What level of toxicity can our lungs tolerate without showing signs of Cell "break down"? I'm not a scientist. Can our lungs recognize toxic substances and set off an alarm which tells the cells to constrict, restrict, extract or kick out the invading contaminants? Maybe if we can understand more about how the lung absorbs or restricts toxic inhalants, we can form logical hypotheses for further research. I say we work together to better our health in every aspect.