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IVHHN Recommended
Dust Masks.pdf
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Following an eruption, volcanic ash can cause irritation
of the airways and lungs and, if breathed in over many years,
could cause lung disease. Whilst volcanic ash is suspended
in the air, it is vital that the population exposed protects
themselves by wearing masks. For the public, use of masks
is only necessary whilst the levels of suspended dust are
above background levels. For those involved in clean-up operations,
garden maintenance or even people who are cleaning houses
and property, masks should be worn at all times whilst the
ash is mobile in the atmosphere.
For protection against volcanic ash, high-efficiency, light-weight
disposable masks/respirators are appropriate. The mask must
provide protection at the highest concentration the person
will experience. Suitable disposable masks are 'CE' marked
to show that the design has been tested to a recognised standard.
They will also be marked with the standard (e.g. EN 149:2001
in the EU or N95 in the US) and an additional code such as
FFP1 (low efficiency), FFP2 (medium efficiency) or FFP3 (high
efficiency) (FFP = Filtering Face Piece) is shown on EU masks.
The US N95 standard is roughly equivalent to FFP2 or 3 as
it is efficient up to 10 x the local occupational exposure
limit (see Table 2). The higher the FFP number, the more protection
the respirator can provide if it is used properly. Pre-2001
masks may also distinguish between those suitable for solids
and liquids e.g. FFP2S. Disposable masks cover the nose, mouth
and part of the chin. Some of them contain exhaling valves.
An elastic band around the head and neck keeps them in place.
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Figures 1 & 2. Masks may either be fitted with or without
valves.
Valve masks are more comfortable, especially for those wearing
spectacles which might otherwise mist up. They are appropriate
for hot and humid climates.
The following tables give examples of appropriate respirators
provided by the company 3M. There are many other manufacturers
(e.g. Willson, Moldex, Uline, Pyramex, see web addresses in
References section)
who make similar masks.
The UK/EU respirators are tested for penetration of particles
> 0.5 µm diameter and the US respirators are tested to > 0.3
µm diameter. We recommend that valved respirators are used
in hot or humid climates although they will aid comfort in
all environments. The respirators distributed to a population
should be chosen with the occupation of the people and the
airborne dust concentration in mind. For example, for the
general population exposed to suspended volcanic dust, the
FFP1 mask might be appropriate if the dust levels do not exceed
4 x the local occupational exposure limit. For workers involved
in clean-up operations, gardening or other high-exposure jobs,
FFP2 or FFP3 are recommended. We recommend folded masks as
they are individually packed, allowing clean storage, and
easy and hygienic distribution. However, the folded masks
can fit less well on people with small faces or chins.
A respirator must pass three tests:
- It must be capable of providing adequate protection.
- It must fit you properly and it must be compatible with
any other personal protective equipment that you wear at
the same time.
- In addition, you must always use it correctly for it to
be fully effective.
Respirators only protect you if they fit properly without any
leakage around the nose or chin. Even expensive respirators
are unsuitable if they do not give a good seal with the face.
A good fit relies on close contact between the respirator and
smooth skin without hair in the region of the seal. Consequently
a beard or beard stubble can affect the fit and reduce protection.
Many manufacturers make respirators in different sizes to allow
for variations in the shape and size of faces. You should not
expect one respirator to fit everyone. If you are responsible
for providing masks for a community, you should order them in
several different sizes and types. It will not be possible to
individually fit masks to every person in a population, however.
If resources allow, special effort should be taken to fit masks
for occupationally-exposed individuals and other high-exposure
groups.
To check if a respirator fits properly, ensure that the straps
and any strip for moulding the respirator around the bridge
of your nose are correctly adjusted. Then hold the respirator
in place and breathe in or out sharply. If you detect any
leakage around your face you should readjust the respirator
and retest. See bottom of document for further instructions.
Unfortunately respirators are not made to fit children's
faces. For this reason, children must be kept indoors and
stopped from playing in dusty environments whilst ash is present.
For continuous labour in dusty conditions, full-face non-disposable
respirators with changeable filters will be more appropriate
and are also more comfortable to wear in hot, humid conditions.
For extreme conditions see: http://www.3m.com/intl/za/ohes_airstream.html
for Airstream Powered Helmets.
Although the masks are disposable, if supplies are limited
they can be stored for re-use in a clean bag or box to ensure
that dust from the outside does not contaminate them. They
should not be hung in a dusty environment. They must be replaced
at the first sign of breathing difficulty.
It is possible to buy cheap masks called 'nuisance dust masks',
'comfort masks' or 'hygiene masks'. They may look similar
to lightweight disposable masks but they are not intended
for use in dusty environments and are not marked 'CE' or 'EN149/N95'.
Instead, the package may say something like 'This product
does not provide respiratory protection'. Unless the product
clearly states that it conforms to a recognised standard,
do not use these masks for protection from volcanic ash.
Dust mask manufacturers:
Mask fitting instructions:
Health & safety guidelines:
Acknowledgements
This document was written by a panel of IVHHN expert members.
IVHHN is grateful to the Leverhulme Trust, UK, for funding
associated meetings.
IVHHN is also grateful to the following people:
Yasuhiro Ishimine, National Research Institute for Earth Science
and Disaster Prevention, Bosai, Japan for researching Japanese
health and safety guidelines.
Jim Chisholm, UK Health & Safety Executive, for reviewing
the document.
3M Mask Fitting Instructions
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