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Airborne Particles CPS Talk 9.2.15

By zccasle, on 23 February 2015

10495706_973275192683535_6066155244544101331_oStalwart of the SCI Dr Fred Parrat led an illuminating discussion on the ebbs and flows of airborne particles. Dr Parrat is a Big Band enthusiast, enjoys observing demolition and has his own brand of Dust Meters.

Dust is not something many of us spend a lot of time pondering on but it’s always encouraging to know that someone somewhere is. When it comes to dust (but not limited to dust) Dr Parrat is thinking on it. Indeed nothing can be so mesmerising as watching the dust glide through a beam of light in the still air of a darkened room…

Dust can refer to a variety of non living airborne particulates between 1 and 100 microns and before long Dr Parrat had reminded us that dust is not trivial. Remember how an unpronounceable Icelandic volcano brought the aviation industry of the northern hemisphere to a halt in 2010? The combination of dust with weather killed at least 4000 people in the 50’s because of the burning of coal in the city of London. The dust that was released after the collapse of the Twin Towers has since caused subsequent fatalities. It can be a slow and silent killer, hence it’s difficult to follow directly its effects.

Dust can originate naturally or by industrial or agricultural agitation, workers in certain industries are at high risk from unsafe exposure to dust and hence Dr Parrat’s dust concentration instruments are of important use making sure that safety standards are being met. The most heavily offending industries, dust wise, are Tapioca and Rice Bran.

Levels and varieties of dust are strongly dependent on locality, unsurprisingly in cities we are subjected to a vast amount of it from cars, from their exhausts and the wear and tear of their tyres. Humans are also very generous contributors to the dusty milieu by our frequent shedding of dead skin cells.

How does Dr Parrat fit in to the dust business? First of all he doesn’t limit himself, he said since beginning life as a Consultant he has learnt to say “yes” first and work out the details later. A large part of his business has been that of monitoring or containment of dust in industrial settings. However his instruments have been developed to include the detection of living air borne particles, from viruses up to fungi. He has developed a machine that passes a known volume of air over an Agar plate, this is then cultivated to figure out the number of colony forming units per m3. Such a device could be very useful in calculating the concentration of airborne microbes as a function of locale or time. For example, an intrepid researcher was able to conclude that the period of most heightened airborne bacterial frenzy, in the vicinity of a toilet, is right after it’s been flushed. But was that with lid down or up? Find out below…

“Potential for aerosolization of Clostridium Difficile after flushing toilets: the role of toilet lids in reducing environmental contamination risk” E.L. Best, J.A.T. Sandoe, M.H. Wilcox. Journal of Hospital Infection, 80, 2012, 1-5.

The word “dust” does not do dust justice. Dust is something we brush under the carpet, or attempt to banish with cleaning products. It is a heady mixture, consisting of just about any stable substance from anthropogenic or natural sources. Once consigned to the atmosphere dust undergoes a radical unchecked global redistribution, like Saharan grains of sand being swept onto the bonnets of SUV’s in St Johns Wood. I’m glad to have spent some time thinking about dust.

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