michel boutin, andré dufresne, - american industrial … · 2006-06-19 · michel boutin, andré...
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May 17, 2006 1
Determination of Airborne IsocyanatesGenerated During the Thermal Degradation
of Car Paint in Body Repair Shops
Michel Boutin, André Dufresne,Claude Ostiguy, and Jacques Lesage
André Dufresne, MSc, PhD, CIHChemist, Associate Professor
e-mail: [email protected]
May 17, 2006 2
Plan
• 1) Introduction• 2) Objectives of the research work• 3) Material and methods• 4) Results• 5) Basis of interpretation• 6) Conclusions
May 17, 2006 3
Introduction (1)
• Polyurethanes are widely used in car paint formulations.
• During thermal degradation, such polymeric systems can generate powerful asthmatic sensitizing agents named isocyanates.(1)
(1) Karlsson et al., 2002; Pronk et al., 2005; Tinnerberg et al., 1997; Boutin et al., 2004, 2005
May 17, 2006 4
Introduction (2)
• In body repair shops, the thermal degradation of car paint can occur during abrasive processes that generate enough heat to involve isocyanatesrelease in air.(1)
(1) Henriks-Eckerman et al., 2002; Karlsson et al., 2000
May 17, 2006 5
Objective of the Research Work
• The purpose of this research was to use the high sensitivity and the high selectivity of LC/MS to quantify the greatest possible number of isocyanatesgenerated during the thermal degradation processes occurring in auto body shops and to evaluate the potential exposure of workers.
May 17, 2006 6
Material and Methods (1)
• Air measurements were performed at three different workplaces: two auto body repair training schools (A and B) and a body repair shop.
May 17, 2006 8
Material and Methods (3)
• Green Honda Civic 2000 for school A,
• Grey Isuzu Rodeo 4WD 2001 for school B,
• Red Honda Civic 2000 for the body repair shop.
May 17, 2006 9
Material and Methods (4)• Two sampling systems were used:
– HSE (Cassette containing two MOPIP-coated filters and bubblers containing 15 mL of MOPIP in toluene);
– IRSST (Cassette containing two MOPIP-coated filters only (≈5 mg of MOPIP per filter) ).
R NCO +
Isocyanate MOPIP Urea
NNH
CH3O
R N C
H
O
N N
CH3O
May 17, 2006 11
Material and Methods (6)• Two LC/MSD Trap methods (I and II) were
needed to separate and analyze the MOPIP derivatives of the 18 isocyanates monitored during this study.(1)
• The instrumental detection limits (LOD) were in the 0.13-0.75 µg(NCO) / m3 range for 15 L air samples converted into 3 mL liquid samples.
(1) Boutin, M., (Post-Doc) Dufresne, A., Ostiguy, C., Lesage J. Determination of airborne isocyanates during the thermal degradation of car paint in body repair shops. Accepted in The Annals of Occupational Hygiene.
May 17, 2006 12
Basis of Interpretation
• Schedule 1 (Health & Safety Executive (UK) (HSE, 2005) of the Control of Substances Hazardous to Health (COSHH) Regulations specifies a Workplace Exposure Limit (WEL) of 20 µg / m3, 8-hour time-weighed average (TWA) reference period, for isocyanates in air.
• These limits are expressed as “weight of equivalent NCO groups”.
