occupational health

Why would you wear that? PART 4

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Respiratory Protection in Asia – The Truth About Masks Used

Do you want the truth?  Think you can handle the truth?

Well, the truth is the following three methods used to protect yourself from breathing in contaminated air will not provide you any protection at all!

IMG_2087 Respiratory Protection2 IMG_2298

Sorry to be the bearer of bad news, however, this blog is not all about sunshine 1F304 and rainbows 1F308
This blog is intended to shed some light on the “masks” commonly used to protect people from airborne hazards in Asia, and tell you why they don’t work.

NOTE: The information presented below is not based on rigorous filtration efficiency testing repeated in a laboratory.   The information presented answers one simple question i.e. “will that mask protect me?”  It’s pretty simple to answer, either it will or it won’t protect you.

In Part 3 of this Respiratory Protection in Asia Series, we explored the Principals of Protection.  We now know that a mask will only protect you when all of the air that goes into your lungs passes through a filter that removes all of the bad stuff from the air. To achieve these two fundamental things need to occur:

1. the filter media has to be designed and tested to prove that the contaminants you are protecting yourself from will be removed from the air; and
2. all of the air has to pass through the filter before it reaches your lungs – that is, no bad air is can pass through the filter or travel through any gap.

So let’s apply these principles to the mask most commonly seen to be worn in Asia……the good old Medical Mask. Surgical-Face-Mask

Firstly what is a medical mask?

In the 1890’s a German bacteriologist and hygienist, by the name of Carl Flügge discovered infectious diseases such as tuberculosis and cholera could be transmitted through droplets released from people’s mouths and noses (AKA Flügge droplets) .  This discovery lead to the development of the first medical masks consisting of gauze strips placed over the wearer’s mouth. It is believed French surgeon Paul Berger was the first to wear a surgical mask while operating in 1897.

These days, despite the introduction of immunisation and antibiotic drugs, used to control communicable diseases and infection such masks continue to be used for purposes of:

– limiting the transmission of infective agents from staff to patients during surgical procedures;
– protecting the wearer against splashes of potentially contaminated liquids; and
– reducing the risk of spreading infections, particularly in epidemic or pandemic situations.

Okay, so let’s apply the respiratory protection principles to test the Medical Mask:

Will the mask filter remove the airborne contaminants?

Dust captured in respirator with crossNo Square1No, the mask will not filter airborne contaminants.  Why? because fundamentally the medical mask is designed to stop germs released by the wearer from reaching the outside world – – they are not designed to stop airborne contaminants from the outside world getting in!



Will the mask fit the wearer’s face so no gaps between the mask and the wearer’s face are possible?

No Square1No, the mask does not mold to the wearer’s face to achieve an adequate seal.




What about the designer masks you ask? Surely they must protect you, they look so good.


I am told that the designer masks are preferred over the medical masks, however, they are more expensive and, therefore, are less common.  I have also been told that an added benefit of these masks is you can wash them and they will last up to 3 or 4 months.




So what are the masks made up of?

FotorCreatedThe masks are made of 3 layers. The first layer is cotton fabric, the second is a foam insert and the third layer is mesh material.IMG_2306_2








So let’s apply the respiratory protection principles to test the Designer Mask:

Will the mask filter remove the airborne contaminants?

IMG_2363IMG_2363_2The simple answer is no No Square1
Why’s that you ask? Well, the material the masks are made of allows airborne contaminants to pass through and into your lungs. In Part 3 of this series, we demonstrated the size of airborne particles (PM10 and PM2.5) in comparison to a human hair. The photo on the left shows a human hair that has been pushed through the mask to demonstrate how big the holes are in the material are. The photo on the right shows how the large holes can be seen with the naked eye.

Will the mask fit the wearer’s face so no gaps between the mask and the wearer’s face are possible?

Designer Mask  No Square1No, the edges of the mask are not adequate to enough for the wearer to achieve a seal and prevent leaks.






What about covering your and mouth and nose with your hand for protection?

