Ah, yes.  Today is the day we “post-celebrate” the Christmas holiday most of you enjoyed yesterday.  Except today is a federal holiday, so it’s a no work day.

A perfect time to discuss items that are important- but usually discussed in more discrete situations.  Well, that’s not my way of doing things.

Here’s the fist of three (related) issues we’ll discuss today… Which way do you put your toilet paper on the roller assembly?  Over or Under?  A lot of folks think that over is a better way to do it.  Claiming that it’s less likely that someone will use their dirty fingers to touch the wall and leave microbial deposits that could infect the next toilet patron.  (Trust me, one is just as likely to touch the wall if the paper is being pulled over or under.  But, it’s a nice sentiment.)

It’s also likely that someone who engages the “over” version can overshoot the mark and leave a bunch of toilet paper hanging free.  Especially since the resistance to continue rolling when the paper is pulled is much lower than when the paper is coming from under the roller.  But, that still isn’t a determining factor.

The real answer is that it is a personal choice.  For now, there is no scientific explanation to choose one method over the other.  (I will let you know that it’s always under at my house and offices. Again, because I want it that way.)

I’ve also told you that after data was developed to show that Serratia marcescens could survive for three days in a slightly humid environment (30% relative humidity), hospital bathroom design got changed.  Instead of painted walls or wallpaper, tile was used.  Because the tile can be easily (and often) washed with a disinfectant solution (dilute chlorine bleach is a simple choice) that will eradicate microbes from the surface. (The chlorine bleach will even cause biofilms to loosen up, which means that the bacteria can’t avoid the disinfecting capability of the chlorine.)

And, then, we get to the argument that is most prevalent among married couples.  Does one leave the toilet seat up or down?  Yes, that could also be considered personal preference (except, generally it is the female gender,  those that sit on the toilet seat, that demand the seat be left down, since they would most prefer to not fall into the toilet, should the seat be left in the up position.

But, then, we get to the real issue.  One you probably have not properly considered. And, it’s not the toilet seat.  It’s the closing of the entire water closet– the lid must be down, before we flush.

Because just like we found that microbes can exist for 3 days in the atmosphere, the turbulent action of the toilet flush creates a plethora of droplets and aerosols that, once launched, can remain in the atmosphere and leave us at risk of infection and disease.

Six researchers from the Civil and Environmental Engineering Department at the University of Colorado (Boulder), Drs. JP Crimaldi, AC True, KG Linden, MT Hernandez, LT Larson, and AK Pauls, published their study that found droplets and aerosols can be projected more than 5 feet from the toilet seat of a commercial toilet, should the lid not be closed. The article, “Commercial toilets emit energetic and rapidly spreading aerosol plumes” was recently published in Scientific Reports, a publication from Nature.

The toilets were all tested using clean water [no toilet deposits], so infectiousness was not determined, nor did this study determine what would happen with two phase (liquid and solid) fluid dynamics from toilet flushing.   Moreover, as stated above, the study used commercial toilets, which operate off water pressure and did not have toilet tanks that supplied the water for flushing.  (Generally, this uses more force for the flush than the toilet tank units.)   With commercial toilets,  the toilet flush started with 60 psi line water pressure for the flush (which lasts about 7.5 seconds), with the termination of flush with the water pressure about 45 psi.

While the droplets don’t remain suspended in air too long, the aerosols (containing particles of about 5 microns of less) remain suspended for considerable time periods.  The velocity of the plume caused by the flush  approached 2 m/s (about 4.5 mph).

In addition to using lasers to measure and observe the plumes produced, particle counts (measuring particles ranging from 0.2 to 10 microns in size) were also effected for the plumes.  It turns out most of the particles were 2.5 microns or smaller;  and there was not much attenuation in the particles found at 1 m or 1.5 m from the toilet; the third location examined was also displaced by 1.5 m laterally; it had a 2 fold reduction in the number of particles (from 10⁵ to about 5 X 10⁴.

 

So, now you know. Make sure you close the toilet lid before your flush.  It’s a way to keep the bathroom free of microbes- and all of us less likely to be subject to any microbes that could disturb our health.

 

 

Today is the last day of Chanuka.  All eight candles of the menorah are lit.  May the Festival of Lights bring illumination and excitement to your lives.