Image: One of the 16 volunteers with the sampler simulating human breathing.  © Greenpeace This was originally posted on Greenpeace International on April 23, 2013. You have seen air pollution before, but not in...

Image: One of the 16 volunteers with the sampler simulating human breathing.  © Greenpeace This was originally posted on Greenpeace International on April 23, 2013. You have seen air pollution before, but not in...

Image: One of the 16 volunteers with the sampler simulating human breathing.  © Greenpeace This was originally posted on Greenpeace International on April 23, 2013. You have seen air pollution before, but not in...

Image: One of the 16 volunteers with the sampler simulating human breathing.  © Greenpeace This was originally posted on Greenpeace International on April 23, 2013. You have seen air pollution before, but not in...