Covering mouth and noseNo Square1It’s actually quite difficult to apply the respiratory protection principles to this method of protection. The human hand is not pervious, i.e. air cannot pass through your hand.
Now, hypothetically speaking just say you were able to seal off your mouth and nose with your hand, then how would you actually breathe? Let’s face it, to breathe in clean air we need to remove the bad contaminants, to do this we need a filter. The hand is not a filter. Once you remove your hand away from your face you will continue to breathe in the contamination.

Don’t miss the final blog in this 5 part series where we take a look at the real challenges for protecting persons lungs in Asia.

Why would you wear that? PART 3

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Respiratory Protection in Asia – Principles of Protection

Last year the World Health Organisation (WHO) reported that sufficient evidence now demonstrates air pollution to be the world’s single largest environmental health risk,  contributing to 1 in every 8 deaths globally (approx 7 million people per year).

I have been working in Asia for some months now and have certainly noticed the significant environmental pollution. The other thing I have noticed is the  “face masks” worn by the Asian population.

With all due respect, I do have some concern regarding the “masks” I have witnessed in use, particularly as the general perception is they will protect against dusts, chemicals and other biological hazards.

This blog is intended to simply explain how a “mask” works and how it actually protects you from all of the bad stuff in the air!

Hygiene 101

Let me provide you with a simple explanation of how clean air gets into your lungs and how bad air can be kept out.

This is a typical picture used to show the emission of pollution

Now, imagine billions of tiny little pollution particles that continue to float around in the air.  Under a microscope, they usually look like this little creature

Dust with Eyeballs-01
See those eyes? He wants to eat your lungs!!

Now the aim of protection is to stop these little creatures from getting into your lungs

Dust in Lungs

So how do we do this?  Well we wear a device that covers the mouth and nose so clean air gets in and bad air stays out

Sounds easy enough, right?  Well, let me tell you it’s not!

You see when you wear a protective mask there will be a myriad of things that influence whether or not those little creatures will get into your lungs.  Fundamentally to provide you with protection, the mask must:

—    remove creatures of all sizes;
—    remove creatures of all chemical states (gas, solid or liquid); and
—    fit your face.

Let’s have a look at these more closely.


Whoever said size doesn’t matter was wrong! You see the tiny creatures that get into your lungs and hurt you are typically not visible to the naked eye, that is you won’t be able to see them!

Dust (or “particulate matter” as occupational hygiene nerds like to call it) comes in many sizes.  The fact that it is floating in the air demonstrates how small it really is, you see the heavy particles will fall out of the air leaving us to deal with the small ones.

Now here’s two facts for you to consider:

1.     the smaller the creature, the deeper it will go into your lungs
2.    the deeper the creature goes into your lungs the less likely it will be for the creature to ever come out

Well, how small does it have to be you ask?

Let’s look at the pictures below. For us to even breathe in a creature it would have to be around about 10μm (AKA PM10), for a creature to get deep into our lungs it will need to be around 2.5μm (AKA PM2.5).  Now let’s compare these sizes to the size of a human hair.
The microscopic image of the hair on the left below demonstrates the diameter of a human hair to be 60μm.  Now looking at the diagram on the right we can compare the size of each creature to the cross section of human hair. Pretty small right?
PM10 and PM2.5 and Human Hair

So for a mask to even work it would need to include filter media that would capture even the smallest particle.


Creatures that “float around” in the air don’t just include particulates. Creatures come in many different forms and include liquids (think of vapours coming from a petrol tank) and gases.  It is important to understand how the mask will actually adsorb the creatures made up of liquids or gases so that they don’t pass through and travel into your lungs. The discussion above regarding size continues to be relevant even when discussing the chemical state of each creature.

Think of the protection you need in the form of an umbrella that you were standing underneath.  Your goal is not to get wet!  If your umbrella was made of cotton (similar to the shirt on your back) and it started raining, would you get wet? Have a think about it.

vectorstock_1994591 white background

It’s important to understand what you are protecting yourself from, whether it be a gas, solid (particulate) or vapour (liquid) so you know that the mask you are wearing is actually not going to let the little creatures travel across to the other side so they can get into your lungs. This is the very reason why different filters are used to capture different types of creatures.  It is also important to note that sometimes no matter how good your mask is there are just some creatures that cannot be captured with a filter, for example, carbon monoxide (CO).

