Month: April 2015
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A classic example of the Tyndall effect used by hygienist’s to observe dust generation during material transfer activities!
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!
Sorry to be the bearer of bad news, however, this blog is not all about sunshine and rainbows
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.
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?
No, 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?
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?
So let’s apply the respiratory protection principles to test the Designer Mask:
Will the mask filter remove the airborne contaminants?
The simple answer is no
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?
What about covering your and mouth and nose with your hand for protection?
It’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.
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!
Let me provide you with a simple explanation of how clean air gets into your lungs and how bad air can be kept out.
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
Now the aim of protection is to stop these little creatures from getting into your lungs
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?
So for a mask to even work it would need to include filter media that would capture even the smallest particle.
CHEMICAL STATE (GAS, SOLID OR LIQUID):
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.
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).
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!
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.
— 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.
Image Posted on Updated on
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If that’s the bucket imagine how big the dragline is!
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).
Smoke-filled air from biomass burning 05.04.2015
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?
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.
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.
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!
Do we need protecting? Yes! or as the Laos would say “man lao”!
READ MORE FROM THE RESPIRATORY PROTECTION IN ASIA SERIES:
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
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!