-

01

American Industrial Hygiene Association, AIHA

1998

1. /

2. 3.

permissible exposure limits, PELs

-

02

2013 11

12

PEL 491 PEL

PEL 90 1

(2016 )

1

CNS 15030

Chemical Control BandingCCB

100 500

-

03

1 0.5 PEL 3 1 PEL

0.5 PEL 1 1 PEL 3 1

1

X95 0.5 PEL 3 1

0.5PEL X95 PEL 1 1

X95 PEL 3

X95 95

PELs 491

90 200

/

AIHAMathematical Models for Estimating

Occupational Exposure to Chemicals

Zero Ventilation Model

-

04

A

1

= (1)

CA Appm mg/m3

MA Amg

Vm3

/

Saturation Vapor Pressure Model

2

2

-

05

2 3

= 10

(2)

= 10

24.45 (3)

CA Appm mg/m3

VPA AmmHg

Patm760 mmHg

MW A

worst-case

1.

2. /Q 0 m3/min

3.

4.

5.

6.

2

2

1/10 1/100

6 1/1000 1/10000 1/100000

-

06

Box Models

3

4

=

+ + (4)

CAroom Amg/m3

CAroom0 At 0mg/m3

CAin Amg/m3

GA Amg/time

Q

ttime

Vm3

3

1.

2. GA

3.

QoutQin

-

07

QinQoutQ

4. CAin

4

1. CA 0

2. 0CAroom0 0

=

(5)

ASteady state

= 1

(6)

CAroomss Amg/m3

Well-mixed Room Model

AIHA

1. Well-mixed Model: Back-

pressure- affected Generation Rate

-

08

7

G = 1000 (7)

Gmg/min

Kt mg/minKt0.518/

MW1/31

MWg/mole

A ( )m2

PV

atm

PVBatm

R8.205 10-5 atmm3/((mole)(K))

TLK

8

C = 1000 1 (8)

Cmg/m3

Ktmg/minKt 0.518/MW1/3

MWg/mole

Am2

PV

atm

R8.205 10-5 atmm3/((mole)(K))

1 Braun, K.O., and K.J. Caplan. An Evaporation Rate of Volatile Liquids. (NTIS PB No. 92B232305). PACE Laboratories Inc. Project 890501.315/EPA/

744BRB92B001. Study conducted for the U.S. Environmental Protection Agency, 1989.

-

09

TLK

Qm3/min

tmin

Vm3

2. Well-mixed Model: Exponentially

Decreasing Emission Rate

9

=

(9)

Ct tmg/m3

kmin-1

L0mg

Vm3

Qm3/min

tmin

9

(1) e^(-Q/V t) e^(-k t)

0

(2)

(3)

9

10

-

10

=

(10)

Two-Zone Model

4near field

far field

4

11

= +

+

+ +

+ + (11)

=

(12)

-

11

CN,t CF,tmg/m3

VN VFm3

Gmg/min

m3/min

Qm3/min

t (min)

12min-1 13

(13)

(14)

1.

2.

3.

4. Qin=Qout=Qm3/min

5. Gmg/min

6.

Turbulent Eddy diffusion model

(Fick's Law)

5

eddies

15

16 17

3

-

12

5

3

t r

=

1 1

(15)

r

= (16)

=

(17)

Cr,t Crmg/m3

Gmg/minDm3/minrmtmin

1.

2.

3.

4.

5. infinite space

-

13

Statistical models

2006 AIHABayesian statistical approach

similar exposure group, SEG

exposure

reconstruction

A1, A2,,An SB S

P(B) 0 B Ak 18

| (18)

P(Ak)Ak

P(Ak B) BAk

prior

distributionlikelihood function

posterior distribution

Bayesian Decision Analysis, BDA

prior

distribution

likelihood

prior distribution

likelihood functionposterior

distribution

-

14

1.2.3.

1.2. 253.4.5.

-

15

1.

1. 2. 3.

4. GA

5.

6. 7.

Additional: 1.

CA 0

2. 0CAroom0 0

1. 2.

3.

4.

5. t=0

6.

7. 8.

1. 2.

3.

4.

5.

6. 7.

-

16

2.

1. vs

2. 3. 4.

5. 6.

1.

eddies2. 3.

4. 5. 6. 7. infinite

space

D

-

17

GHSCCB

1. AIHA Exposure Assessment Strategies Committee Modeling Subcommittee. 2000. Mathematical Models for Estimating Occupational Exposure to Chemicals. AIHA Press. Fairfax, VA, USA.

2. Ignacio, Joselito S. and William H. Bullock. 2006. A Strategy for Assessing and Managing Occupational Exposures, 3rd Edition. AIHA Press. Fairfax, VA, USA.

3. Chris Keil and Robert Murphy. 2006. An Application of Exposure Modeling in Exposure Assessments for a University Chemistry Teaching Laboratory, Journal of Occupational and Environmental Hygiene, 3:2, 99-106.

-

18

4. 2012 100IOSH100 A307

5. 2013 102.7.36. 2014 103.12.317. 2014 103.12.318. 2014 103.6.279. 2015 104.12.2