I read online that it is scientifically proven that pollen particles can trigger cloud formation "is that true"? if true ,does it mean that no clouds can be formed without pollen particles' role?

Is it scientifically proven that some clouds can be formed without a pollen particle's role?

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    $\begingroup$ A can trigger B does not imply that B always needs A to happen. $\endgroup$ Commented Apr 11, 2021 at 9:44
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    $\begingroup$ Clouds exist on other planets (notably Mars, for similarity to Earth clouds), but pollen doesn't. (To the best of our knowledge, anyway.) $\endgroup$
    – jamesqf
    Commented Apr 14, 2021 at 4:32
  • $\begingroup$ Pollen did not exist in the entirety of the existence of the Earth, Assumingly that clouds can form without pollen and as Jamesqf noted also. $\endgroup$
    – Tardy
    Commented Apr 14, 2021 at 16:41

1 Answer 1


Pollen is one of many types of cloud condensation nuclei (CCN). So can you make clouds without pollen? Yes, but you still need other sources of CC. Don’t fall into the false dilemma that pollen is a requirement for cloud formation. The more soluble the CCN is, the easier it is to form a cloud (see Koehler theory).

Can a cloud be formed without CCN? I saw it once calculated that it would take longer than the age of the universe for something like that to occur.

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    $\begingroup$ @BaroclinicCplusplus Is snow therefore 100 percent water or does it have CCN impurities in it ? $\endgroup$
    – user1066
    Commented Apr 11, 2021 at 11:18
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    $\begingroup$ @gansub usually the nuclei are present but occasionally it seems a particle can act as a "catalyst" for crystal formation while remaining free. $\endgroup$
    – hobbs
    Commented Apr 11, 2021 at 17:10
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    $\begingroup$ @gansub The process to create an ice cloud particle is quite a bit different to the process to create a liquid cloud particle. Instead of CCN, that requires a ice nuclei (IN). There are several ways for an IN to create an ice particle from an IN, $\endgroup$ Commented Apr 11, 2021 at 19:51

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