The seas also get "polluted" by underwater volcanic vents, amongst other natural things, constantly...
It makes no sense to stand over a fire and inhale the smoke, or to drink the water from too close to those vents, but are we really trying to change the nature of the planet?
I mean, who's going to stop the sand from the Sahara Desert making it's way over to the UK for everything that breaths air to breath in, not to mention leaving a layer of red dust everywhere, especially on vehicles and the like, caught by the dew that happens naturally when the temperature changes.
Shouldn't the focus be more on what industry is doing to the air and water and soil, and what we seem to be inadvertently supporting with the present lifestyle?