Dust captured in respirator with tickDust captured in respirator with cross


Sometimes people say to me that they don’t like wearing a mask because it makes their glasses fog up.  Well, I can tell you there is only one reason for that – – – – the mask actually doesn’t fit!

So your still a little confused when I talk about a mask “fitting” you?  Well it is simple, the mask you wear is designed to cover both your mouth and nose as these are the two locations air will go in and out of your body (other than farting of course!). We know that all of the air needs to pass through a filter to remove all of the bad creatures, therefore if there is a gap between your mask and your face, then bad air will enter your lungs, its that simple!

                    Gap between mask and face
Face Seal Leak
                  Gap lets bad air into lungs
Face fit - breathing in contaminants

Source: Fit2Fit

Mask seal against the wearer’s face

What’s not simple is actually getting a seal between the mask and your face, that is getting your mask to fit! Remember the picture showing the tiny size of the creatures in comparison to a human hair?  Well, the picture below demonstrates how something as simple as facial hair will create a gap between a mask and a person’s face resulting in a broken seal. Once this seal is broken it is easy for the little particles to travel through the gap and into the lungs.

Face Seal Leak - Human HairOther things that can affect a seal and create a gap between a mask and a person’s face includes:

—    the material the mask is made from;
—    the shape of the persons face;
—    features such as a persons nose;
—    the size of the mask; and even
—    chewing and talking!

So what do I need to remember?

The only thing I want you to remember from this blog is never assume a mask will protect you

A mask will only protect you when all of the air that goes into your lungs passes through a filter that removes all of the bad creatures. To achieve this two fundamental things need to occur:

1. the filter media has to be designed and tested to prove that the creature you are protecting yourself from will be removed from the air; and

2. all of the air has to pass though the filter before it reaches your lungs – that is, no bad air is can pass though the filter or travel though any gap.

Don’t miss the next blog in this 5 part series where we take a look at and apply the above principles to the following three types of respiratory protection or “masks” commonly used in Asia to protect against all sorts of airborne health hazards.

Respiratory Protection2 IMG_2087  IMG_2058

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Why would you wear that? PART 2

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Respiratory Protection in Asia – Do we actually need protecting?

Okay, so Part 1 of this series introduced you to “masks” I have observed to be used in Asia to protect against contaminated air.  I must admit I have never seen so many people wearing respiratory protection in some form or another in my life. Which raises the questions “is there really that much contaminant (AKA “bad stuff”) in the air?” and “do we actually need protection?”

Since working in Laos, I have noticed significant changes in seasonal air quality. I arrived in October, the end of the rain season. It is now the dry season and rural populations are preparing land to plant rice by slashing and burning all vegetable matter (termed by scientists as “biomass burning”). It is obvious to anyone with eyes that the burning activities significantly burdens the air with contaminants. The pictures below, taken at the same location show the visible difference in the seasonal air quality (October 2014 and April 2015).

Asian Air Pollution

Smoke-filled air from biomass burning 05.04.2015

Buring Season in Laos

So what are the facts?

Well, the World Health Organisation (WHO) reports:
– in 2012, 1 in 8 of all global deaths (approx 7 million ppl) was resultant of air pollution exposure; and
– sufficient evidence now demonstrates that air pollution is the world’s single largest environmental health risk.

So what is “Air Pollution” then?

Simply put, air pollution is made up of Indoor Air Pollution and Outdoor Air Pollution

Indoor Air Pollution – The Facts:

Pollution and Exposure Source: Pollutants generated from open fires and simple stoves used to cook and heat the home using solid fuels such as wood, crop wastes, charcoal, coal and animal dung. Such fuels produce small soot particles that penetrate deep into the lungs. In poorly ventilated dwellings, indoor smoke can be 100 times higher than acceptable levels.

