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A search following a recent news item led me to a CDC Morbidity and Mortality Weekly Report for 23 March 2020 which says in part:

SARS-CoV-2 RNA was identified on a variety of surfaces in cabins of both symptomatic and asymptomatic infected passengers up to 17 days after cabins were vacated on the Diamond Princess but before disinfection procedures had been conducted (Takuya Yamagishi, National Institute of Infectious Diseases, personal communication, 2020). Although these data cannot be used to determine whether transmission occurred from contaminated surfaces, further study of fomite transmission of SARS-CoV-2 aboard cruise ships is warranted.

Identifying bits of RNA does not imply a surface is infectious and that's not what I am asking about here.

This reminded me of answer(s) to Was 14,000+ year old DNA “laying around in cave dirt” protected from degradation, or is it just naturally this robust? which explain that small fragments of DNA can be quite stable in some environments; in some places on Earth the DNA in the soil can be ten thousand years old.

Question: Roughly speaking how stable are short sections of single-stranded RNA in exposed environments compared to double-stranded DNA?

The answer is likely to contain "It depends on..." as did the answer to the DNA stability question, I'm primarily interested in the differential stability between the two.

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    $\begingroup$ Because the cited source is a personal communication, we do not know if the extraction protocol used is sufficient to disrupt viral capsids, so it's hard to say whether the RNA recovered was naked RNA or virus-bound RNA. $\endgroup$
    – acvill
    Commented Mar 25, 2020 at 17:27
  • $\begingroup$ @PolypipeWrangler that sounds like it could be quite a reasonable and acceptable answer. $\endgroup$
    – uhoh
    Commented Mar 26, 2020 at 13:41
  • $\begingroup$ Like stretching a rubber band until it breaks, comparing the elastic limits of dsDNA and ssRNA might be useful to do a direct comparison of energetic stability. I haven't found much online about RNA rupture experiments, but looking up ssDNA might serve as an upper bound on ssRNA stability, as ribose is less stable than deoxyribose. $\endgroup$
    – Alex Reynolds
    Commented Mar 26, 2020 at 17:32

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The main difference in stability is due to the very high amounts of RNase in pretty much all fresh biological materials. Naked RNA is easily degraded by just touching it with skin. The first step in most RNA extractions is often to add an RNase inhibitor.

For example, from Wikipedia's Ribonuclease; RNase contamination during RNA extraction:

The extraction of RNA in molecular biology experiments is greatly complicated by the presence of ubiquitous and hardy ribonucleases that degrade RNA samples. Certain RNases can be extremely hardy and inactivating them is difficult compared to neutralizing DNases. In addition to the cellular RNases that are released, there are several RNases that are present in the environment. RNases have evolved to have many extracellular functions in various organisms.

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  • $\begingroup$ This covers it nicely, thanks! $\endgroup$
    – uhoh
    Commented Mar 26, 2020 at 14:07

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