Mark Wagstaffe Research Fellow Centre for Public Health Research, Massey University 102 Adelaide Road, Wellington 6140 m.wagstaffe@massey.ac.nz (P02, Wednesday 26, Civic Room 1, 11.30)

1. Video Exposure Monitoring
– Reducing Peak Exposures
Mark Wagstaffe
Centre for Public Health Research

2. Acknowledgements
• Purdue University – Professor Jim McGlothlin and Mark Sharpe
– From “Wow” to “What’s Next? The Future of Video Exposure
Monitoring - http://www.aihasynergist-
digital.org/aihasynergist/201001?pg=30#pg30
• Centre for Public Health Research, Massey University
– Professor Jeroen Douwes
– Professor Bill Glass
– Kerry Cheung
– Brad Prezant
– Samuel Keer
• Safe Work Australia
• HRC, DoL and ACC

3. Exposure Surveillance
• NOHSAC noted in 2006 that (outcome) surveillance is, to
some extent, “the ambulance at the bottom of the cliff ”.
• What is really required are actions to prevent occupational
disease and injury happening, by preventing the workplace
exposures that cause them.
• The surveillance of “exposures and hazards and controls” is
just as important as, and should ideally be integrated with,
the surveillance of disease and injury.

4. Workplace Exposures
• Disorders that have a relatively long latency between
exposure and occurrence are appropriate candidates for an
exposure surveillance system, because the outcome
monitoring reflects exposures years beforehand rather than
current or recent exposures.
• Using outcome information to plan prevention measures in
long-latency conditions means that prevention initiatives are
based on historical exposures that may not reflect current
occupational exposures. In such situations, monitoring
current exposures seems more logical and more likely to
lead to faster improvements in OH&S.

5. Latency

6. Workplace Exposures
• Workplace exposures can be consistent over a work shift or
quite variable. The variability in exposure patterns is
generally not measured, although it has been suggested
that peak exposures may be associated with more severe
health effects.
• For example, if two workers have identical average
exposures, the one who occasionally experiences peak
exposures may be at greater risk than the one whose
exposure remains relatively constant.

7. Multi Channel Video Exposure
Monitoring
• Video exposure monitoring (VEM) synchronises real time (or
near real time) chemical, biological, radiological and/or
physical exposure data, wirelessly with a video recording of
workers and/or environmental activities.
• Over exposure to chemical, physical or radiological agents
usually occurs during 20 per cent or less of the overall work
cycle, that is, approximately 80 per cent of a worker’s
exposure occurs during one-fifth of the time needed to
complete a task.

8. Peak Exposures
• A small reduction in peak exposures however can have a large effect on
reducing the time-weighted average exposure. The effectiveness of the
intervention in reducing overall exposure and preventing disease can be
much greater using VEM technology.
• Multi-channel VEM technology can now be used to add additional
monitoring capability by providing monitoring of multiple exposures
simultaneously, such as dust, UV radiation, solvents and noise, into a
single “job exposure” record
• VEM permits a detailed permanent record of the work tasks performed
and associated levels and has been able to identify exposure patterns
previously unrecognized, allowing better and more cost-effective control
of workplace hazards.

9. Effective control measures need to be based on a
thorough understanding of (peak) exposures
• Educational intervention
measures alone result in only a
modest reduction in exposure
(~10-15% in wood workers and
bakery workers)
• 8-hour TWA exposures provide
little insight into peak exposures
and therefore have limited
usability in identifying optimal
control strategies
• Specific task-based interventions
targeting peak exposures can
lead to reductions of more than
50% (example bakery workers;
Meijsters et al., 2008)

10. Exposure survey of airborne dust and formaldehyde in
the New Zealand joinery and furniture making industry
• A significant proportion of joinery
and furniture workers (19% and
8% respectively) are exposed to
dust levels in excess of the
current occupational exposure
limit of 5 mg/m3.
• The majority of joinery and
furniture workers (87% and 63%
respectively) are exposed to
inhalable dust levels in excess of
current international standards of
1 mg/m3.

11. Average inhalable dust concentrations (mg/m3) of
joineries and furniture makers.

12. Hand Electric Sander
This video is available at
http://youtu.be/MdaOtfkfL0g

13. Fumigants in shipping containers
• Measuring real time exposure to
Methyl Bromide and other fumigants
as workers unload shipping containers.
• Use of VEM to characterize peak
exposures to fumigants (VOC’s)
• Remote grab samples of air for
observed peaks

14. Fumigants in shipping containers
• 8 hours sample for off gassing
after unloading.
• Evaluation of current controls e.g.
5 ppm when container closed
after being fumigated
• Health questionnaire and
observed work practices for
unloading shipping containers.

15. Fumigants in shipping containers

16. Fumigants in shipping containers

17. Year in the Life of a Farmer
• Measuring real time worker exposure to noise
(vibration), dust, heat and UV using multi channel
VEM.
– Measuring of health parameters such as heart rate,
internal temperature at the same time and questionnaire.
– Sampling for pesticides, (skin, urine and carpet samples)
– Peak activity periods not just a single event
• Single exposure record for a task or occupation.
• Observed work practices and suggested improvements proven
by data.