°√ÿß‡∑æ·Ààß∑’Ë Õß ‡ªìπµâπ ‡æ◊ËÕ√Õß√—∫°“√

¢¬“¬µ—«¢Õß‡¡◊Õß„πÕπ“§µ ‡æ◊ËÕ∑√“∫ ∂“π°“√≥å

ªí≠À“¡≈æ‘…∑“ß‡ ’¬ß„π‡¢µ°√ÿß‡∑æ¡À“π§√ °√¡

§«∫§ÿ¡¡≈æ‘…‰¥âµ√«®«—¥√–¥—∫‡ ’¬ß‡©≈’Ë¬ 24 ™—Ë«‚¡ß

*»Ÿπ¬å«‘®—¬·≈–Ωñ°Õ∫√¡¥â“π ‘Ëß·«¥≈âÕ¡ °√¡ àß‡ √‘¡§ÿ≥¿“æ ‘Ëß·«¥≈âÕ¡ ‡∑§‚π∏“π’ µ.§≈ÕßÀâ“ Õ.§≈ÕßÀ≈«ß ®.ª∑ÿ¡∏“π’ 12120 ‚∑√. 0-2577-1136 ‚∑√ “√. 0-2577-1138Environmental Research and Training Center, Department of Environmental Quality Promotion. Technopolis. Klong 5, Klong Luang, Pathumthani 12120 e-mail: [email protected]**§≥–«‘∑¬“»“ µ√å ®ÿÃ“≈ß°√≥å¡À“«‘∑¬“≈—¬

Sound Level Meter

Fig. 1 Map of Measurement Point

(Leq (24 hrs)) ‡ªìπ®”π«πÀ≈“¬®ÿ¥µ√«®«—¥∑ÿ°ªï

µ“¡¡“µ√∞“π ISO ·µà‡ªìπ°“√¬“°∑’Ë®–∑”°“√µ√«®«—¥

Leq (24 hrs) ∑—Ë«æ◊Èπ∑’Ë¢Õß°√ÿß‡∑æ¡À“π§√ ‡π◊ËÕß®“°

¡’æ◊Èπ∑’Ë°«â“ß„À≠à¡“° ®÷ß¡’°“√»÷°…“§«“¡‡ªìπ‰ª‰¥â„π

°“√„™â«‘∏’°“√µ√«®«—¥‡ªìπ√–¬–‡«≈“ —ÈπÊ ®“°º≈°“√

»÷°…“· ¥ß„Àâ‡ÀÁπ«à“∂â“¬Õ¡√—∫§«“¡§≈“¥‡§≈◊ËÕπ

± 3 ‡¥´‘‡∫≈‡Õ ‡√“ “¡“√∂ª√–¡“≥§à“ Leq (24 hrs)

‰¥â®“°§à“ Leq (10 min) ®“°°“√µ√«®«—¥„π™à«ß‡«≈“

10:00-18:00 π. ·≈– 22:00-0:00 π.

ABSTRACTAt present, noise pollution in Thailand

has become a big social problem and getting

more serious as other kinds of pollution

especially in Bangkok Metropolitan, the center

of economic and social development. It has

been planning to construct many projects for

example express way, outer O-ring road,

mass transportation system and the second

Bangkok International Airport, in order to

support the expansion of the city in the future.

To Know the situation of noise problems

in Bangkok Metropolitan area, the Pollution

Control Department measures Leq (24 hrs) at

several sites every year according to ISO. But,

it is difficult to get the real Leq (24 hrs) values

for the whole of Bangkok because of its large

area. The possible short-term method has to

be investigated. From the study, the result

shows that if +3 dB(A) error is acceptable,

the estimated Leq (24 hrs) value which

calculated from a pair of the measurement

values of Leq (10 min) during 10:00 to 18:00

oûclock and 22:00 to 0:00 oûclock can

effectively represent Leq (24 hrs).

1. IntroductionAt present, noise pollution in Thailand

has become a big social problem and getting

more serious as other kinds of pollution-

Especially in Bangkok Metropolis, the center

of economic and social development, has

been planning to construct many projects for

examples express way, outer O-ring road,

mass transportation system and the second

Bangkok International Airport, in order to

support the expansion of city in the future.

