Greenie WEENIE alert!
You do realize that Mount Saint Helens put more particulate matter into the atmosphere in a day than all the cars on the earth have EVER.
So? If someone pointed out to you that there is already microbes living in your water, would you pour more in because "there are already some there"?
I see no reason to deliberately pollute MORE than we have to -- it's not like people have proven that pollution is good for us.
Boy Scouts taught me to leave the area cleaner than I found it. If I wish to personally try to minimize my ecological footprint, why should anybody have a problem with that? I'm not making you do anything, other than listen to my reasoning.