1 General
Air quality testing should be planned and results evaluated by competent persons with
specialist training in air quality evaluation and occupational exposure. Tests should be
carried out in consultation with the ship's safety delegate and any other relevant
authorities.
The duration of the tests will depend on the operating cycles and working practices on
board the vessel. Monitoring should be carried out during several "normal" cycles, i.e.
with representative vehicles, activities and ventilation practices.
Both short-term and long-term (over the working day) exposure to air pollutants should be
investigated. Either static or personal samplers or ideally a combination of bath
techniques should be used in order to provide the most accurate picture of contaminant
concentrations and occupational exposure.
2 Air quality measurements
Air quality measurements should be representative of all exposed persons.
Pollutants
The concentrations of the following pollutants should be determined; nitric oxide (NO),
nitrogen dioxide (NO2), carbon monoxide (CO). In addition concentrations of
benzene, toluene, xylene and suspended particulate matter (SPM) should also be
determined whenever possible.
There are two general approaches to air quality sampling that can be adopted. Static site
monitoring, typically involving continuous monitoring techniques and personal sampling
which employs both passive and active methods. Static site monitoring usually includes
the more accurate and sensitive techniques, but as the sampling site is fixed the
measurements are not entirely representative of exposure. Personal samplers are worn by
a representative sub-set of exposed individuals throughout the sampling period. Personal
sampling techniques are not usually as sensitive or accurate. Ideally, personal sampling
methods should be validated using more sophisticated techniques at regular intervals.
The following exemplary methods are recommended.
Static site monitoring
-
| Pollutant:
|
Sampling and analysis
method:
|
| Nitrogen dioxide
|
Chemiluminescence, reagent
tube, grab sampling/laboratory analysis
|
| Nitric oxide
|
Chemiluminescence reagent
tube, grab sampling/laboratory analysis
|
| Carbon monoxide
|
Non-dispersive infra-red
absorption, reagent tube, grab sampling/laboratory
analysis
|
| Benzene
|
Real time gas
chromatography
|
| Toluene
|
Real time gas
chromatography
|
| Xylene
|
Real time gas
chromatography
|
| Suspended
particulates*
|
Dual beam radiation
absorption, Tapered Element Oscillating Microbalance,
gravimetric
|
| *
Suspended particulate matter can be sampled as total suspended
particulate matter, PM10 respirable dust (≤ 5 μm).
|
Personal monitoring
-
| Pollutant:
|
Sampling and analysis
method:
|
| Nitrogen dioxide
|
Passive (badge) sampler-ion
chromatography
|
| Nitric oxide
|
Electrochemical*
|
| Carbon monoxide
|
Electrochemical*
|
| Benzene
|
Passive badge sampler-gas
chromatography/FID (Flame Ionization Detection)
|
| Toluene
|
Passive badge sampler-gas
chromatography/FID
|
| Xylene
|
Passive badge sampler-gas
chromatography/FID
|
| Suspended particulates
**
|
Personal sampler,
gravimetric
|
| *
Electrochemical methods are susceptible to interference;
therefore, it is recommended that these methods are regularly
validated by intercomparison with other techniques in the test
environment.
|
| ** Suspended particulate matter can be sampled as total
suspended particulate matter or respirable dust (≤ 5
μm).
|
Supplementary measurements of local air velocity, temperature and relative
humidity should also be undertaken.
3 Calculation of occupational exposure to air pollutants
Long-term Reference Period
The occupational exposure over a 24-hour period is determined by treating the cumulative
exposure over 24 hours as equivalent to a single uniform exposure. This is generally
converted to an 8-hour time-weighted average (TWA) exposure and is represented
mathematically by:
where Cn is the occupational exposure and
Tn is the associated exposure time in hours in any 24-hour
period.
Short-Term Reference Period
The short-term reference period generally relates to a period of 10 or 15 minutes,
dependent upon the national occupational exposure standards. Exposure is therefore
recorded as the average over a 10 or 15-minute reference period. Where the exposure
period is less than 10 or 15 minutes, the measurement result is averaged over 10 or 15
minutes. Where the exposure period exceeds the short term reference period, results are
averaged for the 10 or 15 minutes period during which maximum exposure occurs.
4 Report
A written report should be provided containing the following information: completed,
taking into account paragraph 4 of appendix 2.