Maybe this question sounds obvious, but I wonder how dangerous might be publishing a public key for an asymmetric encryption system?

I know public keys are meant for encrypting messages by anyone who's meant to do so, that's why we can even download a public cert of the most common CAs from web browsers.

But is it secure if I publish my public key on a webserver so anyone can download it? What risks am I facing doing this?

Thanks.

None, that's why it is called a public key.  It can not be used to access anything encrypted for you without solving math problems that are currently prohibitively difficult to solve.  It is possible that in the future it may be possible to solve these problems and that would cause the public key to allow messages to be decoded, but there is no current known threat.

The flip side is that if you do not share your public key, then your private key doesn't do you any good.  The only reason to use asymmetric cryptography over symmetric is if you need to let someone have your public key.  Otherwise, if you are just doing stuff for yourself, symmetric is far faster and more secure.