May 17, 2006 14
0 10 20 30 40 50 60 Time (min)
1
2
3 4 5 6 7 8
9
1011 12
Rel
ativ
e In
tens
ity
0 10 20 30 40 50 60 Time (min)
1
2
3 4 5 6 7 8
9
1011 12
Rel
ativ
e In
tens
ity
LC/MSD Ion Trap chromatogram obtained using Method I; School A; Cutting process; Emission source;
HN
CO
-MO
PIP
Me-
i-MO
PIP
Et-i
-MO
PIP
Pro
pyle
ne-i-
MO
PIP
Pro
p-i-M
OP
IP
But
ylen
e-i-M
OP
IP
But
-i-M
OP
IP
Pen
tyle
ne-i-
MO
PIP
HD
I-MO
PIP
Pen
t-i-M
OP
IP
Hex
ylen
e-i-M
OP
IP
Hex
-i-M
OP
IP
May 17, 2006 15
10.0
2
Rel
ativ
e In
tens
ity
34
5
6
7
12.5 15.0 17.5 20.0 22.5 25.0 27.5 Time (min)
1
10.0
2
Rel
ativ
e In
tens
ity
34
5
6
7
12.5 15.0 17.5 20.0 22.5 25.0 27.5 Time (min)
1
LC/MSD Ion Trap chromatogram obtained using Method II; Body repair shop; Cutting process; Emission source;
2,6-
TDI-M
OP
IP
Ph-
i-MO
PIP
2,4-
TDI-M
OP
IP
p-To
l-i-M
OP
IP
cis-
IPD
I-MO
PIP
trans
-IPD
I-MO
PI
2,4’
-; 2,
2’an
d 4,
4’-M
DI-M
OP
IP
May 17, 2006 16
Results
• The highest isocyanate concentrations were observed during the cutting process.
May 17, 2006 17
Cutting Process(Source) (µg(NCO)m-3)
Hex-iPent-iBut-i
Prop-iEt-iMe-i
HDI
IDPI (trans,cis)
Aliphatic
ndnd0.30nd0.210.35
0.171.460.570.130.520.510.503.451.608.4976.844.1
2.092.0654.8
9.58ndnd
Shop (n=2)School B (n=4)School A (n=4)
May 17, 2006 18
Cutting Process(BZ) (µg(NCO)m-3)
Hex-i
Pent-i
But-i
Prop-i
Et-i
Me-IHDI
IDPI (trans,cis)Aliphatic
ndndnd
ndndnd
ndndnd
ndndnd
ndnd0.10
1.090.612.83
0.27nd1.86
1.36ndndShop (n=2)School B (n=4)School A (n=4)
May 17, 2006 19
Cutting Process(Source) (µg(NCO)m-3)
0.270.151.42Hexylene-i
0.160.380.95Pentylene-i
0.190.430.49Butylene-i
0.421.951.52Propylene-i
Body Shop(n=2)
School B(n=4)
School A(n=4)
Alkenyl
May 17, 2006 20
Cutting Process(BZ) (µg(NCO)m-3)
ndndndHexylene-indndndPentylene-i
ndndndButylene-i
ndndndPropylene-i
Body Shop(n=2)
School B(n=4)
School A(n=4)
Alkenyl
May 17, 2006 21
Cutting Process(Source) (µg(NCO)m-3)
27.071.169.1MDI(2,4’;2,2’;4,4’)
2.893.3112.82,4-TDI
0.09ND0.412,6-TDI0.210.560.57p-Tol-i
1.044.082.00Ph-i
Body Shop(n=2)
School B(n=4)
School A(n=4)
Aromatic
May 17, 2006 22
Cutting Process(BZ) (µg(NCO)m-3)
2.130.464.20MDI(2,4’;2,2’;4,4’)
0.44nd0.812,4-TDIndndnd2,6-TDIndndndp-Tol-i
ndndndPh-i
Body Shop(n=2)
School B(n=4)
School A(n=4)
Aromatic
May 17, 2006 23
Cutting Process(Source) (µg(NCO)m-3)
53167192Total(aliphatic + alkenyl + aromatic)
61437165HNCO
Body Shop(n=2)
School B(n=4)
School A(n=4)
May 17, 2006 24
Cutting Process(BZ) (µg(NCO)m-3)
5.291.079.8Total(aliphatic + alkenyl + aromatic)
nd2.616.9HNCO
Body Shop(n=2)
School B(n=4)
School A(n=4)
May 17, 2006 26
Conclusion
• The isocyanate concentrations detected in the workers' breathing zone were in the range
– Cutting: 1.07-9.80 µg(NCO) / m3
– Grinding: 0.63-3.62 µg(NCO) / m3
– Sanding: 0-1.29 µg(NCO) / m3
May 17, 2006 27
Conclusion
• The isocyanate concentrations measured rapidly decreased from the emission source to the sampling tree, 2 m away.
• The use of posture, which maximizes the distance between the worker and the emission source could thus reduce significantly the isocyanate exposure.