Challenges in exposure assessment to Diesel soot

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Challenges in exposure assessment to Diesel soot

• M.P. Guillemin
• Institute of Occupational Health Sciences
• Lausanne - Switzerland

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Michel Guillemin

• Director of the Institute of Occupational Health
  Sciences in Lausanne, Switzerland
• Chemist and occupational hygienist most
  interested by the exposure assessment strategies
• Committed to the development of our knowledge in
  the area of complex mixtures and not well
  specified hazards

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Outline
Introduction What is Diesel exhaust ? Health
effects Mechanisms Exposure assessment Fine
dust Carbon Further developments Conclusion
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What is diesel exhaust ?
Gas phase Usual gases found after the burning of
fuels Particulate phase A core of elemental
carbon coated with organic compounds and
inorganic compounds
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Effect on the workers lung
Acute and temporary effects irritation chest
tightness wheeze Chronic effects alteration of
the lung function response of the immune
system inflammation reaction cancer
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Health effects
Animal
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Mechanisms of action - pneumoconiosis
Risk of pneumoconiosis in relation to cumulative
exposure
90
80
Quartz
70
60
50
Risk ()
40
30
Coal
20
PVC
10
0
0
20
40
60
80
100
120
Exposure (mg/m3 years)
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Mechanisms of action - clearance
Clearance half-time for ultrafine particles and
other dusts
1000
Ultrafine TiO
2
800
Diesel
600
Quartz
Clearance half-time (days)
400
PVC
200
TiO
2
0
0
5
10
15
20
3
Dust concentration mg/m
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Health effects
Pooled relative risk estimates and
heterogeneity-adjusted 95 confidence intervals
Bus workers
Truck drivers
Equipment operators
Railroad workers
0.5
0.75
1
1.25
1.5
1.75
2
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Diesel exhaust-induced carcinogenesis
Particle
Macrophage
Inflammation Cell injury Cell proliferation Hyperp
lasia Fibrosis
Cytokines Growth factors Proteases
Nongenotoxic Pathway
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Diesel exhaust-induced carcinogenesis
Initiated cell
Activation of protooncogenes Inactivation
of tumor supressor genes
Promotion
Organic Chemicals
Preneoplastic lesion
Detoxification Excretion
Progression
Activation
Initiation
DNA Adducts
Mutations
DNA Repair
Genotoxic Pathway
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First attempts in measuring exposure

• Gases and total dust
• Respirable particles
• Respirable particles and nicotine
• Total carbon

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Potential Surrogate of Diesel Exhaust
Particulates

• Elemental carbon
• Small particles counting
• Particles identification and counting
• Dinitro-Polynuclear Aromatic Hydrocarbons
• ...

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Conclusions

• Real Occupational Health problem
• Potential problem in Public Health
• Need of a multidisciplinary approach
• Political awareness and financial support