As a society, we have, in the past as well as currently, made decisions based on greed. The end result of this is that we seem to be basking in our own filth. Now, if we go rough camping, we accept that we will have to leave behind some natural human pollutants, and in such a case, there is enough space to allow natural decomposition. By if we look at a city, the waste is concentrated. So we have to be sure to allow for this. And it is not just water that carries pollutants. The air we breathe is polluted too, and we are running out of space globally to escape from this. This is why it is important in cases where we are moving air around with fans and similar things such as humidifiers and air conditioners, to be sure to have the particular device fitted with air conditioner or humidifier filters. That way, we can clean up the air, at least in small areas, and reduce the overall exposure that we have to the dirty air that surrounds us.