A Chinese business man has begun selling canned clean air inside of Beijing as a result of the heavy levels of air pollution in that city. His motivations are based on attempting to encourage environmental responsibility.
You can view a news story about his project here: http://www.youtube.com/watch?v=rQTiJHok1u8
This is a story that should be taken very seriously by everyone that resides on this planet. With over two thirds of the worlds forests having already been eliminated and with the amount of pollution that humans are creating constantly increasing, the day that clean air is considered a commodity to be bought and sold is likely not far off, in the same manner that it currently is for clean water.
An example of this can be found with the natives that inhabited North America prior to European settlement. Back then, there was effectively no human pollution to speak of and it was safe to drink directly from most bodies of water. Think of a stream or river that is near your current residence. Would you ever consider drinking from it? It was likely only less than three hundred years ago that there were native tribes in addition to many other native species that would freely drink from it at will, without any fear of suffering as a result of it. To them, water was something that was free and available to everyone, that it was not something that could be bought or sold and the notion that it would be necessary for water to undergo special treatment before consumption would have been ridiculous.
Once European settlers arrived and began their campaigns of environmental destruction and exploitation nearly all of the water bodies in their path became severely polluted and the once pristine, free sources of water were turned into dangerously polluted bodies that were not fit for human or many other species consumption.
The actions of those first settlers and their descendants deprived every future generation of the access to free, unpolluted sources of water and the same is going to occur with the air if the trend of environmental destruction that humans have engaged in since the beginning of their existence is not stopped.