To know the situat ion of noise

problems in Bangkok Metropolitan area, the

Pollution Control Department measures Leq

(24 hrs) at several sites every year1) according

to ISO2). But, it is difficult to get the real Leq

(24 hrs) values for the whole of Bangkok

because of its large area. The possible short-

term method has to be investigated.3), 4)

Up to now, Thailand has no any

standard about environmental/community

noise. The U.S.EPAûs standard, Leq( 24 hrs)

= 70 dB(A), is used1) as a guideline in many

cases. In the draft of community noise

standard5), show in Table 1, standard levels of

long-term and short-term measurement were

set according to four kinds of land use. So in

order to support the feasibility in using

short-term measurement method instead of

long-term method, the suitable period of time

and time interval in the measurement were

tried to find out in this study.

2. Measurement

2.1 Measurement pointsMeasurement points, shown in Fig. 1,

were set up 1 point per sq.km. in 9 sq.km.

of the inner Bangkok Metropolitan area. This

area has been affected by not only road

traffic noise but also other kinds of human

activities. One of the measurement points was

set in a residential area, another in a park and

the others, 7 points, were set on roadside.

2.2 Set up for measurementBlock diagram of instrumentation for

measuring noise continuously 24-hour period

is shown in Fig. 2. The Printer was set up to

print out the values of Leq(10 min) while

the level recorder continuously recording the

»Ÿπ¬å«‘®—¬·≈–Ωñ°Õ∫√¡¥â“π ‘Ëß·«¥≈âÕ¡ °√¡ àß‡ √‘¡§ÿ≥¿“æ ‘Ëß·«¥≈âÕ¡ §-87

sound pressure levels and in each hour the

number of vehicles in 10 minutes was counted

at the roadside points.

3. Results and discussionThe values of Leq(24 hrs), Ldn, Lday

(hereafter called Ld) and Lnight(hereafter

called Ln) of all measurement points are

shown in Table 3. The minimum value of Leq

(24 hrs), 55.7 dB(A), was at Areesamphan 6

(residential area) while other three roadside

measurement points showed the values over

70 dB(A). The values of Ld and Ln of each

roadside measurement point were almost

same levels except a point; which a few events

of rather high levels occurred during the

measurement, while those values of the

measurement points in residential area and

park had about 5 dB(A) in difference.

Fig. 3 shows variation of difference

between Leq(10 min) and Ld, Ln of a point,

for daytime during 9:00 or 10:00 oûclock to

18:00 or 19:00 oûclock and for nighttime

during 22:00 oûclock to 0:00 or 1:00 oûclock,

the differences were approximately within

± 3 dB(A).

The average and standard deviation

of the difference between Leq(10 min) and Ld,

Table 1 Community Noise Standards (Draft)

Land use Standard levels, dB(A)

long-term meas. short-term meas.

Agricultural area Leq(24 hrs) < 55 Leq(5 min) < 60 ;anytime

Residential area Ld-n < 67 Leq(5 min) < 65 ;daytime

Commercial area Ld-n < 70 Leq(5 min) < 70 ;daytime

< 65 ;nighttime

Industrial area Leq(24 hrs) < 70 Leq(5 min) < 75 ;anytime

Leq(24 hrs) : any 24 hrs. measurement

Ld-n : 7:00 - 7:00 next daydaytime : 7:00 - 22:00nighttime : 22:00 - 7.00 next day

Fig. 2 Instrumentration for Noise Measurement

§-88 »Ÿπ¬å«‘®—¬·≈–Ωñ°Õ∫√¡¥â“π ‘Ëß·«¥≈âÕ¡ °√¡ àß‡ √‘¡§ÿ≥¿“æ ‘Ëß·«¥≈âÕ¡

Table 2 Result of Measurements

Measurement Points Location Leq (24hrs) Ldn Lday Lnight

1. Areesamphan 6 residential area 55.7 59.9 57.0 51.5

2. Excise Dep. roadside 74.0 80.1 74.4 73.3

3. Dusit Dist. Off. roadside 69.5 52.5 69.9 68.8

4. Dusit zoo Park 58.0 62.6 59.2 54.5

5. Welfare Fac. 25 m. from road 68.5 74.7 68.7 68.2

6. Phayatai 2 Hosp. roadside 77.1 83.8 77.0 77.1

7. Millitary Dep. roadside 71.2 76.8 71.8 70.1

8. Phayatai School roadside 69.7 73.1 71.1 65.2

9. Horse Race Course roadside 68.0 74.4 68.0 68.1

(measurement date : 28-30 Nov.1995) daytime : 7:00 - 22:00 nighttime : 22:00 - 7:00 next day

Table 3 Summary of the Average and Standard Deviation of the difference between Leq(10 min)

and Lday, Lnight

Measurement Points

Daytime Nighttime

Avg. of Diff. S.D. Avg. of Diff. S.D.

