The Cloth Diaper Geek Explains it all! Does sunning really kill bacteria?

I know this topic was covered briefly in another recent Cloth Diaper Geek post, but just last week another question was asked and it really brought to light some interesting info on sunning that you might not have known.

Question: I live in the Catskills of NY state and now that the weather is getting chilly, it takes hours & hours or days for my diapers to dry outside. The sun just isn't hot enough to do it in a short time like in the summer months. So, my question is, if I still want to use the sun for killing bacteria and icky stuff, how long should I leave them outside?

The Geek's Answer: Thanks for such a great question. The truth is, the Geek had to do a little digging this time, to be sure to provide as accurate an answer as possible. The information found on this topic was quite interesting and really eye opening.

According to numerous sources on Google, direct exposure to UV (ultra violet) light is necessary for the destruction of bacteria and microorganisms in the air or on exposed surfaces. The rays must directly strike the organism, either at a high intensity for a short amount of time or a low intensity for an extended amount of time.

If bacteria or mold spores are hidden beneath the surface of a material and not in the direct path of the rays then they will not be destroyed, UV light does not penetrate most substances, including fabrics. According to the National Weather Service, different types of clouds can either enhance or block UV rays. A good rule of thumb is that if you can see areas of blue sky, then you are being exposed to either direct or reflected UV rays.

So how does this information affect the practice of sunning cloth diapers in order to rid them of unwanted bacteria? Well, the answer so far as I can tell, is that you cannot rely 100% on the UV rays to kill ALL of the bacteria and/or mold spores that may be lurking in your diapers. But...you can increase the amount of bacteria affected by making sure your diapers are exposed to direct UV rays, turning them over to expose both sides, turning them inside out (if possible) and exposing the inside surfaces to direct rays as well.

As for how much bacteria is being killed and/or how to measure how much UV rays you're exposing your diapers to? I am going to have to leave those answers up to the real scientists. In my opinion, it seems that any amount of bacteria killed by either a lot or a little exposure to UV rays is better than no bacteria killed by not sunning your diapers at all.

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