Public Lab Research note

Airborne Asbestos Detection

by el_tonio | October 25, 2014 14:16 25 Oct 14:16 | #11300 | #11300

What I want to do

  • To detect airborne asbestos
  • To create a small, cheap instrument that is easy to use
  • To be able to detect the asbestos in the presence of other airborne particles

Current research

At this point I have not attempted any experiments, however within publiclab Amysoyka has looked at the detection of settled asbestos fibers using sticky tape. The next stage to this would be to look at airborne asbestos as this would mean that members of the public could determine quickly if they have asbestos particles in the air they are breathing.

Why is this important?

Asbestos comes into several classes blue, brown and white, all are needle like particles with varying flexibility. One of the reasons that asbestos is bad for the body is that it can puncture parts of the lung. With many properties pre-2000 containing asbestos the remaining asbestos in the building can cause health issues for builders, engineers and ardent DIYers. The current mode of detection utilises X-rays and microscopy, these are time intensive processes, and can be quite expensive. Due to the long processing time it means that people can still be walking around in an area in which it is not safe to be.

ALERT sensor

The centre for atmospheric and instrumentation research (CAIR) at the University of Hertfordshire have developed a method which uses two lasers and a magnetic field in order to detect asbestos. The initial reports of this method were unclear about why the magnetic field was needed, especially as it is an expensive addition. The reason behind using the magnetic field is that asbestos particles are para-magnetic this means the structure aligns in a magnetic field. The premise of their method is that you monitor the airborne dust pre-field and either post-field or while the particles are in the field. The former measuring if there are fibrous particles present and the latter measuring how many are aligned.

What I am thinking

Having seen the ALERT sensor I am not 100% how their sensor works step-by-step however, as shown in the diagram I think it can be simplified. The first laser detecting unaligned particles and the second detecting the aligned particles. I haven't quite worked out the best way to get an air flow, or the best positioning of the second laser.

Questions and next steps

Having looked at what is out there the question is; can we replicate it at a lower cost than the $800 that they estimate? The next step will be to do a cost analysis of IR lasers and detectors as they are likely to be the bulk cost. A consistent low power method of generating an electric field also needs to be explored.

If you have any thoughts, please input. The more people there are the better we can make it.


Further questions that need exploring:

Following some literature * What does the data look like * What is a positive result? * What is a negative result? * How does detection work? * What wavelength do they use? * Can we get a hold of a broad range IR light for IR spec characterisation or do we just use a single wavelength and stick with diffraction?

I am reading through this journal now/ by monday and will post findings as and when.

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Your image has me thinking it might be worth using a piece of metal piping & turning it into an electromagnet.

Also, found this article online:

It explains quit well three different methods used for testing for asbestos fibers.

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My initial thought was an electromagnet might be best. Reading the journal though, they use two small neodymium magnets. The major issue with rough design I am having is an efficient way of drawing air through, I'm thinking maybe a design like a slide whistle or bike pump may work well for drawing in the air, but placing detectors then becomes a challenge. Looking at the article you linked, we could use PLM really cheaply and effectively using a cheap microscope and a polariser. The other 2 are unfeasible, since the aim is for a quick, cheap method that anyone can use. The main issue with using a microscopy method also is that it would be for settled particles.

It would be useful to see if PLM works for your tape method on some settled dust.

On an aside, it is unlikely that I will be able to do anything practical for a few months, because I have just finished studying and so any big build projects will need to wait until funds are available. Though I will pick up a microscope at some point soon, since I have just found out that USB microscopes aren't that expensive. In the meantime if you could (safely) collect some asbestos and test it via your method that would be great.

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I'm wondering if two off-the-shelf Shinyei sensors could be coupled together with an electromagnet to make this work:

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Ooh, great idea mathew!

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...If you scroll down in the page linked above, it tells you the different refractive indexes for different kinds of asbestos when suspended in a cargill liquid and between two glass slides.

Wouldn't the mineral water/baby oil from the testing kit do the same thing as a cargille liquid?

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How's this project going? Would love to hear an update!

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