7:00- 10:00- 7:00- 10:00- 22:00- 22:00- 22:00- 22:00-22:00 18:00 22:00 18:00 7:00 0:00 7:00 0:00

1. Areesamphan 6 -1.16 -1.32 3.01 2.85 -3.82 -1.36 5.79 4.16

2. Excise Dep. -0.21 0.08 1.37 1.07 -1.22 -1.13 3.03 1.13

3. Dusit Dist. Off. -0.20 -0.28 1.23 0.93 -0.71 1.70 2.38 2.32

4. Dusit zoo -0.50 0.01 2.49 0.99 -0.91 -1.07 2.54 0.75

5. Welfare Fac. -0.41 -0.90 1.86 1.62 -0.50 0.59 2.20 1.38

6. Phayatai 2 Hosp. -0.25 -0.46 1.42 1.45 -0.18 -0.56 1.23 0.91

7. Millitary Dep. -1.10 -1.67 2.28 1.23 -0.22 -0.20 1.35 1.26

8. Phayatai School -3.41 -3.38 1.88 1.67 -0.18 0.63 1.26 0.87

9. Horse Race Course -0.23 -0.44 1.87 1.66 -0.19 0.41 1.35 0.95

Fig. 3 Difference between Leq(10 min) and Lday, Lnight : 1. Areesamphan 6


Ln during 10:00 to 18:00 oûclock and 22:00

to 0:00 oûclock were calculated and compared

to the whole daytime and nighttime values

as shown in Table 3. The values of the

average of the difference of all measurement

points in daytime changed not so much.

On the other hand, most of those values at

nighttime shifted to a little higher because

Leq(10 min) tend to decline from about 1:00

oûclock and rised up about 5:00 oûclock.

And most of the values of the standard

deviation became smaller.

Each pair of Leq(10 min) during 10:00

oûclock to 18:00 oûclock and 22:00 to 0:00

oûclock was calculated to be an estimated Leq

(24 hrs) value, Leq(24 hrs)est, by using the

following formula;

Leq(24 hrs)est = 10 log 1/24(15*10Leq(10 min)day/10

+9*10Leq(10 min)night/10)

It was found that more than 80% of

Leq(24 hrs)est values were within ± 3 dB(A)

different from the true Leq(24 hrs). Fig. 4 shows

histogram of a point.

4. ConclusionIf within ± 3 dB(A) error is acceptable,

the estimated Leq(24 hrs) value which

calculated from a pair of the measurement

acceptable values of Leq(10 min) during 10:00

oûclock to 18:00 oûclock and 22:00 to 0:00

oûclock will be effectively represent Leq

(24 hrs).

5. AcknowledgmentThe authors would like to thank the

hosts of measurement points for their

assistance in setting up the measuring

instruments. This research has been supported

by the Technical Cooperat ion Project

between the Government of Japan and the

Kingdom of Thailand, and was carried out

under JICA (Japan International Cooperation

Agency) expertûs guidance.

6. References1. Pollution Control Department, Ministry of

Science Technology and Environment,

Thailand, (1994) Repor t of Pollution

Situation in Thailand, 31-33

Fig. 4 Cumulative frequency of difference between Leq(24 hrs)est and Leq(24 hrs)obs

§-90 »Ÿπ¬å«‘®—¬·≈–Ωñ°Õ∫√¡¥â“π ‘Ëß·«¥≈âÕ¡ °√¡ àß‡ √‘¡§ÿ≥¿“æ ‘Ëß·«¥≈âÕ¡

2. ISO 1996/1, (1982) Description and

Measurement of Environmental Noise

3. C.M. Harris; (1979) Handbook of Noise

Control, Mcgraw Hill, 35-23-26

4. I . Aoi, G.Hathairatana (ERTC), 1992

Temporal Sampling Techniques for the

measurement of Environmental noise (Total

Measurement time), JICA Final Report

5. National Environment Board, (1993)

Thailand, Community Noise Standard

(Draft)


noise3

Documents

Transcript of noise3