Population Affected: Approx. 3 billion globally. Exposure is high among women and young children in low and middle-income countries, who spend the most time near the domestic fire.

Health Outcomes: 4.3 million premature deaths annually.

(WHO, 2012)

Outdoor Air Pollution – The Facts:

Pollution and Exposure Source: Pollutants arise from household solid fuel fires, motor vehicles, agricultural waste incineration, forest fires, certain agroforestry activities (e.g. charcoal production) and power plants.  Exposure concentrations differ by geographic areas and time spent in various settings.

Population Affected: Persons who live in the Western Pacific and South-East Asia regions disproportionately experience the burden of outdoor air pollution accounting for 88% of all premature deaths globally.

Health Outcomes: 3.7 million premature deaths annually.

NOTE: In 2013 an assessment by the International Agency for Research on Cancer (IARC) concluded that outdoor air pollution is carcinogenic to humans, with the particulate matter component of air pollution most closely associated with increased cancer incidence, especially cancer of the lung.

(WHO, 2012)

Okay, air pollution is a real issue for people who live in the Western Pacific and South-East Asia regions:

When combined, the population of the Western Pacific and South East Asian regions approximates to 3.2 billion people. Almost half of the world’s population!

South East Asian and Western Pacific Countries

Do we need protecting?   Yes!  or as the Laos would say “man lao”!


PART 1  – Whats the deal?

PART 3 – How will a mask protect me?

Why would you wear that? PART 1

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Respiratory Protection in Asia – What’s the Deal?

Okay, so I have been working in Asia long enough now to recognise that many people of the general public and workers get around wearing makeshift respiratory protection.

So I asked one of my Lao colleagues “what are those things people wear on their faces”? She simply replied “masks”.

So when you try to protect yourself from “bad air” in Asia what do you use? Well I have observed three typical methods that include:

1.    Wearing a medical “mask”


2.   Wearing a “designer mask” purchased at the local village


3.    My personal favorite – Covering your mouth and nose with your hand

Respiratory Protection2

Apparently the last method is quite effective when riding a motorbike!

Firstly I have to acknowledge the willingness of the Asian population to wear some form of protection in an attempt to stop them from breathing in all the bad stuff that fills the air. A cultural characteristic I rarely witness in Australia!

However and with all due respect I do have some concern regarding the “masks” I have witnessed in use, particularly as the general perception is they will protect against dusts, chemicals and other biological hazards.

So what’s the big deal and why would I be blogging about this?  Well, to reduce harm to persons requires controls to be implemented.  Firstly, no control will be bullet proof unless the hazard is eliminated.  Secondly, to actually know if a control will work (or not) requires an understanding of its limitations.

This 5 part blogging series aims to promote awareness of the limitations of controlling exposure to “dirty air” in Asia when using the three methods described above.  Tune in tomorrow for Part 2 to learn if we actually do need protecting!

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Occupational Hygiene Training Materials

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Are you interested in Occupational Health? Are you a Health and Safety Manager with the need to understand more about the “H” in “H&S”? Perhaps you’ve just started a new job and all of a sudden you realise you need to know about noise in the workplace?

These are just some of the reasons why you will love OH Learning. You can search for upcoming training events in your area, such the Basic Principles of Occupational Hygiene which is a great course to take if you need to manage or provide advice on workplace health issues, or what about the Thermal Environment  where you can master the art of controlling heat stress. Have a browse and start planning the rest of your year with good quality training courses. Or if you can’t make them, then there are freely available training materials to get you started.

The very popular one-week Basic Principles in Occupational Hygiene course in Perth is coming up next…so book it in before it sells out once again.



What’s Occupational Health like in Germany?

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This is what I thought to myself when I once again woke up at 4am. So in a slightly jet-lagged state I set about to find out the answer.

The WHO reported in 2012 that Germany had a total workforce of over 40 million (nearly half were reported to be women!), the majority (approx.. 60%) of which, were employed by small and medium-sized enterprises (SMEs).

As I understand it, Germany’s OSH legislation is harmonized with EU directives, with health and safety at work administered by the Ministries for Labour and Social Affairs.

