Hello! So I'm writing a science fiction story about this fictional human civilization on another planet where it constantly rains. My main characters are scientists who work on atmospheric readings and such. I want the facts to be mostly correct. Is there possibly a chemical that could be dissolved in the rain that would alter their readings? For example could it make them mistakenly pick up a toxic chemical in the atmosphere that really wasn't there? A website or credible source would be helpful as well. Thank you so very much, and have a happy Thanksgiving!