Thursday, May 26, 2016

Exposure Modeling will Make You a Super Star

I see spectacular headlines when I am checking out of the Super Market.  Indeed, spectacular headlines seem to work for the National Enquirer so I hoped that they would work for me here.

I have literally grown old extolling the virtues and power of Exposure Assessment Modeling for Industrial Hygienists; however, my friend and colleague, Perry Logan tells me that what I have done is not enough.  He advises that one has to mention something many many times before it sinks in.  I do not remember how many times Perry suggested but it was many more than a few times.   Also, committing to using models is not a trivial decision without at least some considerable effort.   Thus, Perry is almost certainly correct, I have not promoted modeling enough.

I may be older but I am not done and I am going to list some of the very basic, with some self-serving, reasons an IH should get into learning exposure modeling:

    It will definitely enhance your standing with your employer and/or your clients

You will present yourself as “one of the few” a relatively rare professional who can take the factors that cause and predict exposure and apply them in a systematic manner to rendering predictions of exposure and risk.  This often occurs without the need for a lot of data which managers seem to particularly like.

Indeed, many people see models as technological magic and those who use them as wizards.  It often does not hurt you or your career to subtly let them think this is so even while you might tell them otherwise.

.  You will have confidence born of the knowledge and ability that you personally gained to estimate exposures using models and no one can take that from you.

These models are, for the most part, made up of first principles; that is,  basic laws of nature like the conservation of mass and are therefore, pretty true and useful on their face.   Clearly they can be both wrong and misused but at their core they are aimed at being reasoned and reasonable descriptors of reality or at least the reality that we know.  If they fall short, then they provide a mechanism and framework to fix themselves.  They can become complicated but they can also be “pulled apart” so that their pieces can be examined individually as to whether they make sense.

    Complex mathematical operations are no longer an issue with available free software.

I am prone to math errors.  Running long strings of calculations invariably has led me to make simple mistakes and the wrong answers.  In order to save my credibility I learned early on in my career that programing the calculation steps into a spreadsheet or BASIC program took more time initially but assured I had a tool that would not produce math errors.   That early effort has grown dramatically with other talented colleagues (like Tom Armstrong and Daniel Drolet) taking up the cause and the result is IH MOD – which is a free Excel Spreadsheet with mostly any modeling calculation you might need.

    Like any other skill (or Rome) Modeling Acumen will not be built in a day but the inputs can be structured to be very simple at first and then build on themselves.

Simple models can be learned in a day (or even less than an hour) but they are typically less useful than more complicated models; however, they have some use and, most important, they form the basis for building your knowledge, background, comfort level and skill base in this critical area.   How many times have you climbed a long hill (or task) one step at a time only to look back after a time to appreciate how far you have come?

If you go back through this blog to earlier entries you can hopefully see this progression.   Start with an equilibrium model and build from there.   Perhaps the simplest model I know is the equilibrium model:  C = G/Q  or concentration (C) is equal to generation rate (G) of a contaminant divided by ventilation rate (Q).    If you do not understand this model, PLEASE write to me and let me know where you get lost.  I will put together a brief blog that goes into enough detail to explain it.  Once you have this model, we will move on to more complicated models but I need your help to give me feedback via email ( as to whether the lessons are working or not and if not where you get lost.  

If any of you are willing start this journey, I am willing to teach you in short 10-20 minutes blogs.

I cannot think of anything that has helped my career more than an interest and understanding of exposure assessment models.