In terms of occupational hygienists – specialised training in occupational hygiene is available for medical specialists only (usually occupational physicians), with postgraduate occupational hygiene courses no longer in existence (how terrible!)..

Employers by law are obliged to seek the advice of specialists in occupational health and safety. This may include occupational physicians and safety professionals – who may be internal to the company (in large organisations), or alternatively contracted in by the hour. The overall responsibility for H&S rests with the employer, with legislation enforcement provided by over 6500 government inspectors.

The most common occupational disease in Germany recorded in 2010 was reported to be noise induced hearing loss (> 5,700 cases), followed by asbestosis and silicosis. That looks pretty similar to the situation we have in Australia. Also similar is that health surveillance is obligatory for employees exposed to hazardous substances, with employers also obliged to measure exposure, assess risk, and take preventative measures to avoid or reduce the risk of the hazard eg: noise and vibration.

When the EU Framework Directive was adopted, Germany apparently experienced a paradigm shift with the way that health and safety was managed. The Directive sought a holistic and risk-based approach to ensure the health and safety of workers.

So there are a few similarities between our health and safety systems. The differences become apparent however, when I started to delve into the details surrounding hazardous substances and carcinogens.

The German equivalent of the Australian workplace exposure standards (WES) are the AGW (Arbeitsplatzgrenzwerte). The differences between the WES and the AGW however are huge. Australian WES’s are designed to protect ‘nearly all workers’, which by definition means that some risk still remains. Our WES also include both carcinogenic and non-carcinogenic chemicals. By contrast, the AGW are health-based limit values which are used to regulate non-carcinogenic substances only. It is stated that if the AGW limits are met, then no health risks are expected. Coming from a risk-based background I think it’s brave to say ‘no-risk’, but who am I to criticise the Germans!

Germany used to have technical guidance concentrations (technische Richt-Konzentrationen, ‘TRKs’), to regulate carcinogenic substances, although these were abolished in 2005. TRKs were determined in accordance with the ‘best available’ technology or ‘state of the art’ and only marginally reflected health criteria. They reported to provide no information about the extent of the residual risk or about the probability of incurring cancer through exposure at the workplace, thus according to the Germans, they lacked transparency.

The new approach (although still in its trial period as I understand it), is the ‘Risk Concept for Carcinogenic Substances’, commonly known as the Risk Concept. This is a graduated approach where the higher the level of exposure to a carcinogen, the higher the pressure to minimise exposure.

risk concept

(picture courtesy of, ‘The risk-based concept for carcinogenic substances developed by the Committee for Hazardous Substances’ (BAuA, 2013)

The ‘acceptable risk’ (where the green ends) relates to the point where statistically 4 out of 10,000 persons exposed to that substance throughout their working life will develop cancer. That number corresponds to the risk of cancer outside of the workplace. The result is that the ‘tolerable limit’ is very very low. Therefore I wonder if this practical given the technology we have today?

John Cherrie commented on this late last year when he asked the question, ‘this sounds like a good idea but it does produce limits that are much lower than can probably currently be achieved…is this a practical approach? Will it promote greater reduction in exposures in the future? The answers I’m sure will come in good time.

What does seem like a positive approach within this Risk Concept, is the idea of ‘individual measures’, which are obligatory to be applied, dependant on the respective risk area. These measures are classified into 5 categories (administration, technology, organisation, occupational medicine, and substitution)…similar in a way to our hierarchy of controls. So in a sense – this Risk Concept is both based on risk, but then has mandatory elements that follow that must be applied in certain situations. In a way this is similar to some aspects of Australian legislation (eg: a risk assessment must be performed, but in the case of asbestos there are mandatory elements that must be applied upon discovery of that hazardous substance).

In the end, the real test of whether legislation has a positive effect on occupational hygiene issues is to follow the numbers of reported occupational illness and disease over time (I’m going to assume that it’s reported accurately…which is probably a discussion for a separate blog post!).

Disclaimer: This blog post was written whist jet-lagged and has used thisthis, this, and this reference to provide a commentary on a very complicated topic!