Weekly Riddle #1!

Weekly Riddle #1!

I have a large impact on the world but I don't have mass. 

I sometimes come from large black towers, yet dirt and soot comes with me. 

It is possible for me turn metropolis' into ghost towns, but I cannot be seen. 

People can die because of me or make someone extremely happy. 

I warn people of danger, however I sometimes lead them to danger. 

What am I?

(I will be posting the answer in the "Once upon a time..." group notes on Wednesday)