OCCUPATIONAL HEALTH MONITORING

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OCCUPATIONAL HEALTHMONITORING SURVEILLANCE

• INSTRUMENTATION EQUIPMENT
• TYPES OF AIR CONTAMINANTS
• TYPES OF AIR SAMPLING
• SELECTION OF EQUIPMENT
• GRAB SAMPLING
• DIRECT-READING SAMPLING

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TYPES OF AIR CONTAMINANTS

• GASES
• VAPOUR
• PARTICULATES

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Air Contaminants

• Gases
• Gas- normal temperature/pressure
• Diffuse and mix
• Liquified by increase pressure decrease
  temperature
• Not affected by inertia/electrostatic force
• Easier to sample than dust/fumes
• Vapour
• Liquid-normal temp
• Behave like gas

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Air Contaminants

• Particulates
• Solids( dust, fumes, smoke )
• Liquid ( mists, fogs )
• Particle size - visible to sub microscopic
• Respirable
• Dust
• Penetrate into lungs
• lt 10 micron in aerodynamic diameter
• Fibrogenic dust ( eg silica )

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Air contaminants ( particulates)

• Total and Inspirable dust
• All particles that enter nose
• Includes respirable
• lt 100 micron aerodynamic diameter
• Used for toxic dusts
• Different collection method

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Types of Air Sampling

• Area Sampling
• monitor general environment
• locate contaminated areas
• not good indicator of exposure
• Necessary for Confined Space
• Personal Sampling
• Samples air from breathing zone
• Device worn by worker
• Good measure of exposure

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Types of air sampling ( continued )

• Grab sampling
• short period
• measures ceiling and peak
• Intergrated Sampling
• Longer period ( usually 8 hrs )
• measures TWA
• single sample and series

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Selection of EquipmentDepends on many factors

• Sampling objectives ( exposure/compliances )
• Characteristic of contaminant (physical/chemical)
• Require accuracy or precision
• Cost
• Type of sample ( area / personal )
• Duration of sampling

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Types of samplingGrab Sampling ( Gas Vapour )

• Collection devices
• flask , bags
• analyse in laboratory
• Gas chromatography, spectrophotometry
• Direct Reading Instrument
• many types
• fixed or portable
• Colourimetric tubes
• Infra red eg miran
• Portable Gas Chromatography
• Electrochemical methods ( gases )

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Types of samplingIntergrated Sampling

• Air sampling train
• air-inlet orifice
• Collection media
• F low rate meter/ control valve
• Suction pump
• Collection media
• liquid media
• solid sorbent gases, vapour
• eg charcoal, silica gel, polymer

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Types of samplingIntergrated Sampling

• Collection device
• Cyclone ( respirable )
• 7 hole or IOM ( inspirable )
• Filter ( eg PVC, mixed, glass )
• Impactor ( particle size )
• Direct reading devices ( intergrated )
• Fibrous aerosol monitor ( particles )
• Infra red ( miran, photoacoustic )
• Portable GC

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Sampling Analytical methods

• Standard methods
• US NIOSH
• UK HSE
• ASTM ( American Society of Testing Methods )

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Principle Strategies ofOccupational Hygiene
Monitoring

• Hazard Recognition
• Walk through Survey
• Field Survey
• Pre survey Information
• Monitoring
• Errors
• Sampling

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Hazard Recognition

• Raw Material
• Finished product
• By product
• Exposure standards
• Length of shift
• Physical environment

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Hazards RecognitionTo determine -

• Level of exposure
• The effectiveness of control measures
• Investigate complaints
• Compliance with regulations

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Hazards RecognitionSurvey

• Walk through Survey
• Locate existing hazards
• Review process
• See, smell, feel
• Control measures
• Field Survey
• More detail
• Monitoring
• Normal and abnormal conditions

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Field SurveyInformation required..

• Excessive noise
• Excessive heat
• Inadequate ventilation
• Radiation exposure
• Excessive air contaminant
• Ergonomic problems

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Sampling MethodsMonitoring- Observation
measurement judgment

• Personal
• Environmental
• Biological
• Medical Surveillance

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Sampling MethodsErrors...

• Accuracy- relationship b/w measured-true
• Precision - degree of agreement
• Systematic errors controlable( calibration)
• Random errors not controlable

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Sampling MethodsWhen to sample

• Different shifts
• Climatic conditions
• Changes of process
• Modified controls
• New hazards introduced

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Sampling MethodsHow long to sample

• 8 Hours
• 15 minutes ( STEL )
• Instantenous ( Peak )

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Sampling MethodsWhere to sample

• Breathing zone ( exposure )
• Close to source ( control )
• General Environment

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Sampling MethodsWhom to sample

• Highest exposure ( most common )
• Representatives task
• Special circumstances

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Sampling MethodsHow many samples

• No set rule
• Depends on purpose
• Worst case
• Statistical valid ( confidence interval )
• Method available

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BIOLOGICAL MEDICALSURVEILLANCE

• Health Surveillance
• Monitoring of individual to identify changes in
  health.
• Biological Monitoring
• Measurement of contaminants or its metabolites in
  body...

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Health Surveillance

• Substances is hazardous in workplace
• Evidence or suspect injury
• Atmospheric monitoring insufficient
• Techniques available
• Will benefit those at risk
• Method acceptable to workers
• Method practical and ethical

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Types of Health Surveillance

• Biological Monitoring
• Medical tests
• Medical examination
• Review work and medical history
• Review of medical records Occ. Exposure
• May include more than one of above..

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Employee requiring Health Surveillance

• Exposed to hazard for which there is-
• identifiable health effects/ diseases
• likelihood that it could occur
• valid techniques for detecting effects
• valid biological monitoring method value might
  be exceeded.

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Health SurveillanceBiological Monitoring

• Takes into account
• Skin absorption and injections
• individual variations in
• uptake
• metabolism
• excretion

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Health SurveillanceMedical Confidentiality

• All results are confidentials
• should not disclose personal details
• should not disclose the diagnosis
• Written Consents needed . . . . .
• Provide sufficient information to control hazards

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ANY QUESTION ?!!. . . .